Date:   Thu, 2 Jul 2020 03:48:26 +0000
From:   Pawel Laszczak <pawell@...ence.com>
To:     Dan Carpenter <dan.carpenter@...cle.com>
CC:     "gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
        "robh+dt@...nel.org" <robh+dt@...nel.org>,
        "linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "balbi@...nel.org" <balbi@...nel.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "ben.dooks@...ethink.co.uk" <ben.dooks@...ethink.co.uk>,
        "colin.king@...onical.com" <colin.king@...onical.com>,
        "rogerq@...com" <rogerq@...com>,
        "peter.chen@....com" <peter.chen@....com>,
        "weiyongjun1@...wei.com" <weiyongjun1@...wei.com>,
        Jayshri Dajiram Pawar <jpawar@...ence.com>,
        Rahul Kumar <kurahul@...ence.com>,
        Sanket Parmar <sparmar@...ence.com>
Subject: RE: [PATCH RFC 4/5] usb: cdnsp: usb:cdns3 Add main part of Cadence
 USBSSP DRD Driver

Hi Dan, 

Thanks for the review.
I made your suggestions in cdnsp driver. 

Taking into account my 4 weeks holiday in July and 
Suggestions from Greg that require bigger changes,
the next version will be released In August.

>
>
>On Fri, Jun 26, 2020 at 06:54:49AM +0200, Pawel Laszczak wrote:
>> This patch introduces the main part of Cadence USBSSP DRD driver
>> to Linux kernel.
>> To reduce the patch size a little bit, the header file gadget.h was
>> intentionally added as separate patch.
>>
>> The Cadence USBSSP DRD Controller is a highly configurable IP Core which
>> can be instantiated as Dual-Role Device (DRD), Peripheral Only and
>> Host Only (XHCI)configurations.
>>
>> The current driver has been validated with FPGA platform. We have
>> support for PCIe bus, which is used on FPGA prototyping.
>>
>> The host side of USBSS DRD controller is compliant with XHCI.
>> The architecture for device side is almost the same as for host side,
>> and most of the XHCI specification can be used to understand how
>> this controller operates.
>>
>> Signed-off-by: Pawel Laszczak <pawell@...ence.com>
>> ---
>>  drivers/usb/cdnsp/Kconfig  |   23 +
>>  drivers/usb/cdnsp/Makefile |    7 +
>>  drivers/usb/cdnsp/core.c   |  632 ++++++++++
>>  drivers/usb/cdnsp/core.h   |   90 ++
>>  drivers/usb/cdnsp/drd.c    |  372 ++++++
>>  drivers/usb/cdnsp/drd.h    |  127 ++
>>  drivers/usb/cdnsp/ep0.c    |  462 +++++++
>>  drivers/usb/cdnsp/export.h |   36 +
>>  drivers/usb/cdnsp/gadget.c | 1935 +++++++++++++++++++++++++++++
>>  drivers/usb/cdnsp/gadget.h |  138 +++
>>  drivers/usb/cdnsp/host.c   |   74 ++
>>  drivers/usb/cdnsp/mem.c    | 1327 ++++++++++++++++++++
>>  drivers/usb/cdnsp/ring.c   | 2380 ++++++++++++++++++++++++++++++++++++
>>  13 files changed, 7603 insertions(+)
>>  create mode 100644 drivers/usb/cdnsp/core.c
>>  create mode 100644 drivers/usb/cdnsp/core.h
>>  create mode 100644 drivers/usb/cdnsp/drd.c
>>  create mode 100644 drivers/usb/cdnsp/drd.h
>>  create mode 100644 drivers/usb/cdnsp/ep0.c
>>  create mode 100644 drivers/usb/cdnsp/export.h
>>  create mode 100644 drivers/usb/cdnsp/gadget.c
>>  create mode 100644 drivers/usb/cdnsp/host.c
>>  create mode 100644 drivers/usb/cdnsp/mem.c
>>  create mode 100644 drivers/usb/cdnsp/ring.c
>>
>> diff --git a/drivers/usb/cdnsp/Kconfig b/drivers/usb/cdnsp/Kconfig
>> index 5796a19bb8a0..d177ce7a8bb2 100644
>> --- a/drivers/usb/cdnsp/Kconfig
>> +++ b/drivers/usb/cdnsp/Kconfig
>> @@ -12,6 +12,29 @@ config USB_CDNSP
>>
>>  if USB_CDNSP
>>
>> +config USB_CDNSP_GADGET
>> +	bool "Cadence CDNSP device controller"
>> +	depends on USB_GADGET=y || USB_GADGET=USB_CDNSP
>> +	help
>> +	  Say Y here to enable device controller functionality of the
>> +	  Cadence CDNSP-DEV driver.
>> +
>> +	  Cadence CDNSP Device Controller in device mode is
>> +	  very similar to XHCI controller. Therefore some algorithms
>> +	  used has been taken from host driver.
>> +	  This controller supports FF, HS, SS and SSP mode.
>> +	  It doesn't support LS.
>> +
>> +config USB_CDNSP_HOST
>> +	bool "Cadence CDNSP host controller"
>> +	depends on USB=y || USB=USB_CDNSP
>> +	help
>> +	  Say Y here to enable host controller functionality of the
>> +	  Cadence driver.
>> +
>> +	  Host controller is compliant with XHCI so it uses
>> +	  standard XHCI driver.
>> +
>>  config USB_CDNSP_PCI
>>  	tristate "Cadence CDNSP support on PCIe-based platforms"
>>  	depends on USB_PCI && ACPI
>> diff --git a/drivers/usb/cdnsp/Makefile b/drivers/usb/cdnsp/Makefile
>> index 21adf3eb2f7d..386b6a7b8b4e 100644
>> --- a/drivers/usb/cdnsp/Makefile
>> +++ b/drivers/usb/cdnsp/Makefile
>> @@ -1,3 +1,10 @@
>>  # SPDX-License-Identifier: GPL-2.0
>>
>> +cdnsp-y					:= core.o drd.o
>> +
>> +obj-$(CONFIG_USB_CDNSP) 		+= cdnsp.o
>> +cdnsp-$(CONFIG_USB_CDNSP_GADGET)	+= ring.o gadget.o mem.o ep0.o
>> +
>> +cdnsp-$(CONFIG_USB_CDNSP_HOST)		+= host.o
>> +
>>  obj-$(CONFIG_USB_CDNSP_PCI)		+= cdnsp-pci.o
>> diff --git a/drivers/usb/cdnsp/core.c b/drivers/usb/cdnsp/core.c
>> new file mode 100644
>> index 000000000000..215783623c6b
>> --- /dev/null
>> +++ b/drivers/usb/cdnsp/core.c
>> @@ -0,0 +1,632 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Cadence CDNSP DRD Driver.
>> + *
>> + * Copyright (C) 2020 Cadence.
>> + *
>> + * Author: Pawel Laszczak <pawell@...ence.com>
>> + *
>> + * Code based on Cadence USBSS DRD driver.
>> + * Origin: Copyright (C) 2018-2019 Cadence.
>> + *         Copyright (C) 2017-2018 NXP
>> + *         Copyright (C) 2019 Texas Instruments
>> + */
>> +
>> +#include <linux/platform_device.h>
>> +#include <linux/dma-mapping.h>
>> +#include <linux/pm_runtime.h>
>> +#include <linux/interrupt.h>
>> +#include <linux/module.h>
>> +#include <linux/kernel.h>
>> +#include <linux/io.h>
>> +
>> +#include "gadget.h"
>> +#include "core.h"
>> +#include "export.h"
>> +#include "drd.h"
>> +
>> +static int cdnsp_idle_init(struct cdnsp *cdns);
>> +
>> +static inline
>> +struct cdnsp_role_driver *cdnsp_get_current_role_driver(struct cdnsp *cdns)
>> +{
>> +	WARN_ON(!cdns->roles[cdns->role]);
>> +	return cdns->roles[cdns->role];
>> +}
>> +
>> +static int cdnsp_role_start(struct cdnsp *cdns, enum usb_role role)
>> +{
>> +	int ret;
>> +
>> +	if (WARN_ON(role > USB_ROLE_DEVICE))
>> +		return 0;
>> +
>> +	mutex_lock(&cdns->mutex);
>> +	cdns->role = role;
>> +	mutex_unlock(&cdns->mutex);
>> +
>> +	if (!cdns->roles[role])
>> +		return -ENXIO;
>> +
>> +	if (cdns->roles[role]->state == CDNSP_ROLE_STATE_ACTIVE)
>> +		return 0;
>> +
>> +	mutex_lock(&cdns->mutex);
>> +	ret = cdns->roles[role]->start(cdns);
>> +	if (!ret)
>> +		cdns->roles[role]->state = CDNSP_ROLE_STATE_ACTIVE;
>> +	mutex_unlock(&cdns->mutex);
>> +
>> +	return ret;
>> +}
>> +
>> +static void cdnsp_role_stop(struct cdnsp *cdns)
>> +{
>> +	enum usb_role role = cdns->role;
>> +
>> +	if (WARN_ON(role > USB_ROLE_DEVICE))
>> +		return;
>> +
>> +	if (cdns->roles[role]->state == CDNSP_ROLE_STATE_INACTIVE)
>> +		return;
>> +
>> +	mutex_lock(&cdns->mutex);
>> +	cdns->roles[role]->stop(cdns);
>> +	cdns->roles[role]->state = CDNSP_ROLE_STATE_INACTIVE;
>> +	mutex_unlock(&cdns->mutex);
>> +}
>> +
>> +static void cdnsp_exit_roles(struct cdnsp *cdns)
>> +{
>> +	cdnsp_role_stop(cdns);
>> +	cdnsp_drd_exit(cdns);
>> +}
>> +
>> +/**
>> + * cdnsp_core_init_role - initialize role of operation.
>> + * @cdns: Pointer to cdnsp structure.
>> + *
>> + * Returns 0 on success otherwise negative errno.
>> + */
>> +static int cdnsp_core_init_role(struct cdnsp *cdns)
>> +{
>> +	struct device *dev = cdns->dev;
>> +	enum usb_dr_mode best_dr_mode;
>> +	enum usb_dr_mode dr_mode;
>> +	int ret = 0;
>
>Don't initialize
>
>> +
>> +	dr_mode = usb_get_dr_mode(dev);
>> +	cdns->role = USB_ROLE_NONE;
>> +
>> +	/*
>> +	 * If driver can't read mode by means of usb_get_dr_mode function then
>> +	 * chooses mode according with Kernel configuration. This setting
>> +	 * can be restricted later depending on strap pin configuration.
>> +	 */
>> +	if (dr_mode == USB_DR_MODE_UNKNOWN) {
>> +		if (IS_ENABLED(CONFIG_USB_CDNSP_HOST) &&
>> +		    IS_ENABLED(CONFIG_USB_CDNSP_GADGET))
>> +			dr_mode = USB_DR_MODE_OTG;
>> +		else if (IS_ENABLED(CONFIG_USB_CDNSP_HOST))
>> +			dr_mode = USB_DR_MODE_HOST;
>> +		else if (IS_ENABLED(CONFIG_USB_CDNSP_GADGET))
>> +			dr_mode = USB_DR_MODE_PERIPHERAL;
>> +	}
>> +
>> +	/*
>> +	 * At this point cdns->dr_mode contains strap configuration.
>> +	 * Driver try update this setting considering kernel configuration.
>> +	 */
>> +	best_dr_mode = cdns->dr_mode;
>> +
>> +	ret = cdnsp_idle_init(cdns);
>> +	if (ret)
>> +		return ret;
>> +
>> +	if (dr_mode == USB_DR_MODE_OTG) {
>> +		best_dr_mode = cdns->dr_mode;
>> +	} else if (cdns->dr_mode == USB_DR_MODE_OTG) {
>> +		best_dr_mode = dr_mode;
>> +	} else if (cdns->dr_mode != dr_mode) {
>> +		dev_err(dev, "Incorrect DRD configuration\n");
>> +		return -EINVAL;
>> +	}
>> +
>> +	dr_mode = best_dr_mode;
>> +
>> +	if (dr_mode == USB_DR_MODE_OTG || dr_mode == USB_DR_MODE_HOST) {
>> +		ret = cdnsp_host_init(cdns);
>> +		if (ret) {
>> +			dev_err(dev, "Host initialization failed with %d\n",
>> +				ret);
>> +			goto err;
>> +		}
>> +	}
>> +
>> +	if (dr_mode == USB_DR_MODE_OTG || dr_mode == USB_DR_MODE_PERIPHERAL) {
>> +		ret = cdnsp_gadget_init(cdns);
>> +		if (ret) {
>> +			dev_err(dev, "Device initialization failed with %d\n",
>> +				ret);
>> +			goto err;
>> +		}
>> +	}
>> +
>> +	cdns->dr_mode = dr_mode;
>> +
>> +	ret = cdnsp_drd_update_mode(cdns);
>> +	if (ret)
>> +		goto err;
>> +
>> +	/* Initialize idle role to start with. */
>> +	ret = cdnsp_role_start(cdns, USB_ROLE_NONE);
>> +	if (ret)
>> +		goto err;
>> +
>> +	switch (cdns->dr_mode) {
>> +	case USB_DR_MODE_OTG:
>> +		ret = cdnsp_hw_role_switch(cdns);
>> +		if (ret)
>> +			goto err;
>> +		break;
>> +	case USB_DR_MODE_PERIPHERAL:
>> +		ret = cdnsp_role_start(cdns, USB_ROLE_DEVICE);
>> +		if (ret)
>> +			goto err;
>> +		break;
>> +	case USB_DR_MODE_HOST:
>> +		ret = cdnsp_role_start(cdns, USB_ROLE_HOST);
>> +		if (ret)
>> +			goto err;
>> +		break;
>> +	default:
>> +		ret = -EINVAL;
>> +		goto err;
>> +	}
>> +
>> +	return ret;
>
>This could be return 0;
>
>> +err:
>> +	cdnsp_exit_roles(cdns);
>> +	return ret;
>> +}
>> +
>> +/**
>> + * cdnsp_hw_role_state_machine  - role switch state machine based on hw events.
>> + * @cdns: Pointer to controller structure.
>> + *
>> + * Returns next role to be entered based on hw events.
>> + */
>> +static enum usb_role cdnsp_hw_role_state_machine(struct cdnsp *cdns)
>> +{
>> +	enum usb_role role = USB_ROLE_NONE;
>> +	int id, vbus;
>> +
>> +	if (cdns->dr_mode != USB_DR_MODE_OTG)
>> +		goto not_otg;
>
>No need for this goto.  Move the code here.
>
>> +
>> +	id = cdnsp_get_id(cdns);
>> +	vbus = cdnsp_get_vbus(cdns);
>> +
>> +	/*
>> +	 * Role change state machine
>> +	 * Inputs: ID, VBUS
>> +	 * Previous state: cdns->role
>> +	 * Next state: role
>> +	 */
>> +	role = cdns->role;
>> +
>> +	switch (role) {
>> +	case USB_ROLE_NONE:
>> +		/*
>> +		 * Driver treats USB_ROLE_NONE synonymous to IDLE state from
>> +		 * controller specification.
>> +		 */
>> +		if (!id)
>> +			role = USB_ROLE_HOST;
>> +		else if (vbus)
>> +			role = USB_ROLE_DEVICE;
>> +		break;
>> +	case USB_ROLE_HOST: /* from HOST, we can only change to NONE. */
>> +		if (id)
>> +			role = USB_ROLE_NONE;
>> +		break;
>> +	case USB_ROLE_DEVICE: /* from GADGET, we can only change to NONE. */
>> +		if (!vbus)
>> +			role = USB_ROLE_NONE;
>> +		break;
>> +	}
>> +
>> +	dev_dbg(cdns->dev, "role %d -> %d\n", cdns->role, role);
>> +
>> +	return role;
>> +
>> +not_otg:
>> +	if (cdnsp_is_host(cdns))
>> +		role = USB_ROLE_HOST;
>> +	if (cdnsp_is_device(cdns))
>> +		role = USB_ROLE_DEVICE;
>> +
>> +	return role;
>> +}
>> +
>> +static int cdnsp_idle_role_start(struct cdnsp *cdns)
>> +{
>> +	return 0;
>> +}
>> +
>> +static void cdnsp_idle_role_stop(struct cdnsp *cdns)
>> +{
>> +	/* Program Lane swap and bring PHY out of RESET. */
>> +	phy_reset(cdns->usb3_phy);
>> +}
>> +
>> +static int cdnsp_idle_init(struct cdnsp *cdns)
>> +{
>> +	struct cdnsp_role_driver *rdrv;
>> +
>> +	rdrv = devm_kzalloc(cdns->dev, sizeof(*rdrv), GFP_KERNEL);
>> +	if (!rdrv)
>> +		return -ENOMEM;
>> +
>> +	rdrv->start = cdnsp_idle_role_start;
>> +	rdrv->stop = cdnsp_idle_role_stop;
>> +	rdrv->state = CDNSP_ROLE_STATE_INACTIVE;
>> +	rdrv->suspend = NULL;
>> +	rdrv->resume = NULL;
>> +	rdrv->name = "idle";
>> +
>> +	cdns->roles[USB_ROLE_NONE] = rdrv;
>> +
>> +	return 0;
>> +}
>> +
>> +/**
>> + * cdnsp_hw_role_switch - switch roles based on HW state.
>> + * @cdns: Pointer to controller structure.
>> + */
>> +int cdnsp_hw_role_switch(struct cdnsp *cdns)
>> +{
>> +	enum usb_role real_role, current_role;
>> +	int ret = 0;
>> +
>> +	pm_runtime_get_sync(cdns->dev);
>> +
>> +	current_role = cdns->role;
>> +	real_role = cdnsp_hw_role_state_machine(cdns);
>> +
>> +	/* Do nothing if nothing changed. */
>> +	if (current_role == real_role)
>> +		goto exit;
>> +
>> +	cdnsp_role_stop(cdns);
>> +
>> +	dev_dbg(cdns->dev, "Switching role %d -> %d", current_role, real_role);
>> +
>> +	ret = cdnsp_role_start(cdns, real_role);
>> +	if (ret) {
>> +		/* Back to current role. */
>> +		dev_err(cdns->dev, "set %d has failed, back to %d\n",
>> +			real_role, current_role);
>> +		ret = cdnsp_role_start(cdns, current_role);
>> +		if (ret)
>> +			dev_err(cdns->dev, "back to %d failed too\n",
>> +				current_role);
>> +	}
>> +exit:
>> +	pm_runtime_put_sync(cdns->dev);
>> +	return ret;
>> +}
>> +
>> +/**
>> + * cdsn3_role_get - get current role of controller.
>> + * @sw: Pointer to usb_role_switch object.
>> + *
>> + * Returns role.
>> + */
>> +static enum usb_role cdnsp_role_get(struct usb_role_switch *sw)
>> +{
>> +	struct cdnsp *cdns = usb_role_switch_get_drvdata(sw);
>> +
>> +	return cdns->role;
>> +}
>> +
>> +/**
>> + * cdnsp_role_set - set current role of controller.
>> + * @sw: Pointer to usb_role_switch object.
>> + * @role: The previous role.
>> + * Handles below events:
>> + * - Role switch for dual-role devices.
>> + * - USB_ROLE_GADGET <--> USB_ROLE_NONE for peripheral-only devices.
>> + */
>> +static int cdnsp_role_set(struct usb_role_switch *sw, enum usb_role role)
>> +{
>> +	struct cdnsp *cdns = usb_role_switch_get_drvdata(sw);
>> +	int ret = 0;
>> +
>> +	pm_runtime_get_sync(cdns->dev);
>> +
>> +	if (cdns->role == role)
>> +		goto pm_put;
>> +
>> +	if (cdns->dr_mode == USB_DR_MODE_HOST) {
>> +		switch (role) {
>> +		case USB_ROLE_NONE:
>> +		case USB_ROLE_HOST:
>> +			break;
>> +		default:
>> +			ret = -EPERM;
>> +			goto pm_put;
>> +		}
>> +	}
>> +
>> +	if (cdns->dr_mode == USB_DR_MODE_PERIPHERAL) {
>> +		switch (role) {
>> +		case USB_ROLE_NONE:
>> +		case USB_ROLE_DEVICE:
>> +			break;
>> +		default:
>> +			ret = -EPERM;
>> +			goto pm_put;
>> +		}
>> +	}
>> +
>> +	cdnsp_role_stop(cdns);
>> +	ret = cdnsp_role_start(cdns, role);
>> +	if (ret) {
>> +		dev_err(cdns->dev, "set role %d has failed\n", role);
>> +		ret = -EPERM;
>
>Why not preserve the error code?
>
>> +	}
>> +
>> +pm_put:
>> +	pm_runtime_put_sync(cdns->dev);
>> +	return ret;
>> +}
>> +
>> +/**
>> + * cdnsp_probe - probe for cdnsp core device.
>> + * @pdev: Pointer to cdnsp core platform device.
>> + *
>> + * Returns 0 on success otherwise negative errno.
>> + */
>> +static int cdnsp_probe(struct platform_device *pdev)
>> +{
>> +	struct usb_role_switch_desc sw_desc = { };
>> +	struct device *dev = &pdev->dev;
>> +	struct resource	*res;
>> +	struct cdnsp *cdns;
>> +	void __iomem *regs;
>> +	int ret;
>> +
>> +	ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(64));
>> +	if (ret) {
>> +		dev_err(dev, "error setting dma mask: %d\n", ret);
>> +		return -ENODEV;
>
>Preserve the error code?
>
>> +	}
>> +
>> +	cdns = devm_kzalloc(dev, sizeof(*cdns), GFP_KERNEL);
>> +	if (!cdns)
>> +		return -ENOMEM;
>> +
>> +	cdns->dev = dev;
>> +
>> +	platform_set_drvdata(pdev, cdns);
>> +
>> +	res = platform_get_resource_byname(pdev, IORESOURCE_IRQ, "host");
>> +	if (!res) {
>> +		dev_err(dev, "missing host IRQ\n");
>> +		return -ENODEV;
>> +	}
>> +
>> +	cdns->xhci_res[0] = *res;
>> +
>> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "xhci");
>> +	if (!res) {
>> +		dev_err(dev, "couldn't get xhci resource\n");
>> +		return -ENXIO;
>> +	}
>> +
>> +	cdns->xhci_res[1] = *res;
>> +
>> +	cdns->dev_irq = platform_get_irq_byname(pdev, "peripheral");
>> +	if (cdns->dev_irq == -EPROBE_DEFER)
>> +		return cdns->dev_irq;
>> +
>> +	if (cdns->dev_irq < 0)
>> +		dev_err(dev, "couldn't get peripheral irq\n");
>
>It really feels like this should be an error return.

Driver still can support only Host side. 
It can be configured as only Host, only Device or HOST +  DEVICE. 
cdns->otg_irq is mandatory. 

>
>> +
>> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dev");
>> +	regs = devm_ioremap_resource(dev, res);
>> +	if (IS_ERR(regs))
>> +		return PTR_ERR(regs);
>> +	cdns->dev_regs	= regs;
>> +
>> +	cdns->otg_irq = platform_get_irq_byname(pdev, "otg");
>> +	if (cdns->otg_irq == -EPROBE_DEFER)
>> +		return cdns->otg_irq;
>> +
>> +	if (cdns->otg_irq < 0) {
>> +		dev_err(dev, "couldn't get otg irq\n");
>> +		return cdns->otg_irq;
>> +	}
>> +
>> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "otg");
>> +	if (!res) {
>> +		dev_err(dev, "couldn't get otg resource\n");
>> +		return -ENXIO;
>> +	}
>> +
>> +	cdns->otg_res = *res;
>> +
>> +	mutex_init(&cdns->mutex);
>> +
>> +	cdns->usb2_phy = devm_phy_optional_get(dev, "cdnsp,usb2-phy");
>> +	if (IS_ERR(cdns->usb2_phy))
>> +		return PTR_ERR(cdns->usb2_phy);
>> +
>> +	ret = phy_init(cdns->usb2_phy);
>> +	if (ret)
>> +		return ret;
>> +
>> +	cdns->usb3_phy = devm_phy_optional_get(dev, "cdnsp,usb3-phy");
>> +	if (IS_ERR(cdns->usb3_phy))
>> +		return PTR_ERR(cdns->usb3_phy);
>> +
>> +	ret = phy_init(cdns->usb3_phy);
>> +	if (ret)
>> +		goto err1;
>> +
>> +	ret = phy_power_on(cdns->usb2_phy);
>> +	if (ret)
>> +		goto err2;
>> +
>> +	ret = phy_power_on(cdns->usb3_phy);
>> +	if (ret)
>> +		goto err3;
>> +
>> +	sw_desc.set = cdnsp_role_set;
>> +	sw_desc.get = cdnsp_role_get;
>> +	sw_desc.allow_userspace_control = true;
>> +	sw_desc.driver_data = cdns;
>> +	if (device_property_read_bool(dev, "usb-role-switch"))
>> +		sw_desc.fwnode = dev->fwnode;
>> +
>> +	cdns->role_sw = usb_role_switch_register(dev, &sw_desc);
>> +	if (IS_ERR(cdns->role_sw)) {
>> +		ret = PTR_ERR(cdns->role_sw);
>> +		dev_warn(dev, "Unable to register Role Switch\n");
>> +		goto err4;
>> +	}
>> +
>> +	ret = cdnsp_drd_init(cdns);
>> +	if (ret)
>> +		goto err5;
>> +
>> +	ret = cdnsp_core_init_role(cdns);
>> +	if (ret)
>> +		goto err5;
>> +
>> +	device_set_wakeup_capable(dev, true);
>> +	pm_runtime_set_active(dev);
>> +	pm_runtime_enable(dev);
>> +
>> +	/*
>> +	 * The controller needs less time between bus and controller suspend,
>> +	 * and we also needs a small delay to avoid frequently entering low
>> +	 * power mode.
>> +	 */
>> +	pm_runtime_set_autosuspend_delay(dev, 20);
>> +	pm_runtime_mark_last_busy(dev);
>> +	pm_runtime_use_autosuspend(dev);
>> +	dev_dbg(dev, "Cadence CDNSP core: probe succeed\n");
>> +
>> +	return 0;
>> +err5:
>> +	cdnsp_drd_exit(cdns);
>> +	usb_role_switch_unregister(cdns->role_sw);
>> +err4:
>> +	phy_power_off(cdns->usb3_phy);
>> +
>> +err3:
>> +	phy_power_off(cdns->usb2_phy);
>> +err2:
>> +	phy_exit(cdns->usb3_phy);
>> +err1:
>> +	phy_exit(cdns->usb2_phy);
>> +
>> +	return ret;
>> +}
>> +
>> +/**
>> + * cdnsp_remove - unbind drd driver and clean up.
>> + * @pdev: Pointer to Linux platform device.
>> + *
>> + * Returns 0 on success otherwise negative errno.
>> + */
>> +static int cdnsp_remove(struct platform_device *pdev)
>> +{
>> +	struct cdnsp *cdns = platform_get_drvdata(pdev);
>> +
>> +	pm_runtime_get_sync(&pdev->dev);
>> +	pm_runtime_disable(&pdev->dev);
>> +	pm_runtime_put_noidle(&pdev->dev);
>> +	cdnsp_exit_roles(cdns);
>> +	usb_role_switch_unregister(cdns->role_sw);
>> +	phy_power_off(cdns->usb2_phy);
>> +	phy_power_off(cdns->usb3_phy);
>> +	phy_exit(cdns->usb2_phy);
>> +	phy_exit(cdns->usb3_phy);
>> +	return 0;
>> +}
>> +
>> +#ifdef CONFIG_PM_SLEEP
>> +
>> +static int cdnsp_suspend(struct device *dev)
>> +{
>> +	struct cdnsp *cdns = dev_get_drvdata(dev);
>> +	unsigned long flags;
>> +
>> +	if (cdns->role == USB_ROLE_HOST)
>> +		return 0;
>> +
>> +	if (pm_runtime_status_suspended(dev))
>> +		pm_runtime_resume(dev);
>> +
>> +	if (cdns->roles[cdns->role]->suspend) {
>> +		spin_lock_irqsave(&cdns->gadget_dev->lock, flags);
>> +		cdns->roles[cdns->role]->suspend(cdns, false);
>> +		spin_unlock_irqrestore(&cdns->gadget_dev->lock, flags);
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +static int cdnsp_resume(struct device *dev)
>> +{
>> +	struct cdnsp *cdns = dev_get_drvdata(dev);
>> +	unsigned long flags;
>> +
>> +	if (cdns->role == USB_ROLE_HOST)
>> +		return 0;
>> +
>> +	if (cdns->roles[cdns->role]->resume) {
>> +		spin_lock_irqsave(&cdns->gadget_dev->lock, flags);
>> +		cdns->roles[cdns->role]->resume(cdns, false);
>> +		spin_unlock_irqrestore(&cdns->gadget_dev->lock, flags);
>> +	}
>> +
>> +	pm_runtime_disable(dev);
>> +	pm_runtime_set_active(dev);
>> +	pm_runtime_enable(dev);
>> +
>> +	return 0;
>> +}
>> +#endif
>> +
>> +static const struct dev_pm_ops cdnsp_pm_ops = {
>> +	SET_SYSTEM_SLEEP_PM_OPS(cdnsp_suspend, cdnsp_resume)
>> +};
>> +
>> +#ifdef CONFIG_OF
>> +static const struct of_device_id of_cdnsp_match[] = {
>> +	{ .compatible = "cdns,usbssp" },
>> +	{ },
>> +};
>> +MODULE_DEVICE_TABLE(of, of_cdnsp_match);
>> +#endif
>> +
>> +static struct platform_driver cdnsp_driver = {
>> +	.probe		= cdnsp_probe,
>> +	.remove		= cdnsp_remove,
>> +	.driver		= {
>> +		.name	= "cdns-usbssp",
>> +		.of_match_table	= of_match_ptr(of_cdnsp_match),
>> +		.pm	= &cdnsp_pm_ops,
>> +	},
>> +};
>> +
>> +module_platform_driver(cdnsp_driver);
>> +
>> +MODULE_ALIAS("platform:cdnsp");
>> +MODULE_AUTHOR("Pawel Laszczak <pawell@...ence.com>");
>> +MODULE_LICENSE("GPL v2");
>> +MODULE_DESCRIPTION("Cadence CDNSP DRD Controller Driver");
>> diff --git a/drivers/usb/cdnsp/core.h b/drivers/usb/cdnsp/core.h
>> new file mode 100644
>> index 000000000000..408889fdd2d9
>> --- /dev/null
>> +++ b/drivers/usb/cdnsp/core.h
>> @@ -0,0 +1,90 @@
>> +/* SPDX-License-Identifier: GPL-2.0 */
>> +/*
>> + * Cadence CDNSP DRD Driver.
>> + *
>> + * Copyright (C) 2020 Cadence.
>> + *
>> + * Authors: Pawel Laszczak <pawell@...ence.com>
>> + *
>> + */
>> +#include <linux/usb/role.h>
>> +#include <linux/usb/otg.h>
>> +
>> +#ifndef __LINUX_CDNSP_CORE_H
>> +#define __LINUX_CDNSP_CORE_H
>> +
>> +struct cdnsp;
>> +
>> +/**
>> + * struct cdnsp_role_driver - host/gadget role driver.
>> + * @start: Start this role.
>> + * @stop: Stop this role.
>> + * @suspend: Suspend callback for this role.
>> + * @resume: Resume callback for this role.
>> + * @irq: irq handler for this role.
>> + * @name: Role name string (host/gadget).
>> + * @state: Current state.
>> + */
>> +struct cdnsp_role_driver {
>> +	int (*start)(struct cdnsp *cdns);
>> +	void (*stop)(struct cdnsp *cdns);
>> +	int (*suspend)(struct cdnsp *cdns, bool do_wakeup);
>> +	int (*resume)(struct cdnsp *cdns, bool hibernated);
>> +	const char *name;
>> +#define CDNSP_ROLE_STATE_INACTIVE	0
>> +#define CDNSP_ROLE_STATE_ACTIVE		1
>> +	int state;
>> +};
>> +
>> +#define CDNSP_XHCI_RESOURCES_NUM	2
>> +
>> +/**
>> + * struct cdnsp - Representation of Cadence USB3 DRD controller.
>> + * @dev: Pointer to Cadence device struct.
>> + * @xhci_regs: Pointer to base of xhci registers.
>> + * @xhci_res: The resource for xhci.
>> + * @dev_regs: Pointer to base of dev registers.
>> + * @otg_res: The resource for otg.
>> + * @otg_regs: Pointer to base of otg registers.
>> + * @otg_irq: irq number for otg controller.
>> + * @dev_irq: irq number for device controller.
>> + * @roles: Array of supported roles for this controller.
>> + * @role: Current role.
>> + * @host_dev: The child host device pointer for cdnsp core.
>> + * @gadget_dev: The child gadget device pointer for cdnsp core.
>> + * @usb2_phy: Pointer to USB2 PHY.
>> + * @usb3_phy: Pointer to USB3 PHY.
>> + * @mutex: The mutex for concurrent code at driver.
>> + * @dr_mode: Supported mode of operation it can be only Host, only Device
>> + *           or OTG mode that allow to switch between Device and Host mode.
>> + *           This field based on firmware setting, kernel configuration
>> + *           and hardware configuration.
>> + * @role_sw: Pointer to role switch object.
>> + */
>> +struct cdnsp {
>> +	struct device *dev;
>> +	void __iomem *xhci_regs;
>> +	struct resource xhci_res[CDNSP_XHCI_RESOURCES_NUM];
>> +	struct cdnsp_usb_regs __iomem *dev_regs;
>> +
>> +	struct resource otg_res;
>> +	struct cdnsp_otg_regs *otg_regs;
>> +
>> +	int otg_irq;
>> +	int dev_irq;
>> +	struct cdnsp_role_driver *roles[USB_ROLE_DEVICE + 1];
>> +	enum usb_role role;
>> +	struct platform_device *host_dev;
>> +	struct cdnsp_device *gadget_dev;
>> +	struct phy *usb2_phy;
>> +	struct phy *usb3_phy;
>> +
>> +	/* mutext used in workqueue. */
>> +	struct mutex mutex;
>> +	enum usb_dr_mode dr_mode;
>> +	struct usb_role_switch *role_sw;
>> +};
>> +
>> +int cdnsp_hw_role_switch(struct cdnsp *cdns);
>> +
>> +#endif /* __LINUX_CDNSP_CORE_H */
>> diff --git a/drivers/usb/cdnsp/drd.c b/drivers/usb/cdnsp/drd.c
>> new file mode 100644
>> index 000000000000..8a8d244278ef
>> --- /dev/null
>> +++ b/drivers/usb/cdnsp/drd.c
>> @@ -0,0 +1,372 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Cadence CDNSP DRD Driver.
>> + *
>> + * Copyright (C) 2020 Cadence.
>> + *
>> + * Author: Pawel Laszczak <pawell@...ence.com>
>> + *
>> + * Code based on Cadence USBSS DRD driver.
>> + * Origin: Copyright (C) 2018-2019 Cadence.
>> + *         Copyright (C) 2019 Texas Instruments
>> + */
>> +
>> +#include <linux/interrupt.h>
>> +#include <linux/usb/otg.h>
>> +#include <linux/kernel.h>
>> +#include <linux/iopoll.h>
>> +#include <linux/delay.h>
>> +
>> +#include "gadget.h"
>> +#include "core.h"
>> +#include "drd.h"
>> +
>> +/**
>> + * cdnsp_set_mode - change mode of OTG Core.
>> + * @cdns: Pointer to context structure.
>> + * @mode: Selected mode from cdns_role.
>> + *
>> + * Returns 0 on success otherwise negative errno.
>> + */
>> +static int cdnsp_set_mode(struct cdnsp *cdns, enum usb_dr_mode mode)
>> +{
>> +	int ret = 0;
>> +	u32 reg;
>> +
>> +	switch (mode) {
>> +	case USB_DR_MODE_PERIPHERAL:
>> +		break;
>> +	case USB_DR_MODE_HOST:
>> +		break;
>> +	case USB_DR_MODE_OTG:
>> +		dev_dbg(cdns->dev, "Set controller to OTG mode\n");
>> +		reg = readl(&cdns->otg_regs->override);
>> +		reg |= OVERRIDE_IDPULLUP;
>> +		writel(reg, &cdns->otg_regs->override);
>> +
>> +		/*
>> +		 * Hardware specification says: "ID_VALUE must be valid within
>> +		 * 50ms after idpullup is set to '1" so driver must wait
>> +		 * 50ms before reading this pin.
>> +		 */
>> +		usleep_range(50000, 60000);
>> +		break;
>> +	default:
>> +		dev_err(cdns->dev, "Unsupported mode of operation %d\n", mode);
>> +		return -EINVAL;
>> +	}
>> +
>> +	return ret;
>
>return 0;  delete the "ret" variable.
>
>> +}
>> +
>> +int cdnsp_get_id(struct cdnsp *cdns)
>> +{
>> +	int id;
>> +
>> +	id = readl(&cdns->otg_regs->sts) & OTGSTS_ID_VALUE;
>
>It took me a while to spot the & OTGSTS_ID_VALUE.  Could you move that
>to its own line:
>
>	id = readl(&cdns->otg_regs->sts);
>	id &= OTGSTS_ID_VALUE;
>
>I'm not sure I understand what ID means in this context.  I would have
>expected both 0 and 1 to be valid identifiers?  The two identifiers
>should have human readable names so change:
>
>-	if (!cdnsp_get_id())
>
>to
>
>+	if (cdnsp_get_id() == MY_WHATEVER_IDENDTIFIER) {
>
>
>> +	dev_dbg(cdns->dev, "OTG ID: %d", id);
>> +
>> +	return id;
>> +}
>> +
>> +int cdnsp_get_vbus(struct cdnsp *cdns)
>> +{
>> +	int vbus;
>> +
>> +	vbus = !!(readl(&cdns->otg_regs->sts) & OTGSTS_VBUS_VALID);
>> +	dev_dbg(cdns->dev, "OTG VBUS: %d", vbus);
>> +
>> +	return vbus;
>> +}
>> +
>> +int cdnsp_is_host(struct cdnsp *cdns)
>
>Make this bool.  return true/false.
>
>> +{
>> +	if (cdns->dr_mode == USB_DR_MODE_HOST)
>> +		return 1;
>> +	else if (!cdnsp_get_id(cdns))
>> +		return 1;
>> +
>> +	return 0;
>> +}
>> +
>> +int cdnsp_is_device(struct cdnsp *cdns)
>
>Bool
>
>> +{
>> +	if (cdns->dr_mode == USB_DR_MODE_PERIPHERAL)
>> +		return 1;
>> +	else if (cdns->dr_mode == USB_DR_MODE_OTG)
>> +		if (cdnsp_get_id(cdns))
>> +			return 1;
>> +
>> +	return 0;
>> +}
>> +
>> +void cdnsp_clear_vbus(struct cdnsp *cdns)
>> +{
>> +	u32 reg;
>> +
>> +	reg = readl(&cdns->otg_regs->override);
>> +	reg |= OVERRIDE_SESS_VLD_SEL;
>> +	writel(reg, &cdns->otg_regs->override);
>> +}
>> +
>> +void cdnsp_set_vbus(struct cdnsp *cdns)
>> +{
>> +	u32 reg;
>> +
>> +	reg = readl(&cdns->otg_regs->override);
>> +	reg &= ~OVERRIDE_SESS_VLD_SEL;
>> +	writel(reg, &cdns->otg_regs->override);
>> +}
>> +
>> +/**
>> + * cdnsp_otg_disable_irq - Disable all OTG interrupts.
>> + * @cdns: Pointer to controller context structure.
>> + */
>> +static void cdnsp_otg_disable_irq(struct cdnsp *cdns)
>> +{
>> +	writel(0, &cdns->otg_regs->ien);
>> +}
>> +
>> +/**
>> + * cdnsp_otg_enable_irq - enable id and sess_valid interrupts.
>> + * @cdns: Pointer to controller context structure.
>> + */
>> +static void cdnsp_otg_enable_irq(struct cdnsp *cdns)
>> +{
>> +	writel(OTGIEN_ID_CHANGE_INT | OTGIEN_VBUSVALID_RISE_INT |
>> +	       OTGIEN_VBUSVALID_FALL_INT, &cdns->otg_regs->ien);
>> +}
>> +
>> +/**
>> + * cdnsp_drd_switch_host - start/stop host.
>> + * @cdns: Pointer to controller context structure.
>> + * @on: 1 for start, 0 for stop.
>> + *
>> + * Returns 0 on success otherwise negative errno.
>> + */
>> +int cdnsp_drd_switch_host(struct cdnsp *cdns, int on)
>
>Split this into separate _on/off() functions.
>
>> +{
>> +	u32 reg = OTGCMD_OTG_DIS;
>> +	u32 val;
>> +	int ret;
>> +
>> +	/* switch OTG core */
>> +	if (on) {
>> +		writel(OTGCMD_HOST_BUS_REQ | reg, &cdns->otg_regs->cmd);
>> +
>> +		dev_dbg(cdns->dev, "Waiting till Host mode is turned on\n");
>> +		ret = readl_poll_timeout_atomic(&cdns->otg_regs->sts, val,
>> +						val & OTGSTS_HOST_READY,
>> +						1, 100000);
>> +		if (ret) {
>> +			dev_err(cdns->dev, "timeout waiting for xhci_ready\n");
>> +			return ret;
>> +		}
>> +	} else {
>> +		writel(OTGCMD_HOST_BUS_DROP | OTGCMD_DEV_BUS_DROP,
>> +		       &cdns->otg_regs->cmd);
>> +
>> +		/* Waiting till H_IDLE state. */
>> +		readl_poll_timeout_atomic(&cdns->otg_regs->state, val,
>> +					  !(val & OTGSTATE_HOST_STATE_MASK),
>> +					  1, 2000000);
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +/**
>> + * cdnsp_drd_switch_gadget - start/stop gadget.
>> + * @cdns: Pointer to controller context structure.
>> + * @on: 1 for start, 0 for stop.
>> + *
>> + * Returns 0 on success otherwise negative errno.
>> + */
>> +int cdnsp_drd_switch_gadget(struct cdnsp *cdns, int on)
>
>There is no shared code for start and stop.  Just split this into two
>functions:
>
>int cdnsp_drd_gadget_on(struct cdnsp *cdns);
>int cdnsp_drd_gadget_off(struct cdnsp *cdns);
>
>
>> +{
>> +	u32 reg = OTGCMD_OTG_DIS;
>
>Delete the "reg" variable and use OTGCMD_OTG_DIS directly.
>
>> +	u32 val;
>> +	int ret;
>> +
>> +	/* switch OTG core */
>> +	if (on) {
>> +		writel(OTGCMD_DEV_BUS_REQ | reg, &cdns->otg_regs->cmd);
>> +
>> +		dev_dbg(cdns->dev, "Waiting till Device mode is turned on\n");
>> +
>> +		ret = readl_poll_timeout_atomic(&cdns->otg_regs->sts, val,
>> +						val & OTGSTS_DEV_READY,
>> +						1, 100000);
>> +		if (ret) {
>> +			dev_err(cdns->dev, "timeout waiting for dev_ready\n");
>> +			return ret;
>> +		}
>> +	} else {
>> +		/*
>> +		 * Driver should wait at least 10us after disabling Device
>> +		 * before turning-off Device (DEV_BUS_DROP).
>> +		 */
>> +		usleep_range(20, 30);
>> +		writel(OTGCMD_HOST_BUS_DROP | OTGCMD_DEV_BUS_DROP,
>> +		       &cdns->otg_regs->cmd);
>> +
>> +		/* Waiting till DEV_IDLE state. */
>> +		readl_poll_timeout_atomic(&cdns->otg_regs->state, val,
>> +					  !(val & OTGSTATE_DEV_STATE_MASK),
>> +					  1, 2000000);
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +/**
>> + * cdnsp_init_otg_mode - initialize drd controller.
>> + * @cdns: Pointer to controller context structure.
>> + *
>> + * Returns 0 on success otherwise negative errno.
>> + */
>> +static int cdnsp_init_otg_mode(struct cdnsp *cdns)
>> +{
>> +	int ret = 0;
>
>No need to initialize this.  It causes an unused assignment static
>checker warning and it disables checking for uninitialized variables.
>
>> +
>> +	cdnsp_otg_disable_irq(cdns);
>> +	/* clear all interrupts */
>> +	writel(~(u32)0, &cdns->otg_regs->ivect);
>> +
>> +	ret = cdnsp_set_mode(cdns, USB_DR_MODE_OTG);
>> +	if (ret)
>> +		return ret;
>> +
>> +	cdnsp_otg_enable_irq(cdns);
>> +	return ret;
>
>	return 0;
>
>> +}
>> +
>> +/**
>> + * cdnsp_drd_update_mode - initialize mode of operation.
>> + * @cdns: Pointer to controller context structure.
>> + *
>> + * Returns 0 on success otherwise negative errno.
>> + */
>> +int cdnsp_drd_update_mode(struct cdnsp *cdns)
>> +{
>> +	int ret = 0;
>
>Don't initialize.
>
>> +
>> +	switch (cdns->dr_mode) {
>> +	case USB_DR_MODE_PERIPHERAL:
>> +		ret = cdnsp_set_mode(cdns, USB_DR_MODE_PERIPHERAL);
>> +		break;
>> +	case USB_DR_MODE_HOST:
>> +		ret = cdnsp_set_mode(cdns, USB_DR_MODE_HOST);
>> +		break;
>> +	case USB_DR_MODE_OTG:
>> +		ret = cdnsp_init_otg_mode(cdns);
>> +		break;
>> +	default:
>> +		dev_err(cdns->dev, "Unsupported mode of operation %d\n",
>> +			cdns->dr_mode);
>> +		return -EINVAL;
>> +	}
>> +
>> +	return ret;
>> +}
>> +
>> +static irqreturn_t cdnsp_drd_thread_irq(int irq, void *data)
>> +{
>> +	struct cdnsp *cdns = data;
>> +
>> +	cdnsp_hw_role_switch(cdns);
>> +
>> +	return IRQ_HANDLED;
>> +}
>> +
>> +/**
>> + * cdnsp_drd_irq - interrupt handler for OTG events.
>> + *
>> + * @irq: irq number for cdnsp core device.
>> + * @data: Structure of cdnsp.
>> + *
>> + * Returns IRQ_HANDLED or IRQ_NONE.
>> + */
>> +static irqreturn_t cdnsp_drd_irq(int irq, void *data)
>> +{
>> +	irqreturn_t ret = IRQ_NONE;
>> +	struct cdnsp *cdns = data;
>> +	u32 reg;
>> +
>> +	if (cdns->dr_mode != USB_DR_MODE_OTG)
>> +		return ret;
>
>return IRQ_NONE;
>
>> +
>> +	reg = readl(&cdns->otg_regs->ivect);
>> +
>
>Delte this blank line.
>
>> +	if (!reg)
>> +		return ret;
>
>return IRQ_NONE;
>
>> +
>> +	if (reg & OTGIEN_ID_CHANGE_INT) {
>> +		dev_dbg(cdns->dev, "OTG IRQ: new ID: %d\n",
>> +			cdnsp_get_id(cdns));
>> +
>> +		ret = IRQ_WAKE_THREAD;
>> +	}
>> +
>> +	if (reg & (OTGIEN_VBUSVALID_RISE_INT | OTGIEN_VBUSVALID_FALL_INT)) {
>> +		dev_dbg(cdns->dev, "OTG IRQ: new VBUS: %d\n",
>> +			cdnsp_get_vbus(cdns));
>> +
>> +		ret = IRQ_WAKE_THREAD;
>> +	}
>> +
>> +	writel(~(u32)0, &cdns->otg_regs->ivect);
>> +
>> +	return ret;
>> +}
>> +
>> +int cdnsp_drd_init(struct cdnsp *cdns)
>> +{
>> +	int ret = 0;
>
>Don't initialize
>
>> +	u32 state;
>> +
>> +	cdns->otg_regs = devm_ioremap_resource(cdns->dev, &cdns->otg_res);
>> +	if (IS_ERR(cdns->otg_regs))
>> +		return PTR_ERR(cdns->otg_regs);
>> +
>> +	dev_info(cdns->dev, "DRD version (ID: %08x, rev: %08x)\n",
>> +		 readl(&cdns->otg_regs->did),
>> +		 readl(&cdns->otg_regs->rid));
>> +
>> +	state = OTGSTS_STRAP(readl(&cdns->otg_regs->sts));
>> +
>> +	/* Update dr_mode according to STRAP configuration. */
>> +	cdns->dr_mode = USB_DR_MODE_OTG;
>> +	if (state == OTGSTS_STRAP_HOST) {
>> +		dev_dbg(cdns->dev, "Controller strapped to HOST\n");
>> +		cdns->dr_mode = USB_DR_MODE_HOST;
>> +	} else if (state == OTGSTS_STRAP_GADGET) {
>> +		dev_dbg(cdns->dev, "Controller strapped to PERIPHERAL\n");
>> +		cdns->dr_mode = USB_DR_MODE_PERIPHERAL;
>> +	}
>> +
>> +	ret = devm_request_threaded_irq(cdns->dev, cdns->otg_irq,
>> +					cdnsp_drd_irq,
>> +					cdnsp_drd_thread_irq,
>> +					IRQF_SHARED,
>> +					dev_name(cdns->dev), cdns);
>> +
>
>Delete the blank line.
>
>> +	if (ret) {
>> +		dev_err(cdns->dev, "couldn't get otg_irq\n");
>> +		return ret;
>> +	}
>> +
>> +	state = readl(&cdns->otg_regs->sts);
>> +	if (OTGSTS_OTG_NRDY(state) != 0) {
>
>Remove the != 0
>
>	if (OTGSTS_OTG_NRDY(state)) {
>
>> +		dev_err(cdns->dev, "Cadence USB3 OTG device not ready\n");
>> +		return -ENODEV;
>> +	}
>> +
>> +	return ret;
>
>return 0;
>
>> +}
>> +
>> +int cdnsp_drd_exit(struct cdnsp *cdns)
>> +{
>> +	cdnsp_otg_disable_irq(cdns);
>> +	return 0;
>> +}
>> diff --git a/drivers/usb/cdnsp/drd.h b/drivers/usb/cdnsp/drd.h
>> new file mode 100644
>> index 000000000000..183080fd489e
>> --- /dev/null
>> +++ b/drivers/usb/cdnsp/drd.h
>> @@ -0,0 +1,127 @@
>> +/* SPDX-License-Identifier: GPL-2.0 */
>> +/*
>> + * Cadence CDNSP DRD header file.
>> + *
>> + * Copyright (C) 2020 Cadence.
>> + *
>> + * Author: Pawel Laszczak <pawell@...ence.com>
>> + */
>> +
>> +#ifndef __LINUX_CDNSP_DRD
>> +#define __LINUX_CDNSP_DRD
>> +
>> +#include <linux/usb/otg.h>
>> +#include <linux/phy/phy.h>
>> +#include "core.h"
>> +
>> +/* DRD register interface. */
>> +struct cdnsp_otg_regs {
>> +	__le32 did;
>> +	__le32 rid;
>> +	__le32 cfgs1;
>> +	__le32 cfgs2;
>> +	__le32 cmd;
>> +	__le32 sts;
>> +	__le32 state;
>> +	__le32 ien;
>> +	__le32 ivect;
>> +	__le32 tmr;
>> +	__le32 simulate;
>> +	__le32 adpbc_sts;
>> +	__le32 adp_ramp_time;
>> +	__le32 adpbc_ctrl1;
>> +	__le32 adpbc_ctrl2;
>> +	__le32 override;
>> +	__le32 vbusvalid_dbnc_cfg;
>> +	__le32 sessvalid_dbnc_cfg;
>> +	__le32 susp_timing_ctrl;
>> +};
>> +
>> +/* CDNS_RID - bitmasks. */
>> +#define CDNS_RID(p)			((p) & GENMASK(15, 0))
>> +
>> +/* CDNS_VID - bitmasks. */
>> +#define CDNS_DID(p)			((p) & GENMASK(31, 0))
>> +
>> +/* OTGCMD - bitmasks. */
>> +/* "Request the bus for Device mode. */
>> +#define OTGCMD_DEV_BUS_REQ		BIT(0)
>> +/* Request the bus for Host mode. */
>> +#define OTGCMD_HOST_BUS_REQ		BIT(1)
>> +/* Enable OTG mode. */
>> +#define OTGCMD_OTG_EN			BIT(2)
>> +/* Disable OTG mode. */
>> +#define OTGCMD_OTG_DIS			BIT(3)
>> +/*"Configure OTG as A-Device. */
>> +#define OTGCMD_A_DEV_EN			BIT(4)
>> +/*"Configure OTG as A-Device. */
>> +#define OTGCMD_A_DEV_DIS		BIT(5)
>> +/* Drop the bus for Device mode. */
>> +#define OTGCMD_DEV_BUS_DROP		BIT(8)
>> +/* Drop the bus for Host mode. */
>> +#define OTGCMD_HOST_BUS_DROP		BIT(9)
>> +
>> +/* OTGSTS - bitmasks. */
>> +/*
>> + * Current value of the ID pin. It is only valid when idpullup in
>> + * OTGCTRL1_TYPE register is set to '1'.
>> + */
>> +#define OTGSTS_ID_VALUE			BIT(0)
>> +/* Current value of the vbus_valid. */
>> +#define OTGSTS_VBUS_VALID		BIT(1)
>> +/* Current value of the b_sess_vld. */
>> +#define OTGSTS_SESSION_VALID		BIT(2)
>> +/* Device mode is active. */
>> +#define OTGSTS_DEV_ACTIVE		BIT(3)
>> +/* Host mode is active. */
>> +#define OTGSTS_HOST_ACTIVE		BIT(4)
>> +/* OTG Controller not ready. */
>> +#define OTGSTS_OTG_NRDY(p)		((p) & BIT(11))
>> +/*
>> + * Value of the strap pins.
>> + * 000 - No default configuration.
>> + * 010 - Controller initiall configured as Host.
>> + * 100 - Controller initially configured as Device.
>> + */
>> +#define OTGSTS_STRAP(p)			(((p) & GENMASK(13, 12)) >> 12)
>> +#define OTGSTS_STRAP_NO_DEFAULT_CFG	0x00
>> +#define OTGSTS_STRAP_HOST		0x01
>> +#define OTGSTS_STRAP_GADGET		0x02
>> +/* Device reade flag. */
>> +#define OTGSTS_DEV_READY		BIT(26)
>> +/* Host ready. */
>> +#define OTGSTS_HOST_READY		BIT(27)
>> +
>> +/* OTGSTATE- bitmasks. */
>> +#define OTGSTATE_DEV_STATE_MASK		GENMASK(2, 0)
>> +#define OTGSTATE_HOST_STATE_MASK	GENMASK(5, 3)
>> +#define OTGSTATE_HOST_STATE_IDLE	0x0
>> +#define OTGSTATE_HOST_STATE_VBUS_FALL	0x7
>> +#define OTGSTATE_HOST_STATE(p)		(((p) & OTGSTATE_HOST_STATE_MASK) >> 3)
>> +
>> +/* OTGIEN - bitmasks. */
>> +/* ID change interrupt enable. */
>> +#define OTGIEN_ID_CHANGE_INT		BIT(0)
>> +/* Vbusvalid fall detected interrupt enable. */
>> +#define OTGIEN_VBUSVALID_RISE_INT	BIT(4)
>> +/* Vbusvalid fall detected interrupt enable. */
>> +#define OTGIEN_VBUSVALID_FALL_INT	BIT(5)
>> +
>> +/* OVERRIDE - bitmasks. */
>> +#define OVERRIDE_IDPULLUP		BIT(0)
>> +/* Vbusvalid/Sesvalid override select. */
>> +#define OVERRIDE_SESS_VLD_SEL		BIT(10)
>> +
>> +int cdnsp_is_host(struct cdnsp *cdns);
>> +int cdnsp_is_device(struct cdnsp *cdns);
>> +int cdnsp_get_id(struct cdnsp *cdns);
>> +int cdnsp_get_vbus(struct cdnsp *cdns);
>> +void cdnsp_clear_vbus(struct cdnsp *cdns);
>> +void cdnsp_set_vbus(struct cdnsp *cdns);
>> +int cdnsp_drd_init(struct cdnsp *cdns);
>> +int cdnsp_drd_exit(struct cdnsp *cdns);
>> +int cdnsp_drd_update_mode(struct cdnsp *cdns);
>> +int cdnsp_drd_switch_gadget(struct cdnsp *cdns, int on);
>> +int cdnsp_drd_switch_host(struct cdnsp *cdns, int on);
>> +
>> +#endif /* __LINUX_CDNSP_DRD */
>> diff --git a/drivers/usb/cdnsp/ep0.c b/drivers/usb/cdnsp/ep0.c
>> new file mode 100644
>> index 000000000000..407a7ad06ddb
>> --- /dev/null
>> +++ b/drivers/usb/cdnsp/ep0.c
>> @@ -0,0 +1,462 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Cadence CDNSP DRD Driver.
>> + *
>> + * Copyright (C) 2020 Cadence.
>> + *
>> + * Author: Pawel Laszczak <pawell@...ence.com>
>> + *
>> + */
>> +
>> +#include <linux/usb/composite.h>
>> +#include <linux/usb/gadget.h>
>> +#include <linux/list.h>
>> +
>> +#include "gadget.h"
>> +
>> +static void cdnsp_ep0_stall(struct cdnsp_device *pdev)
>> +{
>> +	struct cdnsp_request *preq;
>> +	struct cdnsp_ep *pep;
>> +	int ret = 0;
>
>Delete the ret variable.  No one ever checks it.
>
>> +
>> +	pep = &pdev->eps[0];
>> +	preq = next_request(&pep->pending_list);
>> +
>> +	if (pdev->three_stage_setup) {
>> +		ret = cdnsp_halt_endpoint(pdev, pep, true);
>> +
>> +		if (preq)
>> +			cdnsp_gadget_giveback(pep, preq, -ECONNRESET);
>> +	} else {
>> +		pep->ep_state |= EP0_HALTED_STATUS;
>> +
>> +		if (preq)
>> +			list_del(&preq->list);
>> +
>> +		cdnsp_status_stage(pdev);
>> +	}
>> +}
>> +
>> +static int cdnsp_ep0_delegate_req(struct cdnsp_device *pdev,
>> +				  struct usb_ctrlrequest *ctrl)
>> +{
>> +	int ret;
>> +
>> +	spin_unlock(&pdev->lock);
>> +	ret = pdev->gadget_driver->setup(&pdev->gadget, ctrl);
>> +	spin_lock(&pdev->lock);
>> +
>> +	return ret;
>> +}
>> +
>> +static int cdnsp_ep0_set_config(struct cdnsp_device *pdev,
>> +				struct usb_ctrlrequest *ctrl)
>> +{
>> +	enum usb_device_state state = pdev->gadget.state;
>> +	u32 cfg;
>> +	int ret;
>> +
>> +	cfg = le16_to_cpu(ctrl->wValue);
>> +
>> +	switch (state) {
>> +	case USB_STATE_ADDRESS:
>> +		ret = cdnsp_ep0_delegate_req(pdev, ctrl);
>> +		if (!cfg && !ret)
>> +			usb_gadget_set_state(&pdev->gadget, USB_STATE_ADDRESS);
>
>Always do error handling, not success handling.
>
>		if (ret)
>			return ret;
>
>Move the usb_gadget_set_state() after the end of the switch statement.
>
>
>> +		break;
>> +	case USB_STATE_CONFIGURED:
>> +		ret = cdnsp_ep0_delegate_req(pdev, ctrl);
>> +		if (!cfg && !ret)
>> +			usb_gadget_set_state(&pdev->gadget, USB_STATE_ADDRESS);
>> +		break;
>> +	default:
>> +		dev_err(pdev->dev, "Set Configuration - bad device state\n");
>> +		ret = -EINVAL;
>> +	}
>
>
>	if (!cfg)
>		usb_gadget_set_state(&pdev->gadget, USB_STATE_ADDRESS);
>
>	return 0;
>
>
>> +
>> +	return ret;
>> +}
>> +
>> +static int cdnsp_ep0_set_address(struct cdnsp_device *pdev,
>> +				 struct usb_ctrlrequest *ctrl)
>> +{
>> +	enum usb_device_state state = pdev->gadget.state;
>> +	struct cdnsp_slot_ctx *slot_ctx;
>> +	unsigned int slot_state;
>> +	int dev_state;
>> +	int ret = 0;
>
>don't initialize
>
>> +	u32 addr;
>> +
>> +	addr = le16_to_cpu(ctrl->wValue);
>> +
>> +	if (addr > 127) {
>> +		dev_err(pdev->dev, "Invalid device address %d\n", addr);
>> +		return -EINVAL;
>> +	}
>> +
>> +	slot_ctx = cdnsp_get_slot_ctx(&pdev->out_ctx);
>> +	dev_state = GET_SLOT_STATE(le32_to_cpu(slot_ctx->dev_state));
>> +
>> +	if (state == USB_STATE_CONFIGURED) {
>> +		dev_err(pdev->dev, "Can't Set Address from Configured State\n");
>> +		return -EINVAL;
>> +	}
>> +
>> +	pdev->device_address = le16_to_cpu(ctrl->wValue);
>> +
>> +	slot_ctx = cdnsp_get_slot_ctx(&pdev->out_ctx);
>> +	slot_state = GET_SLOT_STATE(le32_to_cpu(slot_ctx->dev_state));
>> +	if (slot_state == SLOT_STATE_ADDRESSED)
>> +		cdnsp_reset_device(pdev);
>> +
>> +	/*set device address*/
>> +	ret = cdnsp_setup_device(pdev, SETUP_CONTEXT_ADDRESS);
>> +	if (ret)
>> +		return ret;
>> +
>> +	if (addr)
>> +		usb_gadget_set_state(&pdev->gadget, USB_STATE_ADDRESS);
>> +	else
>> +		usb_gadget_set_state(&pdev->gadget, USB_STATE_DEFAULT);
>> +
>> +	return 0;
>> +}
>> +
>> +int cdnsp_status_stage(struct cdnsp_device *pdev)
>> +{
>> +	pdev->ep0_stage = CDNSP_STATUS_STAGE;
>> +	pdev->ep0_preq.request.length = 0;
>> +
>> +	return cdnsp_ep_enqueue(pdev->ep0_preq.pep, &pdev->ep0_preq);
>> +}
>> +
>> +int cdnsp_w_index_to_ep_index(__le32  wIndex)
>> +{
>> +	wIndex = le32_to_cpu(wIndex);
>> +
>> +	if (!(wIndex & USB_ENDPOINT_NUMBER_MASK))
>> +		return 0;
>> +
>> +	return ((wIndex & USB_ENDPOINT_NUMBER_MASK) * 2) +
>> +		(wIndex & USB_ENDPOINT_DIR_MASK ? 1 : 0) - 1;
>> +}
>> +
>> +static int cdnsp_ep0_handle_status(struct cdnsp_device *pdev,
>> +				   struct usb_ctrlrequest *ctrl)
>> +{
>> +	struct cdnsp_ep *pep;
>> +	__le16 *response;
>> +	int ep_sts = 0;
>> +	u16 status = 0;
>> +	u32 recipient;
>> +
>> +	recipient = ctrl->bRequestType & USB_RECIP_MASK;
>> +
>> +	switch (recipient) {
>> +	case USB_RECIP_DEVICE:
>> +		status = pdev->gadget.is_selfpowered |
>> +			 ((pdev->u1_allowed) ? BIT(USB_DEV_STAT_U1_ENABLED) : 0) |
>> +			 ((pdev->u2_allowed) ? BIT(USB_DEV_STAT_U2_ENABLED) : 0);
>> +		break;
>> +	case USB_RECIP_INTERFACE:
>> +		break;
>> +	case USB_RECIP_ENDPOINT:
>> +		pep = &pdev->eps[cdnsp_w_index_to_ep_index(ctrl->wIndex)];
>> +		ep_sts = GET_EP_CTX_STATE(pep->out_ctx);
>> +
>> +		/* check if endpoint is stalled */
>> +		if (ep_sts == EP_STATE_HALTED)
>> +			status =  BIT(USB_ENDPOINT_HALT);
>> +		break;
>> +	default:
>> +		return -EINVAL;
>> +	}
>> +
>> +	response = (__le16 *)pdev->setup_buf;
>> +	*response = cpu_to_le16(status);
>> +
>> +	pdev->ep0_preq.request.length = sizeof(*response);
>> +	pdev->ep0_preq.request.buf = pdev->setup_buf;
>> +
>> +	return cdnsp_ep_enqueue(pdev->ep0_preq.pep, &pdev->ep0_preq);
>> +}
>> +
>> +void cdnsp_enter_test_mode(struct cdnsp_device *pdev)
>> +{
>> +	u32 temp;
>> +
>> +	temp = readl(&pdev->active_port->regs->portpmsc) & ~GENMASK(31, 28);
>> +	temp |= PORT_TEST_MODE(pdev->test_mode);
>> +	writel(temp, &pdev->active_port->regs->portpmsc);
>> +	pdev->test_mode = 0;
>> +}
>> +
>> +static int cdnsp_ep0_handle_feature_device(struct cdnsp_device *pdev,
>> +					   struct usb_ctrlrequest *ctrl,
>> +					   int set)
>> +{
>> +	enum usb_device_state state;
>> +	enum usb_device_speed speed;
>> +	int ret = 0;
>
>Get rid of the "ret" variable and just return -EINVAL directly everywhere.
>
>> +	u16 tmode;
>> +
>> +	state = pdev->gadget.state;
>> +	speed = pdev->gadget.speed;
>> +
>> +	switch (le16_to_cpu(ctrl->wValue)) {
>> +	case USB_DEVICE_REMOTE_WAKEUP:
>> +		pdev->remote_wakeup_allowed = !!set;
>> +		break;
>> +	case USB_DEVICE_U1_ENABLE:
>> +		if (state != USB_STATE_CONFIGURED || speed < USB_SPEED_SUPER)
>> +			return -EINVAL;
>> +
>> +		pdev->u1_allowed = !!set;
>> +		break;
>> +	case USB_DEVICE_U2_ENABLE:
>> +		if (state != USB_STATE_CONFIGURED || speed < USB_SPEED_SUPER)
>> +			return -EINVAL;
>> +
>> +		pdev->u2_allowed = !!set;
>> +		break;
>> +	case USB_DEVICE_LTM_ENABLE:
>> +		ret = -EINVAL;
>> +		break;
>> +	case USB_DEVICE_TEST_MODE:
>> +		if (state != USB_STATE_CONFIGURED || speed > USB_SPEED_HIGH)
>> +			return -EINVAL;
>> +
>> +		tmode = le16_to_cpu(ctrl->wIndex);
>> +
>> +		if (!set || (tmode & 0xff) != 0)
>> +			return -EINVAL;
>> +
>> +		tmode = tmode >> 8;
>> +
>> +		if (tmode > TEST_FORCE_EN || tmode < TEST_J)
>> +			return -EINVAL;
>> +
>> +		pdev->test_mode = tmode;
>> +
>> +		/*
>> +		 * Test mode must be set before Status Stage but controller
>> +		 * will start testing sequence after Status Stage.
>> +		 */
>> +		cdnsp_enter_test_mode(pdev);
>> +		break;
>> +	default:
>> +		ret = -EINVAL;
>> +	}
>> +
>> +	return ret;
>> +}
>> +
>> +static int cdnsp_ep0_handle_feature_intf(struct cdnsp_device *pdev,
>> +					 struct usb_ctrlrequest *ctrl,
>> +					 int set)
>> +{
>> +	u32 wValue;
>> +	int ret = 0;
>> +
>> +	wValue = le16_to_cpu(ctrl->wValue);
>> +
>> +	switch (wValue) {
>> +	case USB_INTRF_FUNC_SUSPEND:
>
>
>Is this function supposed to do something?

Yes,  I think that this request should be delegate to function. 
I will fix it.

>
>> +		break;
>> +	default:
>> +		ret = -EINVAL;
>> +	}
>> +
>> +	return ret;
>> +}
>> +
>> +static int cdnsp_ep0_handle_feature_endpoint(struct cdnsp_device *pdev,
>> +					     struct usb_ctrlrequest *ctrl,
>> +					     int set)
>> +{
>> +	struct cdnsp_ring *ep_ring;
>> +	struct cdnsp_ep *pep;
>> +	int ret = 0;
>
>Don't initialize
>
>> +	u32 wValue;
>> +
>> +	wValue = le16_to_cpu(ctrl->wValue);
>> +	pep = &pdev->eps[cdnsp_w_index_to_ep_index(ctrl->wIndex)];
>> +	ep_ring = pep->ring;
>> +
>> +	switch (wValue) {
>> +	case USB_ENDPOINT_HALT:
>> +		if (!set && (pep->ep_state & EP_WEDGE)) {
>> +			/* Resets Sequence Number */
>> +			cdnsp_halt_endpoint(pdev, pep, 0);
>> +			cdnsp_halt_endpoint(pdev, pep, 1);
>> +			break;
>> +		}
>> +
>> +		ret = cdnsp_halt_endpoint(pdev, pep, set);
>> +		break;
>> +	default:
>> +		dev_warn(pdev->dev, "WARN Incorrect wValue %04x\n", wValue);
>> +		return -EINVAL;
>> +	}
>> +
>> +	return ret;
>> +}
>> +
>> +int cdnsp_ep0_handle_feature(struct cdnsp_device *pdev,
>> +			     struct usb_ctrlrequest *ctrl,
>> +			     int set)
>> +{
>> +	switch (ctrl->bRequestType & USB_RECIP_MASK) {
>> +	case USB_RECIP_DEVICE:
>> +		return cdnsp_ep0_handle_feature_device(pdev, ctrl, set);
>> +	case USB_RECIP_INTERFACE:
>> +		return cdnsp_ep0_handle_feature_intf(pdev, ctrl, set);
>> +	case USB_RECIP_ENDPOINT:
>> +		return cdnsp_ep0_handle_feature_endpoint(pdev, ctrl, set);
>> +	default:
>> +		return -EINVAL;
>> +	}
>> +}
>> +
>> +static int cdnsp_ep0_set_sel(struct cdnsp_device *pdev,
>> +			     struct usb_ctrlrequest *ctrl)
>> +{
>> +	enum usb_device_state state = pdev->gadget.state;
>> +	u16 wLength;
>> +
>> +	if (state == USB_STATE_DEFAULT)
>> +		return -EINVAL;
>> +
>> +	wLength = le16_to_cpu(ctrl->wLength);
>> +
>> +	if (wLength != 6) {
>> +		dev_err(pdev->dev, "Set SEL should be 6 bytes, got %d\n",
>> +			wLength);
>> +		return -EINVAL;
>> +	}
>> +
>> +	/*
>> +	 * To handle Set SEL we need to receive 6 bytes from Host. So let's
>> +	 * queue a usb_request for 6 bytes.
>> +	 */
>> +	pdev->ep0_preq.request.length = 0x6;
>
>Just use decimal size values.
>
>> +	pdev->ep0_preq.request.buf = pdev->setup_buf;
>> +
>> +	return cdnsp_ep_enqueue(pdev->ep0_preq.pep, &pdev->ep0_preq);
>> +}
>> +
>> +static int cdnsp_ep0_set_isoch_delay(struct cdnsp_device *pdev,
>> +				     struct usb_ctrlrequest *ctrl)
>> +{
>> +	if (le16_to_cpu(ctrl->wIndex) || le16_to_cpu(ctrl->wLength))
>> +		return -EINVAL;
>> +
>> +	pdev->gadget.isoch_delay = le16_to_cpu(ctrl->wValue);
>> +
>> +	return 0;
>> +}
>> +
>> +static int cdnsp_ep0_std_request(struct cdnsp_device *pdev,
>> +				 struct usb_ctrlrequest *ctrl)
>> +{
>> +	int ret = 0;
>
>Don't initialize
>
>> +
>> +	switch (ctrl->bRequest) {
>> +	case USB_REQ_GET_STATUS:
>> +		ret = cdnsp_ep0_handle_status(pdev, ctrl);
>> +		break;
>> +	case USB_REQ_CLEAR_FEATURE:
>> +		ret = cdnsp_ep0_handle_feature(pdev, ctrl, 0);
>> +		break;
>> +	case USB_REQ_SET_FEATURE:
>> +		ret = cdnsp_ep0_handle_feature(pdev, ctrl, 1);
>> +		break;
>> +	case USB_REQ_SET_ADDRESS:
>> +		ret = cdnsp_ep0_set_address(pdev, ctrl);
>> +		break;
>> +	case USB_REQ_SET_CONFIGURATION:
>> +		ret = cdnsp_ep0_set_config(pdev, ctrl);
>> +		break;
>> +	case USB_REQ_SET_SEL:
>> +		ret = cdnsp_ep0_set_sel(pdev, ctrl);
>> +		break;
>> +	case USB_REQ_SET_ISOCH_DELAY:
>> +		ret = cdnsp_ep0_set_isoch_delay(pdev, ctrl);
>> +		break;
>> +	case USB_REQ_SET_INTERFACE:
>> +		/*
>> +		 * Add request into pending list to block sending status stage
>> +		 * by libcomposite.
>> +		 */
>> +		list_add_tail(&pdev->ep0_preq.list,
>> +			      &pdev->ep0_preq.pep->pending_list);
>> +
>> +		ret = cdnsp_ep0_delegate_req(pdev, ctrl);
>> +		if (ret == -EBUSY)
>> +			ret = 0;
>> +
>> +		list_del(&pdev->ep0_preq.list);
>> +		break;
>> +	default:
>> +		ret = cdnsp_ep0_delegate_req(pdev, ctrl);
>> +		break;
>> +	}
>> +	return ret;
>> +}
>> +
>> +void cdnsp_setup_analyze(struct cdnsp_device *pdev)
>> +{
>> +	struct usb_ctrlrequest *ctrl = &pdev->setup;
>> +	int ret = 0;
>> +	__le16 len;
>> +
>> +	if (!pdev->gadget_driver)
>> +		goto out;
>> +
>> +	if (pdev->gadget.state == USB_STATE_NOTATTACHED) {
>> +		dev_err(pdev->dev, "ERR: Setup detected in unattached state\n");
>> +		ret = -EINVAL;
>> +		goto out;
>> +	}
>> +
>> +	/* Restore the ep0 to Stopped/Running state. */
>> +	if (pdev->eps[0].ep_state & EP_HALTED)
>> +		cdnsp_halt_endpoint(pdev, &pdev->eps[0], 0);
>> +
>> +	/*
>> +	 * Finishing previous SETUP transfer by removing request from
>> +	 * list and informing upper layer
>> +	 */
>> +	if (!list_empty(&pdev->eps[0].pending_list)) {
>> +		struct cdnsp_request	*req;
>> +
>> +		req = next_request(&pdev->eps[0].pending_list);
>> +		cdnsp_ep_dequeue(&pdev->eps[0], req);
>> +	}
>> +
>> +	len = le16_to_cpu(ctrl->wLength);
>> +	if (!len) {
>> +		pdev->three_stage_setup = false;
>> +		pdev->ep0_expect_in = false;
>> +	} else {
>> +		pdev->three_stage_setup = true;
>> +		pdev->ep0_expect_in = !!(ctrl->bRequestType & USB_DIR_IN);
>> +	}
>> +
>> +	if ((ctrl->bRequestType & USB_TYPE_MASK) == USB_TYPE_STANDARD)
>> +		ret = cdnsp_ep0_std_request(pdev, ctrl);
>> +	else
>> +		ret = cdnsp_ep0_delegate_req(pdev, ctrl);
>> +
>> +	if (!len)
>> +		pdev->ep0_stage = CDNSP_STATUS_STAGE;
>> +
>> +	if (ret == USB_GADGET_DELAYED_STATUS)
>> +		return;
>> +out:
>> +	if (ret < 0)
>> +		cdnsp_ep0_stall(pdev);
>> +	else if (pdev->ep0_stage == CDNSP_STATUS_STAGE)
>> +		cdnsp_status_stage(pdev);
>> +}
>> diff --git a/drivers/usb/cdnsp/export.h b/drivers/usb/cdnsp/export.h
>> new file mode 100644
>> index 000000000000..0d8797ef7840
>> --- /dev/null
>> +++ b/drivers/usb/cdnsp/export.h
>> @@ -0,0 +1,36 @@
>> +/* SPDX-License-Identifier: GPL-2.0 */
>> +/*
>> + * Cadence CDNSP DRD Driver - Gadget/Host Export APIs.
>> + *
>> + * Copyright (C) 2020 Cadence.
>> + *
>> + * Author: Pawel Laszczak <pawell@...ence.com>
>> + */
>> +#ifndef __LINUX_CDNSP_EXPORT
>> +#define __LINUX_CDNSP_EXPORT
>> +
>> +#if IS_ENABLED(CONFIG_USB_CDNSP_GADGET)
>> +int cdnsp_gadget_init(struct cdnsp *cdns);
>> +void cdnsp_gadget_exit(struct cdnsp *cdns);
>> +#else
>> +static inline int cdnsp_gadget_init(struct cdnsp *cdns)
>> +{
>> +	return -ENXIO;
>> +}
>> +
>> +static inline void cdnsp_gadget_exit(struct cdnsp *cdns) { }
>> +#endif /* CONFIG_USB_CDNSP_GADGET */
>> +
>> +#if IS_ENABLED(CONFIG_USB_CDNSP_HOST)
>> +int cdnsp_host_init(struct cdnsp *cdns);
>> +void cdnsp_host_exit(struct cdnsp *cdns);
>> +#else
>> +static inline int cdnsp_host_init(struct cdnsp *cdns)
>> +{
>> +	return -ENXIO;
>> +}
>> +
>> +static inline void cdnsp_host_exit(struct cdnsp *cdns) { }
>> +#endif /* CONFIG_USB_CDNSP_HOST */
>> +
>> +#endif /* __LINUX_CDNSP_EXPORT */
>> diff --git a/drivers/usb/cdnsp/gadget.c b/drivers/usb/cdnsp/gadget.c
>> new file mode 100644
>> index 000000000000..8cba6a22c998
>> --- /dev/null
>> +++ b/drivers/usb/cdnsp/gadget.c
>> @@ -0,0 +1,1935 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Cadence CDNSP DRD Driver.
>> + *
>> + * Copyright (C) 2020 Cadence.
>> + *
>> + * Author: Pawel Laszczak <pawell@...ence.com>
>> + *
>> + */
>> +
>> +#include <linux/moduleparam.h>
>> +#include <linux/dma-mapping.h>
>> +#include <linux/module.h>
>> +#include <linux/iopoll.h>
>> +#include <linux/delay.h>
>> +#include <linux/log2.h>
>> +#include <linux/slab.h>
>> +#include <linux/pci.h>
>> +#include <linux/irq.h>
>> +#include <linux/dmi.h>
>> +
>> +#include "gadget.h"
>> +#include "core.h"
>> +#include "drd.h"
>> +
>> +unsigned int cdnsp_port_speed(unsigned int port_status)
>> +{
>> +	/*Detect gadget speed based on PORTSC register*/
>> +	if (DEV_SUPERSPEEDPLUS(port_status))
>> +		return USB_SPEED_SUPER_PLUS;
>> +	else if (DEV_SUPERSPEED(port_status))
>> +		return USB_SPEED_SUPER;
>> +	else if (DEV_HIGHSPEED(port_status))
>> +		return USB_SPEED_HIGH;
>> +	else if (DEV_FULLSPEED(port_status))
>> +		return USB_SPEED_FULL;
>> +
>> +	/* If device is detached then speed will be USB_SPEED_UNKNOWN.*/
>> +	return USB_SPEED_UNKNOWN;
>> +}
>> +
>> +/*
>> + * Given a port state, this function returns a value that would result in the
>> + * port being in the same state, if the value was written to the port status
>> + * control register.
>> + * Save Read Only (RO) bits and save read/write bits where
>> + * writing a 0 clears the bit and writing a 1 sets the bit (RWS).
>> + * For all other types (RW1S, RW1CS, RW, and RZ), writing a '0' has no effect.
>> + */
>> +u32 cdnsp_port_state_to_neutral(u32 state)
>> +{
>> +	/* Save read-only status and port state. */
>> +	return (state & CDNSP_PORT_RO) | (state & CDNSP_PORT_RWS);
>> +}
>> +
>> +/**
>> + * Find the offset of the extended capabilities with capability ID id.
>> + * @base: PCI MMIO registers base address.
>> + * @start: Address at which to start looking, (0 or HCC_PARAMS to start at
>> + *         beginning of list)
>> + * @id: Extended capability ID to search for.
>> + *
>> + * Returns the offset of the next matching extended capability structure.
>> + * Some capabilities can occur several times,
>> + * e.g., the EXT_CAPS_PROTOCOL, and this provides a way to find them all.
>> + */
>> +int cdnsp_find_next_ext_cap(void __iomem *base, u32 start, int id)
>> +{
>> +	u32 offset = start;
>> +	u32 next;
>> +	u32 val;
>> +
>> +	if (!start || start == HCC_PARAMS_OFFSET) {
>> +		val = readl(base + HCC_PARAMS_OFFSET);
>> +		if (val == ~0)
>> +			return 0;
>> +
>> +		offset = HCC_EXT_CAPS(val) << 2;
>> +		if (!offset)
>> +			return 0;
>> +	};
>> +
>> +	do {
>> +		val = readl(base + offset);
>> +		if (val == ~0)
>> +			return 0;
>> +
>> +		if (EXT_CAPS_ID(val) == id && offset != start)
>> +			return offset;
>> +
>> +		next = EXT_CAPS_NEXT(val);
>> +		offset += next << 2;
>> +	} while (next);
>> +
>> +	return 0;
>> +}
>> +
>> +void cdnsp_set_link_state(struct cdnsp_device *pdev,
>> +			  __le32 __iomem *port_regs,
>> +			  u32 link_state)
>> +{
>> +	int port_num = 0xFF;
>> +	u32 temp;
>> +
>> +	temp = readl(port_regs);
>> +	temp = cdnsp_port_state_to_neutral(temp);
>> +	temp |= PORT_WKCONN_E | PORT_WKDISC_E;
>> +	writel(temp, port_regs);
>> +
>> +	temp &= ~PORT_PLS_MASK;
>> +	temp |= PORT_LINK_STROBE | link_state;
>> +
>> +	if (pdev->active_port)
>> +		port_num = pdev->active_port->port_num;
>> +
>> +	writel(temp, port_regs);
>> +}
>> +
>> +static void cdnsp_disable_port(struct cdnsp_device *pdev,
>> +			       __le32 __iomem *port_regs)
>> +{
>> +	u32 temp = cdnsp_port_state_to_neutral(readl(port_regs));
>> +
>> +	writel(temp | PORT_PED, port_regs);
>> +}
>> +
>> +static void cdnsp_clear_port_change_bit(struct cdnsp_device *pdev,
>> +					__le32 __iomem *port_regs)
>> +{
>> +	u32 portsc = readl(port_regs);
>> +
>> +	writel(cdnsp_port_state_to_neutral(portsc) |
>> +	       (portsc & PORT_CHANGE_BITS), port_regs);
>> +}
>> +
>> +static void cdnsp_set_chicken_bits_2(struct cdnsp_device *pdev, u32 bit)
>> +{
>> +	__le32 __iomem *reg;
>> +	void __iomem *base;
>> +	u32 offset = 0;
>> +
>> +	base = &pdev->cap_regs->hc_capbase;
>> +	offset = cdnsp_find_next_ext_cap(base, offset, D_XEC_PRE_REGS_CAP);
>> +	reg = base + offset + REG_CHICKEN_BITS_2_OFFSET;
>> +
>> +	bit = readl(reg) | bit;
>> +	writel(bit, reg);
>> +}
>> +
>> +static void cdnsp_clear_chicken_bits_2(struct cdnsp_device *pdev, u32 bit)
>> +{
>> +	__le32 __iomem *reg;
>> +	void __iomem *base;
>> +	u32 offset = 0;
>> +
>> +	base = &pdev->cap_regs->hc_capbase;
>> +	offset = cdnsp_find_next_ext_cap(base, offset, D_XEC_PRE_REGS_CAP);
>> +	reg = base + offset + REG_CHICKEN_BITS_2_OFFSET;
>> +
>> +	bit = readl(reg) & ~bit;
>> +	writel(bit, reg);
>> +}
>> +
>> +/*
>> + * Disable interrupts and begin the controller halting process.
>> + */
>> +static void cdnsp_quiesce(struct cdnsp_device *pdev)
>> +{
>> +	u32 halted;
>> +	u32 mask;
>> +	u32 cmd;
>> +
>> +	mask = ~(u32)(CDNSP_IRQS);
>> +
>> +	halted = readl(&pdev->op_regs->status) & STS_HALT;
>> +	if (!halted)
>> +		mask &= ~(CMD_R_S | CMD_DEVEN);
>> +
>> +	cmd = readl(&pdev->op_regs->command);
>> +	cmd &= mask;
>> +	writel(cmd, &pdev->op_regs->command);
>> +}
>> +
>> +/*
>> + * Force controller into halt state.
>> + *
>> + * Disable any IRQs and clear the run/stop bit.
>> + * Controller will complete any current and actively pipelined transactions, and
>> + * should halt within 16 ms of the run/stop bit being cleared.
>> + * Read controller Halted bit in the status register to see when the
>> + * controller is finished.
>> + */
>> +int cdnsp_halt(struct cdnsp_device *pdev)
>> +{
>> +	int ret;
>> +	u32 val;
>> +
>> +	cdnsp_quiesce(pdev);
>> +
>> +	ret = readl_poll_timeout_atomic(&pdev->op_regs->status, val,
>> +					val & STS_HALT, 1,
>> +					CDNSP_MAX_HALT_USEC);
>> +	if (ret) {
>> +		dev_err(pdev->dev, "ERROR: Device halt failed\n");
>> +		return ret;
>> +	}
>> +
>> +	pdev->cdnsp_state |= CDNSP_STATE_HALTED;
>> +	return ret;
>
>return 0;
>
>> +}
>> +
>> +/*
>> + * device controller died, register read returns 0xffffffff, or command never
>> + * ends.
>> + */
>> +void cdnsp_died(struct cdnsp_device *pdev)
>> +{
>> +	dev_err(pdev->dev, "ERROR: CDNSP controller not responding\n");
>> +	pdev->cdnsp_state |= CDNSP_STATE_DYING;
>> +	cdnsp_halt(pdev);
>> +}
>> +
>> +/*
>> + * Set the run bit and wait for the device to be running.
>> + */
>> +static int cdnsp_start(struct cdnsp_device *pdev)
>> +{
>> +	u32 temp;
>> +	int ret;
>> +
>> +	temp = readl(&pdev->op_regs->command);
>> +	temp |= (CMD_R_S | CMD_DEVEN);
>> +	writel(temp, &pdev->op_regs->command);
>> +
>> +	/*
>> +	 * Wait for the STS_HALT Status bit to be 0 to indicate the device is
>> +	 * running.
>> +	 */
>> +	ret = readl_poll_timeout_atomic(&pdev->op_regs->status, temp,
>> +					!(temp & STS_HALT), 1,
>> +					CDNSP_MAX_HALT_USEC);
>> +
>> +	pdev->cdnsp_state = 0;
>> +
>> +	if (ret) {
>> +		pdev->cdnsp_state = CDNSP_STATE_DYING;
>> +		dev_err(pdev->dev, "ERROR: Controller run failed\n");
>> +	}
>> +
>> +	return ret;
>> +}
>> +
>> +/*
>> + * Reset a halted controller.
>> + *
>> + * This resets pipelines, timers, counters, state machines, etc.
>> + * Transactions will be terminated immediately, and operational registers
>> + * will be set to their defaults.
>> + */
>> +int cdnsp_reset(struct cdnsp_device *pdev)
>> +{
>> +	u32 command;
>> +	u32 temp;
>> +	int ret;
>> +
>> +	temp = readl(&pdev->op_regs->status);
>> +
>> +	if (temp == ~(u32)0) {
>> +		dev_err(pdev->dev, "Device not accessible, reset failed.\n");
>> +		return -ENODEV;
>> +	}
>> +
>> +	if ((temp & STS_HALT) == 0) {
>> +		dev_err(pdev->dev, "Controller not halted, aborting reset.\n");
>> +		return -EINVAL;
>> +	}
>> +
>> +	command = readl(&pdev->op_regs->command);
>> +	command |= CMD_RESET;
>> +	writel(command, &pdev->op_regs->command);
>> +
>> +	ret = readl_poll_timeout_atomic(&pdev->op_regs->command, temp,
>> +					!(temp & CMD_RESET), 1,
>> +					10 * 1000);
>> +	if (ret) {
>> +		dev_err(pdev->dev, "ERROR: Controller reset failed\n");
>> +		return ret;
>> +	}
>> +
>> +	/*
>> +	 * CDNSP cannot write any doorbells or operational registers other
>> +	 * than status until the "Controller Not Ready" flag is cleared.
>> +	 */
>> +	ret = readl_poll_timeout_atomic(&pdev->op_regs->status, temp,
>> +					!(temp & STS_CNR), 1,
>> +					10 * 1000);
>> +
>> +	if (ret) {
>> +		dev_err(pdev->dev, "ERROR: Controller not ready to work\n");
>> +		return ret;
>> +	}
>> +
>> +	dev_info(pdev->dev, "Controller ready to work");
>> +
>> +	return ret;
>> +}
>> +
>> +/*
>> + * cdnsp_get_endpoint_index - Find the index for an endpoint given its
>> + * descriptor.Use the return value to right shift 1 for the bitmask.
>> + *
>> + * Index = (epnum * 2) + direction - 1,
>> + * where direction = 0 for OUT, 1 for IN.
>> + * For control endpoints, the IN index is used (OUT index is unused), so
>> + * index = (epnum * 2) + direction - 1 = (epnum * 2) + 1 - 1 = (epnum * 2)
>> + */
>> +static unsigned int
>> +	cdnsp_get_endpoint_index(const struct usb_endpoint_descriptor *desc)
>> +{
>> +	unsigned int index = (unsigned int)usb_endpoint_num(desc);
>> +
>> +	if (usb_endpoint_xfer_control(desc))
>> +		return index * 2;
>> +
>> +	return (index * 2) + (usb_endpoint_dir_in(desc) ? 1 : 0) - 1;
>> +}
>> +
>> +/*
>> + * Find the flag for this endpoint (for use in the control context). Use the
>> + * endpoint index to create a bitmask. The slot context is bit 0, endpoint 0 is
>> + * bit 1, etc.
>> + */
>> +static unsigned int
>> +	cdnsp_get_endpoint_flag(const struct usb_endpoint_descriptor *desc)
>> +{
>> +	return 1 << (cdnsp_get_endpoint_index(desc) + 1);
>> +}
>> +
>> +int cdnsp_ep_enqueue(struct cdnsp_ep *pep, struct cdnsp_request *preq)
>> +{
>> +	struct cdnsp_device *pdev = pep->pdev;
>> +	struct usb_request *request;
>> +	int ret = 0;
>
>don't initialize
>
>> +
>> +	if (preq->epnum == 0 && !list_empty(&pep->pending_list))
>> +		return -EBUSY;
>> +
>> +	request = &preq->request;
>> +	request->actual = 0;
>> +	request->status = -EINPROGRESS;
>> +	preq->direction = pep->direction;
>> +	preq->epnum = pep->number;
>> +	preq->td.drbl = 0;
>> +
>> +	ret = usb_gadget_map_request_by_dev(pdev->dev, request, pep->direction);
>> +	if (ret)
>> +		goto err;
>
>Return directly. "return ret;"
>
>> +
>> +	list_add_tail(&preq->list, &pep->pending_list);
>> +
>> +	switch (usb_endpoint_type(pep->endpoint.desc)) {
>> +	case USB_ENDPOINT_XFER_CONTROL:
>> +		ret = cdnsp_queue_ctrl_tx(pdev, preq);
>> +		break;
>> +	case USB_ENDPOINT_XFER_BULK:
>> +	case USB_ENDPOINT_XFER_INT:
>> +		ret = cdnsp_queue_bulk_tx(pdev, preq);
>> +		break;
>> +	case USB_ENDPOINT_XFER_ISOC:
>> +		ret = cdnsp_queue_isoc_tx_prepare(pdev, preq);
>> +	}
>> +
>> +	if (!ret)
>> +		return ret;
>
>Flip this around.  Always to do error handling, not success handling.
>
>	if (ret)
>		goto unmap;
>
>	return 0;
>
>unmap:
>	usb_gadget_unmap_request_by_dev(pdev->dev, &preq->request,
>					pep->direction);
>	list_del(&preq->list);
>	return ret;
>
>> +
>> +	usb_gadget_unmap_request_by_dev(pdev->dev, &preq->request,
>> +					pep->direction);
>> +	list_del(&preq->list);
>> +
>> +err:
>> +
>> +	return ret;
>> +}
>> +
>> +/*
>> + * Remove the request's TD from the endpoint ring. This may cause the
>> + * controller to stop USB transfers, potentially stopping in the middle of a
>> + * TRB buffer. The controller should pick up where it left off in the TD,
>> + * unless a Set Transfer Ring Dequeue Pointer is issued.
>> + *
>> + * The TRBs that make up the buffers for the canceled request will be "removed"
>> + * from the ring. Since the ring is a contiguous structure, they can't be
>> + * physically removed. Instead, there are two options:
>> + *
>> + *  1) If the controller is in the middle of processing the request to be
>> + *     canceled, we simply move the ring's dequeue pointer past those TRBs
>> + *     using the Set Transfer Ring Dequeue Pointer command. This will be
>> + *     the common case, when drivers timeout on the last submitted request
>> + *     and attempt to cancel.
>> + *
>> + *  2) If the controller is in the middle of a different TD, we turn the TRBs
>> + *     into a series of 1-TRB transfer no-op TDs. No-ops shouldn't be chained.
>> + *     The controller will need to invalidate the any TRBs it has cached after
>> + *     the stop endpoint command.
>> + *
>> + *  3) The TD may have completed by the time the Stop Endpoint Command
>> + *     completes, so software needs to handle that case too.
>> + *
>> + */
>> +int cdnsp_ep_dequeue(struct cdnsp_ep *pep, struct cdnsp_request *preq)
>> +{
>> +	struct cdnsp_device *pdev;
>
>	struct cdnsp_device *pdev = pep->pdev;
>
>> +	int ret = 0;
>
>Don't initialize
>
>> +
>> +	pdev = pep->pdev;
>> +
>> +	if (GET_EP_CTX_STATE(pep->out_ctx) == EP_STATE_RUNNING) {
>> +		ret = cdnsp_cmd_stop_ep(pdev, pep);
>> +		if (ret)
>> +			return ret;
>> +	}
>> +
>> +	ret = cdnsp_remove_request(pdev, preq, pep);
>> +
>> +	return ret;
>
>	return cdnsp_remove_request(pdev, preq, pep);
>
>> +}
>> +
>> +static void cdnsp_zero_in_ctx(struct cdnsp_device *pdev)
>> +{
>> +	struct cdnsp_input_control_ctx *ctrl_ctx;
>> +	struct cdnsp_slot_ctx *slot_ctx;
>> +	struct cdnsp_ep_ctx *ep_ctx;
>> +	int i;
>> +
>> +	ctrl_ctx = cdnsp_get_input_control_ctx(&pdev->in_ctx);
>> +
>> +	/*
>> +	 * When a device's add flag and drop flag are zero, any subsequent
>> +	 * configure endpoint command will leave that endpoint's state
>> +	 * untouched. Make sure we don't leave any old state in the input
>> +	 * endpoint contexts.
>> +	 */
>> +	ctrl_ctx->drop_flags = 0;
>> +	ctrl_ctx->add_flags = 0;
>> +	slot_ctx = cdnsp_get_slot_ctx(&pdev->in_ctx);
>> +	slot_ctx->dev_info &= cpu_to_le32(~LAST_CTX_MASK);
>> +
>> +	/* Endpoint 0 is always valid */
>> +	slot_ctx->dev_info |= cpu_to_le32(LAST_CTX(1));
>> +	for (i = 1; i < 31; ++i) {
>> +		ep_ctx = cdnsp_get_ep_ctx(&pdev->in_ctx, i);
>> +		ep_ctx->ep_info = 0;
>> +		ep_ctx->ep_info2 = 0;
>> +		ep_ctx->deq = 0;
>> +		ep_ctx->tx_info = 0;
>> +	}
>> +}
>> +
>> +/* Issue a configure endpoint command and wait for it to finish. */
>> +static int cdnsp_configure_endpoint(struct cdnsp_device *pdev)
>> +{
>> +	int ret;
>> +
>> +	cdnsp_queue_configure_endpoint(pdev, pdev->cmd.in_ctx->dma);
>> +	cdnsp_ring_cmd_db(pdev);
>> +	ret = cdnsp_wait_for_cmd_compl(pdev);
>> +
>
>Delete the blank line.  The call and the error handling are part of the
>same paragraph.
>
>> +	if (ret) {
>> +		ret = -EINVAL;
>> +		dev_err(pdev->dev,
>> +			"ERR: unexpected command completion code 0x%x.\n", ret);
>                                                                           ^^^
>This is always -EINVAL because we just set it on the line before.
>Preserve the error code.
>
>> +	}
>> +
>> +	return ret;
>> +}
>> +
>> +static void cdnsp_invalidate_ep_events(struct cdnsp_device *pdev,
>> +				       struct cdnsp_ep *pep)
>> +{
>> +	struct cdnsp_segment *segment;
>> +	union cdnsp_trb *event;
>> +	u32 cycle_state;
>> +	__le32  data;
>> +
>> +	event = pdev->event_ring->dequeue;
>> +	segment = pdev->event_ring->deq_seg;
>> +	cycle_state = pdev->event_ring->cycle_state;
>> +
>> +	while (1) {
>> +		data = le32_to_cpu(event->trans_event.flags);
>> +
>> +		/* Check the owner of the TRB. */
>> +		if ((data & TRB_CYCLE) != cycle_state)
>> +			break;
>> +
>> +		if (TRB_FIELD_TO_TYPE(data) == TRB_TRANSFER &&
>> +		    TRB_TO_EP_ID(data) == (pep->idx + 1)) {
>> +			data |= TRB_EVENT_INVALIDATE;
>> +			event->trans_event.flags = cpu_to_le32(data);
>> +		}
>> +
>> +		if (cdnsp_last_trb_on_seg(segment, event)) {
>> +			cycle_state ^= 1;
>> +			segment = pdev->event_ring->deq_seg->next;
>> +			event = segment->trbs;
>> +		} else {
>> +			event++;
>> +		}
>> +	}
>> +}
>> +
>> +int cdnsp_wait_for_cmd_compl(struct cdnsp_device *pdev)
>> +{
>> +	struct cdnsp_segment *event_deq_seg;
>> +	dma_addr_t cmd_deq_dma;
>> +	union cdnsp_trb *cmd_trb;
>> +	union cdnsp_trb *event;
>> +	u32 cycle_state;
>> +	__le32  flags;
>> +	int ret, val;
>> +	u64 cmd_dma;
>> +
>> +	cmd_trb = pdev->cmd.command_trb;
>> +	pdev->cmd.status = 0;
>> +
>> +	ret = readl_poll_timeout_atomic(&pdev->op_regs->cmd_ring, val,
>> +					!CMD_RING_BUSY(val), 1,
>> +					CDNSP_CMD_TIMEOUT);
>> +	if (ret) {
>> +		dev_err(pdev->dev, "ERR: Timeout while waiting for command\n");
>> +		pdev->cdnsp_state = CDNSP_STATE_DYING;
>> +		return -ETIMEDOUT;
>> +	}
>> +
>> +	event = pdev->event_ring->dequeue;
>> +	event_deq_seg = pdev->event_ring->deq_seg;
>> +	cycle_state = pdev->event_ring->cycle_state;
>> +
>> +	cmd_deq_dma = cdnsp_trb_virt_to_dma(pdev->cmd_ring->deq_seg, cmd_trb);
>> +
>
>Delete the blank line.
>
>> +	if (!cmd_deq_dma)
>> +		return -EINVAL;
>> +
>> +	while (1) {
>> +		flags = le32_to_cpu(event->event_cmd.flags);
>> +
>> +		/* Check the owner of the TRB. */
>> +		if ((flags & TRB_CYCLE) != cycle_state)
>> +			return -EINVAL;
>> +
>> +		cmd_dma = le64_to_cpu(event->event_cmd.cmd_trb);
>> +
>> +		/*
>> +		 * Check whether the completion event is for last queued
>> +		 * command.
>> +		 */
>> +		if (TRB_FIELD_TO_TYPE(flags) != TRB_COMPLETION ||
>> +		    cmd_dma != (u64)cmd_deq_dma) {
>> +			if (!cdnsp_last_trb_on_seg(event_deq_seg, event)) {
>> +				event++;
>> +				continue;
>> +			}
>> +
>> +			if (cdnsp_last_trb_on_ring(pdev->event_ring,
>> +						   event_deq_seg, event))
>> +				cycle_state ^= 1;
>> +
>> +			event_deq_seg = event_deq_seg->next;
>> +			event = event_deq_seg->trbs;
>> +			continue;
>> +		}
>> +
>> +		pdev->cmd.status = GET_COMP_CODE(le32_to_cpu(event->event_cmd.status));
>> +		if (pdev->cmd.status == COMP_SUCCESS)
>> +			return 0;
>> +
>> +		return -pdev->cmd.status;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +int cdnsp_halt_endpoint(struct cdnsp_device *pdev,
>> +			struct cdnsp_ep *pep,
>> +			int value)
>> +{
>> +	int ret = 0;
>
>Don't initialize
>
>> +
>> +	if (value) {
>> +		ret = cdnsp_cmd_stop_ep(pdev, pep);
>> +		if (ret < 0)
>
>if (ret)
>
>> +			return ret;
>> +
>> +		if (GET_EP_CTX_STATE(pep->out_ctx) == EP_STATE_STOPPED) {
>> +			cdnsp_queue_halt_endpoint(pdev, pep->idx);
>> +			cdnsp_ring_cmd_db(pdev);
>> +			ret = cdnsp_wait_for_cmd_compl(pdev);
>> +		}
>> +
>> +		pep->ep_state |= EP_HALTED;
>> +	} else {
>> +		/*
>> +		 * In device mode driver can call reset endpoint command
>> +		 * from any endpoint state.
>> +		 */
>> +		cdnsp_queue_reset_ep(pdev, pep->idx);
>> +		cdnsp_ring_cmd_db(pdev);
>> +		ret = cdnsp_wait_for_cmd_compl(pdev);
>> +		if (ret)
>> +			return ret;
>> +
>> +		pep->ep_state &= ~EP_HALTED;
>> +
>> +		if (pep->idx != 0 && !(pep->ep_state & EP_WEDGE))
>> +			cdnsp_ring_doorbell_for_active_rings(pdev, pep);
>> +
>> +		pep->ep_state &= ~EP_WEDGE;
>> +	}
>> +
>> +	return ret;
>
>return 0;
>
>> +}
>> +
>> +static int cdnsp_update_eps_configuration(struct cdnsp_device *pdev,
>> +					  struct cdnsp_ep *pep)
>> +{
>> +	struct cdnsp_input_control_ctx *ctrl_ctx;
>> +	u32 new_add_flags, new_drop_flags;
>> +	struct cdnsp_slot_ctx *slot_ctx;
>> +	int ret = 0;
>> +	u32 ep_sts;
>> +	int i;
>> +
>> +	ctrl_ctx = cdnsp_get_input_control_ctx(&pdev->in_ctx);
>> +
>> +	/* Don't issue the command if there's no endpoints to update. */
>> +	if (ctrl_ctx->add_flags == 0 && ctrl_ctx->drop_flags == 0)
>> +		return 0;
>> +
>> +	ctrl_ctx->add_flags |= cpu_to_le32(SLOT_FLAG);
>> +	ctrl_ctx->add_flags &= cpu_to_le32(~EP0_FLAG);
>> +	ctrl_ctx->drop_flags &= cpu_to_le32(~(SLOT_FLAG | EP0_FLAG));
>> +
>> +	/* Fix up Context Entries field. Minimum value is EP0 == BIT(1). */
>> +	slot_ctx = cdnsp_get_slot_ctx(&pdev->in_ctx);
>> +	for (i = 31; i >= 1; i--) {
>> +		__le32 le32 = cpu_to_le32(BIT(i));
>> +
>> +		if ((pdev->eps[i - 1].ring && !(ctrl_ctx->drop_flags & le32)) ||
>> +		    (ctrl_ctx->add_flags & le32) || i == 1) {
>> +			slot_ctx->dev_info &= cpu_to_le32(~LAST_CTX_MASK);
>> +			slot_ctx->dev_info |= cpu_to_le32(LAST_CTX(i));
>> +			break;
>> +		}
>> +	}
>> +
>> +	ep_sts = GET_EP_CTX_STATE(pep->out_ctx);
>> +	new_add_flags = le32_to_cpu(ctrl_ctx->add_flags);
>> +	new_drop_flags = le32_to_cpu(ctrl_ctx->drop_flags);
>> +
>> +	if ((ctrl_ctx->add_flags != cpu_to_le32(SLOT_FLAG) &&
>> +	     ep_sts == EP_STATE_DISABLED) ||
>> +	    (ep_sts != EP_STATE_DISABLED && ctrl_ctx->drop_flags))
>> +		ret = cdnsp_configure_endpoint(pdev);
>> +
>> +	cdnsp_zero_in_ctx(pdev);
>> +
>> +	return ret;
>> +}
>> +
>> +/*
>> + * This submits a Reset Device Command, which will set the device state to 0,
>> + * set the device address to 0, and disable all the endpoints except the default
>> + * control endpoint. The USB core should come back and call
>> + * cdnsp_setup_device(), and then re-set up the configuration.
>> + */
>> +int cdnsp_reset_device(struct cdnsp_device *pdev)
>> +{
>> +	struct cdnsp_slot_ctx *slot_ctx;
>> +	int slot_state;
>> +	int ret = 0;
>
>Don't initialize
>
>> +	int i;
>> +
>> +	slot_ctx = cdnsp_get_slot_ctx(&pdev->in_ctx);
>> +	slot_ctx->dev_info = 0;
>> +	pdev->device_address = 0;
>> +
>> +	/* If device is not setup, there is no point in resetting it. */
>> +	slot_ctx = cdnsp_get_slot_ctx(&pdev->out_ctx);
>> +	slot_state = GET_SLOT_STATE(le32_to_cpu(slot_ctx->dev_state));
>> +
>> +	if (slot_state <= SLOT_STATE_DEFAULT &&
>> +	    pdev->eps[0].ep_state & EP_HALTED) {
>> +		cdnsp_halt_endpoint(pdev, &pdev->eps[0], 0);
>> +	}
>> +
>> +	/*
>> +	 * During Reset Device command controller shall transition the
>> +	 * endpoint ep0 to the Running State.
>> +	 */
>> +	pdev->eps[0].ep_state &= ~(EP_STOPPED | EP_HALTED);
>> +	pdev->eps[0].ep_state |= EP_ENABLED;
>> +
>> +	if (slot_state <= SLOT_STATE_DEFAULT)
>> +		return 0;
>> +
>> +	cdnsp_queue_reset_device(pdev);
>> +	cdnsp_ring_cmd_db(pdev);
>> +	ret = cdnsp_wait_for_cmd_compl(pdev);
>> +
>> +	/*
>> +	 * After Reset Device command all not default endpoints
>> +	 * are in Disabled state.
>> +	 */
>> +	for (i = 1; i < 31; ++i)
>> +		pdev->eps[i].ep_state |= EP_STOPPED;
>> +
>> +	if (ret)
>> +		dev_err(pdev->dev, "Reset device failed with error code %d",
>> +			ret);
>> +
>> +	return ret;
>> +}
>> +
>> +/*
>> + * Sets the MaxPStreams field and the Linear Stream Array field.
>> + * Sets the dequeue pointer to the stream context array.
>> + */
>> +static void cdnsp_setup_streams_ep_input_ctx(struct cdnsp_device *pdev,
>> +					     struct cdnsp_ep_ctx *ep_ctx,
>> +					     struct cdnsp_stream_info *stream_info)
>> +{
>> +	u32 max_primary_streams;
>> +
>> +	/* MaxPStreams is the number of stream context array entries, not the
>> +	 * number we're actually using. Must be in 2^(MaxPstreams + 1) format.
>> +	 * fls(0) = 0, fls(0x1) = 1, fls(0x10) = 2, fls(0x100) = 3, etc.
>> +	 */
>> +	max_primary_streams = fls(stream_info->num_stream_ctxs) - 2;
>> +	ep_ctx->ep_info &= cpu_to_le32(~EP_MAXPSTREAMS_MASK);
>> +	ep_ctx->ep_info |= cpu_to_le32(EP_MAXPSTREAMS(max_primary_streams)
>> +				       | EP_HAS_LSA);
>> +	ep_ctx->deq  = cpu_to_le64(stream_info->ctx_array_dma);
>> +}
>> +
>> +/*
>> + * The drivers use this function to prepare a bulk endpoints to use streams.
>> + *
>> + * Don't allow the call to succeed if endpoint only supports one stream
>> + * (which means it doesn't support streams at all).
>> + */
>> +int cdnsp_alloc_streams(struct cdnsp_device *pdev, struct cdnsp_ep *pep)
>> +{
>> +	unsigned int num_streams = usb_ss_max_streams(pep->endpoint.comp_desc);
>> +	unsigned int num_stream_ctxs;
>> +	int ret = 0;
>
>Don't initialize
>
>> +
>> +	if (num_streams ==  0)
>> +		return 0;
>> +
>> +	if (num_streams > STREAM_NUM_STREAMS)
>> +		return -EINVAL;
>> +
>> +	/*
>> +	 * Add two to the number of streams requested to account for
>> +	 * stream 0 that is reserved for controller usage and one additional
>> +	 * for TASK SET FULL response.
>> +	 */
>> +	num_streams += 2;
>> +
>> +	/* The stream context array size must be a power of two */
>> +	num_stream_ctxs = roundup_pow_of_two(num_streams);
>> +
>> +	ret = cdnsp_alloc_stream_info(pdev, pep, num_stream_ctxs, num_streams);
>> +	if (ret)
>> +		return ret;
>> +
>> +	cdnsp_setup_streams_ep_input_ctx(pdev, pep->in_ctx, &pep->stream_info);
>> +
>> +	pep->ep_state |= EP_HAS_STREAMS;
>> +	pep->stream_info.td_count = 0;
>> +	pep->stream_info.first_prime_det = 0;
>> +
>> +	/* Subtract 1 for stream 0, which drivers can't use. */
>> +	return num_streams - 1;
>> +}
>> +
>> +int cdnsp_disable_slot(struct cdnsp_device *pdev)
>> +{
>> +	int ret = 0;
>
>don't initialize
>
>> +
>> +	cdnsp_queue_slot_control(pdev, TRB_DISABLE_SLOT);
>> +	cdnsp_ring_cmd_db(pdev);
>> +	ret = cdnsp_wait_for_cmd_compl(pdev);
>> +
>> +	pdev->slot_id = 0;
>> +	pdev->active_port = NULL;
>> +
>> +	memset(pdev->in_ctx.bytes, 0, 2112);
>> +	memset(pdev->out_ctx.bytes, 0, 2112);
>
>Replace these magic numbers with defines.
>
>> +
>> +	return ret;
>> +}
>> +
>> +int cdnsp_enable_slot(struct cdnsp_device *pdev)
>> +{
>> +	struct cdnsp_slot_ctx *slot_ctx;
>> +	int slot_state;
>> +	int ret;
>> +
>> +	/* If device is not setup, there is no point in resetting it */
>> +	slot_ctx = cdnsp_get_slot_ctx(&pdev->out_ctx);
>> +	slot_state = GET_SLOT_STATE(le32_to_cpu(slot_ctx->dev_state));
>> +
>> +	if (slot_state != SLOT_STATE_DISABLED)
>> +		return 0;
>> +
>> +	cdnsp_queue_slot_control(pdev, TRB_ENABLE_SLOT);
>> +	cdnsp_ring_cmd_db(pdev);
>> +	ret = cdnsp_wait_for_cmd_compl(pdev);
>> +
>
>Delete the blank line.
>
>	if (ret)
>		return ret;
>
>	pdev->slot_id = 1;
>	return 0;
>
>Always do error handling, never do success handling.  Success should be
>assumed.  Success should be indented one tap, and errors two tabs.
>
>> +	if (!ret)
>> +		pdev->slot_id = 1;
>> +
>> +	return ret;
>> +}
>> +
>> +/*
>> + * Issue an Address Device command with BSR=0 if setup is SETUP_CONTEXT_ONLY
>> + * or with BSR = 1 if set_address is SETUP_CONTEXT_ADDRESS.
>> + */
>> +int cdnsp_setup_device(struct cdnsp_device *pdev, enum cdnsp_setup_dev setup)
>> +{
>> +	struct cdnsp_input_control_ctx *ctrl_ctx;
>> +	struct cdnsp_slot_ctx *slot_ctx;
>> +	int dev_state = 0;
>> +	int ret = 0;
>> +
>> +	if (!pdev->slot_id)
>> +		return -EINVAL;
>> +
>> +	if (!pdev->active_port->port_num)
>> +		return -EINVAL;
>> +
>> +	slot_ctx = cdnsp_get_slot_ctx(&pdev->out_ctx);
>> +	dev_state = GET_SLOT_STATE(le32_to_cpu(slot_ctx->dev_state));
>> +
>> +	if (setup == SETUP_CONTEXT_ONLY && dev_state == SLOT_STATE_DEFAULT)
>> +		goto out;
>
>return 0;
>
>> +
>> +	slot_ctx = cdnsp_get_slot_ctx(&pdev->in_ctx);
>> +	ctrl_ctx = cdnsp_get_input_control_ctx(&pdev->in_ctx);
>> +
>> +	if (!slot_ctx->dev_info || dev_state == SLOT_STATE_DEFAULT) {
>> +		ret = cdnsp_setup_addressable_priv_dev(pdev);
>> +		if (ret)
>> +			goto out;
>
>return ret;
>
>> +	}
>> +
>> +	cdnsp_copy_ep0_dequeue_into_input_ctx(pdev);
>> +
>> +	ctrl_ctx->add_flags = cpu_to_le32(SLOT_FLAG | EP0_FLAG);
>> +	ctrl_ctx->drop_flags = 0;
>> +
>> +	cdnsp_queue_address_device(pdev, pdev->in_ctx.dma, setup);
>> +	cdnsp_ring_cmd_db(pdev);
>> +	ret = cdnsp_wait_for_cmd_compl(pdev);
>> +
>> +	/* Zero the input context control for later use. */
>> +	ctrl_ctx->add_flags = 0;
>> +	ctrl_ctx->drop_flags = 0;
>> +out:
>> +	return ret;
>> +}
>> +
>> +void cdnsp_set_usb2_hardware_lpm(struct cdnsp_device *pdev,
>> +				 struct usb_request *req,
>> +				 int enable)
>> +{
>> +	if (pdev->active_port != &pdev->usb2_port || !pdev->gadget.lpm_capable)
>> +		return;
>> +
>> +	if (enable)
>> +		writel(PORT_BESL(CDNSP_DEFAULT_BESL) | PORT_L1S_NYET | PORT_HLE,
>> +		       &pdev->active_port->regs->portpmsc);
>> +	else
>> +		writel(PORT_L1S_NYET, &pdev->active_port->regs->portpmsc);
>> +}
>> +
>> +static int cdnsp_get_frame(struct cdnsp_device *pdev)
>> +{
>> +	return readl(&pdev->run_regs->microframe_index) >> 3;
>> +}
>> +
>> +static int cdnsp_gadget_ep_enable(struct usb_ep *ep,
>> +				  const struct usb_endpoint_descriptor *desc)
>> +{
>> +	struct cdnsp_input_control_ctx *ctrl_ctx;
>> +	struct cdnsp_device *pdev;
>> +	unsigned long flags = 0;
>
>Don't initialize
>
>> +	struct cdnsp_ep *pep;
>> +	u32 added_ctxs;
>> +	int ret = 0;
>
>Don't initialize
>
>> +
>> +	if (!ep || !desc || desc->bDescriptorType != USB_DT_ENDPOINT ||
>> +	    !desc->wMaxPacketSize)
>> +		return -EINVAL;
>> +
>> +	pep = to_cdnsp_ep(ep);
>> +	pdev = pep->pdev;
>> +
>> +	if (dev_WARN_ONCE(pdev->dev, pep->ep_state & EP_ENABLED,
>> +			  "%s is already enabled\n", pep->name))
>> +		return 0;
>> +
>> +	spin_lock_irqsave(&pdev->lock, flags);
>> +
>> +	added_ctxs = cdnsp_get_endpoint_flag(desc);
>> +	if (added_ctxs == SLOT_FLAG || added_ctxs == EP0_FLAG) {
>> +		dev_err(pdev->dev, "ERROR: Bad endpoint number\n");
>> +		ret = -EINVAL;
>> +		goto finish;
>
>A better label name would be "goto unlock;"
>
>> +	}
>> +
>> +	pep->interval = desc->bInterval ? BIT(desc->bInterval - 1) : 0;
>> +
>> +	if (pdev->gadget.speed == USB_SPEED_FULL) {
>> +		if (usb_endpoint_type(desc) == USB_ENDPOINT_XFER_INT)
>> +			pep->interval = desc->bInterval << 3;
>> +		if (usb_endpoint_type(desc) == USB_ENDPOINT_XFER_ISOC)
>> +			pep->interval = BIT(desc->bInterval - 1) << 3;
>> +	}
>> +
>> +	if (usb_endpoint_type(desc) == USB_ENDPOINT_XFER_ISOC) {
>> +		if (pep->interval > BIT(12)) {
>> +			dev_err(pdev->dev, "bInterval %d not supported\n",
>> +				desc->bInterval);
>> +			ret = -EINVAL;
>> +			goto finish;
>> +		}
>> +		cdnsp_set_chicken_bits_2(pdev, CHICKEN_XDMA_2_TP_CACHE_DIS);
>> +	}
>> +
>> +	ret = cdnsp_endpoint_init(pdev, pep, GFP_ATOMIC);
>> +	if (ret < 0)
>
>Use "if (ret) " everywhere.
>
>> +		goto finish;
>> +
>> +	ctrl_ctx = cdnsp_get_input_control_ctx(&pdev->in_ctx);
>> +	ctrl_ctx->add_flags = cpu_to_le32(added_ctxs);
>> +	ctrl_ctx->drop_flags = 0;
>> +
>> +	ret = cdnsp_update_eps_configuration(pdev, pep);
>> +	if (ret < 0) {
>
>if (ref)
>
>> +		cdnsp_free_endpoint_rings(pdev, pep);
>> +		goto finish;
>> +	}
>> +
>> +	pep->ep_state |= EP_ENABLED;
>> +	pep->ep_state &= ~EP_STOPPED;
>> +
>> +finish:
>> +	spin_unlock_irqrestore(&pdev->lock, flags);
>> +
>> +	return ret;
>> +}
>> +
>> +static int cdnsp_gadget_ep_disable(struct usb_ep *ep)
>> +{
>> +	struct cdnsp_input_control_ctx *ctrl_ctx;
>> +	struct cdnsp_request *preq;
>> +	struct cdnsp_device *pdev;
>> +	unsigned long flags = 0;
>
>Don't initialize
>
>> +	struct cdnsp_ep *pep;
>> +	u32 drop_flag;
>> +	int ret = 0;
>> +
>> +	if (!ep)
>> +		return -EINVAL;
>> +
>> +	pep = to_cdnsp_ep(ep);
>> +	pdev = pep->pdev;
>> +
>> +	spin_lock_irqsave(&pdev->lock, flags);
>> +
>> +	if (!(pep->ep_state & EP_ENABLED)) {
>> +		dev_err(pdev->dev, "%s is already disabled\n", pep->name);
>> +		ret = -EINVAL;
>> +		goto finish;
>> +	}
>> +
>> +	cdnsp_cmd_stop_ep(pdev, pep);
>> +	pep->ep_state |= EP_DIS_IN_RROGRESS;
>> +	cdnsp_cmd_flush_ep(pdev, pep);
>> +
>> +	/* Remove all queued USB requests. */
>> +	while (!list_empty(&pep->pending_list)) {
>> +		preq = next_request(&pep->pending_list);
>> +		cdnsp_ep_dequeue(pep, preq);
>> +	}
>> +
>> +	cdnsp_invalidate_ep_events(pdev, pep);
>> +
>> +	pep->ep_state &= ~EP_DIS_IN_RROGRESS;
>> +	drop_flag = cdnsp_get_endpoint_flag(pep->endpoint.desc);
>> +	ctrl_ctx = cdnsp_get_input_control_ctx(&pdev->in_ctx);
>> +	ctrl_ctx->drop_flags = cpu_to_le32(drop_flag);
>> +	ctrl_ctx->add_flags = 0;
>> +
>> +	cdnsp_endpoint_zero(pdev, pep);
>> +
>> +	ret = cdnsp_update_eps_configuration(pdev, pep);
>> +	cdnsp_free_endpoint_rings(pdev, pep);
>> +
>> +	pep->ep_state &= ~EP_ENABLED;
>> +	pep->ep_state |= EP_STOPPED;
>> +
>> +finish:
>> +	spin_unlock_irqrestore(&pdev->lock, flags);
>> +
>> +	return ret;
>> +}
>> +
>> +static struct usb_request *cdnsp_gadget_ep_alloc_request(struct usb_ep *ep,
>> +							 gfp_t gfp_flags)
>> +{
>> +	struct cdnsp_ep *pep = to_cdnsp_ep(ep);
>> +	struct cdnsp_request *preq;
>> +
>> +	preq = kzalloc(sizeof(*preq), gfp_flags);
>> +	if (!preq)
>> +		return NULL;
>> +
>> +	preq->epnum = pep->number;
>> +	preq->pep = pep;
>> +
>> +	return &preq->request;
>> +}
>> +
>> +static void cdnsp_gadget_ep_free_request(struct usb_ep *ep,
>> +					 struct usb_request *request)
>> +{
>> +	struct cdnsp_request *preq = to_cdnsp_request(request);
>> +
>> +	kfree(preq);
>> +}
>> +
>> +static int cdnsp_gadget_ep_queue(struct usb_ep *ep,
>> +				 struct usb_request *request,
>> +				 gfp_t gfp_flags)
>> +{
>> +	struct cdnsp_request *preq;
>> +	struct cdnsp_device *pdev;
>> +	struct cdnsp_ep *pep;
>> +	unsigned long flags = 0;
>> +	int ret = 0;
>
>Don't initialize these two
>
>
>> +
>> +	if (!request || !ep)
>> +		return -EINVAL;
>> +
>> +	pep = to_cdnsp_ep(ep);
>> +	pdev = pep->pdev;
>> +
>> +	if (!(pep->ep_state & EP_ENABLED)) {
>> +		dev_err(pdev->dev, "%s: can't queue to disabled endpoint\n",
>> +			pep->name);
>> +		return -EINVAL;
>> +	}
>> +
>> +	preq = to_cdnsp_request(request);
>> +	spin_lock_irqsave(&pdev->lock, flags);
>> +	ret = cdnsp_ep_enqueue(pep, preq);
>> +	spin_unlock_irqrestore(&pdev->lock, flags);
>> +
>> +	return ret;
>> +}
>> +
>> +static int cdnsp_gadget_ep_dequeue(struct usb_ep *ep,
>> +				   struct usb_request *request)
>> +{
>> +	struct cdnsp_ep *pep = to_cdnsp_ep(ep);
>> +	struct cdnsp_device *pdev = pep->pdev;
>> +	unsigned long flags;
>> +	int ret;
>> +
>> +	if (!pep->endpoint.desc) {
>> +		dev_err(pdev->dev,
>> +			"%s: can't dequeue to disabled endpoint\n",
>> +			pep->name);
>> +		return -ESHUTDOWN;
>> +	}
>> +
>> +	spin_lock_irqsave(&pdev->lock, flags);
>> +	ret = cdnsp_ep_dequeue(pep, to_cdnsp_request(request));
>> +	spin_unlock_irqrestore(&pdev->lock, flags);
>> +
>> +	return ret;
>> +}
>> +
>> +static int cdnsp_gadget_ep_set_halt(struct usb_ep *ep, int value)
>> +{
>> +	struct cdnsp_ep *pep = to_cdnsp_ep(ep);
>> +	struct cdnsp_device *pdev = pep->pdev;
>> +	struct cdnsp_request *preq;
>> +	unsigned long flags = 0;
>> +	int ret;
>> +
>> +	spin_lock_irqsave(&pdev->lock, flags);
>> +
>> +	preq = next_request(&pep->pending_list);
>> +	if (value) {
>> +		if (preq) {
>> +			ret = -EAGAIN;
>> +			goto done;
>> +		}
>> +	}
>> +
>> +	ret = cdnsp_halt_endpoint(pdev, pep, value);
>> +
>> +done:
>> +	spin_unlock_irqrestore(&pdev->lock, flags);
>> +	return ret;
>> +}
>> +
>> +static int cdnsp_gadget_ep_set_wedge(struct usb_ep *ep)
>> +{
>> +	struct cdnsp_ep *pep = to_cdnsp_ep(ep);
>> +	struct cdnsp_device *pdev = pep->pdev;
>> +	unsigned long flags = 0;
>> +	int ret;
>> +
>> +	spin_lock_irqsave(&pdev->lock, flags);
>> +	pep->ep_state |= EP_WEDGE;
>> +	ret = cdnsp_halt_endpoint(pdev, pep, 1);
>> +	spin_unlock_irqrestore(&pdev->lock, flags);
>> +
>> +	return ret;
>> +}
>> +
>> +static const struct usb_ep_ops cdnsp_gadget_ep0_ops = {
>> +	.enable		= cdnsp_gadget_ep_enable,
>> +	.disable	= cdnsp_gadget_ep_disable,
>> +	.alloc_request	= cdnsp_gadget_ep_alloc_request,
>> +	.free_request	= cdnsp_gadget_ep_free_request,
>> +	.queue		= cdnsp_gadget_ep_queue,
>> +	.dequeue	= cdnsp_gadget_ep_dequeue,
>> +	.set_halt	= cdnsp_gadget_ep_set_halt,
>> +	.set_wedge	= cdnsp_gadget_ep_set_wedge,
>> +};
>> +
>> +static const struct usb_ep_ops cdnsp_gadget_ep_ops = {
>> +	.enable		= cdnsp_gadget_ep_enable,
>> +	.disable	= cdnsp_gadget_ep_disable,
>> +	.alloc_request	= cdnsp_gadget_ep_alloc_request,
>> +	.free_request	= cdnsp_gadget_ep_free_request,
>> +	.queue		= cdnsp_gadget_ep_queue,
>> +	.dequeue	= cdnsp_gadget_ep_dequeue,
>> +	.set_halt	= cdnsp_gadget_ep_set_halt,
>> +	.set_wedge	= cdnsp_gadget_ep_set_wedge,
>> +};
>> +
>> +void cdnsp_gadget_giveback(struct cdnsp_ep *pep,
>> +			   struct cdnsp_request *preq,
>> +			   int status)
>> +{
>> +	struct cdnsp_device *pdev = pep->pdev;
>> +
>> +	list_del(&preq->list);
>> +
>> +	if (preq->request.status == -EINPROGRESS)
>> +		preq->request.status = status;
>> +
>> +	usb_gadget_unmap_request_by_dev(pdev->dev, &preq->request,
>> +					preq->direction);
>> +
>> +	if (preq != &pdev->ep0_preq) {
>> +		spin_unlock(&pdev->lock);
>> +		usb_gadget_giveback_request(&pep->endpoint, &preq->request);
>> +		spin_lock(&pdev->lock);
>> +	}
>> +}
>> +
>> +static struct usb_endpoint_descriptor cdnsp_gadget_ep0_desc = {
>> +	.bLength =		USB_DT_ENDPOINT_SIZE,
>> +	.bDescriptorType =	USB_DT_ENDPOINT,
>> +	.bmAttributes =		USB_ENDPOINT_XFER_CONTROL,
>> +};
>> +
>> +static int cdnsp_run(struct cdnsp_device *pdev,
>> +		     enum usb_device_speed speed)
>> +{
>> +	u32 fs_speed = 0;
>> +	u64 temp_64;
>> +	u32 temp;
>> +	int ret;
>> +
>> +	temp_64 = cdnsp_read_64(pdev, &pdev->ir_set->erst_dequeue);
>> +	temp_64 &= ~ERST_PTR_MASK;
>> +	temp = readl(&pdev->ir_set->irq_control);
>> +	temp &= ~IMOD_INTERVAL_MASK;
>> +	temp |= ((IMOD_DEFAULT_INTERVAL / 250) & IMOD_INTERVAL_MASK);
>> +	writel(temp, &pdev->ir_set->irq_control);
>> +
>> +	temp = readl(&pdev->port3x_regs->mode_addr);
>> +
>> +	switch (speed) {
>> +	case USB_SPEED_SUPER_PLUS:
>> +		temp |= CFG_3XPORT_SSP_SUPPORT;
>> +		break;
>> +	case USB_SPEED_SUPER:
>> +		temp &= ~CFG_3XPORT_SSP_SUPPORT;
>> +		break;
>> +	case USB_SPEED_HIGH:
>> +		break;
>> +	case USB_SPEED_FULL:
>> +		fs_speed = PORT_REG6_FORCE_FS;
>> +		break;
>> +	default:
>> +		dev_err(pdev->dev, "invalid maximum_speed parameter %d\n",
>> +			speed);
>> +		/* fall-through */
>> +	case USB_SPEED_UNKNOWN:
>> +		/* Default to superspeed. */
>> +		speed = USB_SPEED_SUPER;
>> +		break;
>> +	}
>> +
>> +	if (speed >= USB_SPEED_SUPER) {
>> +		writel(temp, &pdev->port3x_regs->mode_addr);
>> +		cdnsp_set_link_state(pdev, &pdev->usb3_port.regs->portsc,
>> +				     XDEV_RXDETECT);
>> +	} else {
>> +		cdnsp_disable_port(pdev, &pdev->usb3_port.regs->portsc);
>> +	}
>> +
>> +	cdnsp_set_link_state(pdev, &pdev->usb2_port.regs->portsc,
>> +			     XDEV_RXDETECT);
>> +
>> +	cdnsp_gadget_ep0_desc.wMaxPacketSize = cpu_to_le16(512);
>> +
>> +	writel(PORT_REG6_L1_L0_HW_EN | fs_speed, &pdev->port20_regs->port_reg6);
>> +
>> +	ret = cdnsp_start(pdev);
>> +	if (ret) {
>> +		ret = -ENODEV;
>> +		goto err;
>> +	}
>> +
>> +	temp = readl(&pdev->op_regs->command);
>> +	temp |= (CMD_INTE);
>> +	writel(temp, &pdev->op_regs->command);
>> +
>> +	temp = readl(&pdev->ir_set->irq_pending);
>> +	writel(IMAN_IE_SET(temp), &pdev->ir_set->irq_pending);
>> +
>> +	return 0;
>> +err:
>> +	cdnsp_halt(pdev);
>> +	return ret;
>> +}
>> +
>> +static int cdnsp_gadget_udc_start(struct usb_gadget *g,
>> +				  struct usb_gadget_driver *driver)
>> +{
>> +	enum usb_device_speed max_speed = driver->max_speed;
>> +	struct cdnsp_device *pdev = gadget_to_cdnsp(g);
>> +	unsigned long flags;
>> +	int ret;
>> +
>> +	spin_lock_irqsave(&pdev->lock, flags);
>> +	pdev->gadget_driver = driver;
>> +
>> +	/* limit speed if necessary */
>> +	max_speed = min(driver->max_speed, g->max_speed);
>> +	ret = cdnsp_run(pdev, max_speed);
>> +
>> +	spin_unlock_irqrestore(&pdev->lock, flags);
>> +
>> +	return ret;
>> +}
>> +
>> +/*
>> + * Update Event Ring Dequeue Pointer:
>> + * - When all events have finished
>> + * - To avoid "Event Ring Full Error" condition
>> + */
>> +void cdnsp_update_erst_dequeue(struct cdnsp_device *pdev,
>> +			       union cdnsp_trb *event_ring_deq,
>> +			       u8 clear_ehb)
>> +{
>> +	u64 temp_64;
>> +	dma_addr_t deq;
>> +
>> +	temp_64 = cdnsp_read_64(pdev, &pdev->ir_set->erst_dequeue);
>> +
>> +	/* If necessary, update the HW's version of the event ring deq ptr. */
>> +	if (event_ring_deq != pdev->event_ring->dequeue) {
>> +		deq = cdnsp_trb_virt_to_dma(pdev->event_ring->deq_seg,
>> +					    pdev->event_ring->dequeue);
>> +		temp_64 &= ERST_PTR_MASK;
>> +		temp_64 |= ((u64)deq & (u64)~ERST_PTR_MASK);
>> +	}
>> +
>> +	/* Clear the event handler busy flag (RW1C). */
>> +	if (clear_ehb)
>> +		temp_64 |= ERST_EHB;
>> +	else
>> +		temp_64 &= ~ERST_EHB;
>> +
>> +	cdnsp_write_64(pdev, temp_64, &pdev->ir_set->erst_dequeue);
>> +}
>> +
>> +static void cdnsp_clear_cmd_ring(struct cdnsp_device *pdev)
>> +{
>> +	struct cdnsp_segment *seg;
>> +	u64 val_64;
>> +	int i;
>> +
>> +	cdnsp_initialize_ring_info(pdev->cmd_ring);
>> +
>> +	seg = pdev->cmd_ring->first_seg;
>> +	for (i = 0; i < pdev->cmd_ring->num_segs; i++) {
>> +		memset(seg->trbs, 0,
>> +		       sizeof(union cdnsp_trb) * (TRBS_PER_SEGMENT - 1));
>> +		seg = seg->next;
>> +	}
>> +
>> +	/* Set the address in the Command Ring Control register. */
>> +	val_64 = cdnsp_read_64(pdev, &pdev->op_regs->cmd_ring);
>> +	val_64 = (val_64 & (u64)CMD_RING_RSVD_BITS) |
>> +		 (pdev->cmd_ring->first_seg->dma & (u64)~CMD_RING_RSVD_BITS) |
>> +		 pdev->cmd_ring->cycle_state;
>> +	cdnsp_write_64(pdev, val_64, &pdev->op_regs->cmd_ring);
>> +}
>> +
>> +static void cdnsp_consume_all_events(struct cdnsp_device *pdev)
>> +{
>> +	struct cdnsp_segment *event_deq_seg;
>> +	union cdnsp_trb *event_ring_deq;
>> +	union cdnsp_trb *event;
>> +	u32 cycle_bit;
>> +
>> +	event_ring_deq = pdev->event_ring->dequeue;
>> +	event_deq_seg = pdev->event_ring->deq_seg;
>> +
>> +	/* Update ring dequeue pointer. */
>> +	while (1) {
>> +		event = pdev->event_ring->dequeue;
>> +		cycle_bit = (le32_to_cpu(event->event_cmd.flags) & TRB_CYCLE);
>> +
>> +		/* Does the controller or driver own the TRB? */
>> +		if (cycle_bit != pdev->event_ring->cycle_state)
>> +			break;
>> +
>> +		cdnsp_inc_deq(pdev, pdev->event_ring);
>> +
>> +		if (!cdnsp_last_trb_on_seg(event_deq_seg, event)) {
>> +			event++;
>
>This incremement is pointless because we set
>"event = pdev->event_ring->dequeue;"  Forever loop?

Yes, it's serious bug.  event should be initialized before while. 
I don't know why it's never caused the problem during testing :) 

>
>
>> +			continue;
>> +		}
>> +
>> +		if (cdnsp_last_trb_on_ring(pdev->event_ring, event_deq_seg,
>> +					   event))
>> +			cycle_bit ^= 1;
>> +
>> +		event_deq_seg = event_deq_seg->next;
>> +		event = event_deq_seg->trbs;
>
>Pointless assignment.
>
>> +		continue;
>
>Delete this continue.
>
>> +	}
>> +
>> +	cdnsp_update_erst_dequeue(pdev,  event_ring_deq, 1);
>> +}
>> +
>> +static void cdnsp_stop(struct cdnsp_device *pdev)
>> +{
>> +	u32 temp;
>> +
>> +	cdnsp_cmd_flush_ep(pdev, &pdev->eps[0]);
>> +
>> +	/* Remove internally queued request for ep0. */
>> +	if (!list_empty(&pdev->eps[0].pending_list)) {
>> +		struct cdnsp_request	*req;
>                                     ^^^
>Extra space characters.
>
>
>> +
>> +		req = next_request(&pdev->eps[0].pending_list);
>> +		if (req == &pdev->ep0_preq)
>> +			cdnsp_ep_dequeue(&pdev->eps[0], req);
>> +	}
>> +
>> +	cdnsp_disable_port(pdev, &pdev->usb2_port.regs->portsc);
>> +	cdnsp_disable_port(pdev, &pdev->usb3_port.regs->portsc);
>> +	cdnsp_disable_slot(pdev);
>> +	cdnsp_halt(pdev);
>> +
>> +	temp = readl(&pdev->op_regs->status);
>> +	writel((temp & ~0x1fff) | STS_EINT, &pdev->op_regs->status);
>> +	temp = readl(&pdev->ir_set->irq_pending);
>> +	writel(IMAN_IE_CLEAR(temp), &pdev->ir_set->irq_pending);
>> +
>> +	cdnsp_clear_port_change_bit(pdev, &pdev->usb2_port.regs->portsc);
>> +	cdnsp_clear_port_change_bit(pdev, &pdev->usb3_port.regs->portsc);
>> +
>> +	/*Clear interrupt line */
>> +	temp = readl(&pdev->ir_set->irq_pending);
>> +	temp |= IMAN_IP;
>> +	writel(temp, &pdev->ir_set->irq_pending);
>> +
>> +	cdnsp_consume_all_events(pdev);
>> +	cdnsp_clear_cmd_ring(pdev);
>> +}
>> +
>> +/*
>> + * Stop controller.
>> + * This function is called by the gadget core when the driver is removed.
>> + * Disable slot, disable IRQs, and quiesce the controller.
>> + */
>> +static int cdnsp_gadget_udc_stop(struct usb_gadget *g)
>> +{
>> +	struct cdnsp_device *pdev = gadget_to_cdnsp(g);
>> +	unsigned long flags = 0;
>
>Don't initialize
>
>> +
>> +	spin_lock_irqsave(&pdev->lock, flags);
>> +	cdnsp_stop(pdev);
>> +	pdev->gadget_driver = NULL;
>> +	spin_unlock_irqrestore(&pdev->lock, flags);
>> +
>> +	return 0;
>> +}
>> +
>> +static int cdnsp_gadget_get_frame(struct usb_gadget *g)
>> +{
>> +	struct cdnsp_device *pdev = gadget_to_cdnsp(g);
>> +
>> +	return cdnsp_get_frame(pdev);
>> +}
>> +
>> +static int cdnsp_gadget_wakeup(struct usb_gadget *g)
>> +{
>> +	struct cdnsp_device *pdev = gadget_to_cdnsp(g);
>> +	struct cdnsp_port_regs __iomem *port_regs;
>> +	unsigned long flags = 0;
>
>Don't initialize
>
>> +	u32 temp;
>> +
>> +	spin_lock_irqsave(&pdev->lock, flags);
>> +
>> +	port_regs = pdev->active_port->regs;
>> +	temp = readl(&port_regs->portpmsc);
>> +	if (!(temp & PORT_RWE))
>> +		return 0;
>
>We have IRQs disabled.  Need to unlock before returning.
>
>> +
>> +	temp = readl(&port_regs->portsc);
>> +	temp &= ~PORT_PLS_MASK;
>> +	writel(temp, &port_regs->portsc);
>> +	spin_unlock_irqrestore(&pdev->lock, flags);
>> +
>> +	return 0;
>> +}
>> +
>> +static int cdnsp_gadget_set_selfpowered(struct usb_gadget *g,
>> +					int is_selfpowered)
>> +{
>> +	struct cdnsp_device *pdev = gadget_to_cdnsp(g);
>> +	unsigned long flags;
>> +
>> +	spin_lock_irqsave(&pdev->lock, flags);
>> +	g->is_selfpowered = !!is_selfpowered;
>> +	spin_unlock_irqrestore(&pdev->lock, flags);
>> +
>> +	return 0;
>> +}
>> +
>> +static int cdnsp_gadget_pullup(struct usb_gadget *gadget, int is_on)
>> +{
>> +	struct cdnsp_device *pdev = gadget_to_cdnsp(gadget);
>> +	struct cdnsp *cdns = dev_get_drvdata(pdev->dev);
>> +
>> +	if (!is_on) {
>> +		cdnsp_reset_device(pdev);
>> +		cdnsp_clear_vbus(cdns);
>> +	} else {
>> +		cdnsp_set_vbus(cdns);
>> +	}
>> +	return 0;
>> +}
>> +
>> +const struct usb_gadget_ops cdnsp_gadget_ops = {
>> +	.get_frame		= cdnsp_gadget_get_frame,
>> +	.wakeup			= cdnsp_gadget_wakeup,
>> +	.set_selfpowered	= cdnsp_gadget_set_selfpowered,
>> +	.pullup			= cdnsp_gadget_pullup,
>> +	.udc_start		= cdnsp_gadget_udc_start,
>> +	.udc_stop		= cdnsp_gadget_udc_stop,
>> +};
>> +
>> +static void cdnsp_get_ep_buffering(struct cdnsp_device *pdev,
>> +				   struct cdnsp_ep *pep)
>> +{
>> +	void __iomem *reg = &pdev->cap_regs->hc_capbase;
>> +	int endpoints;
>> +
>> +	reg += cdnsp_find_next_ext_cap(reg, 0, XBUF_CAP_ID);
>> +
>> +	if (!pep->direction) {
>> +		pep->buffering = readl(reg + XBUF_RX_TAG_MASK_0_OFFSET);
>> +		pep->buffering_period = readl(reg + XBUF_RX_TAG_MASK_1_OFFSET);
>> +		pep->buffering = (pep->buffering + 1) / 2;
>> +		pep->buffering_period = (pep->buffering_period + 1) / 2;
>> +		return;
>> +	}
>> +
>> +	endpoints = HCS_ENDPOINTS(readl(&pdev->hcs_params1)) / 2;
>> +
>> +	/* Set to XBUF_TX_TAG_MASK_0 register. */
>> +	reg += XBUF_TX_CMD_OFFSET + (endpoints * 2 + 2) * sizeof(u32);
>> +	/* Set reg to XBUF_TX_TAG_MASK_N related with this endpoint. */
>> +	reg += (pep->number * sizeof(u32) * 2);
>
>Remove parenthese.
>
>> +
>> +	pep->buffering = (readl(reg) + 1) / 2;
>> +	pep->buffering_period = pep->buffering;
>> +}
>> +
>> +static int cdnsp_gadget_init_endpoints(struct cdnsp_device *pdev)
>> +{
>> +	int max_streams = HCC_MAX_PSA(pdev->hcc_params);
>> +	struct cdnsp_ep *pep;
>> +	int i = 0;
>
>Don't intialize
>
>> +
>> +	INIT_LIST_HEAD(&pdev->gadget.ep_list);
>> +
>> +	if (max_streams < STREAM_LOG_STREAMS) {
>> +		dev_err(pdev->dev, "Stream size %d not supported\n",
>> +			max_streams);
>> +		return -EINVAL;
>> +	}
>> +
>> +	max_streams  = STREAM_LOG_STREAMS;
>                    ^
>Extra space
>
>> +
>> +	for (i = 0; i < CDNSP_ENDPOINTS_NUM; i++) {
>> +		bool direction = !(i & 1); /* Start from OUT endpoint. */
>> +		u8 epnum = ((i + 1) >> 1);
>> +
>> +		if (!CDNSP_IF_EP_EXIST(pdev, epnum, direction))
>> +			continue;
>> +
>> +		pep = &pdev->eps[i];
>> +		pep->pdev = pdev;
>> +		pep->number = epnum;
>> +		pep->direction = direction; /* 0 for OUT, 1 for IN. */
>> +
>> +		/*
>> +		 * Ep0 is bidirectional, so ep0in and ep0out are represented by
>> +		 * pdev->eps[0]
>> +		 */
>> +		if (epnum == 0) {
>> +			snprintf(pep->name, sizeof(pep->name), "ep%d%s",
>> +				 epnum, "BiDir");
>> +
>> +			pep->idx = 0;
>> +			usb_ep_set_maxpacket_limit(&pep->endpoint, 512);
>> +			pep->endpoint.maxburst = 1;
>> +			pep->endpoint.ops = &cdnsp_gadget_ep0_ops;
>> +			pep->endpoint.desc = &cdnsp_gadget_ep0_desc;
>> +			pep->endpoint.comp_desc = NULL;
>> +			pep->endpoint.caps.type_control = true;
>> +			pep->endpoint.caps.dir_in = true;
>> +			pep->endpoint.caps.dir_out = true;
>> +
>> +			pdev->ep0_preq.epnum = pep->number;
>> +			pdev->ep0_preq.pep = pep;
>> +			pdev->gadget.ep0 = &pep->endpoint;
>> +		} else {
>> +			snprintf(pep->name, sizeof(pep->name), "ep%d%s",
>> +				 epnum, (pep->direction) ? "in"  : "out");
>> +
>> +			pep->idx =  (epnum * 2 + (direction ? 1 : 0)) - 1;
>> +			usb_ep_set_maxpacket_limit(&pep->endpoint, 1024);
>> +
>> +			pep->endpoint.max_streams = max_streams;
>> +			pep->endpoint.ops = &cdnsp_gadget_ep_ops;
>> +			list_add_tail(&pep->endpoint.ep_list,
>> +				      &pdev->gadget.ep_list);
>> +
>> +			pep->endpoint.caps.type_iso = true;
>> +			pep->endpoint.caps.type_bulk = true;
>> +			pep->endpoint.caps.type_int = true;
>> +
>> +			pep->endpoint.caps.dir_in = direction;
>> +			pep->endpoint.caps.dir_out = !direction;
>> +		}
>> +
>> +		pep->endpoint.name = pep->name;
>> +		pep->in_ctx = cdnsp_get_ep_ctx(&pdev->in_ctx, pep->idx);
>> +		pep->out_ctx = cdnsp_get_ep_ctx(&pdev->out_ctx, pep->idx);
>> +		cdnsp_get_ep_buffering(pdev, pep);
>> +
>> +		dev_dbg(pdev->dev, "Init %s, MPS: %04x SupType: "
>> +			"CTRL: %s, INT: %s, BULK: %s, ISOC %s, "
>> +			"SupDir IN: %s, OUT: %s\n",
>> +			pep->name, 1024,
>> +			(pep->endpoint.caps.type_control) ? "yes" : "no",
>> +			(pep->endpoint.caps.type_int) ? "yes" : "no",
>> +			(pep->endpoint.caps.type_bulk) ? "yes" : "no",
>> +			(pep->endpoint.caps.type_iso) ? "yes" : "no",
>> +			(pep->endpoint.caps.dir_in) ? "yes" : "no",
>> +			(pep->endpoint.caps.dir_out) ? "yes" : "no");
>> +
>> +		INIT_LIST_HEAD(&pep->pending_list);
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +static void cdnsp_gadget_free_endpoints(struct cdnsp_device *pdev)
>> +{
>> +	struct cdnsp_ep *pep;
>> +	int i;
>> +
>> +	for (i = 0; i < CDNSP_ENDPOINTS_NUM; i++) {
>> +		pep = &pdev->eps[i];
>> +		if (pep->number != 0 && pep->out_ctx)
>> +			list_del(&pep->endpoint.ep_list);
>> +	}
>> +}
>> +
>> +void cdnsp_disconnect_gadget(struct cdnsp_device *pdev)
>> +{
>> +	pdev->cdnsp_state |= CDNSP_STATE_DISCONNECT_PENDING;
>> +
>> +	if (pdev->gadget_driver && pdev->gadget_driver->disconnect) {
>> +		spin_unlock(&pdev->lock);
>> +		pdev->gadget_driver->disconnect(&pdev->gadget);
>> +		spin_lock(&pdev->lock);
>> +	}
>> +
>> +	pdev->gadget.speed = USB_SPEED_UNKNOWN;
>> +	usb_gadget_set_state(&pdev->gadget, USB_STATE_NOTATTACHED);
>> +
>> +	pdev->cdnsp_state &= ~CDNSP_STATE_DISCONNECT_PENDING;
>> +}
>> +
>> +void cdnsp_suspend_gadget(struct cdnsp_device *pdev)
>> +{
>> +	if (pdev->gadget_driver && pdev->gadget_driver->suspend) {
>> +		spin_unlock(&pdev->lock);
>> +		pdev->gadget_driver->suspend(&pdev->gadget);
>> +		spin_lock(&pdev->lock);
>> +	}
>> +}
>> +
>> +void cdnsp_resume_gadget(struct cdnsp_device *pdev)
>> +{
>> +	if (pdev->gadget_driver && pdev->gadget_driver->resume) {
>> +		spin_unlock(&pdev->lock);
>> +		pdev->gadget_driver->resume(&pdev->gadget);
>> +		spin_lock(&pdev->lock);
>> +	}
>> +}
>> +
>> +void cdnp_irq_reset(struct cdnsp_device *pdev)
>> +{
>> +	struct cdnsp_port_regs __iomem *port_regs;
>> +
>> +	cdnsp_reset_device(pdev);
>> +
>> +	port_regs = pdev->active_port->regs;
>> +	pdev->gadget.speed = cdnsp_port_speed(readl(port_regs));
>> +
>> +	spin_unlock(&pdev->lock);
>> +	usb_gadget_udc_reset(&pdev->gadget, pdev->gadget_driver);
>> +	spin_lock(&pdev->lock);
>> +
>> +	switch (pdev->gadget.speed) {
>> +	case USB_SPEED_SUPER_PLUS:
>> +	case USB_SPEED_SUPER:
>> +		cdnsp_gadget_ep0_desc.wMaxPacketSize = cpu_to_le16(512);
>> +		pdev->gadget.ep0->maxpacket = 512;
>> +		break;
>> +	case USB_SPEED_HIGH:
>> +	case USB_SPEED_FULL:
>> +		cdnsp_gadget_ep0_desc.wMaxPacketSize = cpu_to_le16(64);
>> +		pdev->gadget.ep0->maxpacket = 64;
>> +		break;
>> +	default:
>> +		/* Low speed is not supported. */
>> +		dev_err(pdev->dev, "Unknown device speed\n");
>> +		break;
>> +	}
>> +
>> +	cdnsp_clear_chicken_bits_2(pdev, CHICKEN_XDMA_2_TP_CACHE_DIS);
>> +	cdnsp_setup_device(pdev, SETUP_CONTEXT_ONLY);
>> +	usb_gadget_set_state(&pdev->gadget, USB_STATE_DEFAULT);
>> +}
>> +
>> +static void cdnsp_get_rev_cap(struct cdnsp_device *pdev)
>> +{
>> +	void __iomem *reg = &pdev->cap_regs->hc_capbase;
>> +	struct cdnsp_rev_cap *rev_cap;
>> +
>> +	reg += cdnsp_find_next_ext_cap(reg, 0, RTL_REV_CAP);
>> +	rev_cap = reg;
>> +
>> +	pdev->rev_cap.ctrl_revision = readl(&rev_cap->ctrl_revision);
>> +	pdev->rev_cap.rtl_revision = readl(&rev_cap->rtl_revision);
>> +	pdev->rev_cap.ep_supported = readl(&rev_cap->ep_supported);
>> +	pdev->rev_cap.ext_cap = readl(&rev_cap->ext_cap);
>> +	pdev->rev_cap.rx_buff_size = readl(&rev_cap->rx_buff_size);
>> +	pdev->rev_cap.tx_buff_size = readl(&rev_cap->tx_buff_size);
>> +
>> +	dev_info(pdev->dev, "Rev: %08x/%08x, eps: %08x, buff: %08x/%08x\n",
>> +		 pdev->rev_cap.ctrl_revision, pdev->rev_cap.rtl_revision,
>> +		 pdev->rev_cap.ep_supported, pdev->rev_cap.rx_buff_size,
>> +		 pdev->rev_cap.tx_buff_size);
>> +}
>> +
>> +static int cdnsp_gen_setup(struct cdnsp_device *pdev)
>> +{
>> +	int retval;
>
>Use "int ret;" everywhere.
>
>> +
>> +	pdev->cap_regs = pdev->regs;
>> +	pdev->op_regs = pdev->regs +
>> +		HC_LENGTH(readl(&pdev->cap_regs->hc_capbase));
>> +	pdev->run_regs = pdev->regs +
>> +		(readl(&pdev->cap_regs->run_regs_off) & RTSOFF_MASK);
>> +
>> +	/* Cache read-only capability registers */
>> +	pdev->hcs_params1 = readl(&pdev->cap_regs->hcs_params1);
>> +	pdev->hcc_params = readl(&pdev->cap_regs->hc_capbase);
>> +	pdev->hci_version = HC_VERSION(pdev->hcc_params);
>> +	pdev->hcc_params = readl(&pdev->cap_regs->hcc_params);
>> +
>> +	cdnsp_get_rev_cap(pdev);
>> +
>> +	/* Make sure the Device Controller is halted. */
>> +	retval = cdnsp_halt(pdev);
>> +	if (retval)
>> +		return retval;
>> +
>> +	/* Reset the internal controller memory state and registers. */
>> +	retval = cdnsp_reset(pdev);
>> +	if (retval)
>> +		return retval;
>> +
>> +	/*
>> +	 * Set dma_mask and coherent_dma_mask to 64-bits,
>> +	 * if controller supports 64-bit addressing.
>> +	 */
>> +	if (HCC_64BIT_ADDR(pdev->hcc_params) &&
>> +	    !dma_set_mask(pdev->dev, DMA_BIT_MASK(64))) {
>> +		dev_dbg(pdev->dev, "Enabling 64-bit DMA addresses.\n");
>> +		dma_set_coherent_mask(pdev->dev, DMA_BIT_MASK(64));
>> +	} else {
>> +		/*
>> +		 * This is to avoid error in cases where a 32-bit USB
>> +		 * controller is used on a 64-bit capable system.
>> +		 */
>> +		retval = dma_set_mask(pdev->dev, DMA_BIT_MASK(32));
>> +		if (retval)
>> +			return retval;
>> +		dev_dbg(pdev->dev, "Enabling 32-bit DMA addresses.\n");
>> +		dma_set_coherent_mask(pdev->dev, DMA_BIT_MASK(32));
>> +	}
>> +
>> +	spin_lock_init(&pdev->lock);
>> +
>> +	retval = cdnsp_mem_init(pdev, GFP_KERNEL);
>> +	if (retval)
>> +		return retval;
>> +
>> +	return 0;
>> +}
>> +
>> +static int __cdnsp_gadget_init(struct cdnsp *cdns)
>> +{
>> +	struct cdnsp_device *pdev;
>> +	u32 max_speed;
>> +	int ret = -ENOMEM;
>> +
>> +	cdnsp_drd_switch_gadget(cdns, 1);
>> +
>> +	pdev = kzalloc(sizeof(*pdev), GFP_KERNEL);
>> +	if (!pdev)
>> +		return ret;
>
>return -ENOMEM;
>
>Returning a literal is more readable than returning a variable you have
>to look up.
>
>> +
>> +	pm_runtime_get_sync(cdns->dev);
>> +
>> +	cdns->gadget_dev = pdev;
>> +	pdev->dev = cdns->dev;
>> +	pdev->regs = cdns->dev_regs;
>> +
>> +	max_speed = usb_get_maximum_speed(cdns->dev);
>> +
>> +	switch (max_speed) {
>> +	case USB_SPEED_FULL:
>> +	case USB_SPEED_HIGH:
>> +	case USB_SPEED_SUPER:
>> +	case USB_SPEED_SUPER_PLUS:
>> +		break;
>> +	default:
>> +		dev_err(cdns->dev, "invalid speed parameter %d\n", max_speed);
>> +		/* fall-through */
>> +	case USB_SPEED_UNKNOWN:
>> +		/* Default to SSP */
>> +		max_speed = USB_SPEED_SUPER_PLUS;
>> +		break;
>> +	}
>> +
>> +	pdev->gadget.ops = &cdnsp_gadget_ops;
>> +	pdev->gadget.name = "cdnsp-gadget";
>> +	pdev->gadget.speed = USB_SPEED_UNKNOWN;
>> +	pdev->gadget.sg_supported = 1;
>> +	pdev->gadget.max_speed = USB_SPEED_SUPER_PLUS;
>> +	pdev->gadget.lpm_capable = 1;
>> +
>> +	pdev->setup_buf = kzalloc(CDNSP_EP0_SETUP_SIZE, GFP_KERNEL);
>> +	if (!pdev->setup_buf)
>> +		goto err1;
>> +
>> +	/*
>> +	 * Controller supports not aligned buffer but it should improve
>> +	 * performance.
>> +	 */
>> +	pdev->gadget.quirk_ep_out_aligned_size = true;
>> +
>> +	ret = cdnsp_gen_setup(pdev);
>> +	if (ret < 0) {
>
>Use "if (ret) " everywhere unless the function returns positive values
>on success.  Don't mix styles.
>
>> +		dev_err(pdev->dev, "Generic initialization failed %d\n", ret);
>> +		goto err2;
>> +	}
>> +
>> +	ret = cdnsp_gadget_init_endpoints(pdev);
>> +	if (ret < 0) {
>> +		dev_err(pdev->dev, "failed to initialize endpoints\n");
>> +		goto err3;
>> +	}
>> +
>> +	ret = usb_add_gadget_udc(pdev->dev, &pdev->gadget);
>> +	if (ret) {
>> +		dev_err(pdev->dev, "failed to register udc\n");
>> +		goto err4;
>> +	}
>> +
>> +	ret = devm_request_threaded_irq(pdev->dev, cdns->dev_irq,
>> +					cdnsp_irq_handler,
>> +					cdnsp_thread_irq_handler,
>> +					IRQF_SHARED /*| IRQF_ONESHOT*/,
>> +					dev_name(pdev->dev), pdev);
>> +	if (ret < 0)
>> +		goto err5;
>> +
>> +	return 0;
>> +
>> +err5:
>
>This is like GW-BASIC "goto 10;" where you have numbers instead of names
>and then the code changes and you have to "goto err_2point5;".  Label
>names should say what the goto does just like functions say what happens
>when you call them.
>
>goto del_gadget; goto free_endpoints; goto halt_pdev; goto free_setup; etc.
>
>Better to move everything you can to devm_kzalloc().

Failure in this case doesn't guarantee that device will be detached or driver
removed. 
>
>> +	usb_del_gadget_udc(&pdev->gadget);
>> +err4:
>> +	cdnsp_gadget_free_endpoints(pdev);
>> +err3:
>> +	cdnsp_halt(pdev);
>> +	cdnsp_reset(pdev);
>> +	cdnsp_mem_cleanup(pdev);
>> +err2:
>> +	kfree(pdev->setup_buf);
>> +err1:
>> +	kfree(pdev);
>> +
>> +	return ret;
>> +}
>> +
>> +void cdnsp_gadget_exit(struct cdnsp *cdns)
>> +{
>> +	struct cdnsp_device *pdev = cdns->gadget_dev;
>> +
>> +	devm_free_irq(pdev->dev, cdns->dev_irq, pdev);
>
>Hopefully, there is no need to free devm_ allocated code otherwise it
>defeats the purpose.
>

It can be called during changing role from device to host, device still 
Is attached and the role can be changed again.

>> +
>> +	pm_runtime_mark_last_busy(cdns->dev);
>> +	pm_runtime_put_autosuspend(cdns->dev);
>> +
>> +	usb_del_gadget_udc(&pdev->gadget);
>> +	cdnsp_gadget_free_endpoints(pdev);
>> +
>> +	cdnsp_mem_cleanup(pdev);
>> +	kfree(pdev);
>> +	cdns->gadget_dev = NULL;
>> +
>> +	cdnsp_drd_switch_gadget(cdns, 0);
>> +}
>> +
>> +static int cdnsp_gadget_suspend(struct cdnsp *cdns, bool do_wakeup)
>> +{
>> +	struct cdnsp_device *pdev = cdns->gadget_dev;
>> +
>> +	cdnsp_disconnect_gadget(pdev);
>> +	cdnsp_stop(pdev);
>> +
>> +	return 0;
>> +}
>> +
>> +static int cdnsp_gadget_resume(struct cdnsp *cdns, bool hibernated)
>> +{
>> +	struct cdnsp_device *pdev = cdns->gadget_dev;
>> +	enum usb_device_speed max_speed;
>> +	int ret;
>> +
>> +	if (!pdev->gadget_driver)
>> +		return 0;
>> +
>> +	max_speed = pdev->gadget_driver->max_speed;
>> +
>> +	/* Limit speed if necessary. */
>> +	max_speed = min(max_speed, pdev->gadget.max_speed);
>> +	ret = cdnsp_run(pdev, max_speed);
>> +
>> +	return ret;
>
>	return cdnsp_run(pdev, max_speed);
>
>> +}
>> +
>> +/**
>> + * cdnsp_gadget_init - initialize device structure
>> + * @cdns: cdnsp instance
>> + *
>> + * This function initializes the gadget.
>> + */
>> +int cdnsp_gadget_init(struct cdnsp *cdns)
>> +{
>> +	struct cdnsp_role_driver *rdrv;
>> +
>> +	rdrv = devm_kzalloc(cdns->dev, sizeof(*rdrv), GFP_KERNEL);
>> +	if (!rdrv)
>> +		return -ENOMEM;
>> +
>> +	rdrv->start	= __cdnsp_gadget_init;
>> +	rdrv->stop	= cdnsp_gadget_exit;
>> +	rdrv->suspend	= cdnsp_gadget_suspend;
>> +	rdrv->resume	= cdnsp_gadget_resume;
>> +	rdrv->state	= CDNSP_ROLE_STATE_INACTIVE;
>> +	rdrv->name	= "gadget";
>> +	cdns->roles[USB_ROLE_DEVICE] = rdrv;
>> +
>> +	return 0;
>> +}
>> diff --git a/drivers/usb/cdnsp/gadget.h b/drivers/usb/cdnsp/gadget.h
>> index edc37763a3b7..298f97be24ad 100644
>> --- a/drivers/usb/cdnsp/gadget.h
>> +++ b/drivers/usb/cdnsp/gadget.h
>> @@ -1443,4 +1443,142 @@ struct cdnsp_device {
>>  	u16 test_mode;
>>  };
>>
>> +/*
>> + * Registers should always be accessed with double word or quad word accesses.
>> + *
>> + * Registers with 64-bit address pointers should be written to with
>> + * dword accesses by writing the low dword first (ptr[0]), then the high dword
>> + * (ptr[1]) second. controller implementations that do not support 64-bit
>> + * address pointers will ignore the high dword, and write order is irrelevant.
>> + */
>> +static inline u64 cdnsp_read_64(const struct cdnsp_device *pdev,
>> +				__le64 __iomem *regs)
>> +{
>> +	return lo_hi_readq(regs);
>> +}
>> +
>> +static inline void cdnsp_write_64(struct cdnsp_device *pdev,
>> +				  const u64 val, __le64 __iomem *regs)
>> +{
>> +	lo_hi_writeq(val, regs);
>> +}
>> +
>> +/* CDNSP memory management functions. */
>> +void cdnsp_mem_cleanup(struct cdnsp_device *pdev);
>> +int cdnsp_mem_init(struct cdnsp_device *pdev, gfp_t flags);
>> +int cdnsp_setup_addressable_priv_dev(struct cdnsp_device *pdev);
>> +void cdnsp_copy_ep0_dequeue_into_input_ctx(struct cdnsp_device *pdev);
>> +void cdnsp_endpoint_zero(struct cdnsp_device *pdev, struct cdnsp_ep *ep);
>> +int cdnsp_endpoint_init(struct cdnsp_device *pdev,
>> +			struct cdnsp_ep *pep,
>> +			gfp_t mem_flags);
>> +int cdnsp_ring_expansion(struct cdnsp_device *pdev,
>> +			 struct cdnsp_ring *ring,
>> +			 unsigned int num_trbs, gfp_t flags);
>> +struct cdnsp_ring *cdnsp_dma_to_transfer_ring(struct cdnsp_ep *ep, u64 address);
>> +int cdnsp_alloc_stream_info(struct cdnsp_device *pdev,
>> +			    struct cdnsp_ep *pep,
>> +			    unsigned int num_stream_ctxs,
>> +			    unsigned int num_streams);
>> +int cdnsp_alloc_streams(struct cdnsp_device *pdev, struct cdnsp_ep *pep);
>> +void cdnsp_free_endpoint_rings(struct cdnsp_device *pdev, struct cdnsp_ep *pep);
>> +
>> +/* Device controller glue. */
>> +int cdnsp_find_next_ext_cap(void __iomem *base, u32 start, int id);
>> +int cdnsp_halt(struct cdnsp_device *pdev);
>> +void cdnsp_died(struct cdnsp_device *pdev);
>> +int cdnsp_reset(struct cdnsp_device *pdev);
>> +irqreturn_t cdnsp_irq_handler(int irq, void *priv);
>> +int cdnsp_setup_device(struct cdnsp_device *pdev, enum cdnsp_setup_dev setup);
>> +void cdnsp_set_usb2_hardware_lpm(struct cdnsp_device *usbsssp_data,
>> +				 struct usb_request *req, int enable);
>> +irqreturn_t cdnsp_thread_irq_handler(int irq, void *data);
>> +
>> +/* Ring, segment, TRB, and TD functions. */
>> +dma_addr_t cdnsp_trb_virt_to_dma(struct cdnsp_segment *seg,
>> +				 union cdnsp_trb *trb);
>> +bool cdnsp_last_trb_on_seg(struct cdnsp_segment *seg, union cdnsp_trb *trb);
>> +bool cdnsp_last_trb_on_ring(struct cdnsp_ring *ring,
>> +			    struct cdnsp_segment *seg,
>> +			    union cdnsp_trb *trb);
>> +int cdnsp_wait_for_cmd_compl(struct cdnsp_device *pdev);
>> +void cdnsp_update_erst_dequeue(struct cdnsp_device *pdev,
>> +			       union cdnsp_trb *event_ring_deq,
>> +			       u8 clear_ehb);
>> +void cdnsp_initialize_ring_info(struct cdnsp_ring *ring);
>> +void cdnsp_ring_cmd_db(struct cdnsp_device *pdev);
>> +void cdnsp_queue_slot_control(struct cdnsp_device *pdev, u32 trb_type);
>> +void cdnsp_queue_address_device(struct cdnsp_device *pdev,
>> +				dma_addr_t in_ctx_ptr,
>> +				enum cdnsp_setup_dev setup);
>> +void cdnsp_queue_stop_endpoint(struct cdnsp_device *pdev,
>> +			       unsigned int ep_index);
>> +int cdnsp_queue_ctrl_tx(struct cdnsp_device *pdev, struct cdnsp_request *preq);
>> +int cdnsp_queue_bulk_tx(struct cdnsp_device *pdev, struct cdnsp_request *preq);
>> +int cdnsp_queue_isoc_tx_prepare(struct cdnsp_device *pdev,
>> +				struct cdnsp_request *preq);
>> +void cdnsp_queue_configure_endpoint(struct cdnsp_device *pdev,
>> +				    dma_addr_t in_ctx_ptr);
>> +void cdnsp_queue_reset_ep(struct cdnsp_device *pdev, unsigned int ep_index);
>> +void cdnsp_queue_halt_endpoint(struct cdnsp_device *pdev,
>> +			       unsigned int ep_index);
>> +void cdnsp_queue_flush_endpoint(struct cdnsp_device *pdev,
>> +				unsigned int ep_index);
>> +void cdnsp_queue_reset_device(struct cdnsp_device *pdev);
>> +void cdnsp_queue_new_dequeue_state(struct cdnsp_device *pdev,
>> +				   struct cdnsp_ep *pep,
>> +				   struct cdnsp_dequeue_state *deq_state);
>> +void cdnsp_ring_doorbell_for_active_rings(struct cdnsp_device *pdev,
>> +					  struct cdnsp_ep *pep);
>> +void cdnsp_inc_deq(struct cdnsp_device *pdev, struct cdnsp_ring *ring);
>> +void cdnsp_set_link_state(struct cdnsp_device *pdev,
>> +			  __le32 __iomem *port_regs, u32 link_state);
>> +u32 cdnsp_port_state_to_neutral(u32 state);
>> +
>> +/* CDNSP device controller contexts. */
>> +int cdnsp_enable_slot(struct cdnsp_device *pdev);
>> +int cdnsp_disable_slot(struct cdnsp_device *pdev);
>> +struct cdnsp_input_control_ctx
>> +	*cdnsp_get_input_control_ctx(struct cdnsp_container_ctx *ctx);
>> +struct cdnsp_slot_ctx *cdnsp_get_slot_ctx(struct cdnsp_container_ctx *ctx);
>> +struct cdnsp_ep_ctx *cdnsp_get_ep_ctx(struct cdnsp_container_ctx *ctx,
>> +				      unsigned int ep_index);
>> +/* CDNSP gadget interface. */
>> +void cdnsp_suspend_gadget(struct cdnsp_device *pdev);
>> +void cdnsp_resume_gadget(struct cdnsp_device *pdev);
>> +void cdnsp_disconnect_gadget(struct cdnsp_device *pdev);
>> +void cdnsp_gadget_giveback(struct cdnsp_ep *pep, struct cdnsp_request *preq,
>> +			   int status);
>> +int cdnsp_ep_enqueue(struct cdnsp_ep *pep, struct cdnsp_request *preq);
>> +int cdnsp_ep_dequeue(struct cdnsp_ep *pep, struct cdnsp_request *preq);
>> +unsigned int cdnsp_port_speed(unsigned int port_status);
>> +void cdnp_irq_reset(struct cdnsp_device *pdev);
>> +int cdnsp_halt_endpoint(struct cdnsp_device *pdev,
>> +			struct cdnsp_ep *pep, int value);
>> +int cdnsp_cmd_stop_ep(struct cdnsp_device *pdev, struct cdnsp_ep *pep);
>> +int cdnsp_cmd_flush_ep(struct cdnsp_device *pdev, struct cdnsp_ep *pep);
>> +void cdnsp_setup_analyze(struct cdnsp_device *pdev);
>> +int cdnsp_status_stage(struct cdnsp_device *pdev);
>> +int cdnsp_reset_device(struct cdnsp_device *pdev);
>> +
>> +/**
>> + * next_request - gets the next request on the given list
>> + * @list: the request list to operate on
>> + *
>> + * Caller should take care of locking. This function return NULL or the first
>> + * request available on list.
>> + */
>> +static inline struct cdnsp_request *next_request(struct list_head *list)
>> +{
>> +	return list_first_entry_or_null(list, struct cdnsp_request, list);
>> +}
>> +
>> +#define to_cdnsp_ep(ep) (container_of(ep, struct cdnsp_ep, endpoint))
>> +#define gadget_to_cdnsp(g) (container_of(g, struct cdnsp_device, gadget))
>> +#define request_to_cdnsp_request(r) (container_of(r, struct cdnsp_request, \
>> +				     request))
>> +#define to_cdnsp_request(r) (container_of(r, struct cdnsp_request, request))
>> +int cdnsp_remove_request(struct cdnsp_device *pdev, struct cdnsp_request *preq,
>> +			 struct cdnsp_ep *pep);
>> +
>>  #endif /* __LINUX_CDNSP_GADGET_H */
>> diff --git a/drivers/usb/cdnsp/host.c b/drivers/usb/cdnsp/host.c
>> new file mode 100644
>> index 000000000000..355fe63149e4
>> --- /dev/null
>> +++ b/drivers/usb/cdnsp/host.c
>> @@ -0,0 +1,74 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Cadence USBSS DRD Driver - host side
>> + *
>> + * Copyright (C) 2018-2019 Cadence Design Systems.
>> + * Copyright (C) 2017-2018 NXP
>> + *
>> + * Authors: Peter Chen <peter.chen@....com>
>> + *          Pawel Laszczak <pawell@...ence.com>
>> + */
>> +
>> +#include <linux/platform_device.h>
>> +#include "core.h"
>> +#include "drd.h"
>> +
>> +int __cdnsp_host_init(struct cdnsp *cdns)
>> +{
>> +	struct platform_device *xhci;
>> +	int ret;
>> +
>> +	cdnsp_drd_switch_host(cdns, 1);
>> +
>> +	xhci = platform_device_alloc("xhci-hcd", PLATFORM_DEVID_AUTO);
>> +	if (!xhci) {
>> +		dev_err(cdns->dev, "couldn't allocate xHCI device\n");
>> +		return -ENOMEM;
>> +	}
>> +
>> +	xhci->dev.parent = cdns->dev;
>> +	cdns->host_dev = xhci;
>> +
>> +	ret = platform_device_add_resources(xhci, cdns->xhci_res,
>> +					    CDNSP_XHCI_RESOURCES_NUM);
>> +	if (ret) {
>> +		dev_err(cdns->dev, "couldn't add resources to xHCI device\n");
>> +		goto err1;
>> +	}
>> +
>> +	ret = platform_device_add(xhci);
>> +	if (ret) {
>> +		dev_err(cdns->dev, "failed to register xHCI device\n");
>> +		goto err1;
>> +	}
>> +
>> +	return 0;
>> +err1:
>> +	platform_device_put(xhci);
>> +	return ret;
>> +}
>> +
>> +void cdnsp_host_exit(struct cdnsp *cdns)
>> +{
>> +	platform_device_unregister(cdns->host_dev);
>> +	cdns->host_dev = NULL;
>> +	cdnsp_drd_switch_host(cdns, 0);
>> +}
>> +
>> +int cdnsp_host_init(struct cdnsp *cdns)
>> +{
>> +	struct cdnsp_role_driver *rdrv;
>> +
>> +	rdrv = devm_kzalloc(cdns->dev, sizeof(*rdrv), GFP_KERNEL);
>> +	if (!rdrv)
>> +		return -ENOMEM;
>> +
>> +	rdrv->start	= __cdnsp_host_init;
>> +	rdrv->stop	= cdnsp_host_exit;
>> +	rdrv->state	= CDNSP_ROLE_STATE_INACTIVE;
>> +	rdrv->name	= "host";
>> +
>> +	cdns->roles[USB_ROLE_HOST] = rdrv;
>> +
>> +	return 0;
>> +}
>> diff --git a/drivers/usb/cdnsp/mem.c b/drivers/usb/cdnsp/mem.c
>> new file mode 100644
>> index 000000000000..4a72c7d833ab
>> --- /dev/null
>> +++ b/drivers/usb/cdnsp/mem.c
>> @@ -0,0 +1,1327 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Cadence CDNSP DRD Driver.
>> + *
>> + * Copyright (C) 2020 Cadence.
>> + *
>> + * Author: Pawel Laszczak <pawell@...ence.com>
>> + *
>> + * Code based on Linux XHCI driver.
>> + * Origin: Copyright (C) 2008 Intel Corp.
>> + */
>> +
>> +#include <linux/dma-mapping.h>
>> +#include <linux/dmapool.h>
>> +#include <linux/slab.h>
>> +#include <linux/usb.h>
>> +
>> +#include "gadget.h"
>> +
>> +static void cdnsp_free_stream_info(struct cdnsp_device *pdev,
>> +				   struct cdnsp_ep *pep);
>> +/*
>> + * Allocates a generic ring segment from the ring pool, sets the dma address,
>> + * initializes the segment to zero, and sets the private next pointer to NULL.
>> + *
>> + * "All components of all Command and Transfer TRBs shall be initialized to '0'"
>> + */
>> +static struct cdnsp_segment *cdnsp_segment_alloc(struct cdnsp_device *pdev,
>> +						 unsigned int cycle_state,
>> +						 unsigned int max_packet,
>> +						 gfp_t flags)
>> +{
>> +	struct cdnsp_segment *seg;
>> +	dma_addr_t dma;
>> +	int i;
>> +
>> +	seg = kzalloc(sizeof(*seg), flags);
>> +	if (!seg)
>> +		return NULL;
>> +
>> +	seg->trbs = dma_pool_zalloc(pdev->segment_pool, flags, &dma);
>> +
>
>Delete the blank line.
>
>	if (!seg->trbs)
>		goto free_seg;
>
>> +	if (!seg->trbs) {
>> +		kfree(seg);
>> +		return NULL;
>> +	}
>> +
>> +	if (max_packet) {
>> +		seg->bounce_buf = kzalloc(max_packet, flags | GFP_DMA);
>> +		if (!seg->bounce_buf) {
>> +			dma_pool_free(pdev->segment_pool, seg->trbs, dma);
>> +			kfree(seg);
>> +
>> +			return NULL;
>
>		if (!seg->bounce_buf)
>			goto free_dma;
>
>
>> +		}
>> +	}
>> +
>> +	/* If the cycle state is 0, set the cycle bit to 1 for all the TRBs. */
>> +	if (cycle_state == 0) {
>> +		for (i = 0; i < TRBS_PER_SEGMENT; i++)
>> +			seg->trbs[i].link.control |= cpu_to_le32(TRB_CYCLE);
>> +	}
>> +	seg->dma = dma;
>> +	seg->next = NULL;
>> +
>> +	return seg;
>> +}
>> +
>> +static void cdnsp_segment_free(struct cdnsp_device *pdev,
>> +			       struct cdnsp_segment *seg)
>> +{
>> +	if (seg->trbs) {
>> +		dma_pool_free(pdev->segment_pool, seg->trbs, seg->dma);
>> +		seg->trbs = NULL;
>
>No need to make this NULL because "seg" is freed two lines later.
>
>> +	}
>> +
>> +	kfree(seg->bounce_buf);
>> +	kfree(seg);
>> +}
>> +
>> +static void cdnsp_free_segments_for_ring(struct cdnsp_device *pdev,
>> +					 struct cdnsp_segment *first)
>> +{
>> +	struct cdnsp_segment *seg;
>> +
>> +	seg = first->next;
>> +
>> +	while (seg != first) {
>> +		struct cdnsp_segment *next = seg->next;
>> +
>> +		cdnsp_segment_free(pdev, seg);
>> +		seg = next;
>> +	}
>> +
>> +	cdnsp_segment_free(pdev, first);
>> +}
>> +
>> +/*
>> + * Make the prev segment point to the next segment.
>> + *
>> + * Change the last TRB in the prev segment to be a Link TRB which points to the
>> + * DMA address of the next segment. The caller needs to set any Link TRB
>> + * related flags, such as End TRB, Toggle Cycle, and no snoop.
>> + */
>> +static void cdnsp_link_segments(struct cdnsp_device *pdev,
>> +				struct cdnsp_segment *prev,
>> +				struct cdnsp_segment *next,
>> +				enum cdnsp_ring_type type)
>> +{
>> +	struct cdnsp_link_trb *link;
>> +	u32 val;
>> +
>> +	if (!prev || !next)
>> +		return;
>> +
>> +	prev->next = next;
>> +	if (type != TYPE_EVENT) {
>> +		link = &prev->trbs[TRBS_PER_SEGMENT - 1].link;
>> +		link->segment_ptr = cpu_to_le64(next->dma);
>> +
>> +		/*
>> +		 * Set the last TRB in the segment to have a TRB type ID
>> +		 * of Link TRB
>> +		 */
>> +		val = le32_to_cpu(link->control);
>> +		val &= ~TRB_TYPE_BITMASK;
>> +		val |= TRB_TYPE(TRB_LINK);
>> +		link->control = cpu_to_le32(val);
>> +	}
>> +}
>> +
>> +/*
>> + * Link the ring to the new segments.
>> + * Set Toggle Cycle for the new ring if needed.
>> + */
>> +static void cdnsp_link_rings(struct cdnsp_device *pdev,
>> +			     struct cdnsp_ring *ring,
>> +			     struct cdnsp_segment *first,
>> +			     struct cdnsp_segment *last,
>> +			     unsigned int num_segs)
>> +{
>> +	struct cdnsp_segment *next;
>> +
>> +	if (!ring || !first || !last)
>> +		return;
>> +
>> +	next = ring->enq_seg->next;
>> +	cdnsp_link_segments(pdev, ring->enq_seg, first, ring->type);
>> +	cdnsp_link_segments(pdev, last, next, ring->type);
>> +	ring->num_segs += num_segs;
>> +	ring->num_trbs_free += (TRBS_PER_SEGMENT - 1) * num_segs;
>> +
>> +	if (ring->type != TYPE_EVENT && ring->enq_seg == ring->last_seg) {
>> +		ring->last_seg->trbs[TRBS_PER_SEGMENT - 1].link.control &=
>> +			~cpu_to_le32(LINK_TOGGLE);
>> +		last->trbs[TRBS_PER_SEGMENT - 1].link.control |=
>> +			cpu_to_le32(LINK_TOGGLE);
>> +		ring->last_seg = last;
>> +	}
>> +}
>> +
>> +/*
>> + * We need a radix tree for mapping physical addresses of TRBs to which stream
>> + * ID they belong to. We need to do this because the device controller won't
>> + * tell us which stream ring the TRB came from. We could store the stream ID
>> + * in an event data TRB, but that doesn't help us for the cancellation case,
>> + * since the endpoint may stop before it reaches that event data TRB.
>> + *
>> + * The radix tree maps the upper portion of the TRB DMA address to a ring
>> + * segment that has the same upper portion of DMA addresses. For example,
>> + * say I have segments of size 1KB, that are always 1KB aligned. A segment may
>> + * start at 0x10c91000 and end at 0x10c913f0. If I use the upper 10 bits, the
>> + * key to the stream ID is 0x43244. I can use the DMA address of the TRB to
>> + * pass the radix tree a key to get the right stream ID:
>> + *
>> + *	0x10c90fff >> 10 = 0x43243
>> + *	0x10c912c0 >> 10 = 0x43244
>> + *	0x10c91400 >> 10 = 0x43245
>> + *
>> + * Obviously, only those TRBs with DMA addresses that are within the segment
>> + * will make the radix tree return the stream ID for that ring.
>> + *
>> + * Caveats for the radix tree:
>> + *
>> + * The radix tree uses an unsigned long as a key pair. On 32-bit systems, an
>> + * unsigned long will be 32-bits; on a 64-bit system an unsigned long will be
>> + * 64-bits. Since we only request 32-bit DMA addresses, we can use that as the
>> + * key on 32-bit or 64-bit systems (it would also be fine if we asked for 64-bit
>> + * PCI DMA addresses on a 64-bit system). There might be a problem on 32-bit
>> + * extended systems (where the DMA address can be bigger than 32-bits),
>> + * if we allow the PCI dma mask to be bigger than 32-bits. So don't do that.
>> + */
>> +static int cdnsp_insert_segment_mapping(struct radix_tree_root *trb_address_map,
>> +					struct cdnsp_ring *ring,
>> +					struct cdnsp_segment *seg,
>> +					gfp_t mem_flags)
>> +{
>> +	unsigned long key;
>> +	int ret;
>> +
>> +	key = (unsigned long)(seg->dma >> TRB_SEGMENT_SHIFT);
>> +
>> +	/* Skip any segments that were already added. */
>> +	if (radix_tree_lookup(trb_address_map, key))
>> +		return 0;
>> +
>> +	ret = radix_tree_maybe_preload(mem_flags);
>> +	if (ret)
>> +		return ret;
>> +
>> +	ret = radix_tree_insert(trb_address_map, key, ring);
>> +	radix_tree_preload_end();
>> +
>> +	return ret;
>> +}
>> +
>> +static void cdnsp_remove_segment_mapping(struct radix_tree_root *trb_address_map,
>> +					 struct cdnsp_segment *seg)
>> +{
>> +	unsigned long key;
>> +
>> +	key = (unsigned long)(seg->dma >> TRB_SEGMENT_SHIFT);
>> +	if (radix_tree_lookup(trb_address_map, key))
>> +		radix_tree_delete(trb_address_map, key);
>> +}
>> +
>> +static int cdnsp_update_stream_segment_mapping(struct radix_tree_root *trb_address_map,
>> +					       struct cdnsp_ring *ring,
>> +					       struct cdnsp_segment *first_seg,
>> +					       struct cdnsp_segment *last_seg,
>> +					       gfp_t mem_flags)
>> +{
>> +	struct cdnsp_segment *failed_seg;
>> +	struct cdnsp_segment *seg;
>> +	int ret;
>> +
>> +	seg = first_seg;
>> +	do {
>> +		ret = cdnsp_insert_segment_mapping(trb_address_map, ring, seg,
>> +						   mem_flags);
>> +		if (ret)
>> +			goto remove_streams;
>> +		if (seg == last_seg)
>> +			return 0;
>> +		seg = seg->next;
>> +	} while (seg != first_seg);
>> +
>> +	return 0;
>> +
>> +remove_streams:
>> +	failed_seg = seg;
>> +	seg = first_seg;
>> +	do {
>> +		cdnsp_remove_segment_mapping(trb_address_map, seg);
>> +		if (seg == failed_seg)
>> +			return ret;
>> +		seg = seg->next;
>> +	} while (seg != first_seg);
>> +
>> +	return ret;
>> +}
>> +
>> +static void cdnsp_remove_stream_mapping(struct cdnsp_ring *ring)
>> +{
>> +	struct cdnsp_segment *seg;
>> +
>> +	seg = ring->first_seg;
>> +	do {
>> +		cdnsp_remove_segment_mapping(ring->trb_address_map, seg);
>> +		seg = seg->next;
>> +	} while (seg != ring->first_seg);
>> +}
>> +
>> +static int cdnsp_update_stream_mapping(struct cdnsp_ring *ring)
>> +{
>> +	return cdnsp_update_stream_segment_mapping(ring->trb_address_map, ring,
>> +			ring->first_seg, ring->last_seg, GFP_ATOMIC);
>> +}
>> +
>> +void cdnsp_ring_free(struct cdnsp_device *pdev, struct cdnsp_ring *ring)
>> +{
>> +	if (!ring)
>> +		return;
>> +
>> +	if (ring->first_seg) {
>> +		if (ring->type == TYPE_STREAM)
>> +			cdnsp_remove_stream_mapping(ring);
>> +
>> +		cdnsp_free_segments_for_ring(pdev, ring->first_seg);
>> +	}
>> +
>> +	kfree(ring);
>> +}
>> +
>> +void cdnsp_initialize_ring_info(struct cdnsp_ring *ring)
>> +{
>> +	ring->enqueue = ring->first_seg->trbs;
>> +	ring->enq_seg = ring->first_seg;
>> +	ring->dequeue = ring->enqueue;
>> +	ring->deq_seg = ring->first_seg;
>> +
>> +	/*
>> +	 * The ring is initialized to 0. The producer must write 1 to the cycle
>> +	 * bit to handover ownership of the TRB, so PCS = 1. The consumer must
>> +	 * compare CCS to the cycle bit to check ownership, so CCS = 1.
>> +	 *
>> +	 * New rings are initialized with cycle state equal to 1; if we are
>> +	 * handling ring expansion, set the cycle state equal to the old ring.
>> +	 */
>> +	ring->cycle_state = 1;
>> +
>> +	/*
>> +	 * Each segment has a link TRB, and leave an extra TRB for SW
>> +	 * accounting purpose
>> +	 */
>> +	ring->num_trbs_free = ring->num_segs * (TRBS_PER_SEGMENT - 1) - 1;
>> +}
>> +
>> +/* Allocate segments and link them for a ring. */
>> +static int cdnsp_alloc_segments_for_ring(struct cdnsp_device *pdev,
>> +					 struct cdnsp_segment **first,
>> +					 struct cdnsp_segment **last,
>> +					 unsigned int num_segs,
>> +					 unsigned int cycle_state,
>> +					 enum cdnsp_ring_type type,
>> +					 unsigned int max_packet,
>> +					 gfp_t flags)
>> +{
>> +	struct cdnsp_segment *prev;
>> +
>> +	/* Allocate first segment. */
>> +	prev = cdnsp_segment_alloc(pdev, cycle_state,
>> +				   max_packet, flags);
>
>This fits on one line.
>
>	prev = cdnsp_segment_alloc(pdev, cycle_state, max_packet, flags);
>
>
>> +	if (!prev)
>> +		return -ENOMEM;
>> +
>> +	num_segs--;
>> +	*first = prev;
>> +
>> +	/* Allocate all other segments. */
>> +	while (num_segs > 0) {
>> +		struct cdnsp_segment	*next;
>> +
>> +		next = cdnsp_segment_alloc(pdev, cycle_state,
>> +					   max_packet, flags);
>> +		if (!next) {
>> +			prev = *first;
>> +
>> +			/*Free all reserved segment*/
>> +			while (prev) {
>> +				next = prev->next;
>> +				cdnsp_segment_free(pdev, prev);
>> +				prev = next;
>> +			}
>> +
>> +			return -ENOMEM;
>
>Can this free loop be replaced with cdnsp_free_segments_for_ring()?
>
>> +		}
>> +
>> +		cdnsp_link_segments(pdev, prev, next, type);
>> +
>> +		prev = next;
>> +		num_segs--;
>> +	}
>> +
>> +	cdnsp_link_segments(pdev, prev, *first, type);
>> +	*last = prev;
>> +
>> +	return 0;
>> +}
>> +
>> +/*
>> + * Create a new ring with zero or more segments.
>> + *
>> + * Link each segment together into a ring.
>> + * Set the end flag and the cycle toggle bit on the last segment.
>> + */
>> +static struct cdnsp_ring *cdnsp_ring_alloc(struct cdnsp_device *pdev,
>> +					   unsigned int num_segs,
>> +					   enum cdnsp_ring_type type,
>> +					   unsigned int max_packet,
>> +					   gfp_t flags)
>> +{
>> +	struct cdnsp_ring *ring;
>> +	int ret;
>> +
>> +	ring = kzalloc(sizeof *(ring), flags);
>> +	if (!ring)
>> +		return NULL;
>> +
>> +	ring->num_segs = num_segs;
>> +	ring->bounce_buf_len = max_packet;
>> +	INIT_LIST_HEAD(&ring->td_list);
>> +	ring->type = type;
>> +
>> +	if (num_segs == 0)
>> +		return ring;
>> +
>> +	ret = cdnsp_alloc_segments_for_ring(pdev, &ring->first_seg,
>> +					    &ring->last_seg, num_segs,
>> +					    1, type, max_packet, flags);
>> +	if (ret)
>> +		goto fail;
>> +
>> +	/* Only event ring does not use link TRB. */
>> +	if (type != TYPE_EVENT)
>> +		ring->last_seg->trbs[TRBS_PER_SEGMENT - 1].link.control |=
>> +			cpu_to_le32(LINK_TOGGLE);
>> +
>> +	cdnsp_initialize_ring_info(ring);
>> +
>> +	return ring;
>> +fail:
>> +	kfree(ring);
>> +	return NULL;
>> +}
>> +
>> +void cdnsp_free_endpoint_rings(struct cdnsp_device *pdev, struct cdnsp_ep *pep)
>> +{
>> +	cdnsp_ring_free(pdev, pep->ring);
>> +	pep->ring = NULL;
>> +	cdnsp_free_stream_info(pdev, pep);
>> +}
>> +
>> +/*
>> + * Expand an existing ring.
>> + * Allocate a new ring which has same segment numbers and link the two rings.
>> + */
>> +int cdnsp_ring_expansion(struct cdnsp_device *pdev,
>> +			 struct cdnsp_ring *ring,
>> +			 unsigned int num_trbs,
>> +			 gfp_t flags)
>> +{
>> +	unsigned int num_segs_needed;
>> +	struct cdnsp_segment *first;
>> +	struct cdnsp_segment *last;
>> +	unsigned int num_segs;
>> +	int ret;
>> +
>> +	num_segs_needed = (num_trbs + (TRBS_PER_SEGMENT - 1) - 1) /
>> +			(TRBS_PER_SEGMENT - 1);
>> +
>> +	/* Allocate number of segments we needed, or double the ring size. */
>> +	num_segs = ring->num_segs > num_segs_needed ?
>> +		   ring->num_segs : num_segs_needed;
>
>	num_segs = max(ring->num_segs, num_segs_needed);
>
>> +
>> +	ret = cdnsp_alloc_segments_for_ring(pdev, &first, &last, num_segs,
>> +					    ring->cycle_state, ring->type,
>> +					    ring->bounce_buf_len, flags);
>> +	if (ret)
>> +		return -ENOMEM;
>> +
>> +	if (ring->type == TYPE_STREAM)
>> +		ret = cdnsp_update_stream_segment_mapping(ring->trb_address_map,
>> +							  ring, first,
>> +							  last, flags);
>> +
>> +	if (ret) {
>> +		struct cdnsp_segment *next;
>> +
>> +		do {
>> +			next = first->next;
>> +			cdnsp_segment_free(pdev, first);
>> +			if (first == last)
>> +				break;
>> +			first = next;
>> +		} while (true);
>> +		return ret;
>
>I really hope this can be replaced with cdnsp_free_segments_for_ring().
 
>
>> +	}
>> +
>> +	cdnsp_link_rings(pdev, ring, first, last, num_segs);
>> +
>> +	return 0;
>> +}
>> +
>> +static int cdnsp_init_device_ctx(struct cdnsp_device *pdev)
>> +{
>> +	int size = HCC_64BYTE_CONTEXT(pdev->hcc_params) ? 2048 : 1024;
>> +
>> +	pdev->out_ctx.type = CDNSP_CTX_TYPE_DEVICE;
>> +	pdev->out_ctx.size = size;
>> +	pdev->out_ctx.ctx_size = CTX_SIZE(pdev->hcc_params);
>> +	pdev->out_ctx.bytes = dma_pool_zalloc(pdev->device_pool, GFP_ATOMIC,
>> +					      &pdev->out_ctx.dma);
>> +
>> +	if (!pdev->out_ctx.bytes)
>> +		return -ENOMEM;
>> +
>> +	pdev->in_ctx.type = CDNSP_CTX_TYPE_INPUT;
>> +	pdev->in_ctx.ctx_size = pdev->out_ctx.ctx_size;
>> +	pdev->in_ctx.size = size + pdev->out_ctx.ctx_size;
>> +	pdev->in_ctx.bytes = dma_pool_zalloc(pdev->device_pool, GFP_ATOMIC,
>> +					     &pdev->in_ctx.dma);
>> +
>> +	if (!pdev->in_ctx.bytes) {
>> +		dma_pool_free(pdev->device_pool, pdev->out_ctx.bytes,
>> +			      pdev->out_ctx.dma);
>> +		return -ENOMEM;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +struct cdnsp_input_control_ctx
>> +	*cdnsp_get_input_control_ctx(struct cdnsp_container_ctx *ctx)
>> +{
>> +	if (ctx->type != CDNSP_CTX_TYPE_INPUT)
>> +		return NULL;
>> +
>> +	return (struct cdnsp_input_control_ctx *)ctx->bytes;
>> +}
>> +
>> +struct cdnsp_slot_ctx *cdnsp_get_slot_ctx(struct cdnsp_container_ctx *ctx)
>> +{
>> +	if (ctx->type == CDNSP_CTX_TYPE_DEVICE)
>> +		return (struct cdnsp_slot_ctx *)ctx->bytes;
>> +
>> +	return (struct cdnsp_slot_ctx *)(ctx->bytes + ctx->ctx_size);
>> +}
>> +
>> +struct cdnsp_ep_ctx *cdnsp_get_ep_ctx(struct cdnsp_container_ctx *ctx,
>> +				      unsigned int ep_index)
>> +{
>> +	/* Increment ep index by offset of start of ep ctx array. */
>> +	ep_index++;
>> +	if (ctx->type == CDNSP_CTX_TYPE_INPUT)
>> +		ep_index++;
>> +
>> +	return (struct cdnsp_ep_ctx *)(ctx->bytes +
>> +		(ep_index * ctx->ctx_size));
>
>
>This fits in 80 characters:
>
>	return (struct cdnsp_ep_ctx *)(ctx->bytes + (ep_index * ctx->ctx_size));
>
>> +}
>> +
>> +static void cdnsp_free_stream_ctx(struct cdnsp_device *pdev,
>> +				  struct cdnsp_ep *pep)
>> +{
>> +	size_t size = sizeof(struct cdnsp_stream_ctx) *
>> +		      pep->stream_info.num_stream_ctxs;
>> +
>> +	dma_free_coherent(pdev->dev, size, pep->stream_info.stream_ctx_array,
>> +			  pep->stream_info.ctx_array_dma);
>> +}
>> +
>> +/* The stream context array must be a power of 2. */
>> +static struct cdnsp_stream_ctx
>> +	*cdnsp_alloc_stream_ctx(struct cdnsp_device *pdev, struct cdnsp_ep *pep)
>> +{
>> +	size_t size = sizeof(struct cdnsp_stream_ctx) *
>> +		      pep->stream_info.num_stream_ctxs;
>> +
>> +	return dma_alloc_coherent(pdev->dev, size,
>> +				  &pep->stream_info.ctx_array_dma,
>> +				  GFP_DMA32 | GFP_ATOMIC);
>> +}
>> +
>> +struct cdnsp_ring *cdnsp_dma_to_transfer_ring(struct cdnsp_ep *pep, u64 address)
>> +{
>> +	if (pep->ep_state & EP_HAS_STREAMS)
>> +		return radix_tree_lookup(&pep->stream_info.trb_address_map,
>> +					 address >> TRB_SEGMENT_SHIFT);
>> +
>> +	return pep->ring;
>> +}
>> +
>> +/*
>> + * Change an endpoint's internal structure so it supports stream IDs.
>> + * The number of requested streams includes stream 0, which cannot be used by
>> + * driver.
>> + *
>> + * The number of stream contexts in the stream context array may be bigger than
>> + * the number of streams the driver wants to use. This is because the number of
>> + * stream context array entries must be a power of two.
>> + */
>> +int cdnsp_alloc_stream_info(struct cdnsp_device *pdev,
>> +			    struct cdnsp_ep *pep,
>> +			    unsigned int num_stream_ctxs,
>> +			    unsigned int num_streams)
>> +{
>> +	struct cdnsp_stream_info *stream_info;
>> +	struct cdnsp_ring *cur_ring;
>> +	u32 cur_stream;
>> +	u64 addr;
>> +	int ret;
>> +	int mps;
>> +
>> +	stream_info = &pep->stream_info;
>> +	stream_info->num_streams = num_streams;
>> +	stream_info->num_stream_ctxs = num_stream_ctxs;
>> +
>> +	/* Initialize the array of virtual pointers to stream rings. */
>> +	stream_info->stream_rings = kcalloc(num_streams,
>> +					    sizeof(struct cdnsp_ring *),
>> +					    GFP_ATOMIC);
>> +	if (!stream_info->stream_rings)
>> +		return -ENOMEM;
>> +
>> +	/* Initialize the array of DMA addresses for stream rings for the HW. */
>> +	stream_info->stream_ctx_array = cdnsp_alloc_stream_ctx(pdev, pep);
>> +	if (!stream_info->stream_ctx_array)
>> +		goto cleanup_ctx;
>> +
>> +	memset(stream_info->stream_ctx_array, 0,
>> +	       sizeof(struct cdnsp_stream_ctx) * num_stream_ctxs);
>> +	INIT_RADIX_TREE(&stream_info->trb_address_map, GFP_ATOMIC);
>> +	mps = usb_endpoint_maxp(pep->endpoint.desc);
>> +
>> +	/*
>> +	 * Allocate rings for all the streams that the driver will use,
>> +	 * and add their segment DMA addresses to the radix tree.
>> +	 * Stream 0 is reserved.
>> +	 */
>> +	for (cur_stream = 1; cur_stream < num_streams; cur_stream++) {
>> +		cur_ring = cdnsp_ring_alloc(pdev, 2, TYPE_STREAM, mps,
>> +					    GFP_ATOMIC);
>> +		stream_info->stream_rings[cur_stream] = cur_ring;
>> +
>> +		if (!cur_ring)
>> +			goto cleanup_rings;
>> +
>> +		cur_ring->stream_id = cur_stream;
>> +		cur_ring->trb_address_map = &stream_info->trb_address_map;
>> +
>> +		/* Set deq ptr, cycle bit, and stream context type. */
>> +		addr = cur_ring->first_seg->dma | SCT_FOR_CTX(SCT_PRI_TR) |
>> +		       cur_ring->cycle_state;
>> +
>> +		stream_info->stream_ctx_array[cur_stream].stream_ring =
>> +			cpu_to_le64(addr);
>> +
>> +		ret = cdnsp_update_stream_mapping(cur_ring);
>> +		if (ret) {
>> +			cdnsp_ring_free(pdev, cur_ring);
>> +			stream_info->stream_rings[cur_stream] = NULL;
>
>
> This is the same as the error handling code so just do:
>	goto cleanup_rings;
>
>Presumably it's ok to undo the mappings if cdnsp_update_stream_mapping()
>failed.
>
>> +			goto cleanup_rings;
>> +		}
>> +	}
>> +
>> +	return 0;
>> +
>> +cleanup_rings:
>> +	for (cur_stream = 1; cur_stream < num_streams; cur_stream++) {
>> +		cur_ring = stream_info->stream_rings[cur_stream];
>> +		if (cur_ring) {
>> +			cdnsp_ring_free(pdev, cur_ring);
>> +			stream_info->stream_rings[cur_stream] = NULL;
>> +		}
>> +	}
>> +
>> +cleanup_ctx:
>> +	kfree(pep->stream_info.stream_rings);
>
>It could be nicer to say:  kfree(stream_info->stream_rings);  maybe the
>function name could be "free_rings;" or something?  I don't understand
>what "ctx" means here.
>
>
>> +
>> +	return -ENOMEM;
>> +}
>> +
>> +/* Frees all stream contexts associated with the endpoint. */
>> +static void cdnsp_free_stream_info(struct cdnsp_device *pdev,
>> +				   struct cdnsp_ep *pep)
>> +{
>> +	struct cdnsp_stream_info *stream_info = &pep->stream_info;
>> +	struct cdnsp_ring *cur_ring;
>> +	int cur_stream;
>> +
>> +	if (!(pep->ep_state & EP_HAS_STREAMS))
>> +		return;
>> +
>> +	for (cur_stream = 1; cur_stream < stream_info->num_streams;
>> +	     cur_stream++) {
>> +		cur_ring = stream_info->stream_rings[cur_stream];
>> +		if (cur_ring) {
>> +			cdnsp_ring_free(pdev, cur_ring);
>> +			stream_info->stream_rings[cur_stream] = NULL;
>> +		}
>> +	}
>> +
>> +	if (stream_info->stream_ctx_array)
>> +		cdnsp_free_stream_ctx(pdev, pep);
>> +
>> +	kfree(stream_info->stream_rings);
>> +	pep->ep_state &= ~EP_HAS_STREAMS;
>> +}
>> +
>> +/* All the cdnsp_tds in the ring's TD list should be freed at this point.*/
>> +static void cdnsp_free_priv_device(struct cdnsp_device *pdev)
>> +{
>> +	pdev->dcbaa->dev_context_ptrs[1] = 0;
>> +
>> +	cdnsp_free_endpoint_rings(pdev, &pdev->eps[0]);
>> +
>> +	if (pdev->in_ctx.bytes)
>> +		dma_pool_free(pdev->device_pool, pdev->in_ctx.bytes,
>> +			      pdev->in_ctx.dma);
>> +
>> +	if (pdev->out_ctx.bytes)
>> +		dma_pool_free(pdev->device_pool, pdev->out_ctx.bytes,
>> +			      pdev->out_ctx.dma);
>> +
>> +	pdev->in_ctx.bytes = NULL;
>> +	pdev->out_ctx.bytes = NULL;
>> +}
>> +
>> +static int cdnsp_alloc_priv_device(struct cdnsp_device *pdev, gfp_t flags)
>> +{
>> +	int ret = -ENOMEM;
>> +
>> +	ret = cdnsp_init_device_ctx(pdev);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	/* Allocate endpoint 0 ring. */
>> +	pdev->eps[0].ring = cdnsp_ring_alloc(pdev, 2, TYPE_CTRL, 0, flags);
>> +	if (!pdev->eps[0].ring)
>> +		goto fail;
>> +
>> +	/* Point to output device context in dcbaa. */
>> +	pdev->dcbaa->dev_context_ptrs[1] = cpu_to_le64(pdev->out_ctx.dma);
>> +	pdev->cmd.in_ctx = &pdev->in_ctx;
>> +
>> +	return 0;
>> +fail:
>> +	dma_pool_free(pdev->device_pool, pdev->out_ctx.bytes,
>> +		      pdev->out_ctx.dma);
>> +	dma_pool_free(pdev->device_pool, pdev->in_ctx.bytes,
>> +		      pdev->in_ctx.dma);
>> +
>> +	return ret;
>> +}
>> +
>> +void cdnsp_copy_ep0_dequeue_into_input_ctx(struct cdnsp_device *pdev)
>> +{
>> +	struct cdnsp_ep_ctx *ep0_ctx = pdev->eps[0].in_ctx;
>> +	struct cdnsp_ring *ep_ring = pdev->eps[0].ring;
>> +	dma_addr_t dma;
>> +
>> +	dma = cdnsp_trb_virt_to_dma(ep_ring->enq_seg, ep_ring->enqueue);
>> +	ep0_ctx->deq = cpu_to_le64(dma | ep_ring->cycle_state);
>> +}
>> +
>> +/* Setup an controller private device for a Set Address command. */
>> +int cdnsp_setup_addressable_priv_dev(struct cdnsp_device *pdev)
>> +{
>> +	struct cdnsp_slot_ctx *slot_ctx;
>> +	struct cdnsp_ep_ctx *ep0_ctx;
>> +	u32 max_packets, port;
>> +
>> +	ep0_ctx = cdnsp_get_ep_ctx(&pdev->in_ctx, 0);
>> +	slot_ctx = cdnsp_get_slot_ctx(&pdev->in_ctx);
>> +
>> +	/* Only the control endpoint is valid - one endpoint context. */
>> +	slot_ctx->dev_info |= cpu_to_le32(LAST_CTX(1));
>> +
>> +	switch (pdev->gadget.speed) {
>> +	case USB_SPEED_SUPER_PLUS:
>> +		slot_ctx->dev_info |= cpu_to_le32(SLOT_SPEED_SSP);
>> +		max_packets = MAX_PACKET(512);
>> +		break;
>> +	case USB_SPEED_SUPER:
>> +		slot_ctx->dev_info |= cpu_to_le32(SLOT_SPEED_SS);
>> +		max_packets = MAX_PACKET(512);
>> +		break;
>> +	case USB_SPEED_HIGH:
>> +		slot_ctx->dev_info |= cpu_to_le32(SLOT_SPEED_HS);
>> +		max_packets = MAX_PACKET(64);
>> +		break;
>> +	case USB_SPEED_FULL:
>> +		slot_ctx->dev_info |= cpu_to_le32(SLOT_SPEED_FS);
>> +		max_packets = MAX_PACKET(64);
>> +		break;
>> +	default:
>> +		/* Speed was not set , this shouldn't happen. */
>> +		return -EINVAL;
>> +	}
>> +
>> +	port = DEV_PORT(pdev->active_port->port_num);
>> +	slot_ctx->dev_port |= cpu_to_le32(port);
>> +	slot_ctx->dev_state = (pdev->device_address & DEV_ADDR_MASK);
>> +	ep0_ctx->tx_info = EP_AVG_TRB_LENGTH(0x8);
>> +	ep0_ctx->ep_info2 = cpu_to_le32(EP_TYPE(CTRL_EP));
>> +	ep0_ctx->ep_info2 |= cpu_to_le32(MAX_BURST(0) | ERROR_COUNT(3) |
>> +					 max_packets);
>> +
>> +	ep0_ctx->deq = cpu_to_le64(pdev->eps[0].ring->first_seg->dma |
>> +				   pdev->eps[0].ring->cycle_state);
>> +
>> +	return 0;
>> +}
>> +
>> +/*
>> + * Convert interval expressed as 2^(bInterval - 1) == interval into
>> + * straight exponent value 2^n == interval.
>> + */
>> +static unsigned int cdnsp_parse_exponent_interval(struct usb_gadget *g,
>> +						  struct cdnsp_ep *pep)
>> +{
>> +	unsigned int interval;
>> +
>> +	interval = clamp_val(pep->endpoint.desc->bInterval, 1, 16) - 1;
>> +	if (interval != pep->endpoint.desc->bInterval - 1)
>> +		dev_warn(&g->dev, "ep %s - rounding interval to %d %sframes\n",
>> +			 pep->name, 1 << interval,
>> +			 g->speed == USB_SPEED_FULL ? "" : "micro");
>> +
>> +	/*
>> +	 * Full speed isoc endpoints specify interval in frames,
>> +	 * not microframes. We are using microframes everywhere,
>> +	 * so adjust accordingly.
>> +	 */
>> +	if (g->speed == USB_SPEED_FULL)
>> +		interval += 3;	/* 1 frame = 2^3 uframes */
>> +
>> +	/* Controller handles only up to 512ms (2^12). */
>> +	if (interval > 12)
>> +		interval = 12;
>> +
>> +	return interval;
>> +}
>> +
>> +/*
>> + * Convert bInterval expressed in microframes (in 1-255 range) to exponent of
>> + * microframes, rounded down to nearest power of 2.
>> + */
>> +static unsigned int cdnsp_microframes_to_exponent(struct usb_gadget *g,
>> +						  struct cdnsp_ep *pep,
>> +						  unsigned int desc_interval,
>> +						  unsigned int min_exponent,
>> +						  unsigned int max_exponent)
>> +{
>> +	unsigned int interval;
>> +
>> +	interval = fls(desc_interval) - 1;
>> +	return clamp_val(interval, min_exponent, max_exponent);
>> +}
>> +
>> +/*
>> + * Return the polling interval.
>> + *
>> + * The polling interval is expressed in "microframes". If controllers's Interval
>> + * field is set to N, it will service the endpoint every 2^(Interval)*125us.
>> + */
>> +static unsigned int cdnsp_get_endpoint_interval(struct usb_gadget *g,
>> +						struct cdnsp_ep *pep)
>> +{
>> +	unsigned int interval = 0;
>> +
>> +	switch (g->speed) {
>> +	case USB_SPEED_HIGH:
>> +	case USB_SPEED_SUPER_PLUS:
>> +	case USB_SPEED_SUPER:
>> +		if (usb_endpoint_xfer_int(pep->endpoint.desc) ||
>> +		    usb_endpoint_xfer_isoc(pep->endpoint.desc))
>> +			interval = cdnsp_parse_exponent_interval(g, pep);
>> +		break;
>> +	case USB_SPEED_FULL:
>> +		if (usb_endpoint_xfer_isoc(pep->endpoint.desc)) {
>> +			interval = cdnsp_parse_exponent_interval(g, pep);
>> +		} else if (usb_endpoint_xfer_int(pep->endpoint.desc)) {
>> +			interval = pep->endpoint.desc->bInterval << 3;
>> +			interval = cdnsp_microframes_to_exponent(g, pep,
>> +								 interval,
>> +								 3, 10);
>> +		}
>> +
>> +		break;
>> +	default:
>> +		WARN_ON(1);
>> +	}
>> +
>> +	return interval;
>> +}
>> +
>> +/*
>> + * The "Mult" field in the endpoint context is only set for SuperSpeed isoc eps.
>> + * High speed endpoint descriptors can define "the number of additional
>> + * transaction opportunities per microframe", but that goes in the Max Burst
>> + * endpoint context field.
>> + */
>> +static u32 cdnsp_get_endpoint_mult(struct usb_gadget *g, struct cdnsp_ep *pep)
>> +{
>> +	if (g->speed < USB_SPEED_SUPER ||
>> +	    !usb_endpoint_xfer_isoc(pep->endpoint.desc))
>> +		return 0;
>> +
>> +	return pep->endpoint.comp_desc->bmAttributes;
>> +}
>> +
>> +static u32 cdnsp_get_endpoint_max_burst(struct usb_gadget *g,
>> +					struct cdnsp_ep *pep)
>> +{
>> +	/* Super speed and Plus have max burst in ep companion desc */
>> +	if (g->speed >= USB_SPEED_SUPER)
>> +		return pep->endpoint.comp_desc->bMaxBurst;
>> +
>> +	if (g->speed == USB_SPEED_HIGH &&
>> +	    (usb_endpoint_xfer_isoc(pep->endpoint.desc) ||
>> +	     usb_endpoint_xfer_int(pep->endpoint.desc)))
>> +		return (usb_endpoint_maxp(pep->endpoint.desc) & 0x1800) >> 11;
>> +
>> +	return 0;
>> +}
>> +
>> +static u32 cdnsp_get_endpoint_type(const struct usb_endpoint_descriptor *desc)
>> +{
>> +	int in;
>> +
>> +	in = usb_endpoint_dir_in(desc);
>> +
>> +	switch (usb_endpoint_type(desc)) {
>> +	case USB_ENDPOINT_XFER_CONTROL:
>> +		return CTRL_EP;
>> +	case USB_ENDPOINT_XFER_BULK:
>> +		return in ? BULK_IN_EP : BULK_OUT_EP;
>> +	case USB_ENDPOINT_XFER_ISOC:
>> +		return in ? ISOC_IN_EP : ISOC_OUT_EP;
>> +	case USB_ENDPOINT_XFER_INT:
>> +		return in ? INT_IN_EP : INT_OUT_EP;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +/*
>> + * Return the maximum endpoint service interval time (ESIT) payload.
>> + * Basically, this is the maxpacket size, multiplied by the burst size
>> + * and mult size.
>> + */
>> +static u32 cdnsp_get_max_esit_payload(struct usb_gadget *g,
>> +				      struct cdnsp_ep *pep)
>> +{
>> +	int max_packet;
>> +	int max_burst;
>> +
>> +	/* Only applies for interrupt or isochronous endpoints*/
>> +	if (usb_endpoint_xfer_control(pep->endpoint.desc) ||
>> +	    usb_endpoint_xfer_bulk(pep->endpoint.desc))
>> +		return 0;
>> +
>> +	/* SuperSpeedPlus Isoc ep sending over 48k per EIST. */
>> +	if (g->speed >= USB_SPEED_SUPER_PLUS &&
>> +	    USB_SS_SSP_ISOC_COMP(pep->endpoint.desc->bmAttributes))
>> +		return le32_to_cpu(pep->endpoint.comp_desc->wBytesPerInterval);
>> +	/* SuperSpeed or SuperSpeedPlus Isoc ep with less than 48k per esit */
>> +	else if (g->speed >= USB_SPEED_SUPER)
>> +		return le16_to_cpu(pep->endpoint.comp_desc->wBytesPerInterval);
>> +
>> +	max_packet = usb_endpoint_maxp(pep->endpoint.desc);
>> +	max_burst = usb_endpoint_maxp_mult(pep->endpoint.desc);
>> +
>> +	/* A 0 in max burst means 1 transfer per ESIT */
>> +	return max_packet * max_burst;
>> +}
>> +
>> +int cdnsp_endpoint_init(struct cdnsp_device *pdev,
>> +			struct cdnsp_ep *pep,
>> +			gfp_t mem_flags)
>> +{
>> +	enum cdnsp_ring_type ring_type;
>> +	struct cdnsp_ep_ctx *ep_ctx;
>> +	unsigned int err_count = 0;
>> +	unsigned int avg_trb_len;
>> +	unsigned int max_packet;
>> +	unsigned int max_burst;
>> +	unsigned int interval;
>> +	u32 max_esit_payload;
>> +	unsigned int mult;
>> +	u32 endpoint_type;
>> +	int ret;
>> +
>> +	ep_ctx = pep->in_ctx;
>> +
>> +	endpoint_type = cdnsp_get_endpoint_type(pep->endpoint.desc);
>> +	if (!endpoint_type)
>> +		return -EINVAL;
>> +
>> +	ring_type = usb_endpoint_type(pep->endpoint.desc);
>> +
>> +	/*
>> +	 * Get values to fill the endpoint context, mostly from ep descriptor.
>> +	 * The average TRB buffer length for bulk endpoints is unclear as we
>> +	 * have no clue on scatter gather list entry size. For Isoc and Int,
>> +	 * set it to max available.
>> +	 */
>> +	max_esit_payload = cdnsp_get_max_esit_payload(&pdev->gadget, pep);
>> +	interval = cdnsp_get_endpoint_interval(&pdev->gadget, pep);
>> +	mult = cdnsp_get_endpoint_mult(&pdev->gadget, pep);
>> +	max_packet = usb_endpoint_maxp(pep->endpoint.desc);
>> +	max_burst = cdnsp_get_endpoint_max_burst(&pdev->gadget, pep);
>> +	avg_trb_len = max_esit_payload;
>> +
>> +	/* Allow 3 retries for everything but isoc, set CErr = 3. */
>> +	if (!usb_endpoint_xfer_isoc(pep->endpoint.desc))
>> +		err_count = 3;
>> +	if (usb_endpoint_xfer_bulk(pep->endpoint.desc) &&
>> +	    pdev->gadget.speed == USB_SPEED_HIGH)
>> +		max_packet = 512;
>> +	/* Controller spec indicates that ctrl ep avg TRB Length should be 8. */
>> +	if (usb_endpoint_xfer_control(pep->endpoint.desc))
>> +		avg_trb_len = 8;
>> +
>> +	/* Set up the endpoint ring. */
>> +	pep->ring = cdnsp_ring_alloc(pdev, 2, ring_type, max_packet, mem_flags);
>> +	pep->skip = false;
>> +
>> +	/* Fill the endpoint context */
>> +	ep_ctx->ep_info = cpu_to_le32(EP_MAX_ESIT_PAYLOAD_HI(max_esit_payload) |
>> +				EP_INTERVAL(interval) | EP_MULT(mult));
>> +	ep_ctx->ep_info2 = cpu_to_le32(EP_TYPE(endpoint_type) |
>> +				MAX_PACKET(max_packet) | MAX_BURST(max_burst) |
>> +				ERROR_COUNT(err_count));
>> +	ep_ctx->deq = cpu_to_le64(pep->ring->first_seg->dma |
>> +				  pep->ring->cycle_state);
>> +
>> +	ep_ctx->tx_info = cpu_to_le32(EP_MAX_ESIT_PAYLOAD_LO(max_esit_payload) |
>> +				EP_AVG_TRB_LENGTH(avg_trb_len));
>> +
>> +	if (usb_endpoint_xfer_bulk(pep->endpoint.desc) &&
>> +	    pdev->gadget.speed > USB_SPEED_HIGH) {
>> +		ret = cdnsp_alloc_streams(pdev, pep);
>> +		if (ret < 0)
>> +			return ret;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +void cdnsp_endpoint_zero(struct cdnsp_device *pdev, struct cdnsp_ep *pep)
>> +{
>> +	pep->in_ctx->ep_info = 0;
>> +	pep->in_ctx->ep_info2 = 0;
>> +	pep->in_ctx->deq = 0;
>> +	pep->in_ctx->tx_info = 0;
>> +}
>> +
>> +int cdnsp_alloc_erst(struct cdnsp_device *pdev,
>> +		     struct cdnsp_ring *evt_ring,
>> +		     struct cdnsp_erst *erst,
>> +		     gfp_t flags)
>> +{
>> +	struct cdnsp_erst_entry *entry;
>> +	struct cdnsp_segment *seg;
>> +	unsigned int val;
>> +	size_t size;
>> +
>> +	size = sizeof(struct cdnsp_erst_entry) * evt_ring->num_segs;
>> +	erst->entries = dma_alloc_coherent(pdev->dev, size,
>> +					   &erst->erst_dma_addr, flags);
>> +	if (!erst->entries)
>> +		return -ENOMEM;
>> +
>> +	erst->num_entries = evt_ring->num_segs;
>> +
>> +	seg = evt_ring->first_seg;
>> +	for (val = 0; val < evt_ring->num_segs; val++) {
>> +		entry = &erst->entries[val];
>> +		entry->seg_addr = cpu_to_le64(seg->dma);
>> +		entry->seg_size = cpu_to_le32(TRBS_PER_SEGMENT);
>> +		entry->rsvd = 0;
>> +		seg = seg->next;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +void cdnsp_free_erst(struct cdnsp_device *pdev, struct cdnsp_erst *erst)
>> +{
>> +	size_t size = sizeof(struct cdnsp_erst_entry) * (erst->num_entries);
>> +	struct device *dev = pdev->dev;
>> +
>> +	if (erst->entries)
>> +		dma_free_coherent(dev, size, erst->entries,
>> +				  erst->erst_dma_addr);
>> +
>> +	erst->entries = NULL;
>> +}
>> +
>> +void cdnsp_mem_cleanup(struct cdnsp_device *pdev)
>> +{
>> +	struct device *dev = pdev->dev;
>> +
>> +	cdnsp_free_priv_device(pdev);
>> +	cdnsp_free_erst(pdev, &pdev->erst);
>> +
>> +	if (pdev->event_ring)
>> +		cdnsp_ring_free(pdev, pdev->event_ring);
>> +
>> +	pdev->event_ring = NULL;
>> +
>> +	if (pdev->cmd_ring)
>> +		cdnsp_ring_free(pdev, pdev->cmd_ring);
>> +
>> +	pdev->cmd_ring = NULL;
>> +
>> +	dma_pool_destroy(pdev->segment_pool);
>> +	pdev->segment_pool = NULL;
>> +	dma_pool_destroy(pdev->device_pool);
>> +	pdev->device_pool = NULL;
>> +
>> +	if (pdev->dcbaa)
>> +		dma_free_coherent(dev, sizeof(*pdev->dcbaa),
>> +				  pdev->dcbaa, pdev->dcbaa->dma);
>> +
>> +	pdev->dcbaa = NULL;
>> +
>> +	pdev->usb2_port.exist = 0;
>> +	pdev->usb3_port.exist = 0;
>> +	pdev->usb2_port.port_num = 0;
>> +	pdev->usb3_port.port_num = 0;
>> +	pdev->active_port = NULL;
>> +}
>> +
>> +static void cdnsp_set_event_deq(struct cdnsp_device *pdev)
>> +{
>> +	dma_addr_t deq;
>> +	u64 temp;
>> +
>> +	deq = cdnsp_trb_virt_to_dma(pdev->event_ring->deq_seg,
>> +				    pdev->event_ring->dequeue);
>> +
>> +	/* Update controller event ring dequeue pointer */
>> +	temp = cdnsp_read_64(pdev, &pdev->ir_set->erst_dequeue);
>> +	temp &= ERST_PTR_MASK;
>> +
>> +	/*
>> +	 * Don't clear the EHB bit (which is RW1C) because
>> +	 * there might be more events to service.
>> +	 */
>> +	temp &= ~ERST_EHB;
>> +
>> +	cdnsp_write_64(pdev, ((u64)deq & (u64)~ERST_PTR_MASK) | temp,
>> +		       &pdev->ir_set->erst_dequeue);
>> +}
>> +
>> +static void cdnsp_add_in_port(struct cdnsp_device *pdev,
>> +			      struct cdnsp_port *port,
>> +			      __le32 __iomem *addr)
>> +{
>> +	u32 temp, port_offset, port_count;
>> +
>> +	temp = readl(addr);
>> +	port->maj_rev = CDNSP_EXT_PORT_MAJOR(temp);
>> +	port->min_rev = CDNSP_EXT_PORT_MINOR(temp);
>> +
>> +	/* Port offset and count in the third dword.*/
>> +	temp = readl(addr + 2);
>> +	port_offset = CDNSP_EXT_PORT_OFF(temp);
>> +	port_count = CDNSP_EXT_PORT_COUNT(temp);
>> +
>> +	port->port_num = port_offset;
>> +	port->exist = 1;
>> +}
>> +
>> +/*
>> + * Scan the Extended Capabilities for the "Supported Protocol Capabilities" that
>> + * specify what speeds each port is supposed to be.
>> + */
>> +static int cdnsp_setup_port_arrays(struct cdnsp_device *pdev, gfp_t flags)
>> +{
>> +	void __iomem *base;
>> +	u32 offset = 0;
>> +	int i;
>> +
>> +	base = &pdev->cap_regs->hc_capbase;
>> +	offset = cdnsp_find_next_ext_cap(base, offset,
>> +					 EXT_CAP_CFG_DEV_20PORT_CAP_ID);
>> +	pdev->port20_regs = base + offset;
>> +
>> +	base = &pdev->cap_regs->hc_capbase;
>> +	offset = cdnsp_find_next_ext_cap(base, offset, D_XEC_CFG_3XPORT_CAP);
>> +	pdev->port3x_regs =  base + offset;
>> +
>> +	offset = 0;
>> +	base = &pdev->cap_regs->hc_capbase;
>> +
>> +	/* Driver expects max 2 extended protocol capability. */
>> +	for (i = 0; i < 2; i++) {
>> +		u32 temp;
>> +
>> +		offset = cdnsp_find_next_ext_cap(base, offset,
>> +						 EXT_CAPS_PROTOCOL);
>> +		temp = readl(base + offset);
>> +
>> +		if (CDNSP_EXT_PORT_MAJOR(temp) == 0x03 &&
>> +		    !pdev->usb3_port.port_num)
>> +			cdnsp_add_in_port(pdev, &pdev->usb3_port,
>> +					  base + offset);
>> +
>> +		if (CDNSP_EXT_PORT_MAJOR(temp) == 0x02 &&
>> +		    !pdev->usb2_port.port_num)
>> +			cdnsp_add_in_port(pdev, &pdev->usb2_port,
>> +					  base + offset);
>> +	}
>> +
>> +	if (!pdev->usb2_port.exist || !pdev->usb3_port.exist) {
>> +		dev_err(pdev->dev, "Error: Only one port detected\n");
>> +		return -ENODEV;
>> +	}
>> +
>> +	pdev->usb2_port.regs = (struct cdnsp_port_regs *)
>> +			       (&pdev->op_regs->port_reg_base + NUM_PORT_REGS *
>> +				(pdev->usb2_port.port_num - 1));
>> +
>> +	pdev->usb3_port.regs = (struct cdnsp_port_regs *)
>> +			       (&pdev->op_regs->port_reg_base + NUM_PORT_REGS *
>> +				(pdev->usb3_port.port_num - 1));
>> +
>> +	return 0;
>> +}
>> +
>> +/*
>> + * Initialize memory for CDNSP (one-time init).
>> + *
>> + * Program the PAGESIZE register, initialize the device context array, create
>> + * device contexts, set up a command ring segment, create event
>> + * ring (one for now).
>> + */
>> +int cdnsp_mem_init(struct cdnsp_device *pdev, gfp_t flags)
>> +{
>> +	struct device *dev = pdev->dev;
>> +	unsigned int val;
>> +	dma_addr_t dma;
>> +	u32 page_size;
>> +	u64 val_64;
>> +	int ret;
>> +
>> +	/*
>> +	 * Use 4K pages, since that's common and the minimum the
>> +	 * controller supports
>> +	 */
>> +	page_size = 1 << 12;
>> +
>> +	val = readl(&pdev->op_regs->config_reg);
>> +	val |= ((val & ~MAX_DEVS) | CDNSP_DEV_MAX_SLOTS);
>> +	writel(val, &pdev->op_regs->config_reg);
>> +
>> +	/*
>> +	 * Doorbell array must be physically contiguous
>> +	 * and 64-byte (cache line) aligned.
>> +	 */
>> +	pdev->dcbaa = dma_alloc_coherent(dev, sizeof(*pdev->dcbaa),
>> +					 &dma, GFP_KERNEL);
>> +	if (!pdev->dcbaa)
>> +		goto fail;
>> +
>> +	memset(pdev->dcbaa, 0, sizeof(*pdev->dcbaa));
>> +	pdev->dcbaa->dma = dma;
>> +
>> +	cdnsp_write_64(pdev, dma, &pdev->op_regs->dcbaa_ptr);
>> +
>> +	/*
>> +	 * Initialize the ring segment pool.  The ring must be a contiguous
>> +	 * structure comprised of TRBs. The TRBs must be 16 byte aligned,
>> +	 * however, the command ring segment needs 64-byte aligned segments
>> +	 * and our use of dma addresses in the trb_address_map radix tree needs
>> +	 * TRB_SEGMENT_SIZE alignment, so driver pick the greater alignment
>> +	 * need.
>> +	 */
>> +	pdev->segment_pool = dma_pool_create("CDNSP ring segments", dev,
>> +					     TRB_SEGMENT_SIZE, TRB_SEGMENT_SIZE,
>> +					     page_size);
>> +
>> +	pdev->device_pool = dma_pool_create("CDNSP input/output contexts", dev,
>> +					    2112, 64, page_size);
>
>Replace 2112 with a define.
>
>> +
>> +	if (!pdev->segment_pool || !pdev->device_pool)
>> +		goto fail;
>> +
>> +	/* Set up the command ring to have one segments for now. */
>> +	pdev->cmd_ring = cdnsp_ring_alloc(pdev, 1, TYPE_COMMAND, 0, flags);
>> +	if (!pdev->cmd_ring)
>> +		goto fail;
>> +
>> +	/* Set the address in the Command Ring Control register */
>> +	val_64 = cdnsp_read_64(pdev, &pdev->op_regs->cmd_ring);
>> +	val_64 = (val_64 & (u64)CMD_RING_RSVD_BITS) |
>> +		 (pdev->cmd_ring->first_seg->dma & (u64)~CMD_RING_RSVD_BITS) |
>> +		 pdev->cmd_ring->cycle_state;
>> +	cdnsp_write_64(pdev, val_64, &pdev->op_regs->cmd_ring);
>> +
>> +	val = readl(&pdev->cap_regs->db_off);
>> +	val &= DBOFF_MASK;
>> +	pdev->dba = (void __iomem *)pdev->cap_regs + val;
>> +
>> +	/* Set ir_set to interrupt register set 0 */
>> +	pdev->ir_set = &pdev->run_regs->ir_set[0];
>> +
>> +	/*
>> +	 * Event ring setup: Allocate a normal ring, but also setup
>> +	 * the event ring segment table (ERST).
>> +	 */
>> +	pdev->event_ring = cdnsp_ring_alloc(pdev, ERST_NUM_SEGS, TYPE_EVENT,
>> +					    0, flags);
>> +	if (!pdev->event_ring)
>> +		goto fail;
>> +
>> +	ret = cdnsp_alloc_erst(pdev, pdev->event_ring, &pdev->erst, flags);
>> +	if (ret)
>> +		goto fail;
>> +
>> +	/* Set ERST count with the number of entries in the segment table. */
>> +	val = readl(&pdev->ir_set->erst_size);
>> +	val &= ERST_SIZE_MASK;
>> +	val |= ERST_NUM_SEGS;
>> +	writel(val, &pdev->ir_set->erst_size);
>> +
>> +	/* Set the segment table base address. */
>> +	val_64 = cdnsp_read_64(pdev, &pdev->ir_set->erst_base);
>> +	val_64 &= ERST_PTR_MASK;
>> +	val_64 |= (pdev->erst.erst_dma_addr & (u64)~ERST_PTR_MASK);
>> +	cdnsp_write_64(pdev, val_64, &pdev->ir_set->erst_base);
>> +
>> +	/* Set the event ring dequeue address. */
>> +	cdnsp_set_event_deq(pdev);
>> +
>> +	if (cdnsp_setup_port_arrays(pdev, flags))
>
>Preserve the error code.
>
>> +		goto fail;
>> +
>> +	if (cdnsp_alloc_priv_device(pdev, GFP_ATOMIC)) {
>
>Preserve the error code.
>
>> +		dev_err(pdev->dev,
>> +			"Could not allocate cdnsp_device data structures\n");
>> +		goto fail;
>> +	}
>> +
>> +	return 0;
>> +fail:
>
>I always tell everyone that if there is an error label called "fail:"
>or "err:" or "out:" that's a redflag.  Label names should say what the
>label does.
>
>> +	dev_err(pdev->dev, "Couldn't initialize memory\n");
>> +	cdnsp_halt(pdev);
>> +	cdnsp_reset(pdev);
>> +	cdnsp_mem_cleanup(pdev);
>
>This style of error handling is hopeless.  You've got one big function
>that tries to free everything whether it was allocated or not.  There
>are a few typical bugs with this.
>1) Forget to free something (this style of error handling cannot be
>   audited).
>2) NULL dereference because kfree(foo->bar) when foo wasn't allocated.
>3) Drop a reference count when the reference count wasn't incremented.
>4) Dereferencing an error pointer or uninitialized pointer.
>5) Double free bug because other code uses normal error handling style.
>

I understand that you mean cdnsp_mem_cleanup function.
I agree with you, but in other hand I reuse the code that exist. 
Some other people complain that the code is duplicated.

>This code has at least one double free bug.
>
>The better way to do error handling is to use a system called "Free
>the last allocation".
>
>
>	a = alloc();
>	if (!a)
>		return -ENOMEM;
>
>	b = alloc();
>	if (!b) {
>		ret = -ENOMEM;
>		goto free_a;
>	}
>
>	c = alloc();
>	if (!c) {
>		ret -ENOMEM;
>		goto free_b;
>	}
>
>	return 0;
>
>free_b:
>	free(b);
>free_a:
>	free(a);
>
>Just from looking at the gotos then you know the code is correct.
>What was the most recent allocation?  a.  What does goto free_a; do?
>It frees a.
>
>Then you copy all the error handling and add a free(c) and that is your
>free function:
>
>void free_funtcion(struct whatever *p)
>{
>	free(c);
>	free(b);
>	free(a);
>}
>
>This uses basically the same number of lines (not counting curly braces
>lines and label names) because it means that we can delete the if
>statements in the free_everything_function().
>
>I'm not going to tell you what the double free bug is because I want you
>to try auditing the free everything function yourself.  :P
>
>> +	return -ENOMEM;
>> +}
>> +
>> diff --git a/drivers/usb/cdnsp/ring.c b/drivers/usb/cdnsp/ring.c
>> new file mode 100644
>> index 000000000000..a6baf27ad778
>> --- /dev/null
>> +++ b/drivers/usb/cdnsp/ring.c
>> @@ -0,0 +1,2380 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Cadence CDNSP DRD Driver.
>> + *
>> + * Copyright (C) 2020 Cadence.
>> + *
>> + * Author: Pawel Laszczak <pawell@...ence.com>
>> + *
>> + * Code based on Linux XHCI driver.
>> + * Origin: Copyright (C) 2008 Intel Corp
>> + */
>> +
>> +/*
>> + * Ring initialization rules:
>> + * 1. Each segment is initialized to zero, except for link TRBs.
>> + * 2. Ring cycle state = 0. This represents Producer Cycle State (PCS) or
>> + *    Consumer Cycle State (CCS), depending on ring function.
>> + * 3. Enqueue pointer = dequeue pointer = address of first TRB in the segment.
>> + *
>> + * Ring behavior rules:
>> + * 1. A ring is empty if enqueue == dequeue. This means there will always be at
>> + *    least one free TRB in the ring. This is useful if you want to turn that
>> + *    into a link TRB and expand the ring.
>> + * 2. When incrementing an enqueue or dequeue pointer, if the next TRB is a
>> + *    link TRB, then load the pointer with the address in the link TRB. If the
>> + *    link TRB had its toggle bit set, you may need to update the ring cycle
>> + *    state (see cycle bit rules). You may have to do this multiple times
>> + *    until you reach a non-link TRB.
>> + * 3. A ring is full if enqueue++ (for the definition of increment above)
>> + *    equals the dequeue pointer.
>> + *
>> + * Cycle bit rules:
>> + * 1. When a consumer increments a dequeue pointer and encounters a toggle bit
>> + *    in a link TRB, it must toggle the ring cycle state.
>> + * 2. When a producer increments an enqueue pointer and encounters a toggle bit
>> + *    in a link TRB, it must toggle the ring cycle state.
>> + *
>> + * Producer rules:
>> + * 1. Check if ring is full before you enqueue.
>> + * 2. Write the ring cycle state to the cycle bit in the TRB you're enqueuing.
>> + *    Update enqueue pointer between each write (which may update the ring
>> + *    cycle state).
>> + * 3. Notify consumer. If SW is producer, it rings the doorbell for command
>> + *    and endpoint rings. If controller is the producer for the event ring,
>> + *    and it generates an interrupt according to interrupt modulation rules.
>> + *
>> + * Consumer rules:
>> + * 1. Check if TRB belongs to you. If the cycle bit == your ring cycle state,
>> + *    the TRB is owned by the consumer.
>> + * 2. Update dequeue pointer (which may update the ring cycle state) and
>> + *    continue processing TRBs until you reach a TRB which is not owned by you.
>> + * 3. Notify the producer. SW is the consumer for the event ring, and it
>> + *    updates event ring dequeue pointer. Controller is the consumer for the
>> + *    command and endpoint rings; it generates events on the event ring
>> + *    for these.
>> + */
>> +
>> +#include <linux/scatterlist.h>
>> +#include <linux/dma-mapping.h>
>> +#include <linux/delay.h>
>> +#include <linux/slab.h>
>> +#include <linux/irq.h>
>> +
>> +#include "gadget.h"
>> +
>> +/*
>> + * Returns zero if the TRB isn't in this segment, otherwise it returns the DMA
>> + * address of the TRB.
>> + */
>> +dma_addr_t cdnsp_trb_virt_to_dma(struct cdnsp_segment *seg,
>> +				 union cdnsp_trb *trb)
>> +{
>> +	unsigned long segment_offset;
>> +
>> +	if (!seg || !trb || trb < seg->trbs)
>                            ^^^^^^^^^^^^^^^
>It's alarming that a wild kernel pointer is even a possibility.  Don't
>we also have to check alignment and that it can't go off the other side
>of the array?

This function was borrowed for XHCI driver.  I think that there exist some bugged
XCHI controllers and probably  It was the reason for this extra checking.  
In general, I think tat this function could be limited to:
return seg->dma + (segment_offset * sizeof(*trb));

I have to test it, but rather I haven't seen such cases. 
>
>
>> +		return 0;
>> +
>> +	/* offset in TRBs */
>> +	segment_offset = trb - seg->trbs;
>> +	if (segment_offset >= TRBS_PER_SEGMENT)
>> +		return 0;
>> +
>> +	return seg->dma + (segment_offset * sizeof(*trb));
>> +}
>> +
>> +static bool cdnsp_trb_is_noop(union cdnsp_trb *trb)
>> +{
>> +	return TRB_TYPE_NOOP_LE32(trb->generic.field[3]);
>> +}
>> +
>> +static bool cdnsp_trb_is_link(union cdnsp_trb *trb)
>> +{
>> +	return TRB_TYPE_LINK_LE32(trb->link.control);
>> +}
>> +
>> +bool cdnsp_last_trb_on_seg(struct cdnsp_segment *seg, union cdnsp_trb *trb)
>> +{
>> +	return trb == &seg->trbs[TRBS_PER_SEGMENT - 1];
>> +}
>> +
>> +bool cdnsp_last_trb_on_ring(struct cdnsp_ring *ring,
>> +			    struct cdnsp_segment *seg,
>> +			    union cdnsp_trb *trb)
>> +{
>> +	return cdnsp_last_trb_on_seg(seg, trb) && (seg->next == ring->first_seg);
>> +}
>> +
>> +static bool cdnsp_link_trb_toggles_cycle(union cdnsp_trb *trb)
>> +{
>> +	return le32_to_cpu(trb->link.control) & LINK_TOGGLE;
>> +}
>> +
>> +static void cdnsp_trb_to_noop(union cdnsp_trb *trb, u32 noop_type)
>> +{
>> +	if (cdnsp_trb_is_link(trb)) {
>> +		/* Unchain chained link TRBs. */
>> +		trb->link.control &= cpu_to_le32(~TRB_CHAIN);
>> +	} else {
>> +		trb->generic.field[0] = 0;
>> +		trb->generic.field[1] = 0;
>> +		trb->generic.field[2] = 0;
>> +		/* Preserve only the cycle bit of this TRB. */
>> +		trb->generic.field[3] &= cpu_to_le32(TRB_CYCLE);
>> +		trb->generic.field[3] |= cpu_to_le32(TRB_TYPE(noop_type));
>> +	}
>> +}
>> +
>> +/*
>> + * Updates trb to point to the next TRB in the ring, and updates seg if the next
>> + * TRB is in a new segment. This does not skip over link TRBs, and it does not
>> + * effect the ring dequeue or enqueue pointers.
>> + */
>> +static void cdnsp_next_trb(struct cdnsp_device *pdev,
>> +			   struct cdnsp_ring *ring,
>> +			   struct cdnsp_segment **seg,
>> +			   union cdnsp_trb **trb)
>> +{
>> +	if (cdnsp_trb_is_link(*trb)) {
>> +		*seg = (*seg)->next;
>> +		*trb = ((*seg)->trbs);
>> +	} else {
>> +		(*trb)++;
>> +	}
>> +}
>> +
>> +/*
>> + * See Cycle bit rules. SW is the consumer for the event ring only.
>> + * Don't make a ring full of link TRBs. That would be dumb and this would loop.
>> + */
>> +void cdnsp_inc_deq(struct cdnsp_device *pdev, struct cdnsp_ring *ring)
>> +{
>> +	/* event ring doesn't have link trbs, check for last trb. */
>> +	if (ring->type == TYPE_EVENT) {
>> +		if (!cdnsp_last_trb_on_seg(ring->deq_seg, ring->dequeue)) {
>> +			ring->dequeue++;
>> +			return;
>> +		}
>> +
>> +		if (cdnsp_last_trb_on_ring(ring, ring->deq_seg, ring->dequeue))
>> +			ring->cycle_state ^= 1;
>> +
>> +		ring->deq_seg = ring->deq_seg->next;
>> +		ring->dequeue = ring->deq_seg->trbs;
>> +		return;
>> +	}
>> +
>> +	/* All other rings have link trbs. */
>> +	if (!cdnsp_trb_is_link(ring->dequeue)) {
>> +		ring->dequeue++;
>> +		ring->num_trbs_free++;
>> +	}
>> +	while (cdnsp_trb_is_link(ring->dequeue)) {
>> +		ring->deq_seg = ring->deq_seg->next;
>> +		ring->dequeue = ring->deq_seg->trbs;
>> +	}
>> +}
>> +
>> +/*
>> + * See Cycle bit rules. SW is the consumer for the event ring only.
>> + * Don't make a ring full of link TRBs. That would be dumb and this would loop.
>> + *
>> + * If we've just enqueued a TRB that is in the middle of a TD (meaning the
>> + * chain bit is set), then set the chain bit in all the following link TRBs.
>> + * If we've enqueued the last TRB in a TD, make sure the following link TRBs
>> + * have their chain bit cleared (so that each Link TRB is a separate TD).
>> + *
>> + * @more_trbs_coming:	Will you enqueue more TRBs before ringing the doorbell.
>> + */
>> +static void cdnsp_inc_enq(struct cdnsp_device *pdev,
>> +			  struct cdnsp_ring *ring,
>> +			  bool more_trbs_coming)
>> +{
>> +	union cdnsp_trb *next;
>> +	u32 chain;
>> +
>> +	chain = le32_to_cpu(ring->enqueue->generic.field[3]) & TRB_CHAIN;
>> +
>> +	/* If this is not event ring, there is one less usable TRB. */
>> +	if (!cdnsp_trb_is_link(ring->enqueue))
>> +		ring->num_trbs_free--;
>> +	next = ++(ring->enqueue);
>> +
>> +	/* Update the dequeue pointer further if that was a link TRB */
>> +	while (cdnsp_trb_is_link(next)) {
>> +		/*
>> +		 * If the caller doesn't plan on enqueuing more TDs before
>> +		 * ringing the doorbell, then we don't want to give the link TRB
>> +		 * to the hardware just yet. We'll give the link TRB back in
>> +		 * cdnsp_prepare_ring() just before we enqueue the TD at the
>> +		 * top of the ring.
>> +		 */
>> +		if (!chain && !more_trbs_coming)
>> +			break;
>> +
>> +		next->link.control &= cpu_to_le32(~TRB_CHAIN);
>> +		next->link.control |= cpu_to_le32(chain);
>> +
>> +		/* Give this link TRB to the hardware */
>> +		wmb();
>> +		next->link.control ^= cpu_to_le32(TRB_CYCLE);
>> +
>> +		/* Toggle the cycle bit after the last ring segment. */
>> +		if (cdnsp_link_trb_toggles_cycle(next))
>> +			ring->cycle_state ^= 1;
>> +
>> +		ring->enq_seg = ring->enq_seg->next;
>> +		ring->enqueue = ring->enq_seg->trbs;
>> +		next = ring->enqueue;
>> +	}
>> +}
>> +
>> +/*
>> + * Check to see if there's room to enqueue num_trbs on the ring and make sure
>> + * enqueue pointer will not advance into dequeue segment.
>> + */
>> +static inline int cdnsp_room_on_ring(struct cdnsp_device *pdev,
>> +				     struct cdnsp_ring *ring,
>> +				     unsigned int num_trbs)
>
>Make this a bool.  You can remove the inline as well.  The compiler
>pretty much ignores inline and it's smart enough that we trust it
>normally.
>
>> +{
>> +	int num_trbs_in_deq_seg;
>> +
>> +	if (ring->num_trbs_free < num_trbs)
>> +		return 0;
>> +
>> +	if (ring->type != TYPE_COMMAND && ring->type != TYPE_EVENT) {
>> +		num_trbs_in_deq_seg = ring->dequeue - ring->deq_seg->trbs;
>> +
>> +		if (ring->num_trbs_free < num_trbs + num_trbs_in_deq_seg)
>> +			return 0;
>> +	}
>> +
>> +	return 1;
>> +}
>> +
>> +/* Ring the doorbell after placing a command on the ring. */
>> +void cdnsp_ring_cmd_db(struct cdnsp_device *pdev)
>> +{
>> +	writel(DB_VALUE_CMD, &pdev->dba->cmd_db);
>> +}
>> +
>> +/* Ring the doorbell after placing a transfer on the ring. */
>> +static int cdnsp_ring_ep_doorbell(struct cdnsp_device *pdev,
>> +				  struct cdnsp_ep *pep,
>> +				  unsigned int stream_id)
>> +{
>> +	__le32 __iomem *reg_addr = &pdev->dba->ep_db;
>> +	unsigned int ep_state = pep->ep_state;
>> +	unsigned int db_value;
>> +
>> +	/*
>> +	 * Don't ring the doorbell for this endpoint if endpoint is halted or
>> +	 * disabled.
>> +	 */
>> +	if (ep_state & EP_HALTED || !(ep_state & EP_ENABLED))
>> +		return 0;
>> +
>> +	/* For stream capable endpoints driver can ring doorbell only twice. */
>> +	if (pep->ep_state & EP_HAS_STREAMS) {
>> +		if (pep->stream_info.drbls_count >= 2)
>> +			return 0;
>> +
>> +		pep->stream_info.drbls_count++;
>> +	}
>> +
>> +	pep->ep_state &= ~EP_STOPPED;
>> +
>> +	if (pep->idx == 0 && pdev->ep0_stage == CDNSP_DATA_STAGE &&
>> +	    !pdev->ep0_expect_in)
>> +		db_value = DB_VALUE_EP0_OUT(pep->idx, stream_id);
>> +	else
>> +		db_value = DB_VALUE(pep->idx, stream_id);
>> +
>> +	writel(db_value, reg_addr);
>> +
>> +	return 1;
>
>Please document the return values for this function.
>
>> +}
>> +
>> +/*
>> + * Get the right ring for the given pep and stream_id.
>> + * If the endpoint supports streams, boundary check the USB request's stream ID.
>> + * If the endpoint doesn't support streams, return the singular endpoint ring.
>> + */
>> +static struct cdnsp_ring *cdnsp_get_transfer_ring(struct cdnsp_device *pdev,
>> +						  struct cdnsp_ep *pep,
>> +						  unsigned int stream_id)
>> +{
>> +	if (!(pep->ep_state & EP_HAS_STREAMS))
>> +		return pep->ring;
>> +
>> +	if (stream_id == 0 || stream_id >= pep->stream_info.num_streams) {
>> +		dev_err(pdev->dev, "ERR: %s ring doesn't exist for SID: %d.\n",
>> +			pep->name, stream_id);
>> +		return NULL;
>> +	}
>> +
>> +	return pep->stream_info.stream_rings[stream_id];
>> +}
>> +
>> +static struct cdnsp_ring *
>> +	cdnsp_request_to_transfer_ring(struct cdnsp_device *pdev,
>> +				       struct cdnsp_request *preq)
>> +{
>> +	return cdnsp_get_transfer_ring(pdev, preq->pep,
>> +				       preq->request.stream_id);
>> +}
>> +
>> +/* Ring the doorbell for any rings with pending requests. */
>> +void cdnsp_ring_doorbell_for_active_rings(struct cdnsp_device *pdev,
>> +					  struct cdnsp_ep *pep)
>> +{
>> +	struct cdnsp_stream_info *stream_info;
>> +	unsigned int stream_id;
>> +	int ret;
>> +
>> +	if (pep->ep_state & EP_DIS_IN_RROGRESS)
>> +		return;
>> +
>> +	/* A ring has pending Request if its TD list is not empty. */
>> +	if (!(pep->ep_state & EP_HAS_STREAMS) && pep->number) {
>> +		if (pep->ring && !list_empty(&pep->ring->td_list))
>> +			cdnsp_ring_ep_doorbell(pdev, pep, 0);
>> +		return;
>> +	}
>> +
>> +	stream_info = &pep->stream_info;
>> +
>> +	for (stream_id = 1; stream_id < stream_info->num_streams; stream_id++) {
>> +		struct cdnsp_td *td, *td_temp;
>> +		struct cdnsp_ring *ep_ring;
>> +
>> +		if (stream_info->drbls_count >= 2)
>> +			return;
>> +
>> +		ep_ring = cdnsp_get_transfer_ring(pdev, pep, stream_id);
>> +		if (!ep_ring)
>> +			continue;
>> +
>> +		if (!ep_ring->stream_active || ep_ring->stream_rejected)
>> +			continue;
>> +
>> +		list_for_each_entry_safe(td, td_temp, &ep_ring->td_list,
>> +					 td_list) {
>> +			if (td->drbl)
>> +				continue;
>> +
>> +			ret = cdnsp_ring_ep_doorbell(pdev, pep, stream_id);
>> +			if (ret)
>> +				td->drbl = 1;
>> +		}
>> +	}
>> +}
>> +
>> +/*
>> + * Get the hw dequeue pointer controller stopped on, either directly from the
>> + * endpoint context, or if streams are in use from the stream context.
>> + * The returned hw_dequeue contains the lowest four bits with cycle state
>> + * and possible stream context type.
>> + */
>> +static u64 cdnsp_get_hw_deq(struct cdnsp_device *pdev,
>> +			    unsigned int ep_index,
>> +			    unsigned int stream_id)
>> +{
>> +	struct cdnsp_stream_ctx *st_ctx;
>> +	struct cdnsp_ep *pep;
>> +
>> +	pep = &pdev->eps[stream_id];
>> +
>> +	if (pep->ep_state & EP_HAS_STREAMS) {
>> +		st_ctx = &pep->stream_info.stream_ctx_array[stream_id];
>> +		return le64_to_cpu(st_ctx->stream_ring);
>> +	}
>> +
>> +	return le64_to_cpu(pep->out_ctx->deq);
>> +}
>> +
>> +/*
>> + * Move the controller endpoint ring dequeue pointer past cur_td.
>> + * Record the new state of the controller endpoint ring dequeue segment,
>> + * dequeue pointer, and new consumer cycle state in state.
>> + * Update internal representation of the ring's dequeue pointer.
>> + *
>> + * We do this in three jumps:
>> + *  - First we update our new ring state to be the same as when the
>> + *    controller stopped.
>> + *  - Then we traverse the ring to find the segment that contains
>> + *    the last TRB in the TD. We toggle the controller new cycle state
>> + *    when we pass any link TRBs with the toggle cycle bit set.
>> + *  - Finally we move the dequeue state one TRB further, toggling the cycle bit
>> + *    if we've moved it past a link TRB with the toggle cycle bit set.
>> + */
>> +static void cdnsp_find_new_dequeue_state(struct cdnsp_device *pdev,
>> +					 struct cdnsp_ep *pep,
>> +					 unsigned int stream_id,
>> +					 struct cdnsp_td *cur_td,
>> +					 struct cdnsp_dequeue_state *state)
>> +{
>> +	bool td_last_trb_found = false;
>> +	struct cdnsp_segment *new_seg;
>> +	struct cdnsp_ring *ep_ring;
>> +	union cdnsp_trb *new_deq;
>> +	bool cycle_found = false;
>> +	u64 hw_dequeue;
>> +
>> +	ep_ring = cdnsp_get_transfer_ring(pdev, pep, stream_id);
>> +	if (!ep_ring)
>> +		return;
>> +
>> +	/*
>> +	 * Dig out the cycle state saved by the controller during the
>> +	 * stop endpoint command.
>> +	 */
>> +	hw_dequeue = cdnsp_get_hw_deq(pdev, pep->idx, stream_id);
>> +	new_seg = ep_ring->deq_seg;
>> +	new_deq = ep_ring->dequeue;
>> +	state->new_cycle_state = hw_dequeue & 0x1;
>> +	state->stream_id = stream_id;
>> +
>> +	/*
>> +	 * We want to find the pointer, segment and cycle state of the new trb
>> +	 * (the one after current TD's last_trb). We know the cycle state at
>> +	 * hw_dequeue, so walk the ring until both hw_dequeue and last_trb are
>> +	 * found.
>> +	 */
>> +	do {
>> +		if (!cycle_found && cdnsp_trb_virt_to_dma(new_seg, new_deq)
>> +		    == (dma_addr_t)(hw_dequeue & ~0xf)) {
>> +			cycle_found = true;
>> +
>> +			if (td_last_trb_found)
>> +				break;
>> +		}
>> +
>> +		if (new_deq == cur_td->last_trb)
>> +			td_last_trb_found = true;
>> +
>> +		if (cycle_found && cdnsp_trb_is_link(new_deq) &&
>> +		    cdnsp_link_trb_toggles_cycle(new_deq))
>> +			state->new_cycle_state ^= 0x1;
>> +
>> +		cdnsp_next_trb(pdev, ep_ring, &new_seg, &new_deq);
>> +
>> +		/* Search wrapped around, bail out. */
>> +		if (new_deq == pep->ring->dequeue) {
>> +			dev_err(pdev->dev,
>> +				"Error: Failed finding new dequeue state\n");
>> +			state->new_deq_seg = NULL;
>> +			state->new_deq_ptr = NULL;
>> +			return;
>> +		}
>> +
>> +	} while (!cycle_found || !td_last_trb_found);
>> +
>> +	state->new_deq_seg = new_seg;
>> +	state->new_deq_ptr = new_deq;
>> +}
>> +
>> +/*
>> + * flip_cycle means flip the cycle bit of all but the first and last TRB.
>> + * (The last TRB actually points to the ring enqueue pointer, which is not part
>> + * of this TD.) This is used to remove partially enqueued isoc TDs from a ring.
>> + */
>> +static void cdnsp_td_to_noop(struct cdnsp_device *pdev,
>> +			     struct cdnsp_ring *ep_ring,
>> +			     struct cdnsp_td *td,
>> +			     bool flip_cycle)
>> +{
>> +	struct cdnsp_segment *seg = td->start_seg;
>> +	union cdnsp_trb *trb = td->first_trb;
>> +
>> +	while (1) {
>> +		cdnsp_trb_to_noop(trb, TRB_TR_NOOP);
>> +
>> +		/* flip cycle if asked to */
>> +		if (flip_cycle && trb != td->first_trb && trb != td->last_trb)
>> +			trb->generic.field[3] ^= cpu_to_le32(TRB_CYCLE);
>> +
>> +		if (trb == td->last_trb)
>> +			break;
>> +
>> +		cdnsp_next_trb(pdev, ep_ring, &seg, &trb);
>> +	}
>> +}
>> +
>> +/*
>> + * This TD is defined by the TRBs starting at start_trb in start_seg and ending
>> + * at end_trb, which may be in another segment. If the suspect DMA address is a
>> + * TRB in this TD, this function returns that TRB's segment. Otherwise it
>> + * returns 0.
>> + */
>> +struct cdnsp_segment *cdnsp_trb_in_td(struct cdnsp_device *pdev,
>> +				      struct cdnsp_segment *start_seg,
>> +				      union cdnsp_trb *start_trb,
>> +				      union cdnsp_trb *end_trb,
>> +				      dma_addr_t suspect_dma)
>> +{
>> +	struct cdnsp_segment *cur_seg;
>> +	union cdnsp_trb *temp_trb;
>> +	dma_addr_t end_seg_dma;
>> +	dma_addr_t end_trb_dma;
>> +	dma_addr_t start_dma;
>> +
>> +	start_dma = cdnsp_trb_virt_to_dma(start_seg, start_trb);
>> +	cur_seg = start_seg;
>> +
>> +	do {
>> +		if (start_dma == 0)
>> +			return NULL;
>> +
>> +		temp_trb = &cur_seg->trbs[TRBS_PER_SEGMENT - 1];
>> +		/* We may get an event for a Link TRB in the middle of a TD */
>> +		end_seg_dma = cdnsp_trb_virt_to_dma(cur_seg, temp_trb);
>> +		/* If the end TRB isn't in this segment, this is set to 0 */
>> +		end_trb_dma = cdnsp_trb_virt_to_dma(cur_seg, end_trb);
>> +
>> +		if (end_trb_dma > 0) {
>> +			/*
>> +			 * The end TRB is in this segment, so suspect should
>> +			 * be here
>> +			 */
>> +			if (start_dma <= end_trb_dma) {
>> +				if (suspect_dma >= start_dma &&
>> +				    suspect_dma <= end_trb_dma) {
>> +					return cur_seg;
>> +				}
>> +			} else {
>> +				/*
>> +				 * Case for one segment with a
>> +				 * TD wrapped around to the top
>> +				 */
>> +				if ((suspect_dma >= start_dma &&
>> +				     suspect_dma <= end_seg_dma) ||
>> +				    (suspect_dma >= cur_seg->dma &&
>> +				     suspect_dma <= end_trb_dma)) {
>> +					return cur_seg;
>> +				}
>> +			}
>> +
>> +			return NULL;
>> +		}
>> +
>> +		/* Might still be somewhere in this segment */
>> +		if (suspect_dma >= start_dma && suspect_dma <= end_seg_dma)
>> +			return cur_seg;
>> +
>> +		cur_seg = cur_seg->next;
>> +		start_dma = cdnsp_trb_virt_to_dma(cur_seg, &cur_seg->trbs[0]);
>> +	} while (cur_seg != start_seg);
>> +
>> +	return NULL;
>> +}
>> +
>> +void cdnsp_unmap_td_bounce_buffer(struct cdnsp_device *pdev,
>> +				  struct cdnsp_ring *ring,
>> +				  struct cdnsp_td *td)
>> +{
>> +	struct cdnsp_segment *seg = td->bounce_seg;
>> +	struct cdnsp_request *preq;
>> +	size_t len;
>> +
>> +	if (!seg)
>> +		return;
>> +
>> +	preq = td->preq;
>> +
>> +	if (!preq->direction) {
>> +		dma_unmap_single(pdev->dev, seg->bounce_dma,
>> +				 ring->bounce_buf_len,  DMA_TO_DEVICE);
>> +		return;
>> +	}
>> +
>> +	dma_unmap_single(pdev->dev, seg->bounce_dma, ring->bounce_buf_len,
>> +			 DMA_FROM_DEVICE);
>> +
>> +	/* For in transfers we need to copy the data from bounce to sg */
>> +	len = sg_pcopy_from_buffer(preq->request.sg, preq->request.num_sgs,
>> +				   seg->bounce_buf, seg->bounce_len,
>> +				   seg->bounce_offs);
>> +	if (len != seg->bounce_len)
>> +		dev_warn(pdev->dev, "WARN Wrong bounce buffer read length: %zu != %d\n",
>> +			 len, seg->bounce_len);
>> +
>> +	seg->bounce_len = 0;
>> +	seg->bounce_offs = 0;
>> +}
>> +
>> +static int cdnsp_cmd_set_deq(struct cdnsp_device *pdev,
>> +			     struct cdnsp_ep *pep,
>> +			     struct cdnsp_dequeue_state *deq_state)
>> +{
>> +	struct cdnsp_ring *ep_ring;
>> +	int ret = 0;
>> +
>> +	if (!deq_state->new_deq_ptr || !deq_state->new_deq_seg) {
>> +		cdnsp_ring_doorbell_for_active_rings(pdev, pep);
>> +		return ret;
>
>return 0;
>
>> +	}
>> +
>> +	cdnsp_queue_new_dequeue_state(pdev, pep, deq_state);
>> +	cdnsp_ring_cmd_db(pdev);
>> +	ret = cdnsp_wait_for_cmd_compl(pdev);
>> +
>> +	/*
>> +	 * Update the ring's dequeue segment and dequeue pointer
>> +	 * to reflect the new position.
>> +	 */
>> +	ep_ring = cdnsp_get_transfer_ring(pdev, pep, deq_state->stream_id);
>> +
>> +	if (cdnsp_trb_is_link(ep_ring->dequeue)) {
>> +		ep_ring->deq_seg = ep_ring->deq_seg->next;
>> +		ep_ring->dequeue = ep_ring->deq_seg->trbs;
>> +	}
>> +
>> +	while (ep_ring->dequeue != deq_state->new_deq_ptr) {
>> +		ep_ring->num_trbs_free++;
>> +		ep_ring->dequeue++;
>> +
>> +		if (cdnsp_trb_is_link(ep_ring->dequeue)) {
>> +			if (ep_ring->dequeue == deq_state->new_deq_ptr)
>> +				break;
>> +
>> +			ep_ring->deq_seg = ep_ring->deq_seg->next;
>> +			ep_ring->dequeue = ep_ring->deq_seg->trbs;
>> +		}
>> +	}
>> +
>> +	/*
>> +	 * Probably there was TIMEOUT during handling Set Dequeue Pointer
>> +	 * command. It's critical error and controller will be stopped.
>> +	 */
>> +	if (ret)
>> +		return -ESHUTDOWN;
>> +
>> +	/* Restart any rings with pending requests */
>> +	cdnsp_ring_doorbell_for_active_rings(pdev, pep);
>> +
>> +	return ret;
>
>return 0;
>
>> +}
>> +
>> +int cdnsp_remove_request(struct cdnsp_device *pdev,
>> +			 struct cdnsp_request *preq,
>> +			 struct cdnsp_ep *pep)
>> +{
>> +	struct cdnsp_dequeue_state deq_state;
>> +	struct cdnsp_td *cur_td = NULL;
>> +	struct cdnsp_ring *ep_ring;
>> +	struct cdnsp_segment *seg;
>> +	int status = -ECONNRESET;
>> +	int ret = 0;
>> +	u64 hw_deq;
>> +
>> +	memset(&deq_state, 0, sizeof(deq_state));
>> +
>> +	cur_td = &preq->td;
>> +	ep_ring = cdnsp_request_to_transfer_ring(pdev, preq);
>> +
>> +	/*
>> +	 * If we stopped on the TD we need to cancel, then we have to
>> +	 * move the controller endpoint ring dequeue pointer past
>> +	 * this TD.
>> +	 */
>> +	hw_deq = cdnsp_get_hw_deq(pdev, pep->idx, preq->request.stream_id);
>> +	hw_deq &= ~0xf;
>> +
>> +	seg = cdnsp_trb_in_td(pdev, cur_td->start_seg, cur_td->first_trb,
>> +			      cur_td->last_trb, hw_deq);
>> +
>> +	if (seg && (pep->ep_state & EP_ENABLED))
>> +		cdnsp_find_new_dequeue_state(pdev, pep, preq->request.stream_id,
>> +					     cur_td, &deq_state);
>> +	else
>> +		cdnsp_td_to_noop(pdev, ep_ring, cur_td, false);
>> +
>> +	/*
>> +	 * The event handler won't see a completion for this TD anymore,
>> +	 * so remove it from the endpoint ring's TD list.
>> +	 */
>> +	list_del_init(&cur_td->td_list);
>> +	ep_ring->num_tds--;
>> +	pep->stream_info.td_count--;
>> +
>> +	/*
>> +	 * During disconnecting all endpoint will be disabled so we don't
>> +	 * have to worry about updating dequeue pointer.
>> +	 */
>> +	if (pdev->cdnsp_state & CDNSP_STATE_DISCONNECT_PENDING) {
>> +		status = -ESHUTDOWN;
>> +		ret = cdnsp_cmd_set_deq(pdev, pep, &deq_state);
>> +	}
>> +
>> +	cdnsp_unmap_td_bounce_buffer(pdev, ep_ring, cur_td);
>> +	cdnsp_gadget_giveback(pep, cur_td->preq, status);
>> +
>> +	return ret;
>> +}
>> +
>> +static int cdnsp_update_port_id(struct cdnsp_device *pdev, u32 port_id)
>> +{
>> +	struct cdnsp_port *port = pdev->active_port;
>> +	u8 port_changed  = 0;
>
>Delete the port_changed variable.
>
>> +	u8 old_port = 0;
>> +
>> +	if (port && port->port_num == port_id)
>> +		return 0;
>> +
>> +	if (port)
>> +		old_port = port->port_num;
>> +
>> +	if (port_id == pdev->usb2_port.port_num) {
>> +		port = &pdev->usb2_port;
>> +	} else if (port_id == pdev->usb3_port.port_num) {
>> +		port  = &pdev->usb3_port;
>> +	} else {
>> +		dev_err(pdev->dev, "Port event with invalid port ID %d\n",
>> +			port_id);
>> +		return -EINVAL;
>> +	}
>> +
>> +	if (port_id != old_port) {
>> +		cdnsp_disable_slot(pdev);
>> +		pdev->active_port = port;
>> +		cdnsp_enable_slot(pdev);
>> +		port_changed = 1;
>> +	}
>> +
>> +	if (port_id == pdev->usb2_port.port_num)
>> +		cdnsp_set_usb2_hardware_lpm(pdev, NULL, 1);
>> +	else
>> +		writel(PORT_U1_TIMEOUT(1) | PORT_U2_TIMEOUT(1),
>> +		       &pdev->usb3_port.regs->portpmsc);
>> +
>> +	return 0;
>> +}
>> +
>> +static void cdnsp_handle_port_status(struct cdnsp_device *pdev,
>> +				     union cdnsp_trb *event)
>> +{
>> +	struct cdnsp_port_regs __iomem *port_regs;
>> +	u32 portsc, cmd_regs;
>> +	u32 link_state = 0;
>
>Don't initialize.
>
>> +	u8 port2 = 0;
>
>Make this a bool.
>
>> +	u32 port_id;
>> +
>> +	/* Port status change events always have a successful completion code */
>> +	if (GET_COMP_CODE(le32_to_cpu(event->generic.field[2])) != COMP_SUCCESS)
>> +		dev_err(pdev->dev, "ERR: incorrect PSC event\n");
>> +
>> +	port_id = GET_PORT_ID(le32_to_cpu(event->generic.field[0]));
>> +
>> +	if (cdnsp_update_port_id(pdev, port_id))
>> +		goto cleanup;
>> +
>> +	port_regs = pdev->active_port->regs;
>> +
>> +	if (port_id == pdev->usb2_port.port_num)
>> +		port2 = 1;
>> +
>> +new_event:
>> +	portsc = readl(&port_regs->portsc);
>> +	writel(cdnsp_port_state_to_neutral(portsc) |
>> +	       (portsc & PORT_CHANGE_BITS), &port_regs->portsc);
>> +
>> +	pdev->gadget.speed = cdnsp_port_speed(portsc);
>> +	link_state = portsc & PORT_PLS_MASK;
>> +
>> +	/* Port Link State change detected. */
>> +	if ((portsc & PORT_PLC)) {
>> +		if (link_state == XDEV_RESUME) {
>> +			cmd_regs = readl(&pdev->op_regs->command);
>> +			if (!(cmd_regs & CMD_R_S))
>> +				goto cleanup;
>> +
>> +			if (DEV_SUPERSPEED_ANY(portsc)) {
>> +				cdnsp_set_link_state(pdev, &port_regs->portsc,
>> +						     XDEV_U0);
>> +				cdnsp_resume_gadget(pdev);
>> +				goto cleanup;
>> +			}
>> +		}
>> +
>> +		if (link_state == XDEV_U0 && (pdev->link_state == XDEV_U3 ||
>> +					      pdev->link_state == XDEV_U2 ||
>> +					      pdev->link_state == XDEV_U1)) {
>> +			cdnsp_resume_gadget(pdev);
>> +		}
>> +
>> +		if (link_state == XDEV_U1 && DEV_SUPERSPEED_ANY(portsc))
>> +			cdnsp_suspend_gadget(pdev);
>> +
>> +		pdev->link_state = link_state;
>> +	}
>> +
>> +	if (portsc & PORT_CSC) {
>> +		/* Detach device. */
>> +		if (pdev->gadget.connected && !(portsc & PORT_CONNECT))
>> +			cdnsp_disconnect_gadget(pdev);
>> +
>> +		/* Attach device. */
>> +		if (portsc & PORT_CONNECT) {
>> +			if (!port2)
>> +				cdnp_irq_reset(pdev);
>> +
>> +			usb_gadget_set_state(&pdev->gadget, USB_STATE_ATTACHED);
>> +		}
>> +	}
>> +
>> +	/* Port reset. */
>> +	if ((portsc & (PORT_RC | PORT_WRC)) && (portsc & PORT_CONNECT)) {
>> +		cdnp_irq_reset(pdev);
>> +		pdev->u1_allowed = 0;
>> +		pdev->u2_allowed = 0;
>> +	}
>> +
>> +	if (portsc & PORT_CEC)
>> +		dev_err(pdev->dev, "Port Over Current detected\n");
>> +
>> +	if (portsc & PORT_CEC)
>> +		dev_err(pdev->dev, "Port Configure Error detected\n");
>> +
>> +	if (readl(&port_regs->portsc) & PORT_CHANGE_BITS)
>> +		goto new_event;
>> +
>> +cleanup:
>> +	cdnsp_inc_deq(pdev, pdev->event_ring);
>> +}
>> +
>> +static void cdnsp_td_cleanup(struct cdnsp_device *pdev,
>> +			     struct cdnsp_td *td,
>> +			     struct cdnsp_ring *ep_ring,
>> +			     int *status)
>> +{
>> +	struct cdnsp_request *preq = NULL;
>
>	struct cdnsp_request *preq = td->preq;
>
>> +
>> +	preq = td->preq;
>> +
>> +	/* if a bounce buffer was used to align this td then unmap it */
>> +	cdnsp_unmap_td_bounce_buffer(pdev, ep_ring, td);
>> +
>> +	/*
>> +	 * If the controller said we transferred more data than the buffer
>> +	 * length, Play it safe and say we didn't transfer anything.
>> +	 */
>> +	if (preq->request.actual > preq->request.length) {
>> +		preq->request.actual = 0;
>> +		*status = 0;
>> +	}
>> +
>> +	list_del_init(&td->td_list);
>> +	ep_ring->num_tds--;
>> +	preq->pep->stream_info.td_count--;
>> +
>> +	cdnsp_gadget_giveback(preq->pep, preq, *status);
>> +}
>> +
>> +static void cdnsp_finish_td(struct cdnsp_device *pdev,
>> +			    struct cdnsp_td *td,
>> +			    struct cdnsp_transfer_event *event,
>> +			    struct cdnsp_ep *ep,
>> +			    int *status)
>> +{
>> +	struct cdnsp_ring *ep_ring;
>> +	u32 trb_comp_code;
>> +
>> +	ep_ring = cdnsp_dma_to_transfer_ring(ep, le64_to_cpu(event->buffer));
>> +	trb_comp_code = GET_COMP_CODE(le32_to_cpu(event->transfer_len));
>> +
>> +	if (trb_comp_code == COMP_STOPPED_LENGTH_INVALID ||
>> +	    trb_comp_code == COMP_STOPPED ||
>> +	    trb_comp_code == COMP_STOPPED_SHORT_PACKET) {
>> +		/*
>> +		 * The Endpoint Stop Command completion will take care of any
>> +		 * stopped TDs. A stopped TD may be restarted, so don't update
>> +		 * the ring dequeue pointer or take this TD off any lists yet.
>> +		 */
>> +		return;
>> +	}
>> +
>> +	/* Update ring dequeue pointer */
>> +	while (ep_ring->dequeue != td->last_trb)
>
>I'm a bit surprised we don't check if "ep_ring" can be NULL.

Any Transfer event should be generated only for existing usb endpoint and  ep_ring. 
ep_ring will be null only if there will be some bug in controller and
controller generate unexpected or incorrect event. During testing I've not seen 
such case during testing. 

>
>> +		cdnsp_inc_deq(pdev, ep_ring);
>> +
>> +	cdnsp_inc_deq(pdev, ep_ring);
>> +
>> +	cdnsp_td_cleanup(pdev, td, ep_ring, status);
>> +}
>> +
>> +/* sum trb lengths from ring dequeue up to stop_trb, _excluding_ stop_trb */
>> +static int cdnsp_sum_trb_lengths(struct cdnsp_device *pdev,
>> +				 struct cdnsp_ring *ring,
>> +				 union cdnsp_trb *stop_trb)
>> +{
>> +	struct cdnsp_segment *seg = ring->deq_seg;
>> +	union cdnsp_trb *trb = ring->dequeue;
>> +	u32 sum;
>> +
>> +	for (sum = 0; trb != stop_trb; cdnsp_next_trb(pdev, ring, &seg, &trb)) {
>> +		if (!cdnsp_trb_is_noop(trb) && !cdnsp_trb_is_link(trb))
>> +			sum += TRB_LEN(le32_to_cpu(trb->generic.field[2]));
>> +	}
>> +	return sum;
>> +}
>> +
>> +static int cdnsp_giveback_first_trb(struct cdnsp_device *pdev,
>> +				    struct cdnsp_ep *pep,
>> +				    unsigned int stream_id,
>> +				    int start_cycle,
>> +				    struct cdnsp_generic_trb *start_trb)
>> +{
>> +	/*
>> +	 * Pass all the TRBs to the hardware at once and make sure this write
>> +	 * isn't reordered.
>> +	 */
>> +	wmb();
>> +
>> +	if (start_cycle)
>> +		start_trb->field[3] |= cpu_to_le32(start_cycle);
>> +	else
>> +		start_trb->field[3] &= cpu_to_le32(~TRB_CYCLE);
>> +
>> +	if ((pep->ep_state & EP_HAS_STREAMS) &&
>> +	    !pep->stream_info.first_prime_det)
>> +		return 0;
>> +
>> +	return cdnsp_ring_ep_doorbell(pdev, pep, stream_id);
>> +}
>> +
>> +/*
>> + * Process control tds, update USB request status and actual_length.
>> + */
>> +static void cdnsp_process_ctrl_td(struct cdnsp_device *pdev,
>> +				  struct cdnsp_td *td,
>> +				  union cdnsp_trb *event_trb,
>> +				  struct cdnsp_transfer_event *event,
>> +				  struct cdnsp_ep *pep,
>> +				  int *status)
>> +{
>> +	struct cdnsp_ring *ep_ring;
>> +	u32 remaining;
>> +	u32 trb_type;
>> +
>> +	trb_type = TRB_FIELD_TO_TYPE(le32_to_cpu(event_trb->generic.field[3]));
>> +	ep_ring = cdnsp_dma_to_transfer_ring(pep, le64_to_cpu(event->buffer));
>> +	remaining = EVENT_TRB_LEN(le32_to_cpu(event->transfer_len));
>> +
>> +	/*
>> +	 * if on data stage then update the actual_length of the USB
>> +	 * request and flag it as set, so it won't be overwritten in the event
>> +	 * for the last TRB.
>> +	 */
>> +	if (trb_type == TRB_DATA) {
>> +		td->request_length_set = true;
>> +		td->preq->request.actual = td->preq->request.length - remaining;
>> +	}
>> +
>> +	/* at status stage */
>> +	if (!td->request_length_set)
>> +		td->preq->request.actual = td->preq->request.length;
>> +
>> +	if (pdev->ep0_stage == CDNSP_DATA_STAGE && pep->number == 0 &&
>> +	    pdev->three_stage_setup) {
>> +		td = list_entry(ep_ring->td_list.next, struct cdnsp_td,
>> +				td_list);
>> +		pdev->ep0_stage = CDNSP_STATUS_STAGE;
>> +
>> +		cdnsp_giveback_first_trb(pdev, pep, 0, ep_ring->cycle_state,
>> +					 &td->last_trb->generic);
>> +		return;
>> +	}
>> +
>> +	cdnsp_finish_td(pdev, td, event, pep, status);
>> +}
>> +
>> +/*
>> + * Process isochronous tds, update usb request status and actual_length.
>> + */
>> +static void cdnsp_process_isoc_td(struct cdnsp_device *pdev,
>> +				  struct cdnsp_td *td,
>> +				  union cdnsp_trb *ep_trb,
>> +				  struct cdnsp_transfer_event *event,
>> +				  struct cdnsp_ep *pep,
>> +				  int status)
>> +{
>> +	u32 remaining, requested, ep_trb_len;
>> +	bool sum_trbs_for_length = false;
>> +	struct cdnsp_ring *ep_ring;
>> +	struct cdnsp_request *preq;
>
>	struct cdnsp_request *preq = td->preq;
>
>> +	u32 trb_comp_code;
>> +	u32 td_length;
>> +
>> +	ep_ring = cdnsp_dma_to_transfer_ring(pep, le64_to_cpu(event->buffer));
>> +	trb_comp_code = GET_COMP_CODE(le32_to_cpu(event->transfer_len));
>> +	remaining = EVENT_TRB_LEN(le32_to_cpu(event->transfer_len));
>> +	ep_trb_len = TRB_LEN(le32_to_cpu(ep_trb->generic.field[2]));
>> +
>> +	preq = td->preq;
>> +	requested = preq->request.length;
>> +
>> +	/* handle completion code */
>> +	switch (trb_comp_code) {
>> +	case COMP_SUCCESS:
>> +		preq->request.status = 0;
>> +		break;
>> +	case COMP_SHORT_PACKET:
>> +		preq->request.status = 0;
>> +		sum_trbs_for_length = true;
>> +		break;
>> +	case COMP_ISOCH_BUFFER_OVERRUN:
>> +	case COMP_BABBLE_DETECTED_ERROR:
>> +		preq->request.status = -EOVERFLOW;
>> +		break;
>> +	case COMP_STOPPED:
>> +		sum_trbs_for_length = true;
>> +		break;
>> +	case COMP_STOPPED_SHORT_PACKET:
>> +		/* field normally containing residue now contains transferred */
>> +		preq->request.status  = 0;
>> +		requested = remaining;
>> +		break;
>> +	case COMP_STOPPED_LENGTH_INVALID:
>> +		requested = 0;
>> +		remaining = 0;
>> +		break;
>> +	default:
>> +		sum_trbs_for_length = true;
>> +		preq->request.status = -1;
>> +		break;
>> +	}
>> +
>> +	if (sum_trbs_for_length) {
>> +		td_length = cdnsp_sum_trb_lengths(pdev, ep_ring, ep_trb);
>> +		td_length += ep_trb_len - remaining;
>> +	} else {
>> +		td_length = requested;
>> +	}
>> +
>> +	td->preq->request.actual += td_length;
>> +
>> +	cdnsp_finish_td(pdev, td, event, pep, &status);
>> +}
>> +
>> +static void cdnsp_skip_isoc_td(struct cdnsp_device *pdev,
>> +			       struct cdnsp_td *td,
>> +			       struct cdnsp_transfer_event *event,
>> +			       struct cdnsp_ep *pep,
>> +			       int status)
>> +{
>> +	struct cdnsp_ring *ep_ring;
>> +
>> +	ep_ring = cdnsp_dma_to_transfer_ring(pep, le64_to_cpu(event->buffer));
>> +	td->preq->request.status = -EXDEV;
>> +	td->preq->request.actual = 0;
>> +
>> +	/* Update ring dequeue pointer */
>> +	while (ep_ring->dequeue != td->last_trb)
>> +		cdnsp_inc_deq(pdev, ep_ring);
>> +
>> +	cdnsp_inc_deq(pdev, ep_ring);
>> +
>> +	cdnsp_td_cleanup(pdev, td, ep_ring, &status);
>> +}
>> +
>> +/*
>> + * Process bulk and interrupt tds, update usb request status and actual_length.
>> + */
>> +static void cdnsp_process_bulk_intr_td(struct cdnsp_device *pdev,
>> +				       struct cdnsp_td *td,
>> +				       union cdnsp_trb *ep_trb,
>> +				       struct cdnsp_transfer_event *event,
>> +				       struct cdnsp_ep *ep,
>> +				       int *status)
>> +{
>> +	u32 remaining, requested, ep_trb_len;
>> +	struct cdnsp_ring *ep_ring;
>> +	u32 trb_comp_code;
>> +
>> +	ep_ring = cdnsp_dma_to_transfer_ring(ep, le64_to_cpu(event->buffer));
>> +	trb_comp_code = GET_COMP_CODE(le32_to_cpu(event->transfer_len));
>> +	remaining = EVENT_TRB_LEN(le32_to_cpu(event->transfer_len));
>> +	ep_trb_len = TRB_LEN(le32_to_cpu(ep_trb->generic.field[2]));
>> +	requested = td->preq->request.length;
>> +
>> +	switch (trb_comp_code) {
>> +	case COMP_SUCCESS:
>> +	case COMP_SHORT_PACKET:
>> +		*status = 0;
>> +		break;
>> +	case COMP_STOPPED_SHORT_PACKET:
>> +		td->preq->request.actual = remaining;
>> +		goto finish_td;
>> +	case COMP_STOPPED_LENGTH_INVALID:
>> +		/* stopped on ep trb with invalid length, exclude it */
>> +		ep_trb_len = 0;
>> +		remaining = 0;
>> +		break;
>> +	default:
>> +		/* Others already handled above */
>
>What does this comment mean?

That other important completion codes were handled in cdnsp_handle_tx_event.
It's not needed. I will remove default statement. 

>
>> +		break;
>> +	}
>> +
>> +	if (ep_trb == td->last_trb)
>> +		ep_trb_len = requested - remaining;
>> +	else
>> +		ep_trb_len = cdnsp_sum_trb_lengths(pdev, ep_ring, ep_trb) +
>> +						   ep_trb_len - remaining;
>> +	td->preq->request.actual = ep_trb_len;
>> +
>> +finish_td:
>> +	ep->stream_info.drbls_count--;
>> +
>> +	cdnsp_finish_td(pdev, td, event, ep, status);
>> +}
>> +
>> +static void cdnsp_handle_tx_nrdy(struct cdnsp_device *pdev,
>> +				 struct cdnsp_transfer_event *event)
>> +{
>> +	struct cdnsp_generic_trb *generic;
>> +	struct cdnsp_ring *ep_ring;
>> +	struct cdnsp_ep *pep;
>> +	int cur_stream;
>> +	int ep_index;
>> +	int host_sid;
>> +	int dev_sid;
>> +
>> +	generic = (struct cdnsp_generic_trb *)event;
>> +	ep_index = TRB_TO_EP_ID(le32_to_cpu(event->flags)) - 1;
>> +	dev_sid = TRB_TO_DEV_STREAM(le32_to_cpu(generic->field[0]));
>> +	host_sid = TRB_TO_HOST_STREAM(le32_to_cpu(generic->field[2]));
>> +
>> +	pep = &pdev->eps[ep_index];
>> +
>> +	if (!(pep->ep_state & EP_HAS_STREAMS))
>> +		return;
>> +
>> +	if (host_sid == STREAM_PRIME_ACK) {
>> +		pep->stream_info.first_prime_det = 1;
>> +		for (cur_stream = 1; cur_stream < pep->stream_info.num_streams;
>> +		    cur_stream++) {
>> +			ep_ring = pep->stream_info.stream_rings[cur_stream];
>> +			ep_ring->stream_active = 1;
>> +			ep_ring->stream_rejected = 0;
>> +		}
>> +	}
>> +
>> +	if (host_sid == STREAM_REJECTED) {
>> +		struct cdnsp_td *td, *td_temp;
>> +
>> +		pep->stream_info.drbls_count--;
>> +		ep_ring = pep->stream_info.stream_rings[dev_sid];
>> +		ep_ring->stream_active = 0;
>> +		ep_ring->stream_rejected = 1;
>> +
>> +		list_for_each_entry_safe(td, td_temp, &ep_ring->td_list,
>> +					 td_list) {
>> +			td->drbl = 0;
>> +		}
>> +	}
>> +
>> +	cdnsp_ring_doorbell_for_active_rings(pdev, pep);
>> +}
>> +
>> +/*
>> + * If this function returns an error condition, it means it got a Transfer
>> + * event with a corrupted TRB DMA address or endpoint is disabled.
>> + */
>> +static int cdnsp_handle_tx_event(struct cdnsp_device *pdev,
>> +				 struct cdnsp_transfer_event *event)
>> +{
>> +	const struct usb_endpoint_descriptor *desc;
>> +	bool handling_skipped_tds = false;
>> +	struct cdnsp_segment *ep_seg;
>> +	struct cdnsp_td *td = NULL;
>
>Don't initialize
>
>> +	struct cdnsp_ring *ep_ring;
>> +	int status = -EINPROGRESS;
>> +	union cdnsp_trb *ep_trb;
>> +	dma_addr_t ep_trb_dma;
>> +	struct cdnsp_ep *pep;
>> +	u32 trb_comp_code;
>> +	int invalidate;
>> +	int ep_index;
>> +
>> +	invalidate = le32_to_cpu(event->flags) & TRB_EVENT_INVALIDATE;
>> +	ep_index = TRB_TO_EP_ID(le32_to_cpu(event->flags)) - 1;
>> +	trb_comp_code = GET_COMP_CODE(le32_to_cpu(event->transfer_len));
>> +	ep_trb_dma = le64_to_cpu(event->buffer);
>> +
>> +	pep = &pdev->eps[ep_index];
>> +	ep_ring = cdnsp_dma_to_transfer_ring(pep, le64_to_cpu(event->buffer));
>> +
>> +	/*
>> +	 * If device is disconnect then all requests will be dequeued
>> +	 * by upper layers as part of disconnect sequence.
>> +	 * We don't want handle such event to avoid racing.
>> +	 */
>> +	if (invalidate || !pdev->gadget.connected)
>> +		goto cleanup;
>> +
>> +	if (GET_EP_CTX_STATE(pep->out_ctx) == EP_STATE_DISABLED)
>> +		goto err_out;
>> +
>> +	/* Some transfer events don't always point to a trb*/
>> +	if (!ep_ring) {
>> +		switch (trb_comp_code) {
>> +		case COMP_INVALID_STREAM_TYPE_ERROR:
>> +		case COMP_INVALID_STREAM_ID_ERROR:
>> +		case COMP_RING_UNDERRUN:
>> +		case COMP_RING_OVERRUN:
>> +			goto cleanup;
>> +		default:
>> +			dev_err(pdev->dev, "ERROR: %s event for unknown ring\n",
>> +				pep->name);
>> +			goto err_out;
>> +		}
>> +	}
>> +
>> +	/* Look for some error cases that need special treatment. */
>> +	switch (trb_comp_code) {
>> +	case COMP_BABBLE_DETECTED_ERROR:
>> +		status = -EOVERFLOW;
>> +		break;
>> +	case COMP_RING_UNDERRUN:
>> +	case COMP_RING_OVERRUN:
>> +		/*
>> +		 * When the Isoch ring is empty, the controller will generate
>> +		 * a Ring Overrun Event for IN Isoch endpoint or Ring
>> +		 * Underrun Event for OUT Isoch endpoint.
>> +		 */
>> +		goto cleanup;
>> +	case COMP_MISSED_SERVICE_ERROR:
>> +		/*
>> +		 * When encounter missed service error, one or more isoc tds
>> +		 * may be missed by controller.
>> +		 * Set skip flag of the ep_ring; Complete the missed tds as
>> +		 * short transfer when process the ep_ring next time.
>> +		 */
>> +		pep->skip = true;
>> +		break;
>> +	}
>> +
>> +	do {
>> +		/*
>> +		 * This TRB should be in the TD at the head of this ring's TD
>> +		 * list.
>> +		 */
>> +		if (list_empty(&ep_ring->td_list)) {
>> +			if (pep->skip)
>> +				pep->skip = false;
>> +
>> +			goto cleanup;
>> +		}
>> +
>> +		td = list_entry(ep_ring->td_list.next, struct cdnsp_td,
>> +				td_list);
>> +
>> +		/* Is this a TRB in the currently executing TD? */
>> +		ep_seg = cdnsp_trb_in_td(pdev, ep_ring->deq_seg,
>> +					 ep_ring->dequeue, td->last_trb,
>> +					 ep_trb_dma);
>> +
>> +		/*
>> +		 * Skip the Force Stopped Event. The event_trb(ep_trb_dma)
>> +		 * of FSE is not in the current TD pointed by ep_ring->dequeue
>> +		 * because that the hardware dequeue pointer still at the
>> +		 * previous TRB of the current TD. The previous TRB maybe a
>> +		 * Link TD or the last TRB of the previous TD. The command
>> +		 * completion handle will take care the rest.
>> +		 */
>> +		if (!ep_seg && (trb_comp_code == COMP_STOPPED ||
>> +				trb_comp_code == COMP_STOPPED_LENGTH_INVALID)) {
>> +			pep->skip = false;
>> +			goto cleanup;
>> +		}
>> +
>> +		desc = td->preq->pep->endpoint.desc;
>> +		if (!ep_seg) {
>> +			if (!pep->skip || !usb_endpoint_xfer_isoc(desc)) {
>> +				/* Something is busted, give up! */
>> +				dev_err(pdev->dev,
>> +					"ERROR Transfer event TRB DMA ptr not "
>> +					"part of current TD ep_index %d "
>> +					"comp_code %u\n", ep_index,
>> +					trb_comp_code);
>> +				return -EINVAL;
>> +			}
>> +
>> +			cdnsp_skip_isoc_td(pdev, td, event, pep, status);
>> +			goto cleanup;
>> +		}
>> +
>> +		if (trb_comp_code == COMP_SHORT_PACKET)
>> +			ep_ring->last_td_was_short = true;
>> +		else
>> +			ep_ring->last_td_was_short = false;
>> +
>> +		if (pep->skip) {
>> +			pep->skip = false;
>> +			cdnsp_skip_isoc_td(pdev, td, event, pep, status);
>> +			goto cleanup;
>> +		}
>> +
>> +		ep_trb = &ep_seg->trbs[(ep_trb_dma - ep_seg->dma)
>> +				       / sizeof(*ep_trb)];
>> +
>> +		if (cdnsp_trb_is_noop(ep_trb))
>> +			goto cleanup;
>> +
>> +		if (usb_endpoint_xfer_control(desc))
>> +			cdnsp_process_ctrl_td(pdev, td, ep_trb, event, pep,
>> +					      &status);
>> +		else if (usb_endpoint_xfer_isoc(desc))
>> +			cdnsp_process_isoc_td(pdev, td, ep_trb, event, pep,
>> +					      status);
>> +		else
>> +			cdnsp_process_bulk_intr_td(pdev, td, ep_trb, event, pep,
>> +						   &status);
>> +cleanup:
>> +		handling_skipped_tds = pep->skip;
>> +
>> +		/*
>> +		 * Do not update event ring dequeue pointer if we're in a loop
>> +		 * processing missed tds.
>> +		 */
>> +		if (!handling_skipped_tds)
>> +			cdnsp_inc_deq(pdev, pdev->event_ring);
>> +
>> +	/*
>> +	 * If ep->skip is set, it means there are missed tds on the
>> +	 * endpoint ring need to take care of.
>> +	 * Process them as short transfer until reach the td pointed by
>> +	 * the event.
>> +	 */
>> +	} while (handling_skipped_tds);
>> +	return 0;
>> +
>> +err_out:
>> +	dev_err(pdev->dev, "@%016llx %08x %08x %08x %08x\n",
>> +		(unsigned long long)
>> +		cdnsp_trb_virt_to_dma(pdev->event_ring->deq_seg,
>> +				      pdev->event_ring->dequeue),
>> +		 lower_32_bits(le64_to_cpu(event->buffer)),
>> +		 upper_32_bits(le64_to_cpu(event->buffer)),
>> +		 le32_to_cpu(event->transfer_len),
>> +		 le32_to_cpu(event->flags));
>> +	return -EINVAL;
>> +}
>> +
>> +/*
>> + * This function handles all events on the event ring.
>> + * Returns >0 for "possibly more events to process" (caller should call again),
>> + * otherwise 0 if done.
>> + */
>> +int cdnsp_handle_event(struct cdnsp_device *pdev)
>
>Just return bool.
>
>> +{
>> +	unsigned int comp_code;
>> +	union cdnsp_trb *event;
>> +	int update_ptrs = 1;
>
>bool
>
>> +	__le32 cycle_bit;
>> +	int ret = 0;
>> +	u32 flags;
>> +
>> +	event = pdev->event_ring->dequeue;
>> +	flags = le32_to_cpu(event->event_cmd.flags);
>> +	cycle_bit = (flags & TRB_CYCLE);
>> +
>> +	/* Does the controller or driver own the TRB? */
>> +	if (cycle_bit != pdev->event_ring->cycle_state)
>> +		return 0;
>> +
>> +	/*
>> +	 * Barrier between reading the TRB_CYCLE (valid) flag above and any
>> +	 * reads of the event's flags/data below.
>> +	 */
>> +	rmb();
>> +
>> +	switch (flags & TRB_TYPE_BITMASK) {
>> +	case TRB_TYPE(TRB_COMPLETION):
>> +		/*
>> +		 * Command can't be handled in interrupt context so just
>> +		 * increment command ring dequeue pointer.
>> +		 */
>> +		cdnsp_inc_deq(pdev, pdev->cmd_ring);
>> +		break;
>> +	case TRB_TYPE(TRB_PORT_STATUS):
>> +		cdnsp_handle_port_status(pdev, event);
>> +		update_ptrs = 0;
>> +		break;
>> +	case TRB_TYPE(TRB_TRANSFER):
>> +		ret = cdnsp_handle_tx_event(pdev, &event->trans_event);
>> +
>> +		if (ret >= 0)
>
>	if (ret)
>		break;
>
>	update_ptrs = false;
>
>> +			update_ptrs = 0;
>> +		break;
>> +	case TRB_TYPE(TRB_SETUP):
>> +		pdev->ep0_stage = CDNSP_SETUP_STAGE;
>> +		pdev->setup_id = TRB_SETUPID_TO_TYPE(flags);
>> +		pdev->setup_speed = TRB_SETUP_SPEEDID(flags);
>> +		pdev->setup = *((struct usb_ctrlrequest *)
>> +				&event->trans_event.buffer);
>> +
>> +		cdnsp_setup_analyze(pdev);
>> +		break;
>> +	case TRB_TYPE(TRB_ENDPOINT_NRDY):
>> +		cdnsp_handle_tx_nrdy(pdev, &event->trans_event);
>> +		break;
>> +	case TRB_TYPE(TRB_HC_EVENT): {
>> +		comp_code = GET_COMP_CODE(le32_to_cpu(event->generic.field[2]));
>> +
>> +		switch (comp_code) {
>> +		case COMP_EVENT_RING_FULL_ERROR:
>> +			dev_err(pdev->dev, "Event Ring Full\n");
>> +			break;
>> +		default:
>> +			dev_err(pdev->dev, "Controller error code 0x%02x\n",
>> +				comp_code);
>> +		}
>> +
>> +		break;
>> +	}
>> +	case TRB_TYPE(TRB_MFINDEX_WRAP):
>> +	case TRB_TYPE(TRB_DRB_OVERFLOW):
>> +		break;
>> +	default:
>> +		dev_warn(pdev->dev, "ERROR unknown event type %ld\n",
>> +			 TRB_FIELD_TO_TYPE(flags));
>> +	}
>> +
>> +	if (update_ptrs)
>> +		/* Update SW event ring dequeue pointer. */
>> +		cdnsp_inc_deq(pdev, pdev->event_ring);
>> +
>> +	/*
>> +	 * Caller will call us again to check if there are more items
>> +	 * on the event ring.
>> +	 */
>> +	return 1;
>> +}
>> +
>> +irqreturn_t cdnsp_thread_irq_handler(int irq, void *data)
>> +{
>> +	struct cdnsp_device *pdev = (struct cdnsp_device *)data;
>> +	union cdnsp_trb *event_ring_deq;
>> +	irqreturn_t ret = IRQ_NONE;
>> +	u8 counter = 0;
>
>Just make counter an int.
>
>> +
>> +	spin_lock(&pdev->lock);
>> +
>> +	if (pdev->cdnsp_state & (CDNSP_STATE_HALTED | CDNSP_STATE_DYING)) {
>> +		cdnsp_died(pdev);
>> +		spin_unlock(&pdev->lock);
>> +		return IRQ_HANDLED;
>> +	}
>> +
>> +	event_ring_deq = pdev->event_ring->dequeue;
>> +
>> +	while ((ret = cdnsp_handle_event(pdev)) == 1) {
>
>	while (cdnsp_handle_event(pdev)) {
>
>
>> +		if (++counter >= TRBS_PER_EV_DEQ_UPDATE) {
>> +			cdnsp_update_erst_dequeue(pdev, event_ring_deq, 0);
>> +			event_ring_deq = pdev->event_ring->dequeue;
>> +			counter = 0;
>> +		}
>> +	}
>> +
>> +	cdnsp_update_erst_dequeue(pdev, event_ring_deq, 1);
>> +
>> +	spin_unlock(&pdev->lock);
>> +
>> +	return IRQ_HANDLED;
>> +}
>> +
>> +irqreturn_t cdnsp_irq_handler(int irq, void *priv)
>> +{
>> +	struct cdnsp_device *pdev = (struct cdnsp_device *)priv;
>> +	irqreturn_t ret = IRQ_WAKE_THREAD;
>> +	u32 irq_pending;
>> +	u32 status;
>> +
>> +	status = readl(&pdev->op_regs->status);
>> +
>> +	if (status == ~(u32)0) {
>> +		cdnsp_died(pdev);
>> +		ret = IRQ_HANDLED;
>> +		goto out;
>
>	return IRQ_HANDLED;
>
>> +	}
>> +
>> +	if (!(status & STS_EINT)) {
>> +		ret = IRQ_NONE;
>> +		goto out;
>> +	}
>> +
>> +	writel(status | STS_EINT, &pdev->op_regs->status);
>> +	irq_pending = readl(&pdev->ir_set->irq_pending);
>> +	irq_pending |= IMAN_IP;
>> +	writel(irq_pending, &pdev->ir_set->irq_pending);
>> +
>> +	if (status & STS_FATAL) {
>> +		cdnsp_died(pdev);
>> +		ret = IRQ_HANDLED;
>> +		goto out;
>> +	}
>> +
>> +out:
>> +	return ret;
>> +}
>> +
>> +/*
>> + * Generic function for queuing a TRB on a ring.
>> + * The caller must have checked to make sure there's room on the ring.
>> + *
>> + * @more_trbs_coming:	Will you enqueue more TRBs before setting doorbell?
>> + */
>> +static void cdnsp_queue_trb(struct cdnsp_device *pdev, struct cdnsp_ring *ring,
>> +			    bool more_trbs_coming, u32 field1, u32 field2,
>> +			    u32 field3, u32 field4)
>> +{
>> +	struct cdnsp_generic_trb *trb;
>> +
>> +	trb = &ring->enqueue->generic;
>> +
>> +	trb->field[0] = cpu_to_le32(field1);
>> +	trb->field[1] = cpu_to_le32(field2);
>> +	trb->field[2] = cpu_to_le32(field3);
>> +	trb->field[3] = cpu_to_le32(field4);
>> +
>> +	cdnsp_inc_enq(pdev, ring, more_trbs_coming);
>> +}
>> +
>> +/*
>> + * Does various checks on the endpoint ring, and makes it ready to
>> + * queue num_trbs.
>> + */
>> +static int cdnsp_prepare_ring(struct cdnsp_device *pdev,
>> +			      struct cdnsp_ring *ep_ring,
>> +			      u32 ep_state, unsigned
>> +			      int num_trbs,
>> +			      gfp_t mem_flags)
>> +{
>> +	unsigned int num_trbs_needed;
>> +
>> +	/* Make sure the endpoint has been added to controller schedule. */
>> +	switch (ep_state) {
>> +	case EP_STATE_STOPPED:
>> +	case EP_STATE_RUNNING:
>> +	case EP_STATE_HALTED:
>> +		break;
>> +	default:
>> +		dev_err(pdev->dev, "ERROR: incorrect endpoint state\n");
>> +		return -EINVAL;
>> +	}
>> +
>> +	while (1) {
>> +		if (cdnsp_room_on_ring(pdev, ep_ring, num_trbs))
>> +			break;
>> +
>> +		num_trbs_needed = num_trbs - ep_ring->num_trbs_free;
>> +		if (cdnsp_ring_expansion(pdev, ep_ring, num_trbs_needed,
>> +					 mem_flags)) {
>> +			dev_err(pdev->dev, "Ring expansion failed\n");
>> +			return -ENOMEM;
>> +		}
>> +	}
>> +
>> +	while (cdnsp_trb_is_link(ep_ring->enqueue)) {
>> +		ep_ring->enqueue->link.control |= cpu_to_le32(TRB_CHAIN);
>> +		/* The cycle bit must be set as the last operation. */
>> +		wmb();
>> +		ep_ring->enqueue->link.control ^= cpu_to_le32(TRB_CYCLE);
>> +
>> +		/* Toggle the cycle bit after the last ring segment. */
>> +		if (cdnsp_link_trb_toggles_cycle(ep_ring->enqueue))
>> +			ep_ring->cycle_state ^= 1;
>> +		ep_ring->enq_seg = ep_ring->enq_seg->next;
>> +		ep_ring->enqueue = ep_ring->enq_seg->trbs;
>> +	}
>> +	return 0;
>> +}
>> +
>> +static int cdnsp_prepare_transfer(struct cdnsp_device *pdev,
>> +				  struct cdnsp_request *preq,
>> +				  unsigned int num_trbs)
>> +{
>> +	struct cdnsp_ring *ep_ring;
>> +	int ret;
>> +
>> +	ep_ring = cdnsp_get_transfer_ring(pdev, preq->pep,
>> +					  preq->request.stream_id);
>> +	if (!ep_ring)
>> +		return -EINVAL;
>> +
>> +	ret = cdnsp_prepare_ring(pdev, ep_ring,
>> +				 GET_EP_CTX_STATE(preq->pep->out_ctx),
>> +				 num_trbs, GFP_ATOMIC);
>> +	if (ret)
>> +		return ret;
>> +
>> +	INIT_LIST_HEAD(&preq->td.td_list);
>> +	preq->td.preq = preq;
>> +
>> +	/* Add this TD to the tail of the endpoint ring's TD list. */
>> +	list_add_tail(&preq->td.td_list, &ep_ring->td_list);
>> +	ep_ring->num_tds++;
>> +	preq->pep->stream_info.td_count++;
>> +
>> +	preq->td.start_seg = ep_ring->enq_seg;
>> +	preq->td.first_trb = ep_ring->enqueue;
>> +
>> +	return 0;
>> +}
>> +
>> +static unsigned int cdnsp_count_trbs(u64 addr, u64 len)
>> +{
>> +	unsigned int num_trbs;
>> +
>> +	num_trbs = DIV_ROUND_UP(len + (addr & (TRB_MAX_BUFF_SIZE - 1)),
>> +				TRB_MAX_BUFF_SIZE);
>> +	if (num_trbs == 0)
>> +		num_trbs++;
>> +
>> +	return num_trbs;
>> +}
>> +
>> +static inline unsigned int count_trbs_needed(struct cdnsp_request *preq)
>> +{
>> +	return cdnsp_count_trbs(preq->request.dma, preq->request.length);
>> +}
>> +
>> +static unsigned int count_sg_trbs_needed(struct cdnsp_request *preq)
>> +{
>> +	unsigned int i, len, full_len, num_trbs = 0;
>> +	struct scatterlist *sg;
>> +
>> +	full_len = preq->request.length;
>> +
>> +	for_each_sg(preq->request.sg, sg, preq->request.num_sgs, i) {
>> +		len = sg_dma_len(sg);
>> +		num_trbs += cdnsp_count_trbs(sg_dma_address(sg), len);
>> +		len = min_t(unsigned int, len, full_len);
>
>Just use min().  All the types are unsigned int.
>
>> +		full_len -= len;
>> +		if (full_len == 0)
>> +			break;
>> +	}
>> +
>> +	return num_trbs;
>> +}
>> +
>> +static unsigned int count_isoc_trbs_needed(struct cdnsp_request *preq)
>> +{
>> +	return cdnsp_count_trbs(preq->request.dma, preq->request.length);
>> +}
>> +
>> +static void cdnsp_check_trb_math(struct cdnsp_request *preq, int running_total)
>> +{
>> +	if (running_total != preq->request.length)
>> +		dev_err(preq->pep->pdev->dev,
>> +			"%s - Miscalculated tx length, "
>> +			"queued %#x, asked for %#x (%d)\n",
>> +			preq->pep->name, running_total,
>> +			preq->request.length, preq->request.actual);
>> +}
>> +
>> +/*
>> + * TD size is the number of max packet sized packets remaining in the TD
>> + * (*not* including this TRB).
>> + *
>> + * Total TD packet count = total_packet_count =
>> + *     DIV_ROUND_UP(TD size in bytes / wMaxPacketSize)
>> + *
>> + * Packets transferred up to and including this TRB = packets_transferred =
>> + *     rounddown(total bytes transferred including this TRB / wMaxPacketSize)
>> + *
>> + * TD size = total_packet_count - packets_transferred
>> + *
>> + * It must fit in bits 21:17, so it can't be bigger than 31.
>> + * This is taken care of in the TRB_TD_SIZE() macro
>> + *
>> + * The last TRB in a TD must have the TD size set to zero.
>> + */
>> +static u32 cdnsp_td_remainder(struct cdnsp_device *pdev,
>> +			      int transferred,
>> +			      int trb_buff_len,
>> +			      unsigned int td_total_len,
>> +			      struct cdnsp_request *preq,
>> +			      bool more_trbs_coming)
>> +{
>> +	u32 maxp, total_packet_count;
>> +
>> +	/* One TRB with a zero-length data packet. */
>> +	if (!more_trbs_coming || (transferred == 0 && trb_buff_len == 0) ||
>> +	    trb_buff_len == td_total_len)
>> +		return 0;
>> +
>> +	maxp = usb_endpoint_maxp(preq->pep->endpoint.desc);
>> +	total_packet_count = DIV_ROUND_UP(td_total_len, maxp);
>> +
>> +	/* Queuing functions don't count the current TRB into transferred. */
>> +	return (total_packet_count - ((transferred + trb_buff_len) / maxp));
>> +}
>> +
>> +static int cdnsp_align_td(struct cdnsp_device *pdev,
>> +			  struct cdnsp_request *preq, u32 enqd_len,
>> +			  u32 *trb_buff_len, struct cdnsp_segment *seg)
>> +{
>> +	struct device *dev = pdev->dev;
>> +	unsigned int unalign;
>> +	unsigned int max_pkt;
>> +	u32 new_buff_len;
>> +
>> +	max_pkt = usb_endpoint_maxp(preq->pep->endpoint.desc);
>> +	unalign = (enqd_len + *trb_buff_len) % max_pkt;
>> +
>> +	/* We got lucky, last normal TRB data on segment is packet aligned. */
>> +	if (unalign == 0)
>> +		return 0;
>> +
>> +	/* Is the last nornal TRB alignable by splitting it. */
>> +	if (*trb_buff_len > unalign) {
>> +		*trb_buff_len -= unalign;
>> +		return 0;
>> +	}
>> +
>> +	/*
>> +	 * We want enqd_len + trb_buff_len to sum up to a number aligned to
>> +	 * number which is divisible by the endpoint's wMaxPacketSize. IOW:
>> +	 * (size of currently enqueued TRBs + remainder) % wMaxPacketSize == 0.
>> +	 */
>> +	new_buff_len = max_pkt - (enqd_len % max_pkt);
>> +
>> +	if (new_buff_len > (preq->request.length - enqd_len))
>> +		new_buff_len = (preq->request.length - enqd_len);
>> +
>> +	/* Create a max max_pkt sized bounce buffer pointed to by last trb. */
>> +	if (preq->direction) {
>> +		sg_pcopy_to_buffer(preq->request.sg,
>> +				   preq->request.num_mapped_sgs,
>> +				   seg->bounce_buf, new_buff_len, enqd_len);
>> +		seg->bounce_dma = dma_map_single(dev, seg->bounce_buf,
>> +						 max_pkt, DMA_TO_DEVICE);
>> +	} else {
>> +		seg->bounce_dma = dma_map_single(dev, seg->bounce_buf,
>> +						 max_pkt, DMA_FROM_DEVICE);
>> +	}
>> +
>> +	if (dma_mapping_error(dev, seg->bounce_dma)) {
>> +		/* Try without aligning.*/
>> +		dev_warn(pdev->dev,
>> +			 "Failed mapping bounce buffer, not aligning\n");
>> +		return 0;
>> +	}
>> +
>> +	*trb_buff_len = new_buff_len;
>> +	seg->bounce_len = new_buff_len;
>> +	seg->bounce_offs = enqd_len;
>> +
>> +	return 1;
>
>Please document the error codes.
>
>> +}
>> +
>> +int cdnsp_queue_bulk_tx(struct cdnsp_device *pdev, struct cdnsp_request *preq)
>> +{
>> +	unsigned int enqd_len, block_len, trb_buff_len, full_len;
>> +	unsigned int start_cycle, num_sgs = 0;
>> +	struct cdnsp_generic_trb *start_trb;
>> +	u32 field, length_field, remainder;
>> +	struct scatterlist *sg = NULL;
>> +	bool more_trbs_coming = true;
>> +	bool need_zero_pkt = false;
>> +	bool zero_len_trb = false;
>> +	struct cdnsp_ring *ring;
>> +	bool first_trb = true;
>> +	unsigned int num_trbs;
>> +	struct cdnsp_ep *pep;
>> +	u64 addr, send_addr;
>> +	int sent_len, ret;
>> +
>> +	ring = cdnsp_request_to_transfer_ring(pdev, preq);
>> +	if (!ring)
>> +		return -EINVAL;
>> +
>> +	full_len = preq->request.length;
>> +
>> +	if (preq->request.num_sgs) {
>> +		num_sgs = preq->request.num_sgs;
>> +		sg = preq->request.sg;
>> +		addr = (u64)sg_dma_address(sg);
>> +		block_len = sg_dma_len(sg);
>> +		num_trbs = count_sg_trbs_needed(preq);
>> +	} else {
>> +		num_trbs = count_trbs_needed(preq);
>> +		addr = (u64)preq->request.dma;
>> +		block_len = full_len;
>> +	}
>> +
>> +	pep = preq->pep;
>> +
>> +	/* Deal with request.zero - need one more td/trb. */
>> +	if (preq->request.zero && preq->request.length &&
>> +	    IS_ALIGNED(full_len, usb_endpoint_maxp(pep->endpoint.desc))) {
>> +		need_zero_pkt = true;
>> +		num_trbs++;
>> +	}
>> +
>> +	ret = cdnsp_prepare_transfer(pdev, preq, num_trbs);
>> +	if (ret < 0)
>
>if (ret)
>
>> +		return ret;
>> +
>> +	/*
>> +	 * Don't give the first TRB to the hardware (by toggling the cycle bit)
>> +	 * until we've finished creating all the other TRBs. The ring's cycle
>> +	 * state may change as we enqueue the other TRBs, so save it too.
>> +	 */
>> +	start_trb = &ring->enqueue->generic;
>> +	start_cycle = ring->cycle_state;
>> +	send_addr = addr;
>> +
>> +	/* Queue the TRBs, even if they are zero-length */
>> +	for (enqd_len = 0; zero_len_trb || first_trb || enqd_len < full_len;
>> +	     enqd_len += trb_buff_len) {
>> +		field = TRB_TYPE(TRB_NORMAL);
>> +
>> +		/* TRB buffer should not cross 64KB boundaries */
>> +		trb_buff_len = TRB_BUFF_LEN_UP_TO_BOUNDARY(addr);
>> +		trb_buff_len = min_t(unsigned int, trb_buff_len, block_len);
>> +		if (enqd_len + trb_buff_len > full_len)
>> +			trb_buff_len = full_len - enqd_len;
>> +
>> +		/* Don't change the cycle bit of the first TRB until later */
>> +		if (first_trb) {
>> +			first_trb = false;
>> +			if (start_cycle == 0)
>> +				field |= TRB_CYCLE;
>> +		} else {
>> +			field |= ring->cycle_state;
>> +		}
>> +
>> +		/*
>> +		 * Chain all the TRBs together; clear the chain bit in the last
>> +		 * TRB to indicate it's the last TRB in the chain.
>> +		 */
>> +		if (enqd_len + trb_buff_len < full_len || need_zero_pkt) {
>> +			field |= TRB_CHAIN;
>> +			if (cdnsp_trb_is_link(ring->enqueue + 1)) {
>> +				if (cdnsp_align_td(pdev, preq, enqd_len,
>> +						   &trb_buff_len,
>> +						   ring->enq_seg)) {
>> +					send_addr = ring->enq_seg->bounce_dma;
>> +					/* Assuming TD won't span 2 segs */
>> +					preq->td.bounce_seg = ring->enq_seg;
>> +				}
>> +			}
>> +		}
>> +
>> +		if (enqd_len + trb_buff_len >= full_len) {
>> +			if (need_zero_pkt && zero_len_trb) {
>> +				zero_len_trb = true;
>> +			} else {
>> +				field &= ~TRB_CHAIN;
>> +				field |= TRB_IOC;
>> +				more_trbs_coming = false;
>> +				need_zero_pkt = false;
>> +				preq->td.last_trb = ring->enqueue;
>> +			}
>> +		}
>> +
>> +		/* Only set interrupt on short packet for OUT endpoints. */
>> +		if (!preq->direction)
>> +			field |= TRB_ISP;
>> +
>> +		/* Set the TRB length, TD size, and interrupter fields. */
>> +		remainder = cdnsp_td_remainder(pdev, enqd_len, trb_buff_len,
>> +					       full_len, preq,
>> +					       more_trbs_coming);
>> +
>> +		length_field = TRB_LEN(trb_buff_len) | TRB_TD_SIZE(remainder) |
>> +			TRB_INTR_TARGET(0);
>> +
>> +		cdnsp_queue_trb(pdev, ring, more_trbs_coming | need_zero_pkt,
>> +				lower_32_bits(send_addr),
>> +				upper_32_bits(send_addr),
>> +				length_field,
>> +				field);
>> +
>> +		addr += trb_buff_len;
>> +		sent_len = trb_buff_len;
>> +		while (sg && sent_len >= block_len) {
>> +			/* New sg entry */
>> +			--num_sgs;
>> +			sent_len -= block_len;
>> +			if (num_sgs != 0) {
>> +				sg = sg_next(sg);
>> +				block_len = sg_dma_len(sg);
>> +				addr = (u64)sg_dma_address(sg);
>> +				addr += sent_len;
>> +			}
>> +		}
>> +		block_len -= sent_len;
>> +		send_addr = addr;
>> +	}
>> +
>> +	cdnsp_check_trb_math(preq, enqd_len);
>> +	ret = cdnsp_giveback_first_trb(pdev, pep, preq->request.stream_id,
>> +				       start_cycle, start_trb);
>> +
>> +	if (ret)
>> +		preq->td.drbl = 1;
>> +
>> +	return 0;
>> +}
>> +
>> +int cdnsp_queue_ctrl_tx(struct cdnsp_device *pdev, struct cdnsp_request *preq)
>> +{
>> +	struct cdnsp_generic_trb *start_trb;
>> +	u32 field, length_field, remainder;
>> +	struct cdnsp_ep *pep = preq->pep;
>> +	struct cdnsp_ring *ep_ring;
>> +	int start_cycle;
>> +	int num_trbs;
>> +	int ret;
>> +
>> +	ep_ring = cdnsp_request_to_transfer_ring(pdev, preq);
>> +	if (!ep_ring)
>> +		return -EINVAL;
>> +
>> +	/* 1 TRB for data, 1 for status */
>> +	num_trbs = (pdev->three_stage_setup) ? 2 : 1;
>> +
>> +	ret = cdnsp_prepare_transfer(pdev, preq, num_trbs);
>> +	if (ret < 0)
>
>if (ret)
>
>> +		return ret;
>> +
>> +	/*
>> +	 * Don't give the first TRB to the hardware (by toggling the cycle bit)
>> +	 * until we've finished creating all the other TRBs. The ring's cycle
>> +	 * state may change as we enqueue the other TRBs, so save it too.
>> +	 */
>> +	start_trb = &ep_ring->enqueue->generic;
>> +	start_cycle = ep_ring->cycle_state;
>> +
>> +	/* If there's data, queue data TRBs */
>> +	if (pdev->ep0_expect_in)
>> +		field = TRB_TYPE(TRB_DATA) | TRB_IOC;
>> +	else
>> +		field = TRB_ISP | TRB_TYPE(TRB_DATA) | TRB_IOC;
>> +
>> +	if (preq->request.length > 0) {
>> +		remainder = cdnsp_td_remainder(pdev, 0, preq->request.length,
>> +					       preq->request.length, preq, 1);
>> +
>> +		length_field = TRB_LEN(preq->request.length) |
>> +				TRB_TD_SIZE(remainder) | TRB_INTR_TARGET(0);
>> +
>> +		if (pdev->ep0_expect_in)
>> +			field |= TRB_DIR_IN;
>> +
>> +		cdnsp_queue_trb(pdev, ep_ring, true,
>> +				lower_32_bits(preq->request.dma),
>> +				upper_32_bits(preq->request.dma), length_field,
>> +				field | ep_ring->cycle_state |
>> +				TRB_SETUPID(pdev->setup_id) |
>> +				pdev->setup_speed);
>> +
>> +		pdev->ep0_stage = CDNSP_DATA_STAGE;
>> +	}
>> +
>> +	/* Save the DMA address of the last TRB in the TD. */
>> +	preq->td.last_trb = ep_ring->enqueue;
>> +
>> +	/* Queue status TRB. */
>> +	if (preq->request.length == 0)
>> +		field = ep_ring->cycle_state;
>> +	else
>> +		field = (ep_ring->cycle_state ^ 1);
>> +
>> +	if (preq->request.length > 0 && pdev->ep0_expect_in)
>> +		field |= TRB_DIR_IN;
>> +
>> +	if (pep->ep_state & EP0_HALTED_STATUS) {
>> +		pep->ep_state &= ~EP0_HALTED_STATUS;
>> +		field |= TRB_SETUPSTAT(TRB_SETUPSTAT_STALL);
>> +	} else {
>> +		field |= TRB_SETUPSTAT(TRB_SETUPSTAT_ACK);
>> +	}
>> +
>> +	cdnsp_queue_trb(pdev, ep_ring, false, 0, 0, TRB_INTR_TARGET(0),
>> +			field | TRB_IOC | TRB_SETUPID(pdev->setup_id) |
>> +			TRB_TYPE(TRB_STATUS) | pdev->setup_speed);
>> +
>> +	cdnsp_ring_ep_doorbell(pdev, pep, preq->request.stream_id);
>> +
>> +	return 0;
>> +}
>> +
>> +int cdnsp_cmd_stop_ep(struct cdnsp_device *pdev, struct cdnsp_ep *pep)
>> +{
>> +	u32 ep_state = GET_EP_CTX_STATE(pep->out_ctx);
>> +	int ret = 0;
>> +
>> +	if (ep_state == EP_STATE_STOPPED || ep_state == EP_STATE_DISABLED)
>> +		goto ep_stopped;
>> +
>> +	cdnsp_queue_stop_endpoint(pdev, pep->idx);
>> +	cdnsp_ring_cmd_db(pdev);
>> +	ret = cdnsp_wait_for_cmd_compl(pdev);
>> +
>> +ep_stopped:
>> +	pep->ep_state |= EP_STOPPED;
>> +	return ret;
>> +}
>> +
>> +int cdnsp_cmd_flush_ep(struct cdnsp_device *pdev, struct cdnsp_ep *pep)
>> +{
>> +	int ret;
>> +
>> +	cdnsp_queue_flush_endpoint(pdev, pep->idx);
>> +	cdnsp_ring_cmd_db(pdev);
>> +	ret = cdnsp_wait_for_cmd_compl(pdev);
>> +
>> +	return ret;
>> +}
>> +
>> +/**
>> + * The transfer burst count field of the isochronous TRB defines the number of
>> + * bursts that are required to move all packets in this TD. Only SuperSpeed
>> + * devices can burst up to bMaxBurst number of packets per service interval.
>> + * This field is zero based, meaning a value of zero in the field means one
>> + * burst. Basically, for everything but SuperSpeed devices, this field will be
>> + * zero.
>> + */
>> +static unsigned int cdnsp_get_burst_count(struct cdnsp_device *pdev,
>> +					  struct cdnsp_request *preq,
>> +					  unsigned int total_packet_count)
>> +{
>> +	unsigned int max_burst;
>> +
>> +	if (pdev->gadget.speed < USB_SPEED_SUPER)
>> +		return 0;
>> +
>> +	max_burst = preq->pep->endpoint.comp_desc->bMaxBurst;
>> +	return DIV_ROUND_UP(total_packet_count, max_burst + 1) - 1;
>> +}
>> +
>> +/**
>> + * Returns the number of packets in the last "burst" of packets. This field is
>> + * valid for all speeds of devices. USB 2.0 devices can only do one "burst", so
>> + * the last burst packet count is equal to the total number of packets in the
>> + * TD. SuperSpeed endpoints can have up to 3 bursts. All but the last burst
>> + * must contain (bMaxBurst + 1) number of packets, but the last burst can
>> + * contain 1 to (bMaxBurst + 1) packets.
>> + */
>> +static unsigned int
>> +	cdnsp_get_last_burst_packet_count(struct cdnsp_device *pdev,
>> +					  struct cdnsp_request *preq,
>> +					  unsigned int total_packet_count)
>> +{
>> +	unsigned int max_burst;
>> +	unsigned int residue;
>> +
>> +	if (pdev->gadget.speed >= USB_SPEED_SUPER) {
>> +		/* bMaxBurst is zero based: 0 means 1 packet per burst. */
>> +		max_burst = preq->pep->endpoint.comp_desc->bMaxBurst;
>> +		residue = total_packet_count % (max_burst + 1);
>> +
>> +		/*
>> +		 * If residue is zero, the last burst contains (max_burst + 1)
>> +		 * number of packets, but the TLBPC field is zero-based.
>> +		 */
>> +		if (residue == 0)
>> +			return max_burst;
>> +
>> +		return residue - 1;
>> +	}
>> +	if (total_packet_count == 0)
>> +		return 0;
>> +
>> +	return total_packet_count - 1;
>> +}
>> +
>> +/* Queue function isoc transfer */
>> +static int cdnsp_queue_isoc_tx(struct cdnsp_device *pdev,
>> +			       struct cdnsp_request *preq)
>> +{
>> +	int trb_buff_len, td_len, td_remain_len, ret;
>> +	unsigned int burst_count, last_burst_pkt;
>> +	unsigned int total_pkt_count, max_pkt;
>> +	struct cdnsp_generic_trb *start_trb;
>> +	bool more_trbs_coming = true;
>> +	struct cdnsp_ring *ep_ring;
>> +	int running_total = 0;
>> +	u32 field, length_field;
>> +	int start_cycle;
>> +	int trbs_per_td;
>> +	u64 addr;
>> +	int i;
>> +
>> +	ep_ring = preq->pep->ring;
>> +	start_trb = &ep_ring->enqueue->generic;
>> +	start_cycle = ep_ring->cycle_state;
>> +	td_len = preq->request.length;
>> +	addr = (u64)preq->request.dma;
>> +	td_remain_len = td_len;
>> +
>> +	max_pkt = usb_endpoint_maxp(preq->pep->endpoint.desc);
>> +	total_pkt_count = DIV_ROUND_UP(td_len, max_pkt);
>> +
>> +	/* A zero-length transfer still involves at least one packet. */
>> +	if (total_pkt_count == 0)
>> +		total_pkt_count++;
>> +
>> +	burst_count = cdnsp_get_burst_count(pdev, preq, total_pkt_count);
>> +	last_burst_pkt = cdnsp_get_last_burst_packet_count(pdev, preq,
>> +							   total_pkt_count);
>> +	trbs_per_td = count_isoc_trbs_needed(preq);
>> +
>> +	ret = cdnsp_prepare_transfer(pdev, preq, trbs_per_td);
>> +	if (ret < 0)
>
>if (ret)
>
>> +		goto cleanup;
>> +
>> +	/*
>> +	 * Set isoc specific data for the first TRB in a TD.
>> +	 * Prevent HW from getting the TRBs by keeping the cycle state
>> +	 * inverted in the first TDs isoc TRB.
>> +	 */
>> +	field = TRB_TYPE(TRB_ISOC) | TRB_TLBPC(last_burst_pkt) |
>> +		!start_cycle | TRB_SIA | TRB_TBC(burst_count);
>> +
>> +	/* Fill the rest of the TRB fields, and remaining normal TRBs. */
>> +	for (i = 0; i < trbs_per_td; i++) {
>> +		u32 remainder = 0;
>
>don't initialize
>
>> +
>> +		/* Calculate TRB length. */
>> +		trb_buff_len = TRB_BUFF_LEN_UP_TO_BOUNDARY(addr);
>> +		if (trb_buff_len > td_remain_len)
>> +			trb_buff_len = td_remain_len;
>> +
>> +		/* Set the TRB length, TD size, & interrupter fields. */
>> +		remainder = cdnsp_td_remainder(pdev, running_total,
>> +					       trb_buff_len, td_len, preq,
>> +					       more_trbs_coming);
>> +
>
>regards,
>dan carpenter

regards,
pawel 

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