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Date: Mon, 13 Jun 2016 15:58:35 +0800
From: Peter Chen <hzpeterchen@...il.com>
To: Roger Quadros <rogerq@...com>
Cc: peter.chen@...escale.com, balbi@...nel.org, tony@...mide.com,
gregkh@...uxfoundation.org, dan.j.williams@...el.com,
mathias.nyman@...ux.intel.com, Joao.Pinto@...opsys.com,
sergei.shtylyov@...entembedded.com, jun.li@...escale.com,
grygorii.strashko@...com, yoshihiro.shimoda.uh@...esas.com,
robh@...nel.org, nsekhar@...com, b-liu@...com, joe@...ches.com,
linux-usb@...r.kernel.org, linux-omap@...r.kernel.org,
linux-kernel@...r.kernel.org, devicetree@...r.kernel.org
Subject: Re: [PATCH v11 08/14] usb: otg: add OTG/dual-role core
On Mon, Jun 13, 2016 at 10:56:30AM +0300, Roger Quadros wrote:
> It provides APIs for the following tasks
>
> - Registering an OTG/dual-role capable controller
> - Registering Host and Gadget controllers to OTG core
> - Providing inputs to and kicking the OTG state machine
>
> Provide a dual-role device (DRD) state machine.
> DRD mode is a reduced functionality OTG mode. In this mode
> we don't support SRP, HNP and dynamic role-swap.
>
> In DRD operation, the controller mode (Host or Peripheral)
> is decided based on the ID pin status. Once a cable plug (Type-A
> or Type-B) is attached the controller selects the state
> and doesn't change till the cable in unplugged and a different
> cable type is inserted.
>
> As we don't need most of the complex OTG states and OTG timers
> we implement a lean DRD state machine in usb-otg.c.
> The DRD state machine is only interested in 2 hardware inputs
> 'id' and 'b_sess_vld'.
>
> Signed-off-by: Roger Quadros <rogerq@...com>
> ---
> v11:
> - remove usb_otg_kick_fsm().
> - typo fixes: structa/structure, upto/up to.
> - remove "obj-$(CONFIG_USB_OTG_CORE) += common/" from Makefile.
Acked-by: Peter Chen <peter.chen@....com>
>
> drivers/usb/Kconfig | 18 +
> drivers/usb/common/Makefile | 6 +-
> drivers/usb/common/usb-otg.c | 877 +++++++++++++++++++++++++++++++++++++++++++
> drivers/usb/core/Kconfig | 14 -
> drivers/usb/gadget/Kconfig | 1 +
> include/linux/usb/gadget.h | 2 +
> include/linux/usb/hcd.h | 1 +
> include/linux/usb/otg-fsm.h | 7 +
> include/linux/usb/otg.h | 174 ++++++++-
> 9 files changed, 1070 insertions(+), 30 deletions(-)
> create mode 100644 drivers/usb/common/usb-otg.c
>
> diff --git a/drivers/usb/Kconfig b/drivers/usb/Kconfig
> index 8689dcb..ed596ec 100644
> --- a/drivers/usb/Kconfig
> +++ b/drivers/usb/Kconfig
> @@ -32,6 +32,23 @@ if USB_SUPPORT
> config USB_COMMON
> tristate
>
> +config USB_OTG_CORE
> + tristate
> +
> +config USB_OTG
> + bool "OTG/Dual-role support"
> + depends on PM && USB && USB_GADGET
> + default n
> + ---help---
> + The most notable feature of USB OTG is support for a
> + "Dual-Role" device, which can act as either a device
> + or a host. The initial role is decided by the type of
> + plug inserted and can be changed later when two dual
> + role devices talk to each other.
> +
> + Select this only if your board has Mini-AB/Micro-AB
> + connector.
> +
> config USB_ARCH_HAS_HCD
> def_bool y
>
> @@ -40,6 +57,7 @@ config USB
> tristate "Support for Host-side USB"
> depends on USB_ARCH_HAS_HCD
> select USB_COMMON
> + select USB_OTG_CORE
> select NLS # for UTF-8 strings
> ---help---
> Universal Serial Bus (USB) is a specification for a serial bus
> diff --git a/drivers/usb/common/Makefile b/drivers/usb/common/Makefile
> index f8f2c88..5122b3f 100644
> --- a/drivers/usb/common/Makefile
> +++ b/drivers/usb/common/Makefile
> @@ -7,5 +7,7 @@ usb-common-y += common.o
> usb-common-$(CONFIG_USB_LED_TRIG) += led.o
>
> obj-$(CONFIG_USB_ULPI_BUS) += ulpi.o
> -usbotg-y := usb-otg-fsm.o
> -obj-$(CONFIG_USB_OTG) += usbotg.o
> +ifeq ($(CONFIG_USB_OTG),y)
> +usbotg-y := usb-otg.o usb-otg-fsm.o
> +obj-$(CONFIG_USB_OTG_CORE) += usbotg.o
> +endif
> diff --git a/drivers/usb/common/usb-otg.c b/drivers/usb/common/usb-otg.c
> new file mode 100644
> index 0000000..a23ab1e
> --- /dev/null
> +++ b/drivers/usb/common/usb-otg.c
> @@ -0,0 +1,877 @@
> +/**
> + * drivers/usb/common/usb-otg.c - USB OTG core
> + *
> + * Copyright (C) 2016 Texas Instruments Incorporated - http://www.ti.com
> + * Author: Roger Quadros <rogerq@...com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/list.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_platform.h>
> +#include <linux/usb/of.h>
> +#include <linux/usb/otg.h>
> +#include <linux/usb/gadget.h>
> +#include <linux/workqueue.h>
> +
> +/* OTG device list */
> +LIST_HEAD(otg_list);
> +static DEFINE_MUTEX(otg_list_mutex);
> +
> +static int usb_otg_hcd_is_primary_hcd(struct usb_hcd *hcd)
> +{
> + if (!hcd->primary_hcd)
> + return 1;
> + return hcd == hcd->primary_hcd;
> +}
> +
> +/**
> + * usb_otg_get_data() - get usb_otg data structure
> + * @otg_dev: OTG controller device
> + *
> + * Check if the OTG device is in our OTG list and return
> + * usb_otg data, else NULL.
> + *
> + * otg_list_mutex must be held.
> + *
> + * Return: usb_otg data on success, NULL otherwise.
> + */
> +static struct usb_otg *usb_otg_get_data(struct device *otg_dev)
> +{
> + struct usb_otg *otg;
> +
> + if (!otg_dev)
> + return NULL;
> +
> + list_for_each_entry(otg, &otg_list, list) {
> + if (otg->dev == otg_dev)
> + return otg;
> + }
> +
> + return NULL;
> +}
> +
> +/**
> + * usb_otg_start_host() - start/stop the host controller
> + * @otg: usb_otg instance
> + * @on: true to start, false to stop
> + *
> + * Start/stop the USB host controller. This function is meant
> + * for use by the OTG controller driver.
> + *
> + * Return: 0 on success, error value otherwise.
> + */
> +int usb_otg_start_host(struct usb_otg *otg, int on)
> +{
> + struct otg_hcd_ops *hcd_ops = otg->hcd_ops;
> + int ret;
> +
> + dev_dbg(otg->dev, "otg: %s %d\n", __func__, on);
> + if (!otg->host) {
> + WARN_ONCE(1, "otg: fsm running without host\n");
> + return 0;
> + }
> +
> + if (on) {
> + if (otg->flags & OTG_FLAG_HOST_RUNNING)
> + return 0;
> +
> + /* start host */
> + ret = hcd_ops->add(otg->primary_hcd.hcd,
> + otg->primary_hcd.irqnum,
> + otg->primary_hcd.irqflags);
> + if (ret) {
> + dev_err(otg->dev, "otg: host add failed %d\n", ret);
> + return ret;
> + }
> +
> + if (otg->shared_hcd.hcd) {
> + ret = hcd_ops->add(otg->shared_hcd.hcd,
> + otg->shared_hcd.irqnum,
> + otg->shared_hcd.irqflags);
> + if (ret) {
> + dev_err(otg->dev, "otg: shared host add failed %d\n",
> + ret);
> + hcd_ops->remove(otg->primary_hcd.hcd);
> + return ret;
> + }
> + }
> + otg->flags |= OTG_FLAG_HOST_RUNNING;
> + } else {
> + if (!(otg->flags & OTG_FLAG_HOST_RUNNING))
> + return 0;
> +
> + otg->flags &= ~OTG_FLAG_HOST_RUNNING;
> +
> + /* stop host */
> + if (otg->shared_hcd.hcd)
> + hcd_ops->remove(otg->shared_hcd.hcd);
> +
> + hcd_ops->remove(otg->primary_hcd.hcd);
> + }
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(usb_otg_start_host);
> +
> +/**
> + * usb_otg_start_gadget() - start/stop the gadget controller
> + * @otg: usb_otg instance
> + * @on: true to start, false to stop
> + *
> + * Start/stop the USB gadget controller. This function is meant
> + * for use by the OTG controller driver.
> + *
> + * Return: 0 on success, error value otherwise.
> + */
> +int usb_otg_start_gadget(struct usb_otg *otg, int on)
> +{
> + struct usb_gadget *gadget = otg->gadget;
> + int ret;
> +
> + dev_dbg(otg->dev, "otg: %s %d\n", __func__, on);
> + if (!gadget) {
> + WARN_ONCE(1, "otg: fsm running without gadget\n");
> + return 0;
> + }
> +
> + if (on) {
> + if (otg->flags & OTG_FLAG_GADGET_RUNNING)
> + return 0;
> +
> + ret = otg->gadget_ops->start(otg->gadget);
> + if (ret) {
> + dev_err(otg->dev, "otg: gadget start failed: %d\n",
> + ret);
> + return ret;
> + }
> +
> + otg->flags |= OTG_FLAG_GADGET_RUNNING;
> + } else {
> + if (!(otg->flags & OTG_FLAG_GADGET_RUNNING))
> + return 0;
> +
> + ret = otg->gadget_ops->stop(otg->gadget);
> + if (ret) {
> + dev_err(otg->dev, "otg: gadget stop failed: %d\n",
> + ret);
> + return ret;
> + }
> + otg->flags &= ~OTG_FLAG_GADGET_RUNNING;
> + }
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(usb_otg_start_gadget);
> +
> +/**
> + * drd_set_protocol() - Set USB protocol if possible
> + * @fsm: DRD FSM instance
> + * @protocol: USB protocol to set the state machine to
> + *
> + * Sets the OTG FSM protocol to @protocol if it changed.
> + * fsm->lock must be held.
> + *
> + * Return: 0 on success, error value otherwise.
> + */
> +static int drd_set_protocol(struct otg_fsm *fsm, int protocol)
> +{
> + struct usb_otg *otg = container_of(fsm, struct usb_otg, fsm);
> + int ret = 0;
> +
> + if (fsm->protocol != protocol) {
> + dev_dbg(otg->dev, "otg: changing role fsm->protocol= %d; new protocol= %d\n",
> + fsm->protocol, protocol);
> + /* stop old protocol */
> + if (fsm->protocol == PROTO_HOST) {
> + ret = otg_start_host(otg, 0);
> + } else if (fsm->protocol == PROTO_GADGET) {
> + otg->gadget_ops->connect_control(otg->gadget, false);
> + ret = otg_start_gadget(otg, 0);
> + }
> +
> + if (ret)
> + return ret;
> +
> + /* start new protocol */
> + if (protocol == PROTO_HOST) {
> + ret = otg_start_host(otg, 1);
> + } else if (protocol == PROTO_GADGET) {
> + ret = otg_start_gadget(otg, 1);
> + otg->gadget_ops->connect_control(otg->gadget, true);
> + }
> +
> + if (ret)
> + return ret;
> +
> + fsm->protocol = protocol;
> + return 0;
> + }
> +
> + return 0;
> +}
> +
> +/**
> + * drd_set_state() - Set the DRD state machine state.
> + * @fsm: DRD FSM instance
> + * @new_state: the new state the DRD FSM must be set to
> + *
> + * Sets the state of the DRD state machine.
> + * fsm->lock must be held.
> + */
> +static void drd_set_state(struct otg_fsm *fsm, enum usb_otg_state new_state)
> +{
> + struct usb_otg *otg = container_of(fsm, struct usb_otg, fsm);
> +
> + if (otg->state == new_state)
> + return;
> +
> + fsm->state_changed = 1;
> + dev_dbg(otg->dev, "otg: set state: %s\n",
> + usb_otg_state_string(new_state));
> + switch (new_state) {
> + case OTG_STATE_B_IDLE:
> + drd_set_protocol(fsm, PROTO_UNDEF);
> + otg_drv_vbus(otg, 0);
> + break;
> + case OTG_STATE_B_PERIPHERAL:
> + drd_set_protocol(fsm, PROTO_GADGET);
> + otg_drv_vbus(otg, 0);
> + break;
> + case OTG_STATE_A_HOST:
> + drd_set_protocol(fsm, PROTO_HOST);
> + otg_drv_vbus(otg, 1);
> + break;
> + default:
> + dev_warn(otg->dev, "%s: otg: invalid state: %s\n",
> + __func__, usb_otg_state_string(new_state));
> + break;
> + }
> +
> + otg->state = new_state;
> +}
> +
> +/**
> + * drd_statemachine() - DRD state change judgement
> + * @otg: usb_otg instance
> + *
> + * Checks the state machine inputs and state and makes a state change
> + * if required.
> + *
> + * For DRD we're only interested in some of the OTG states
> + * i.e. OTG_STATE_B_IDLE: both peripheral and host are stopped
> + * OTG_STATE_B_PERIPHERAL: peripheral active
> + * OTG_STATE_A_HOST: host active
> + * we're only interested in the following inputs
> + * fsm->id, fsm->b_sess_vld
> + *
> + * Return: 0 if state wasn't changed, 1 if state changed.
> + */
> +int drd_statemachine(struct usb_otg *otg)
> +{
> + struct otg_fsm *fsm = &otg->fsm;
> + enum usb_otg_state state;
> + int ret;
> +
> + mutex_lock(&fsm->lock);
> +
> + fsm->state_changed = 0;
> + state = otg->state;
> +
> + switch (state) {
> + case OTG_STATE_UNDEFINED:
> + if (!fsm->id)
> + drd_set_state(fsm, OTG_STATE_A_HOST);
> + else if (fsm->id && fsm->b_sess_vld)
> + drd_set_state(fsm, OTG_STATE_B_PERIPHERAL);
> + else
> + drd_set_state(fsm, OTG_STATE_B_IDLE);
> + break;
> + case OTG_STATE_B_IDLE:
> + if (!fsm->id)
> + drd_set_state(fsm, OTG_STATE_A_HOST);
> + else if (fsm->b_sess_vld)
> + drd_set_state(fsm, OTG_STATE_B_PERIPHERAL);
> + break;
> + case OTG_STATE_B_PERIPHERAL:
> + if (!fsm->id)
> + drd_set_state(fsm, OTG_STATE_A_HOST);
> + else if (!fsm->b_sess_vld)
> + drd_set_state(fsm, OTG_STATE_B_IDLE);
> + break;
> + case OTG_STATE_A_HOST:
> + if (fsm->id && fsm->b_sess_vld)
> + drd_set_state(fsm, OTG_STATE_B_PERIPHERAL);
> + else if (fsm->id && !fsm->b_sess_vld)
> + drd_set_state(fsm, OTG_STATE_B_IDLE);
> + break;
> +
> + default:
> + dev_err(otg->dev, "%s: otg: invalid usb-drd state: %s\n",
> + __func__, usb_otg_state_string(state));
> + break;
> + }
> +
> + ret = fsm->state_changed;
> + mutex_unlock(&fsm->lock);
> + dev_dbg(otg->dev, "otg: quit statemachine, changed %d\n",
> + fsm->state_changed);
> +
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(drd_statemachine);
> +
> +/**
> + * usb_drd_work() - Dual-role state machine work function
> + * @work: work_struct context
> + *
> + * Runs the DRD state machine. Scheduled whenever there is a change
> + * in FSM inputs.
> + */
> +static void usb_drd_work(struct work_struct *work)
> +{
> + struct usb_otg *otg = container_of(work, struct usb_otg, work);
> +
> + pm_runtime_get_sync(otg->dev);
> + while (drd_statemachine(otg))
> + ;
> + pm_runtime_put_sync(otg->dev);
> +}
> +
> +/**
> + * usb_otg_register() - Register the OTG/dual-role device to OTG core
> + * @dev: OTG/dual-role controller device.
> + * @config: OTG configuration.
> + *
> + * Registers the OTG/dual-role controller device with the USB OTG core.
> + *
> + * Return: struct usb_otg * if success, ERR_PTR() otherwise.
> + */
> +struct usb_otg *usb_otg_register(struct device *dev,
> + struct usb_otg_config *config)
> +{
> + struct usb_otg *otg;
> + int ret = 0;
> +
> + if (!dev || !config || !config->fsm_ops)
> + return ERR_PTR(-EINVAL);
> +
> + /* already in list? */
> + mutex_lock(&otg_list_mutex);
> + if (usb_otg_get_data(dev)) {
> + dev_err(dev, "otg: %s: device already in otg list\n",
> + __func__);
> + ret = -EINVAL;
> + goto unlock;
> + }
> +
> + /* allocate and add to list */
> + otg = kzalloc(sizeof(*otg), GFP_KERNEL);
> + if (!otg) {
> + ret = -ENOMEM;
> + goto unlock;
> + }
> +
> + otg->dev = dev;
> + /* otg->caps is controller caps + DT overrides */
> + otg->caps = *config->otg_caps;
> + ret = of_usb_update_otg_caps(dev->of_node, &otg->caps);
> + if (ret)
> + goto err_wq;
> +
> + if ((otg->caps.hnp_support || otg->caps.srp_support ||
> + otg->caps.adp_support) && !config->otg_work) {
> + dev_err(dev,
> + "otg: otg_work must be provided for OTG support\n");
> + ret = -EINVAL;
> + goto err_wq;
> + }
> +
> + if (config->otg_work) /* custom otg_work ? */
> + INIT_WORK(&otg->work, config->otg_work);
> + else
> + INIT_WORK(&otg->work, usb_drd_work);
> +
> + otg->wq = create_freezable_workqueue("usb_otg");
> + if (!otg->wq) {
> + dev_err(dev, "otg: %s: can't create workqueue\n",
> + __func__);
> + ret = -ENOMEM;
> + goto err_wq;
> + }
> +
> + /* set otg ops */
> + otg->fsm.ops = config->fsm_ops;
> +
> + mutex_init(&otg->fsm.lock);
> +
> + list_add_tail(&otg->list, &otg_list);
> + mutex_unlock(&otg_list_mutex);
> +
> + return otg;
> +
> +err_wq:
> + kfree(otg);
> +unlock:
> + mutex_unlock(&otg_list_mutex);
> + return ERR_PTR(ret);
> +}
> +EXPORT_SYMBOL_GPL(usb_otg_register);
> +
> +/**
> + * usb_otg_unregister() - Unregister the OTG/dual-role device from USB OTG core
> + * @dev: OTG controller device.
> + *
> + * Unregisters the OTG/dual-role controller device from USB OTG core.
> + * Prevents unregistering till both the associated Host and Gadget controllers
> + * have unregistered from the OTG core.
> + *
> + * Return: 0 on success, error value otherwise.
> + */
> +int usb_otg_unregister(struct device *dev)
> +{
> + struct usb_otg *otg;
> +
> + mutex_lock(&otg_list_mutex);
> + otg = usb_otg_get_data(dev);
> + if (!otg) {
> + dev_err(dev, "otg: %s: device not in otg list\n",
> + __func__);
> + mutex_unlock(&otg_list_mutex);
> + return -EINVAL;
> + }
> +
> + /* prevent unregister till both host & gadget have unregistered */
> + if (otg->host || otg->gadget) {
> + dev_err(dev, "otg: %s: host/gadget still registered\n",
> + __func__);
> + mutex_unlock(&otg_list_mutex);
> + return -EBUSY;
> + }
> +
> + /* OTG FSM is halted when host/gadget unregistered */
> + destroy_workqueue(otg->wq);
> +
> + /* remove from otg list */
> + list_del(&otg->list);
> + kfree(otg);
> + mutex_unlock(&otg_list_mutex);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(usb_otg_unregister);
> +
> +/**
> + * usb_otg_start_fsm() - Start the OTG FSM
> + * @otg: usb_otg instance
> + *
> + * Start the OTG FSM if we can. The HCD, UDC and gadget function driver
> + * must be ready for the OTG FSM to start.
> + *
> + * fsm->lock must be held.
> + */
> +static void usb_otg_start_fsm(struct usb_otg *otg)
> +{
> + struct otg_fsm *fsm = &otg->fsm;
> +
> + if (fsm->running)
> + goto kick_fsm;
> +
> + if (!otg->host) {
> + dev_info(otg->dev, "otg: can't start till host registers\n");
> + return;
> + }
> +
> + if (!otg->gadget) {
> + dev_info(otg->dev,
> + "otg: can't start till gadget UDC registers\n");
> + return;
> + }
> +
> + if (!otg->gadget_ready) {
> + dev_info(otg->dev,
> + "otg: can't start till gadget function registers\n");
> + return;
> + }
> +
> + fsm->running = true;
> +kick_fsm:
> + queue_work(otg->wq, &otg->work);
> +}
> +
> +/**
> + * usb_otg_stop_fsm() - Stop the OTG FSM
> + * @otg: usb_otg instance
> + *
> + * Stops the HCD, UDC and the OTG FSM.
> + *
> + * fsm->lock must be held.
> + */
> +static void usb_otg_stop_fsm(struct usb_otg *otg)
> +{
> + struct otg_fsm *fsm = &otg->fsm;
> +
> + if (!fsm->running)
> + return;
> +
> + /* no more new events queued */
> + fsm->running = false;
> +
> + flush_workqueue(otg->wq);
> + otg->state = OTG_STATE_UNDEFINED;
> +
> + /* stop host/gadget immediately */
> + if (fsm->protocol == PROTO_HOST) {
> + otg_start_host(otg, 0);
> + } else if (fsm->protocol == PROTO_GADGET) {
> + otg->gadget_ops->connect_control(otg->gadget, false);
> + otg_start_gadget(otg, 0);
> + }
> + fsm->protocol = PROTO_UNDEF;
> +}
> +
> +/**
> + * usb_otg_sync_inputs() - Sync OTG inputs with the OTG state machine
> + * @otg: usb_otg instance
> + *
> + * Used by the OTG driver to update the inputs to the OTG
> + * state machine.
> + *
> + * Can be called in IRQ context.
> + */
> +void usb_otg_sync_inputs(struct usb_otg *otg)
> +{
> + /* Don't kick FSM till it has started */
> + if (!otg->fsm.running)
> + return;
> +
> + /* Kick FSM */
> + queue_work(otg->wq, &otg->work);
> +}
> +EXPORT_SYMBOL_GPL(usb_otg_sync_inputs);
> +
> +/**
> + * usb_otg_register_hcd() - Register the host controller to OTG core
> + * @hcd: host controller
> + * @irqnum: interrupt number
> + * @irqflags: interrupt flags
> + * @ops: HCD ops to interface with the HCD
> + *
> + * This is used by the USB Host stack to register the host controller
> + * to the OTG core. Host controller must not be started by the
> + * caller as it is left up to the OTG state machine to do so.
> + * hcd->otg_dev must contain the related otg controller device.
> + *
> + * Return: 0 on success, error value otherwise.
> + */
> +int usb_otg_register_hcd(struct usb_hcd *hcd, unsigned int irqnum,
> + unsigned long irqflags, struct otg_hcd_ops *ops)
> +{
> + struct usb_otg *otg;
> + struct device *hcd_dev = hcd->self.controller;
> + struct device *otg_dev = hcd->otg_dev;
> +
> + if (!otg_dev)
> + return -EINVAL;
> +
> + /* we're otg but otg controller might not yet be registered */
> + mutex_lock(&otg_list_mutex);
> + otg = usb_otg_get_data(otg_dev);
> + mutex_unlock(&otg_list_mutex);
> + if (!otg) {
> + dev_dbg(hcd_dev,
> + "otg: controller not yet registered. deferring.\n");
> + return -EPROBE_DEFER;
> + }
> +
> + /* HCD will be started by OTG fsm when needed */
> + mutex_lock(&otg->fsm.lock);
> + if (otg->primary_hcd.hcd) {
> + /* probably a shared HCD ? */
> + if (usb_otg_hcd_is_primary_hcd(hcd)) {
> + dev_err(otg_dev, "otg: primary host already registered\n");
> + goto err;
> + }
> +
> + if (hcd->shared_hcd == otg->primary_hcd.hcd) {
> + if (otg->shared_hcd.hcd) {
> + dev_err(otg_dev, "otg: shared host already registered\n");
> + goto err;
> + }
> +
> + otg->shared_hcd.hcd = hcd;
> + otg->shared_hcd.irqnum = irqnum;
> + otg->shared_hcd.irqflags = irqflags;
> + otg->shared_hcd.ops = ops;
> + dev_info(otg_dev, "otg: shared host %s registered\n",
> + dev_name(hcd->self.controller));
> + } else {
> + dev_err(otg_dev, "otg: invalid shared host %s\n",
> + dev_name(hcd->self.controller));
> + goto err;
> + }
> + } else {
> + if (!usb_otg_hcd_is_primary_hcd(hcd)) {
> + dev_err(otg_dev, "otg: primary host must be registered first\n");
> + goto err;
> + }
> +
> + otg->primary_hcd.hcd = hcd;
> + otg->primary_hcd.irqnum = irqnum;
> + otg->primary_hcd.irqflags = irqflags;
> + otg->primary_hcd.ops = ops;
> + otg->hcd_ops = ops;
> + dev_info(otg_dev, "otg: primary host %s registered\n",
> + dev_name(hcd->self.controller));
> + }
> +
> + /*
> + * we're ready only if we have shared HCD
> + * or we don't need shared HCD.
> + */
> + if (otg->shared_hcd.hcd || !otg->primary_hcd.hcd->shared_hcd) {
> + otg->host = hcd_to_bus(hcd);
> + /* FIXME: set bus->otg_port if this is true OTG port with HNP */
> +
> + /* start FSM */
> + usb_otg_start_fsm(otg);
> + } else {
> + dev_dbg(otg_dev, "otg: can't start till shared host registers\n");
> + }
> +
> + mutex_unlock(&otg->fsm.lock);
> +
> + return 0;
> +
> +err:
> + mutex_unlock(&otg->fsm.lock);
> + return -EINVAL;
> +}
> +EXPORT_SYMBOL_GPL(usb_otg_register_hcd);
> +
> +/**
> + * usb_otg_unregister_hcd() - Unregister the host controller from OTG core
> + * @hcd: host controller device
> + *
> + * This is used by the USB Host stack to unregister the host controller
> + * from the OTG core. Ensures that host controller is not running
> + * on successful return.
> + *
> + * Returns: 0 on success, error value otherwise.
> + */
> +int usb_otg_unregister_hcd(struct usb_hcd *hcd)
> +{
> + struct usb_otg *otg;
> + struct device *hcd_dev = hcd_to_bus(hcd)->controller;
> + struct device *otg_dev = hcd->otg_dev;
> +
> + if (!otg_dev)
> + return -EINVAL; /* we're definitely not OTG */
> +
> + mutex_lock(&otg_list_mutex);
> + otg = usb_otg_get_data(otg_dev);
> + mutex_unlock(&otg_list_mutex);
> + if (!otg) {
> + dev_err(hcd_dev, "otg: host %s wasn't registered with otg\n",
> + dev_name(hcd_dev));
> + return -EINVAL;
> + }
> +
> + mutex_lock(&otg->fsm.lock);
> + if (hcd == otg->primary_hcd.hcd) {
> + otg->primary_hcd.hcd = NULL;
> + dev_info(otg_dev, "otg: primary host %s unregistered\n",
> + dev_name(hcd_dev));
> + } else if (hcd == otg->shared_hcd.hcd) {
> + otg->shared_hcd.hcd = NULL;
> + dev_info(otg_dev, "otg: shared host %s unregistered\n",
> + dev_name(hcd_dev));
> + } else {
> + mutex_unlock(&otg->fsm.lock);
> + dev_err(otg_dev, "otg: host %s wasn't registered with otg\n",
> + dev_name(hcd_dev));
> + return -EINVAL;
> + }
> +
> + /* stop FSM & Host */
> + usb_otg_stop_fsm(otg);
> + otg->host = NULL;
> +
> + mutex_unlock(&otg->fsm.lock);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(usb_otg_unregister_hcd);
> +
> +/**
> + * usb_otg_register_gadget() - Register the gadget controller to OTG core
> + * @gadget: gadget controller instance
> + * @ops: gadget interface ops
> + *
> + * This is used by the USB gadget stack to register the gadget controller
> + * to the OTG core. Gadget controller must not be started by the
> + * caller as it is left up to the OTG state machine to do so.
> + *
> + * Returns: 0 on success, error value otherwise.
> + */
> +int usb_otg_register_gadget(struct usb_gadget *gadget,
> + struct otg_gadget_ops *ops)
> +{
> + struct usb_otg *otg;
> + struct device *gadget_dev = &gadget->dev;
> + struct device *otg_dev = gadget->otg_dev;
> +
> + if (!otg_dev)
> + return -EINVAL; /* we're definitely not OTG */
> +
> + /* we're otg but otg controller might not yet be registered */
> + mutex_lock(&otg_list_mutex);
> + otg = usb_otg_get_data(otg_dev);
> + mutex_unlock(&otg_list_mutex);
> + if (!otg) {
> + dev_dbg(gadget_dev,
> + "otg: controller not yet registered, deferring.\n");
> + return -EPROBE_DEFER;
> + }
> +
> + mutex_lock(&otg->fsm.lock);
> + if (otg->gadget) {
> + dev_err(otg_dev, "otg: gadget already registered with otg\n");
> + mutex_unlock(&otg->fsm.lock);
> + return -EINVAL;
> + }
> +
> + otg->gadget = gadget;
> + otg->gadget_ops = ops;
> + dev_info(otg_dev, "otg: gadget %s registered\n",
> + dev_name(&gadget->dev));
> +
> + /* FSM will be started in usb_otg_gadget_ready() */
> + mutex_unlock(&otg->fsm.lock);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(usb_otg_register_gadget);
> +
> +/**
> + * usb_otg_unregister_gadget() - Unregister the gadget controller from OTG core
> + * @gadget: gadget controller
> + *
> + * This is used by the USB gadget stack to unregister the gadget controller
> + * from the OTG core. Ensures that gadget controller is not running
> + * on successful return.
> + *
> + * Returns: 0 on success, error value otherwise.
> + */
> +int usb_otg_unregister_gadget(struct usb_gadget *gadget)
> +{
> + struct usb_otg *otg;
> + struct device *gadget_dev = &gadget->dev;
> + struct device *otg_dev = gadget->otg_dev;
> +
> + if (!otg_dev)
> + return -EINVAL;
> +
> + mutex_lock(&otg_list_mutex);
> + otg = usb_otg_get_data(otg_dev);
> + mutex_unlock(&otg_list_mutex);
> + if (!otg) {
> + dev_err(gadget_dev,
> + "otg: gadget %s wasn't registered with otg\n",
> + dev_name(&gadget->dev));
> + return -EINVAL;
> + }
> +
> + mutex_lock(&otg->fsm.lock);
> + if (otg->gadget != gadget) {
> + mutex_unlock(&otg->fsm.lock);
> + dev_err(otg_dev, "otg: gadget %s wasn't registered with otg\n",
> + dev_name(&gadget->dev));
> + return -EINVAL;
> + }
> +
> + /* FSM must be stopped in usb_otg_gadget_ready() */
> + if (otg->gadget_ready) {
> + dev_err(otg_dev,
> + "otg: gadget %s unregistered before being unready, forcing stop\n",
> + dev_name(&gadget->dev));
> + usb_otg_stop_fsm(otg);
> + }
> +
> + otg->gadget = NULL;
> + mutex_unlock(&otg->fsm.lock);
> +
> + dev_info(otg_dev, "otg: gadget %s unregistered\n",
> + dev_name(&gadget->dev));
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(usb_otg_unregister_gadget);
> +
> +/**
> + * usb_otg_gadget_ready() - Notify gadget function driver ready status
> + * @gadget: gadget controller
> + * @ready: 0: function driver ready, 1: function driver not ready
> + *
> + * Notify the OTG core about status of the gadget function driver.
> + * As OTG core is responsible to start/stop the gadget controller, it
> + * must be aware when the gadget function driver is available or not.
> + * This function is used by the Gadget core to inform the OTG core
> + * about the gadget function driver readyness.
> + *
> + * Return: 0 on sucess, error value otherwise.
> + */
> +int usb_otg_gadget_ready(struct usb_gadget *gadget, bool ready)
> +{
> + struct usb_otg *otg;
> + struct device *gadget_dev = &gadget->dev;
> + struct device *otg_dev = gadget->otg_dev;
> +
> + if (!otg_dev)
> + return -EINVAL;
> +
> + mutex_lock(&otg_list_mutex);
> + otg = usb_otg_get_data(otg_dev);
> + mutex_unlock(&otg_list_mutex);
> + if (!otg) {
> + dev_err(gadget_dev,
> + "otg: gadget %s wasn't registered with otg\n",
> + dev_name(&gadget->dev));
> + return -EINVAL;
> + }
> +
> + mutex_lock(&otg->fsm.lock);
> + if (otg->gadget != gadget) {
> + mutex_unlock(&otg->fsm.lock);
> + dev_err(otg_dev, "otg: gadget %s wasn't registered with otg\n",
> + dev_name(&gadget->dev));
> + return -EINVAL;
> + }
> +
> + /* Start/stop FSM & gadget */
> + otg->gadget_ready = ready;
> + if (ready)
> + usb_otg_start_fsm(otg);
> + else
> + usb_otg_stop_fsm(otg);
> +
> + dev_dbg(otg_dev, "otg: gadget %s %sready\n", dev_name(&gadget->dev),
> + ready ? "" : "not ");
> +
> + mutex_unlock(&otg->fsm.lock);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(usb_otg_gadget_ready);
> +
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/usb/core/Kconfig b/drivers/usb/core/Kconfig
> index ae228d0..37f8c54 100644
> --- a/drivers/usb/core/Kconfig
> +++ b/drivers/usb/core/Kconfig
> @@ -41,20 +41,6 @@ config USB_DYNAMIC_MINORS
>
> If you are unsure about this, say N here.
>
> -config USB_OTG
> - bool "OTG support"
> - depends on PM
> - default n
> - help
> - The most notable feature of USB OTG is support for a
> - "Dual-Role" device, which can act as either a device
> - or a host. The initial role is decided by the type of
> - plug inserted and can be changed later when two dual
> - role devices talk to each other.
> -
> - Select this only if your board has Mini-AB/Micro-AB
> - connector.
> -
> config USB_OTG_WHITELIST
> bool "Rely on OTG and EH Targeted Peripherals List"
> depends on USB
> diff --git a/drivers/usb/gadget/Kconfig b/drivers/usb/gadget/Kconfig
> index 3c3f31c..5fc9095 100644
> --- a/drivers/usb/gadget/Kconfig
> +++ b/drivers/usb/gadget/Kconfig
> @@ -16,6 +16,7 @@
> menuconfig USB_GADGET
> tristate "USB Gadget Support"
> select USB_COMMON
> + select USB_OTG_CORE
> select NLS
> help
> USB is a master/slave protocol, organized with one master
> diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h
> index f4fc0aa..1d74fb8 100644
> --- a/include/linux/usb/gadget.h
> +++ b/include/linux/usb/gadget.h
> @@ -328,6 +328,7 @@ struct usb_gadget_ops {
> * @in_epnum: last used in ep number
> * @mA: last set mA value
> * @otg_caps: OTG capabilities of this gadget.
> + * @otg_dev: OTG controller device, if needs to be used with OTG core.
> * @sg_supported: true if we can handle scatter-gather
> * @is_otg: True if the USB device port uses a Mini-AB jack, so that the
> * gadget driver must provide a USB OTG descriptor.
> @@ -385,6 +386,7 @@ struct usb_gadget {
> unsigned in_epnum;
> unsigned mA;
> struct usb_otg_caps *otg_caps;
> + struct device *otg_dev;
>
> unsigned sg_supported:1;
> unsigned is_otg:1;
> diff --git a/include/linux/usb/hcd.h b/include/linux/usb/hcd.h
> index 7729c1f..36bd54f 100644
> --- a/include/linux/usb/hcd.h
> +++ b/include/linux/usb/hcd.h
> @@ -185,6 +185,7 @@ struct usb_hcd {
> struct mutex *bandwidth_mutex;
> struct usb_hcd *shared_hcd;
> struct usb_hcd *primary_hcd;
> + struct device *otg_dev; /* OTG controller device */
>
>
> #define HCD_BUFFER_POOLS 4
> diff --git a/include/linux/usb/otg-fsm.h b/include/linux/usb/otg-fsm.h
> index 26e6531..943714a 100644
> --- a/include/linux/usb/otg-fsm.h
> +++ b/include/linux/usb/otg-fsm.h
> @@ -60,6 +60,11 @@ enum otg_fsm_timer {
> /**
> * struct otg_fsm - OTG state machine according to the OTG spec
> *
> + * DRD mode hardware Inputs
> + *
> + * @id: TRUE for B-device, FALSE for A-device.
> + * @b_sess_vld: VBUS voltage in regulation.
> + *
> * OTG hardware Inputs
> *
> * Common inputs for A and B device
> @@ -132,6 +137,7 @@ enum otg_fsm_timer {
> * a_clr_err: Asserted (by application ?) to clear a_vbus_err due to an
> * overcurrent condition and causes the A-device to transition
> * to a_wait_vfall
> + * running: state machine running/stopped indicator
> */
> struct otg_fsm {
> /* Input */
> @@ -187,6 +193,7 @@ struct otg_fsm {
> int b_ase0_brst_tmout;
> int a_bidl_adis_tmout;
>
> + bool running;
> struct otg_fsm_ops *ops;
>
> /* Current usb protocol used: 0:undefine; 1:host; 2:client */
> diff --git a/include/linux/usb/otg.h b/include/linux/usb/otg.h
> index 85b8fb5..9d72951 100644
> --- a/include/linux/usb/otg.h
> +++ b/include/linux/usb/otg.h
> @@ -10,10 +10,67 @@
> #define __LINUX_USB_OTG_H
>
> #include <linux/phy/phy.h>
> -#include <linux/usb/phy.h>
> -#include <linux/usb/otg-fsm.h>
> +#include <linux/device.h>
> +#include <linux/usb.h>
> #include <linux/usb/hcd.h>
> +#include <linux/usb/gadget.h>
> +#include <linux/usb/otg-fsm.h>
> +#include <linux/usb/phy.h>
> +
> +/**
> + * struct otg_hcd - host controller state and interface
> + *
> + * @hcd: host controller
> + * @irqnum: IRQ number
> + * @irqflags: IRQ flags
> + * @ops: OTG to host controller interface
> + * @otg_dev: OTG controller device
> + */
> +struct otg_hcd {
> + struct usb_hcd *hcd;
> + unsigned int irqnum;
> + unsigned long irqflags;
> + struct otg_hcd_ops *ops;
> + struct device *otg_dev;
> +};
> +
> +/**
> + * struct usb_otg_caps - describes the otg capabilities of the device
> + * @otg_rev: The OTG revision number the device is compliant with, it's
> + * in binary-coded decimal (i.e. 2.0 is 0200H).
> + * @hnp_support: Indicates if the device supports HNP.
> + * @srp_support: Indicates if the device supports SRP.
> + * @adp_support: Indicates if the device supports ADP.
> + */
> +struct usb_otg_caps {
> + u16 otg_rev;
> + bool hnp_support;
> + bool srp_support;
> + bool adp_support;
> +};
>
> +/**
> + * struct usb_otg - usb otg controller state
> + *
> + * @default_a: Indicates we are an A device. i.e. Host.
> + * @phy: USB PHY interface
> + * @usb_phy: old usb_phy interface
> + * @host: host controller bus
> + * @gadget: gadget device
> + * @state: current OTG state
> + * @dev: OTG controller device
> + * @caps: OTG capabilities revision, hnp, srp, etc
> + * @fsm: OTG finite state machine
> + * @hcd_ops: host controller interface
> + * ------- internal use only -------
> + * @primary_hcd: primary host state and interface
> + * @shared_hcd: shared host state and interface
> + * @gadget_ops: gadget controller interface
> + * @list: list of OTG controllers
> + * @work: OTG state machine work
> + * @wq: OTG state machine work queue
> + * @flags: to track if host/gadget is running
> + */
> struct usb_otg {
> u8 default_a;
>
> @@ -24,9 +81,25 @@ struct usb_otg {
> struct usb_gadget *gadget;
>
> enum usb_otg_state state;
> + struct device *dev;
> + struct usb_otg_caps caps;
> struct otg_fsm fsm;
> struct otg_hcd_ops *hcd_ops;
>
> + /* internal use only */
> + struct otg_hcd primary_hcd;
> + struct otg_hcd shared_hcd;
> + struct otg_gadget_ops *gadget_ops;
> + bool gadget_ready;
> + struct list_head list;
> + struct work_struct work;
> + struct workqueue_struct *wq;
> + u32 flags;
> +#define OTG_FLAG_GADGET_RUNNING (1 << 0)
> +#define OTG_FLAG_HOST_RUNNING (1 << 1)
> + /* use otg->fsm.lock for serializing access */
> +
> +/*------------- deprecated interface -----------------------------*/
> /* bind/unbind the host controller */
> int (*set_host)(struct usb_otg *otg, struct usb_bus *host);
>
> @@ -42,26 +115,95 @@ struct usb_otg {
>
> /* start or continue HNP role switch */
> int (*start_hnp)(struct usb_otg *otg);
> -
> +/*---------------------------------------------------------------*/
> };
>
> /**
> - * struct usb_otg_caps - describes the otg capabilities of the device
> - * @otg_rev: The OTG revision number the device is compliant with, it's
> - * in binary-coded decimal (i.e. 2.0 is 0200H).
> - * @hnp_support: Indicates if the device supports HNP.
> - * @srp_support: Indicates if the device supports SRP.
> - * @adp_support: Indicates if the device supports ADP.
> + * struct usb_otg_config - OTG controller configuration
> + * @caps: OTG capabilities of the controller
> + * @ops: OTG FSM operations
> + * @otg_work: optional custom OTG state machine work function
> */
> -struct usb_otg_caps {
> - u16 otg_rev;
> - bool hnp_support;
> - bool srp_support;
> - bool adp_support;
> +struct usb_otg_config {
> + struct usb_otg_caps *otg_caps;
> + struct otg_fsm_ops *fsm_ops;
> + void (*otg_work)(struct work_struct *work);
> };
>
> extern const char *usb_otg_state_string(enum usb_otg_state state);
>
> +#if IS_ENABLED(CONFIG_USB_OTG)
> +struct usb_otg *usb_otg_register(struct device *dev,
> + struct usb_otg_config *config);
> +int usb_otg_unregister(struct device *dev);
> +int usb_otg_register_hcd(struct usb_hcd *hcd, unsigned int irqnum,
> + unsigned long irqflags, struct otg_hcd_ops *ops);
> +int usb_otg_unregister_hcd(struct usb_hcd *hcd);
> +int usb_otg_register_gadget(struct usb_gadget *gadget,
> + struct otg_gadget_ops *ops);
> +int usb_otg_unregister_gadget(struct usb_gadget *gadget);
> +void usb_otg_sync_inputs(struct usb_otg *otg);
> +int usb_otg_start_host(struct usb_otg *otg, int on);
> +int usb_otg_start_gadget(struct usb_otg *otg, int on);
> +int usb_otg_gadget_ready(struct usb_gadget *gadget, bool ready);
> +
> +#else /* CONFIG_USB_OTG */
> +
> +static inline struct usb_otg *usb_otg_register(struct device *dev,
> + struct usb_otg_config *config)
> +{
> + return ERR_PTR(-ENOTSUPP);
> +}
> +
> +static inline int usb_otg_unregister(struct device *dev)
> +{
> + return -ENOTSUPP;
> +}
> +
> +static inline int usb_otg_register_hcd(struct usb_hcd *hcd, unsigned int irqnum,
> + unsigned long irqflags,
> + struct otg_hcd_ops *ops)
> +{
> + return -ENOTSUPP;
> +}
> +
> +static inline int usb_otg_unregister_hcd(struct usb_hcd *hcd)
> +{
> + return -ENOTSUPP;
> +}
> +
> +static inline int usb_otg_register_gadget(struct usb_gadget *gadget,
> + struct otg_gadget_ops *ops)
> +{
> + return -ENOTSUPP;
> +}
> +
> +static inline int usb_otg_unregister_gadget(struct usb_gadget *gadget)
> +{
> + return -ENOTSUPP;
> +}
> +
> +static inline void usb_otg_sync_inputs(struct usb_otg *otg)
> +{
> +}
> +
> +static inline int usb_otg_start_host(struct usb_otg *otg, int on)
> +{
> + return -ENOTSUPP;
> +}
> +
> +static inline int usb_otg_start_gadget(struct usb_otg *otg, int on)
> +{
> + return -ENOTSUPP;
> +}
> +
> +static inline int usb_otg_gadget_ready(struct usb_gadget *gadget, bool ready)
> +{
> + return -ENOTSUPP;
> +}
> +#endif /* CONFIG_USB_OTG */
> +
> +/*------------- deprecated interface -----------------------------*/
> /* Context: can sleep */
> static inline int
> otg_start_hnp(struct usb_otg *otg)
> @@ -113,6 +255,8 @@ otg_start_srp(struct usb_otg *otg)
> return -ENOTSUPP;
> }
>
> +/*---------------------------------------------------------------*/
> +
> /* for OTG controller drivers (and maybe other stuff) */
> extern int usb_bus_start_enum(struct usb_bus *bus, unsigned port_num);
>
> @@ -237,4 +381,6 @@ static inline int otg_start_gadget(struct usb_otg *otg, int on)
> return otg->fsm.ops->start_gadget(otg, on);
> }
>
> +int drd_statemachine(struct usb_otg *otg);
> +
> #endif /* __LINUX_USB_OTG_H */
> --
> 2.7.4
>
>
> --
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--
Best Regards,
Peter Chen
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