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Message-ID: <20141126051454.GA24203@shlinux2>
Date: Wed, 26 Nov 2014 13:14:57 +0800
From: Peter Chen <peter.chen@...escale.com>
To: George Cherian <george.cherian@...com>
CC: <linux-arm-kernel@...ts.infradead.org>,
<linux-kernel@...r.kernel.org>,
<linux-samsung-soc@...r.kernel.org>, <linux-omap@...r.kernel.org>,
<linux-usb@...r.kernel.org>, <sojka@...ica.cz>,
<mathias.nyman@...el.com>, <balbi@...com>,
<gregkh@...uxfoundation.org>, <tony@...mide.com>,
<bcousson@...libre.com>, <kgene.kim@...sung.com>,
<ben-linux@...ff.org>, <linux@....linux.org.uk>,
<galak@...eaurora.org>, <ijc+devicetree@...lion.org.uk>,
<mark.rutland@....com>, <pawel.moll@....com>, <robh+dt@...nel.org>
Subject: Re: [PATCH 01/19] usb: common: drd-lib: Add DRD lib for USB.
On Tue, Nov 25, 2014 at 06:41:37PM +0530, George Cherian wrote:
> Add USB DRD library. This Library facilitates to
> switch roles between HOST and Device modes.
>
> A DRD should be added to the library using usb_drd_add().
> Register the HOST and UDC using usb_drd_register_hcd/udc().
> Un-Register the HOST and UDC using usb_drd_unregister_hcd/udc().
>
> Depending on the state of IP -
> Call the following to start/stop HOST controller
> usb_drd_start/stop_hcd().
> This internally calls usb_add/remove_hcd() or IP specific low level start/stop
> defined in ll_start/stop
>
> Call the following to start/stop UDC
> usb_drd_start/stop_udc().
> This internally calls udc_start/udc_stop() or IP specific low level start/stop
> defined in ll_start/stop
>
> Signed-off-by: George Cherian <george.cherian@...com>
> ---
> drivers/usb/Kconfig | 15 ++
> drivers/usb/common/Makefile | 1 +
> drivers/usb/common/drd-lib.c | 346 +++++++++++++++++++++++++++++++++++++++++++
> include/linux/usb/drd.h | 77 ++++++++++
> 4 files changed, 439 insertions(+)
> create mode 100644 drivers/usb/common/drd-lib.c
> create mode 100644 include/linux/usb/drd.h
>
> diff --git a/drivers/usb/Kconfig b/drivers/usb/Kconfig
> index ae481c3..ea0d944 100644
> --- a/drivers/usb/Kconfig
> +++ b/drivers/usb/Kconfig
> @@ -34,6 +34,21 @@ config USB_COMMON
> default y
> depends on USB || USB_GADGET
>
> +config DRD_LIB
> + tristate "DRD Library support"
> + default y
> + depends on USB && USB_GADGET
> + ---help---
> + This option adds DRD Library support for Universal Serial Bus (USB).
> + DRD Library faciliatets the Role switching by HOST and DEVICE roles,
> + If your hardware has a Dual Role Device.
> +
> + The DRD Library uses USB core API's to start/stop HOST controllers,
> + UDC API's to start/stop DEVICE controllers, ther by enabling to
> + switch roles between HOST and Device modes.
%s/ther by/thereby
> +
> + Say N if unsure.
> +
> config USB_ARCH_HAS_HCD
> def_bool y
>
> diff --git a/drivers/usb/common/Makefile b/drivers/usb/common/Makefile
> index ca2f8bd..e2c1593 100644
> --- a/drivers/usb/common/Makefile
> +++ b/drivers/usb/common/Makefile
> @@ -7,3 +7,4 @@ usb-common-y += common.o
> usb-common-$(CONFIG_USB_LED_TRIG) += led.o
>
> obj-$(CONFIG_USB_OTG_FSM) += usb-otg-fsm.o
> +obj-$(CONFIG_DRD_LIB) += drd-lib.o
> diff --git a/drivers/usb/common/drd-lib.c b/drivers/usb/common/drd-lib.c
> new file mode 100644
> index 0000000..6159436
> --- /dev/null
> +++ b/drivers/usb/common/drd-lib.c
> @@ -0,0 +1,346 @@
> +/**
> + * drd-lib.c - USB DRD library functions
> + *
> + * Copyright (C) 2014 Texas Instruments
> + * Author: George Cherian <george.cherian@...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 of
> + * the License 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.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program. If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include <linux/device.h>
> +#include <linux/err.h>
> +#include <linux/kernel.h>
> +#include <linux/list.h>
> +#include <linux/module.h>
> +#include <linux/usb.h>
> +
> +#include <linux/usb/hcd.h>
> +#include <linux/usb/gadget.h>
> +#include <linux/usb/drd.h>
> +
> +/**
> + * struct usb_drd - describes one dual role device
> + * @host - the HOST controller device of this drd
> + * @gadget - the gadget of drd
> + * @parent - the device to the actual controller
> + * @list - for use by the drd lib
> + * @state - specifies the current state
> + *
> + * This represents the internal data structure which is used by the UDC-class
> + * to hold information about udc driver and gadget together.
> + */
It is dual role struct, why you only talk about device?
> +struct usb_drd {
> + struct usb_drd_host *host;
> + struct usb_drd_gadget *gadget;
> + struct device *parent;
> + struct list_head list;
> + unsigned int state;
> +};
> +
> +static LIST_HEAD(drd_list);
> +static DEFINE_SPINLOCK(drd_lock);
> +
> +static struct usb_drd *usb_drd_get_dev(struct device *parent)
> +{
> + struct usb_drd *drd;
> +
> + spin_lock(&drd_lock);
> + list_for_each_entry(drd, &drd_list, list)
> + if (drd->parent == parent)
> + goto out;
> + drd = NULL;
> +out:
> + spin_unlock(&drd_lock);
> +
> + return drd;
> +}
> +
> +int usb_drd_get_state(struct device *parent)
> +{
> + struct usb_drd *drd;
> +
> + drd = usb_drd_get_dev(parent);
> + if (!drd)
> + return -ENODEV;
> +
> + return drd->state;
> +}
> +EXPORT_SYMBOL_GPL(usb_drd_get_state);
> +
> +int usb_drd_release(struct device *parent)
> +{
> + struct usb_drd *drd;
> + int ret;
> +
> + spin_lock(&drd_lock);
> + list_for_each_entry(drd, &drd_list, list) {
> + if (drd->parent == parent) {
> + kfree(drd);
> + ret = 0;
> + goto out;
> + }
> + }
> + ret = -ENODEV;
> +out:
> + spin_unlock(&drd_lock);
> +
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(usb_drd_release);
> +
> +int usb_drd_add(struct device *parent)
> +{
> + struct usb_drd *drd;
> +
> + drd = kzalloc(sizeof(*drd), GFP_KERNEL);
> + if (!drd)
> + return -ENOMEM;
> +
> + spin_lock(&drd_lock);
> + drd->parent = parent;
> + list_add_tail(&drd->list, &drd_list);
> + drd->state = DRD_UNREGISTERED;
> +
> + spin_unlock(&drd_lock);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(usb_drd_add);
> +
> +int usb_drd_register_hcd(struct device *parent, struct usb_drd_host *host)
> +{
> + struct usb_drd *drd;
> +
> + drd = usb_drd_get_dev(parent);
> + if (!drd)
> + return -ENODEV;
> +
> + spin_lock(&drd_lock);
> + drd->host = host;
> + drd->state |= DRD_HOST_REGISTERED | DRD_HOST_ACTIVE;
> + spin_unlock(&drd_lock);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(usb_drd_register_hcd);
> +
> +int usb_drd_unregister_hcd(struct device *parent)
> +{
> + struct usb_drd *drd;
> +
> + drd = usb_drd_get_dev(parent);
> + if (!drd)
> + return -ENODEV;
> +
> + spin_lock(&drd_lock);
> + drd->state &= ~(DRD_HOST_REGISTERED | DRD_HOST_ACTIVE);
> + spin_unlock(&drd_lock);
> + kfree(drd->host);
It is better to allocate and free memory at the same file, either
both at DRD LIB APIs, or at host controller and udc driver.
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(usb_drd_unregister_hcd);
> +
> +int usb_drd_start_hcd(struct device *parent)
> +{
> + struct usb_drd *drd;
> + struct usb_drd_setup *setup;
> +
> + drd = usb_drd_get_dev(parent);
> + if (!drd)
> + return -ENODEV;
> +
> + if (WARN_ON(!(drd->state & DRD_HOST_REGISTERED)))
> + return -EINVAL;
> +
> + setup = drd->host->host_setup;
> + if (setup && setup->ll_start)
> + setup->ll_start(setup->data);
> +
> + usb_add_hcd(drd->host->main_hcd,
> + drd->host->hcd_irq, IRQF_SHARED);
> + if (drd->host->shared_hcd)
> + usb_add_hcd(drd->host->shared_hcd,
> + drd->host->hcd_irq, IRQF_SHARED);
Check return value please.
Peter
> +
> + spin_lock(&drd_lock);
> + drd->state |= DRD_HOST_ACTIVE;
> + spin_unlock(&drd_lock);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(usb_drd_start_hcd);
> +
> +int usb_drd_stop_hcd(struct device *parent)
> +{
> + struct usb_drd *drd;
> + struct usb_drd_setup *setup;
> +
> + drd = usb_drd_get_dev(parent);
> + if (!drd)
> + return -ENODEV;
> +
> + if (WARN_ON(!(drd->state & DRD_HOST_ACTIVE)))
> + return -EINVAL;
> +
> + setup = drd->host->host_setup;
> + if (setup && setup->ll_stop)
> + setup->ll_stop(setup->data);
> + if (drd->host->shared_hcd)
> + usb_remove_hcd(drd->host->shared_hcd);
> +
> + usb_remove_hcd(drd->host->main_hcd);
> +
> + spin_lock(&drd_lock);
> + drd->state = drd->state & ~DRD_HOST_ACTIVE;
> + spin_unlock(&drd_lock);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(usb_drd_stop_hcd);
> +
> +int usb_drd_register_udc(struct device *parent, struct usb_drd_gadget *gadget)
> +{
> + struct usb_drd *drd;
> +
> + drd = usb_drd_get_dev(parent);
> + if (!drd)
> + return -ENODEV;
> +
> + spin_lock(&drd_lock);
> + drd->gadget = gadget;
> + drd->state |= DRD_DEVICE_REGISTERED;
> + if (drd->gadget->g_driver)
> + drd->state |= DRD_DEVICE_ACTIVE;
> +
> + spin_unlock(&drd_lock);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(usb_drd_register_udc);
> +
> +int usb_drd_register_udc_driver(struct device *parent,
> + struct usb_gadget_driver *driver)
> +{
> + struct usb_drd *drd;
> +
> + drd = usb_drd_get_dev(parent);
> + if (!drd)
> + return -ENODEV;
> +
> + spin_lock(&drd_lock);
> + drd->gadget->g_driver = driver;
> + drd->state |= DRD_DEVICE_ACTIVE;
> + spin_unlock(&drd_lock);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(usb_drd_register_udc_driver);
> +
> +int usb_drd_unregister_udc(struct device *parent)
> +{
> + struct usb_drd *drd;
> +
> + drd = usb_drd_get_dev(parent);
> + if (!drd)
> + return -ENODEV;
> +
> + spin_lock(&drd_lock);
> + drd->state &= ~(DRD_DEVICE_REGISTERED | DRD_DEVICE_ACTIVE);
> + spin_unlock(&drd_lock);
> + kfree(drd->gadget->gadget_setup);
> + kfree(drd->gadget);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(usb_drd_unregister_udc);
> +
> +int usb_drd_unregister_udc_driver(struct device *parent)
> +{
> + struct usb_drd *drd;
> + struct usb_drd_gadget *drd_gadget;
> +
> + drd = usb_drd_get_dev(parent);
> + if (!drd)
> + return -ENODEV;
> + drd_gadget = drd->gadget;
> +
> + spin_lock(&drd_lock);
> + drd->state &= ~DRD_DEVICE_ACTIVE;
> + drd_gadget->g_driver = NULL;
> + spin_unlock(&drd_lock);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(usb_drd_unregister_udc_driver);
> +
> +int usb_drd_start_udc(struct device *parent)
> +{
> + struct usb_drd *drd;
> + struct usb_drd_gadget *drd_gadget;
> + struct usb_drd_setup *setup;
> +
> + drd = usb_drd_get_dev(parent);
> + if (!drd)
> + return -ENODEV;
> +
> + if (WARN_ON(!(drd->state & DRD_DEVICE_REGISTERED)))
> + return -EINVAL;
> +
> + drd_gadget = drd->gadget;
> + setup = drd_gadget->gadget_setup;
> +
> + if (setup && setup->ll_start)
> + setup->ll_start(setup->data);
> +
> + usb_add_gadget_udc_release(parent, drd_gadget->gadget,
> + setup->ll_release);
> + spin_lock(&drd_lock);
> + drd->state |= DRD_DEVICE_ACTIVE;
> + spin_unlock(&drd_lock);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(usb_drd_start_udc);
> +
> +int usb_drd_stop_udc(struct device *parent)
> +{
> + struct usb_drd *drd;
> + struct usb_drd_gadget *drd_gadget;
> + struct usb_drd_setup *setup;
> +
> + drd = usb_drd_get_dev(parent);
> + if (!drd)
> + return -ENODEV;
> +
> + if (WARN_ON(!(drd->state & DRD_DEVICE_REGISTERED)))
> + return -EINVAL;
> +
> + drd_gadget = drd->gadget;
> + setup = drd_gadget->gadget_setup;
> + if (setup && setup->ll_stop)
> + setup->ll_stop(setup->data);
> +
> + usb_del_gadget_udc(drd_gadget->gadget);
> +
> + spin_lock(&drd_lock);
> + drd->state = drd->state & ~DRD_DEVICE_ACTIVE;
> + spin_unlock(&drd_lock);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(usb_drd_stop_udc);
> +
> +MODULE_DESCRIPTION("USB-DRD Library");
> +MODULE_AUTHOR("George Cherian <george.cherian@...com>");
> +MODULE_LICENSE("GPL v2");
> diff --git a/include/linux/usb/drd.h b/include/linux/usb/drd.h
> new file mode 100644
> index 0000000..71c64dc
> --- /dev/null
> +++ b/include/linux/usb/drd.h
> @@ -0,0 +1,77 @@
> +#include <linux/usb/gadget.h>
> +#include <linux/usb/otg.h>
> +#include <linux/usb/hcd.h>
> +
> +struct usb_drd_setup {
> + int (*ll_start)(void *);
> + int (*ll_stop)(void *);
> + void (*ll_release)(struct device *);
> + void *data;
> +};
> +
> +struct usb_drd_host {
> + struct usb_hcd *main_hcd;
> + struct usb_hcd *shared_hcd;
> + int hcd_irq;
> + struct usb_drd_setup *host_setup;
> +};
> +
> +struct usb_drd_gadget {
> + struct usb_gadget_driver *g_driver;
> + struct usb_gadget *gadget;
> + struct usb_drd_setup *gadget_setup;
> +};
> +
> +#define DRD_UNREGISTERED 0x0
> +#define DRD_DEVICE_REGISTERED 0x1
> +#define DRD_HOST_REGISTERED 0x2
> +#define DRD_HOST_ACTIVE 0x4
> +#define DRD_DEVICE_ACTIVE 0x8
> +
> +#if IS_ENABLED(CONFIG_DRD_LIB)
> +int usb_drd_release(struct device *parent);
> +int usb_drd_add(struct device *parent);
> +int usb_drd_register_udc(struct device *parent,
> + struct usb_drd_gadget *gadget);
> +int usb_drd_register_udc_driver(struct device *parent,
> + struct usb_gadget_driver *driver);
> +int usb_drd_unregister_udc(struct device *parent);
> +int usb_drd_unregister_udc_driver(struct device *parent);
> +int usb_drd_register_hcd(struct device *parent,
> + struct usb_drd_host *host);
> +int usb_drd_unregister_hcd(struct device *parent);
> +int usb_drd_start_hcd(struct device *parent);
> +int usb_drd_stop_hcd(struct device *parent);
> +int usb_drd_start_udc(struct device *parent);
> +int usb_drd_stop_udc(struct device *parent);
> +int usb_drd_get_state(struct device *parent);
> +#else
> +static inline int usb_drd_release(struct device *parent)
> +{ return 0; }
> +static inline int usb_drd_add(struct device *parent)
> +{ return 0; }
> +static inline int usb_drd_register_udc(struct device *parent,
> + struct usb_drd_gadget *gadget)
> +{ return 0; }
> +static inline int usb_drd_register_udc_driver(struct device *parent,
> + struct usb_gadget_driver *driver)
> +{ return 0; }
> +static inline int usb_drd_unregister_udc(struct device *parent,
> + struct usb_drd_gadget *gadget)
> +{ return 0; }
> +static inline int usb_drd_unregister_udc_driver(struct device *parent)
> +{ return 0; }
> +static inline int usb_drd_register_hcd(struct device *parent,
> + struct usb_drd_host *host)
> +{ return 0; }
> +static inline int usb_drd_unregister_hcd(struct device *parent)
> +{ return 0; }
> +static inline int usb_drd_stop_hcd(struct device *parent)
> +{ return 0; }
> +static inline int usb_drd_start_udc(struct device *parent)
> +{ return 0; }
> +static inline int usb_drd_stop_udc(struct device *parent)
> +{ return 0; }
> +static inline int usb_drd_get_state(struct device *parent)
> +{ return 0; }
> +#endif
> --
> 1.8.3.1
>
--
Best Regards,
Peter Chen
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