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Date: Thu, 19 Mar 2015 11:30:01 +0800
From: Peter Chen <peter.chen@...escale.com>
To: Roger Quadros <rogerq@...com>
CC: <gregkh@...uxfoundation.org>, <balbi@...com>,
<stern@...land.harvard.edu>, <dan.j.williams@...el.com>,
<jun.li@...escale.com>, <mathias.nyman@...ux.intel.com>,
<linux-usb@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
<linux-omap@...r.kernel.org>
Subject: Re: [RFC][PATCH 2/9] usb: gadget: add usb_gadget_start/stop()
On Wed, Mar 18, 2015 at 03:55:56PM +0200, Roger Quadros wrote:
> The OTG state machine needs a mechanism to start and
> stop the gadget controller. Add usb_gadget_start()
> and usb_gadget_stop().
>
> Signed-off-by: Roger Quadros <rogerq@...com>
> ---
> drivers/usb/gadget/udc/udc-core.c | 166 +++++++++++++++++++++++++++++++++++---
> include/linux/usb/gadget.h | 3 +
> 2 files changed, 158 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/usb/gadget/udc/udc-core.c b/drivers/usb/gadget/udc/udc-core.c
> index 5a81cb0..69b4123 100644
> --- a/drivers/usb/gadget/udc/udc-core.c
> +++ b/drivers/usb/gadget/udc/udc-core.c
> @@ -35,6 +35,8 @@
> * @dev - the child device to the actual controller
> * @gadget - the gadget. For use by the class code
> * @list - for use by the udc class driver
> + * @running - udc is running
Doesn't OTG FSM should know it?
Peter
> + * @softconnect - sysfs softconnect says OK to connect
> *
> * This represents the internal data structure which is used by the UDC-class
> * to hold information about udc driver and gadget together.
> @@ -44,6 +46,8 @@ struct usb_udc {
> struct usb_gadget *gadget;
> struct device dev;
> struct list_head list;
> + bool running;
> + bool softconnect;
> };
>
> static struct class *udc_class;
> @@ -187,7 +191,14 @@ EXPORT_SYMBOL_GPL(usb_gadget_udc_reset);
> */
> static inline int usb_gadget_udc_start(struct usb_udc *udc)
> {
> - return udc->gadget->ops->udc_start(udc->gadget, udc->driver);
> + int ret;
> +
> + dev_dbg(&udc->dev, "%s\n", __func__);
> + ret = udc->gadget->ops->udc_start(udc->gadget, udc->driver);
> + if (!ret)
> + udc->running = 1;
> +
> + return ret;
> }
>
> /**
> @@ -204,10 +215,140 @@ static inline int usb_gadget_udc_start(struct usb_udc *udc)
> */
> static inline void usb_gadget_udc_stop(struct usb_udc *udc)
> {
> + dev_dbg(&udc->dev, "%s\n", __func__);
> udc->gadget->ops->udc_stop(udc->gadget);
> + udc->running = 0;
> }
>
> /**
> + * usb_udc_start - Start the usb device controller only if conditions met
> + * @udc: The UDC to be started
> + *
> + * Start the UDC and connect to bus (enable pull) only if the
> + * following conditions are met
> + * - UDC is not already running
> + * - gadget function driver is loaded
> + * - userspace softconnect says OK to connect
> + *
> + * NOTE: udc_lock must be held by caller.
> + *
> + * Returs 0 on success or not ready to start, else negative errno.
> + */
> +static int usb_udc_start(struct usb_udc *udc)
> +{
> + int ret;
> +
> + if (udc->running) {
> + dev_err(&udc->dev, "%s: not starting as already running\n",
> + __func__);
> + return -EBUSY;
> + }
> +
> + if (udc->driver && udc->softconnect) {
> + ret = usb_gadget_udc_start(udc);
> + if (ret)
> + return ret;
> +
> + usb_gadget_connect(udc->gadget);
> + }
> +
> + return 0;
> +}
> +
> +/**
> + * usb_udc_stop - Stop the usb device controller
> + * @udc: The UDC to be stopped
> + *
> + * Disconnect from bus (disable pull) and stop the UDC.
> + *
> + * NOTE: udc_lock must be held by caller.
> + *
> + * Returs 0 on success, else negative errno.
> + */
> +static int usb_udc_stop(struct usb_udc *udc)
> +{
> + if (!udc->running) {
> + dev_err(&udc->dev, "%s: not stopping as already halted\n",
> + __func__);
> + return -EBUSY;
> + }
> +
> + usb_gadget_disconnect(udc->gadget);
> + udc->driver->disconnect(udc->gadget);
> + usb_gadget_udc_stop(udc);
> +
> + return 0;
> +}
> +
> +/**
> + * usb_gadget_start - start the usb gadget controller
> + * @gadget: the gadget device to start
> + *
> + * This is external API for use by OTG core.
> + *
> + * Start the usb device controller and connect to bus (enable pull).
> + * There is no guarantee that the controller is started
> + * as we might be missing some dependencies
> + * i.e. gadget function driver not loaded or softconnect disabled.
> + */
> +int usb_gadget_start(struct usb_gadget *gadget)
> +{
> + int ret;
> + struct usb_udc *udc = NULL;
> +
> + dev_dbg(&gadget->dev, "%s\n", __func__);
> + mutex_lock(&udc_lock);
> + list_for_each_entry(udc, &udc_list, list)
> + if (udc->gadget == gadget)
> + goto found;
> +
> + dev_err(gadget->dev.parent, "%s: gadget not registered.\n",
> + __func__);
> + mutex_unlock(&udc_lock);
> + return -EINVAL;
> +
> +found:
> + ret = usb_udc_start(udc);
> + mutex_unlock(&udc_lock);
> +
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(usb_gadget_start);
> +
> +/**
> + * usb_gadget_stop - stop the usb gadget
> + * @gadget: The gadget device we want to stop
> + *
> + * This is external API for use by OTG core.
> + *
> + * Disconnect from the bus (disable pull) and stop the
> + * gadget controller.
> + */
> +int usb_gadget_stop(struct usb_gadget *gadget)
> +{
> + int ret;
> + struct usb_udc *udc = NULL;
> +
> + dev_dbg(&gadget->dev, "%s\n", __func__);
> + mutex_lock(&udc_lock);
> + list_for_each_entry(udc, &udc_list, list)
> + if (udc->gadget == gadget)
> + goto found;
> +
> + dev_err(gadget->dev.parent, "%s: gadget not registered.\n",
> + __func__);
> + mutex_unlock(&udc_lock);
> + return -EINVAL;
> +
> +found:
> + ret = usb_udc_stop(udc);
> + mutex_unlock(&udc_lock);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(usb_gadget_stop);
> +
> +/**
> * usb_udc_release - release the usb_udc struct
> * @dev: the dev member within usb_udc
> *
> @@ -278,6 +419,7 @@ int usb_add_gadget_udc_release(struct device *parent, struct usb_gadget *gadget,
> goto err3;
>
> udc->gadget = gadget;
> + udc->softconnect = 1; /* connect by default */
>
> mutex_lock(&udc_lock);
> list_add_tail(&udc->list, &udc_list);
> @@ -329,10 +471,8 @@ static void usb_gadget_remove_driver(struct usb_udc *udc)
>
> kobject_uevent(&udc->dev.kobj, KOBJ_CHANGE);
>
> - usb_gadget_disconnect(udc->gadget);
> - udc->driver->disconnect(udc->gadget);
> + usb_udc_stop(udc);
> udc->driver->unbind(udc->gadget);
> - usb_gadget_udc_stop(udc);
>
> udc->driver = NULL;
> udc->dev.driver = NULL;
> @@ -378,6 +518,7 @@ EXPORT_SYMBOL_GPL(usb_del_gadget_udc);
>
> /* ------------------------------------------------------------------------- */
>
> +/* udc_lock must be held */
> static int udc_bind_to_driver(struct usb_udc *udc, struct usb_gadget_driver *driver)
> {
> int ret;
> @@ -392,12 +533,12 @@ static int udc_bind_to_driver(struct usb_udc *udc, struct usb_gadget_driver *dri
> ret = driver->bind(udc->gadget, driver);
> if (ret)
> goto err1;
> - ret = usb_gadget_udc_start(udc);
> +
> + ret = usb_udc_start(udc);
> if (ret) {
> driver->unbind(udc->gadget);
> goto err1;
> }
> - usb_gadget_connect(udc->gadget);
>
> kobject_uevent(&udc->dev.kobj, KOBJ_CHANGE);
> return 0;
> @@ -510,12 +651,15 @@ static ssize_t usb_udc_softconn_store(struct device *dev,
> }
>
> if (sysfs_streq(buf, "connect")) {
> - usb_gadget_udc_start(udc);
> - usb_gadget_connect(udc->gadget);
> + mutex_lock(&udc_lock);
> + udc->softconnect = 1;
> + usb_udc_start(udc);
> + mutex_unlock(&udc_lock);
> } else if (sysfs_streq(buf, "disconnect")) {
> - usb_gadget_disconnect(udc->gadget);
> - udc->driver->disconnect(udc->gadget);
> - usb_gadget_udc_stop(udc);
> + mutex_lock(&udc_lock);
> + udc->softconnect = 0;
> + usb_udc_stop(udc);
> + mutex_unlock(&udc_lock);
> } else {
> dev_err(dev, "unsupported command '%s'\n", buf);
> return -EINVAL;
> diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h
> index e2f00fd..7ada7e6 100644
> --- a/include/linux/usb/gadget.h
> +++ b/include/linux/usb/gadget.h
> @@ -922,6 +922,9 @@ int usb_gadget_probe_driver(struct usb_gadget_driver *driver);
> */
> int usb_gadget_unregister_driver(struct usb_gadget_driver *driver);
>
> +int usb_gadget_start(struct usb_gadget *gadget);
> +int usb_gadget_stop(struct usb_gadget *gadget);
> +
> extern int usb_add_gadget_udc_release(struct device *parent,
> struct usb_gadget *gadget, void (*release)(struct device *dev));
> extern int usb_add_gadget_udc(struct device *parent, struct usb_gadget *gadget);
> --
> 2.1.0
>
--
Best Regards,
Peter Chen
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