On Fri, Nov 20, 2015 at 09:54:12AM +0100, Marek Szyprowski wrote:
> From: Ruslan Bilovol <ruslan.bilovol@xxxxxxxxx>
>
> Change behavior during registration of gadgets and
> gadget drivers in udc-core. Instead of previous
> approach when for successful probe of usb gadget driver
> at least one usb gadget should be already registered
> use another one where gadget drivers and gadgets
> can be registered in udc-core independently.
>
> Independent registration of gadgets and gadget drivers
> is useful for built-in into kernel gadget and gadget
> driver case - because it's possible that gadget is
> really probed only on late_init stage (due to deferred
> probe) whereas gadget driver's probe is silently failed
> on module_init stage due to no any UDC added.
>
> Also it is useful for modules case - now there is no
> difference what module to insert first: gadget module
> or gadget driver one.
>
> Tested-by: Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx>
> Signed-off-by: Ruslan Bilovol <ruslan.bilovol@xxxxxxxxx>
> [simplified code as requested by Alan Stern and Felipe Balbi]
> Signed-off-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
> ---
> drivers/usb/gadget/udc/udc-core.c | 43 +++++++++++++++++++++++++++++++--------
> include/linux/usb/gadget.h | 2 ++
> 2 files changed, 37 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/usb/gadget/udc/udc-core.c b/drivers/usb/gadget/udc/udc-core.c
> index f76ebc8..461b311 100644
> --- a/drivers/usb/gadget/udc/udc-core.c
> +++ b/drivers/usb/gadget/udc/udc-core.c
> @@ -51,8 +51,12 @@ struct usb_udc {
>
> static struct class *udc_class;
> static LIST_HEAD(udc_list);
> +static LIST_HEAD(gadget_driver_pending_list);
> static DEFINE_MUTEX(udc_lock);
>
> +static int udc_bind_to_driver(struct usb_udc *udc,
> + struct usb_gadget_driver *driver);
> +
> /* ------------------------------------------------------------------------- */
>
> #ifdef CONFIG_HAS_DMA
> @@ -356,6 +360,7 @@ int usb_add_gadget_udc_release(struct device *parent, struct usb_gadget *gadget,
> void (*release)(struct device *dev))
> {
> struct usb_udc *udc;
> + struct usb_gadget_driver *driver;
> int ret = -ENOMEM;
>
> udc = kzalloc(sizeof(*udc), GFP_KERNEL);
> @@ -403,6 +408,18 @@ int usb_add_gadget_udc_release(struct device *parent, struct usb_gadget *gadget,
> usb_gadget_set_state(gadget, USB_STATE_NOTATTACHED);
> udc->vbus = true;
>
> + /* pick up one of pending gadget drivers */
> + list_for_each_entry(driver, &gadget_driver_pending_list, pending) {
> + if (!driver->udc_name || strcmp(driver->udc_name,
> + dev_name(&udc->dev)) == 0) {
> + ret = udc_bind_to_driver(udc, driver);
> + if (ret)
> + goto err4;
> + list_del(&driver->pending);
> + break;
> + }
> + }
> +
> mutex_unlock(&udc_lock);
>
> return 0;
> @@ -475,9 +492,16 @@ void usb_del_gadget_udc(struct usb_gadget *gadget)
> list_del(&udc->list);
> mutex_unlock(&udc_lock);
>
> - if (udc->driver)
> + if (udc->driver) {
> + struct usb_gadget_driver *driver = udc->driver;
> +
> usb_gadget_remove_driver(udc);
>
> + mutex_lock(&udc_lock);
> + list_add(&driver->pending, &gadget_driver_pending_list);
> + mutex_unlock(&udc_lock);
> + }
> +
> kobject_uevent(&udc->dev.kobj, KOBJ_REMOVE);
> flush_work(&gadget->work);
> device_unregister(&udc->dev);
> @@ -535,11 +559,7 @@ int usb_gadget_probe_driver(struct usb_gadget_driver *driver)
> if (!ret)
> break;
> }
> - if (ret)
> - ret = -ENODEV;
> - else if (udc->driver)
> - ret = -EBUSY;
> - else
> + if (!ret && !udc->driver)
> goto found;
> } else {
> list_for_each_entry(udc, &udc_list, list) {
> @@ -549,9 +569,12 @@ int usb_gadget_probe_driver(struct usb_gadget_driver *driver)
> }
> }
>
> - pr_debug("couldn't find an available UDC\n");
> + list_add_tail(&driver->pending, &gadget_driver_pending_list);
> + pr_info("udc-core: couldn't find an available UDC "
> + "- added [%s] to list of pending drivers\n",
> + driver->function);
> mutex_unlock(&udc_lock);
> - return ret;
> + return 0;
> found:
> ret = udc_bind_to_driver(udc, driver);
> mutex_unlock(&udc_lock);
> @@ -577,6 +600,10 @@ int usb_gadget_unregister_driver(struct usb_gadget_driver *driver)
> break;
> }
>
> + if (ret) {
> + list_del(&driver->pending);
> + ret = 0;
> + }
> mutex_unlock(&udc_lock);
> return ret;
> }
> diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h
> index e11f5a2..a3436bf 100644
> --- a/include/linux/usb/gadget.h
> +++ b/include/linux/usb/gadget.h
> @@ -1014,6 +1014,7 @@ static inline int usb_gadget_activate(struct usb_gadget *gadget)
> * @driver: Driver model state for this driver.
> * @udc_name: A name of UDC this driver should be bound to. If udc_name is NULL,
> * this driver will be bound to any available UDC.
> + * @pending: UDC core private data used for deferred probe of this driver.
> *
> * Devices are disabled till a gadget driver successfully bind()s, which
> * means the driver will handle setup() requests needed to enumerate (and
> @@ -1076,6 +1077,7 @@ struct usb_gadget_driver {
> struct device_driver driver;
>
> char *udc_name;
> + struct list_head pending;
> };
>
>
And it seems can't apply for felipe's testing/next which I just rebased
on it.
--
Best Regards,
Peter Chen
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