Commit 49d08cfc authored by Thinh Nguyen's avatar Thinh Nguyen Committed by Greg Kroah-Hartman
Browse files

usb: udc: core: Introduce started state 



For some UDCs, the initialization sequence by udc_start() should not be
repeated until it is properly cleaned up with udc_stop() and vise versa.
We may run into some cleanup failure as seen with the DWC3 driver during
the irq cleanup. This issue can occur when the user triggers
soft-connect/soft-disconnect from the soft_connect sysfs. To avoid
adding checks to every UDC driver, at the UDC framework, introduce a
"started" state to track and prevent the UDC from repeating the
udc_start() and udc_stop() if it had already started/stopped.

Acked-by: default avatarFelipe Balbi <balbi@kernel.org>
Signed-off-by: default avatarThinh Nguyen <Thinh.Nguyen@synopsys.com>
Link: https://lore.kernel.org/r/a7c4112fcd4dc2f0169af94a24f5685ca77f09fd.1610395599.git.Thinh.Nguyen@synopsys.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent babbdfc9

drivers/usb/gadget/udc/core.c

+22 −1
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@ 
 * @list: for use by the udc class driver

 * @vbus: for udcs who care about vbus status, this value is real vbus status;

 * for udcs who do not care about vbus status, this value is always true

 * @started: the UDC's started state. True if the UDC had started.

 *

 * This represents the internal data structure which is used by the UDC-class

 * to hold information about udc driver and gadget together.
@@ -39,6 +40,7 @@ struct usb_udc { 
	struct device			dev;

	struct list_head		list;

	bool				vbus;

	bool				started;

};



static struct class *udc_class;
@@ -1082,7 +1084,18 @@ 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;



	if (udc->started) {

		dev_err(&udc->dev, "UDC had already started\n");

		return -EBUSY;

	}



	ret = udc->gadget->ops->udc_start(udc->gadget, udc->driver);

	if (!ret)

		udc->started = true;



	return ret;

}



/**
@@ -1098,7 +1111,13 @@ static inline int usb_gadget_udc_start(struct usb_udc *udc) 
 */

static inline void usb_gadget_udc_stop(struct usb_udc *udc)

{

	if (!udc->started) {

		dev_err(&udc->dev, "UDC had already stopped\n");

		return;

	}



	udc->gadget->ops->udc_stop(udc->gadget);

	udc->started = false;

}



/**
@@ -1222,6 +1241,8 @@ int usb_add_gadget(struct usb_gadget *gadget) 
	udc->gadget = gadget;

	gadget->udc = udc;



	udc->started = false;



	mutex_lock(&udc_lock);

	list_add_tail(&udc->list, &udc_list);