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. Signed-off-by: Thinh Nguyen <Thinh.Nguyen@xxxxxxxxxxxx> --- Suggested by Felipe: https://lore.kernel.org/linux-usb/87a6tmcxhi.fsf@xxxxxxxxxx/ drivers/usb/gadget/udc/core.c | 23 ++++++++++++++++++++++- 1 file changed, 22 insertions(+), 1 deletion(-) diff --git a/drivers/usb/gadget/udc/core.c b/drivers/usb/gadget/udc/core.c index 6a62bbd01324..98cf9216f3cb 100644 --- a/drivers/usb/gadget/udc/core.c +++ b/drivers/usb/gadget/udc/core.c @@ -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); base-commit: 7c53f6b671f4aba70ff15e1b05148b10d58c2837 -- 2.28.0
