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usb: udc: core: Introduce started state

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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: Felipe Balbi <balbi@kernel.org>
Signed-off-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Link: https://lore.kernel.org/r/a7c4112fcd4dc2f0169af94a24f5685ca77f09fd.1610395599.git.Thinh.Nguyen@synopsys.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Thinh Nguyen 2021-01-11 12:38:05 -08:00 committed by Greg Kroah-Hartman
parent babbdfc9d2
commit 49d08cfc78
1 changed files with 22 additions and 1 deletions
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23
drivers/usb/gadget/udc/core.c
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@ -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);