From: Wesley Cheng wcheng@codeaurora.org
[ Upstream commit 8217f07a50236779880f13e87f99224cd9117f83 ]
There is a race present where the DWC3 runtime resume runs in parallel to the UDC unbind sequence. This will eventually lead to a possible scenario where we are enabling the run/stop bit, without a valid composition defined.
Thread#1 (handling UDC unbind): usb_gadget_remove_driver() -->usb_gadget_disconnect() -->dwc3_gadget_pullup(0) --> continue UDC unbind sequence -->Thread#2 is running in parallel here
Thread#2 (handing next cable connect) __dwc3_set_mode() -->pm_runtime_get_sync() -->dwc3_gadget_resume() -->dwc->gadget_driver is NOT NULL yet -->dwc3_gadget_run_stop(1) --> _dwc3gadget_start() ...
Fix this by tracking the pullup disable routine, and avoiding resuming of the DWC3 gadget. Once the UDC is re-binded, that will trigger the pullup enable routine, which would handle enabling the DWC3 gadget.
Acked-by: Felipe Balbi balbi@kernel.org Signed-off-by: Wesley Cheng wcheng@codeaurora.org Link: https://lore.kernel.org/r/20210917021852.2037-1-wcheng@codeaurora.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Stable-dep-of: 040f2dbd2010 ("usb: dwc3: gadget: Avoid duplicate requests to enable Run/Stop") Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/usb/dwc3/core.h | 2 ++ drivers/usb/dwc3/gadget.c | 4 ++-- 2 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h index da296f888f45..a93c61bc5a7d 100644 --- a/drivers/usb/dwc3/core.h +++ b/drivers/usb/dwc3/core.h @@ -994,6 +994,7 @@ struct dwc3_scratchpad_array { * @tx_max_burst_prd: max periodic ESS transmit burst size * @hsphy_interface: "utmi" or "ulpi" * @connected: true when we're connected to a host, false otherwise + * @softconnect: true when gadget connect is called, false when disconnect runs * @delayed_status: true when gadget driver asks for delayed status * @ep0_bounced: true when we used bounce buffer * @ep0_expect_in: true when we expect a DATA IN transfer @@ -1196,6 +1197,7 @@ struct dwc3 { const char *hsphy_interface;
unsigned connected:1; + unsigned softconnect:1; unsigned delayed_status:1; unsigned ep0_bounced:1; unsigned ep0_expect_in:1; diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c index 80fee7ea83ca..079919b85d87 100644 --- a/drivers/usb/dwc3/gadget.c +++ b/drivers/usb/dwc3/gadget.c @@ -2015,7 +2015,7 @@ static int dwc3_gadget_pullup(struct usb_gadget *g, int is_on) int ret;
is_on = !!is_on; - + dwc->softconnect = is_on; /* * Per databook, when we want to stop the gadget, if a control transfer * is still in process, complete it and get the core into setup phase. @@ -3791,7 +3791,7 @@ int dwc3_gadget_resume(struct dwc3 *dwc) { int ret;
- if (!dwc->gadget_driver) + if (!dwc->gadget_driver || !dwc->softconnect) return 0;
ret = __dwc3_gadget_start(dwc);