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usb: dwc3: gadget: Avoid starting DWC3 gadget during UDC unbind

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[ 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>
This commit is contained in:
Wesley Cheng 2021-09-16 19:18:52 -07:00 committed by Greg Kroah-Hartman
parent 85371aad28
commit e24f90d761
2 changed files with 4 additions and 2 deletions
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2
drivers/usb/dwc3/core.h
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@ -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;

4
drivers/usb/dwc3/gadget.c
View File

@ -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);