usb: dwc3: gadget: Stall and restart EP0 if host is unresponsive

usb: dwc3: gadget: Stall and restart EP0 if host is unresponsive

It was observed that there are hosts that may complete pending SETUP
transactions before the stop active transfers and controller halt occurs,
leading to lingering endxfer commands on DEPs on subsequent pullup/gadget
start iterations.

  dwc3_gadget_ep_disable   name=ep8in flags=0x3009  direction=1
  dwc3_gadget_ep_disable   name=ep4in flags=1  direction=1
  dwc3_gadget_ep_disable   name=ep3out flags=1  direction=0
  usb_gadget_disconnect   deactivated=0  connected=0  ret=0

The sequence shows that the USB gadget disconnect (dwc3_gadget_pullup(0))
routine completed successfully, allowing for the USB gadget to proceed with
a USB gadget connect.  However, if this occurs the system runs into an
issue where:

  BUG: spinlock already unlocked on CPU
  spin_bug+0x0
  dwc3_remove_requests+0x278
  dwc3_ep0_out_start+0xb0
  __dwc3_gadget_start+0x25c

This is due to the pending endxfers, leading to gadget start (w/o lock
held) to execute the remove requests, which will unlock the dwc3
spinlock as part of giveback.

To mitigate this, resolve the pending endxfers on the pullup disable
path by re-locating the SETUP phase check after stop active transfers, since
that is where the DWC3_EP_DELAY_STOP is potentially set.  This also allows
for handling of a host that may be unresponsive by using the completion
timeout to trigger the stall and restart for EP0.

Fixes: c96683798e27 ("usb: dwc3: ep0: Don't prepare beyond Setup stage")
Cc: stable@vger.kernel.org
Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>
Link: https://lore.kernel.org/r/20230413195742.11821-2-quic_wcheng@quicinc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>