[PATCH 5/6] usb: dwc3: gadget: Only End Transfer for ep0 data phase

[Thinh Nguyen <Thinh.Nguyen@synopsys.com>]

The driver shouldn't be able to issue End Transfer to the control
endpoint at anytime. Typically we should only do so in error cases such
as invalid/unexpected direction of Data Phase as described in the
control transfer flow of the programming guide. It _may_ end started
data phase during controller deinitialization from soft disconnect or
driver removal. However, that should not happen because the driver
should be maintained in EP0_SETUP_PHASE during driver tear-down. On
soft-connect, the controller should be reset from a soft-reset and there
should be no issue starting the control endpoint.

Signed-off-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
---
 drivers/usb/dwc3/gadget.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index e5f07c0e8ad9..7c4d5f671687 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -3641,6 +3641,17 @@ static void dwc3_reset_gadget(struct dwc3 *dwc)
 void dwc3_stop_active_transfer(struct dwc3_ep *dep, bool force,
 	bool interrupt)
 {
+	struct dwc3 *dwc = dep->dwc;
+
+	/*
+	 * Only issue End Transfer command to the control endpoint of a started
+	 * Data Phase. Typically we should only do so in error cases such as
+	 * invalid/unexpected direction as described in the control transfer
+	 * flow of the programming guide.
+	 */
+	if (dep->number <= 1 && dwc->ep0state != EP0_DATA_PHASE)
+		return;
+
 	if (!(dep->flags & DWC3_EP_TRANSFER_STARTED) ||
 	    (dep->flags & DWC3_EP_DELAY_STOP) ||
 	    (dep->flags & DWC3_EP_END_TRANSFER_PENDING))
-- 
2.28.0