usb: dwc3: gadget: Check END_TRANSFER completion

While the END_TRANSFER command is sent but not completed, any request
dequeue during this time will cause the driver to issue the END_TRANSFER
command. The driver needs to submit the command only once to stop the
controller from processing further. The controller may take more time to
process the same command multiple times unnecessarily. Let's add a flag
DWC3_EP_END_TRANSFER_PENDING to check for this condition.

Fixes: 3aec99154d ("usb: dwc3: gadget: remove DWC3_EP_END_TRANSFER_PENDING")
Signed-off-by: Thinh Nguyen <thinhn@synopsys.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/dwc3/core.h

@@ -688,6 +688,7 @@ struct dwc3_ep {
 #define DWC3_EP_STALL		BIT(1)
 #define DWC3_EP_WEDGE		BIT(2)
 #define DWC3_EP_TRANSFER_STARTED BIT(3)
+#define DWC3_EP_END_TRANSFER_PENDING BIT(4)
 #define DWC3_EP_PENDING_REQUEST	BIT(5)
 
 	/* This last one is specific to EP0 */

drivers/usb/dwc3/ep0.c

@@ -1136,8 +1136,10 @@ void dwc3_ep0_interrupt(struct dwc3 *dwc,
 	case DWC3_DEPEVT_EPCMDCMPLT:
 		cmd = DEPEVT_PARAMETER_CMD(event->parameters);
 
-		if (cmd == DWC3_DEPCMD_ENDTRANSFER)
+		if (cmd == DWC3_DEPCMD_ENDTRANSFER) {
+			dep->flags &= ~DWC3_EP_END_TRANSFER_PENDING;
 			dep->flags &= ~DWC3_EP_TRANSFER_STARTED;
+		}
 		break;
 	}
 }

drivers/usb/dwc3/gadget.c

@@ -2628,6 +2628,7 @@ static void dwc3_endpoint_interrupt(struct dwc3 *dwc,
 		cmd = DEPEVT_PARAMETER_CMD(event->parameters);
 
 		if (cmd == DWC3_DEPCMD_ENDTRANSFER) {
+			dep->flags &= ~DWC3_EP_END_TRANSFER_PENDING;
 			dep->flags &= ~DWC3_EP_TRANSFER_STARTED;
 			dwc3_gadget_ep_cleanup_cancelled_requests(dep);
 		}
@@ -2686,7 +2687,8 @@ static void dwc3_stop_active_transfer(struct dwc3_ep *dep, bool force,
 	u32 cmd;
 	int ret;
 
-	if (!(dep->flags & DWC3_EP_TRANSFER_STARTED))
+	if (!(dep->flags & DWC3_EP_TRANSFER_STARTED) ||
+	    (dep->flags & DWC3_EP_END_TRANSFER_PENDING))
 		return;
 
 	/*
@@ -2731,6 +2733,8 @@ static void dwc3_stop_active_transfer(struct dwc3_ep *dep, bool force,
 
 	if (!interrupt)
 		dep->flags &= ~DWC3_EP_TRANSFER_STARTED;
+	else
+		dep->flags |= DWC3_EP_END_TRANSFER_PENDING;
 
 	if (dwc3_is_usb31(dwc) || dwc->revision < DWC3_REVISION_310A)
 		udelay(100);