usb: dwc2: gadget: Do not halt endpoint if active

The gadget API function usb_ep_set_halt() expects the gadget to return
-EAGAIN if the ep is active. Add support for this behavior.

Otherwise this may break mass storage protocol if a STALL is attempted
on the endpoint.
Signed-off-by: Vahram Aharonyan <vahrama@synopsys.com>
Signed-off-by: John Youn <johnyoun@synopsys.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/dwc2/gadget.c

@@ -1018,7 +1018,7 @@ static int dwc2_hsotg_process_req_status(struct dwc2_hsotg *hsotg,
 	return 1;
 }
 
-static int dwc2_hsotg_ep_sethalt(struct usb_ep *ep, int value);
+static int dwc2_hsotg_ep_sethalt(struct usb_ep *ep, int value, bool now);
 
 /**
  * get_ep_head - return the first request on the endpoint
@@ -1094,7 +1094,7 @@ static int dwc2_hsotg_process_req_feature(struct dwc2_hsotg *hsotg,
 		case USB_ENDPOINT_HALT:
 			halted = ep->halted;
 
-			dwc2_hsotg_ep_sethalt(&ep->ep, set);
+			dwc2_hsotg_ep_sethalt(&ep->ep, set, true);
 
 			ret = dwc2_hsotg_send_reply(hsotg, ep0, NULL, 0);
 			if (ret) {
@@ -2948,8 +2948,13 @@ static int dwc2_hsotg_ep_dequeue(struct usb_ep *ep, struct usb_request *req)
  * dwc2_hsotg_ep_sethalt - set halt on a given endpoint
  * @ep: The endpoint to set halt.
  * @value: Set or unset the halt.
+ * @now: If true, stall the endpoint now. Otherwise return -EAGAIN if
+ *       the endpoint is busy processing requests.
+ *
+ * We need to stall the endpoint immediately if request comes from set_feature
+ * protocol command handler.
  */
-static int dwc2_hsotg_ep_sethalt(struct usb_ep *ep, int value)
+static int dwc2_hsotg_ep_sethalt(struct usb_ep *ep, int value, bool now)
 {
 	struct dwc2_hsotg_ep *hs_ep = our_ep(ep);
 	struct dwc2_hsotg *hs = hs_ep->parent;
@@ -2969,6 +2974,12 @@ static int dwc2_hsotg_ep_sethalt(struct usb_ep *ep, int value)
 		return 0;
 	}
 
+	if (!now && value && !list_empty(&hs_ep->queue)) {
+		dev_dbg(hs->dev, "%s request is pending, cannot halt\n",
+			ep->name);
+		return -EAGAIN;
+	}
+
 	if (hs_ep->dir_in) {
 		epreg = DIEPCTL(index);
 		epctl = dwc2_readl(hs->regs + epreg);
@@ -3020,7 +3031,7 @@ static int dwc2_hsotg_ep_sethalt_lock(struct usb_ep *ep, int value)
 	int ret = 0;
 
 	spin_lock_irqsave(&hs->lock, flags);
-	ret = dwc2_hsotg_ep_sethalt(ep, value);
+	ret = dwc2_hsotg_ep_sethalt(ep, value, false);
 	spin_unlock_irqrestore(&hs->lock, flags);
 
 	return ret;