usb: dwc3: gadget: Properly handle failed kick_transfer

If dwc3 fails to issue START_TRANSFER/UPDATE_TRANSFER command, then we
should properly end an active transfer and give back all the started
requests. However if it's for an isoc endpoint, the failure maybe due to
bus-expiry status. In this case, don't give back the requests and wait
for the next retry.

Fixes: 72246da4 ("usb: Introduce DesignWare USB3 DRD Driver")
Signed-off-by: Thinh Nguyen <thinhn@synopsys.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>

drivers/usb/dwc3/gadget.c

@@ -1220,6 +1220,8 @@ static void dwc3_prepare_trbs(struct dwc3_ep *dep)
 	}
 }
 
+static void dwc3_gadget_ep_cleanup_cancelled_requests(struct dwc3_ep *dep);
+
 static int __dwc3_gadget_kick_transfer(struct dwc3_ep *dep)
 {
 	struct dwc3_gadget_ep_cmd_params params;
@@ -1259,14 +1261,20 @@ static int __dwc3_gadget_kick_transfer(struct dwc3_ep *dep)
 
 	ret = dwc3_send_gadget_ep_cmd(dep, cmd, &params);
 	if (ret < 0) {
-		/*
-		 * FIXME we need to iterate over the list of requests
-		 * here and stop, unmap, free and del each of the linked
-		 * requests instead of what we do now.
-		 */
-		if (req->trb)
-			memset(req->trb, 0, sizeof(struct dwc3_trb));
-		dwc3_gadget_del_and_unmap_request(dep, req, ret);
+		struct dwc3_request *tmp;
+
+		if (ret == -EAGAIN)
+			return ret;
+
+		dwc3_stop_active_transfer(dep, true, true);
+
+		list_for_each_entry_safe(req, tmp, &dep->started_list, list)
+			dwc3_gadget_move_cancelled_request(req);
+
+		/* If ep isn't started, then there's no end transfer pending */
+		if (!(dep->flags & DWC3_EP_END_TRANSFER_PENDING))
+			dwc3_gadget_ep_cleanup_cancelled_requests(dep);
+
 		return ret;
 	}