usb: dwc3: gadget: Return proper request status

If the user sets the usb_request's no_interrupt, then there will be no
completion event for the request. Currently the driver incorrectly uses
the event status of a different request to report the status for a
request with no_interrupt. The dwc3 driver needs to check the TRB status
associated with the request when reporting its status.

Note: this is only applicable to missed_isoc TRB completion status, but
the other status are also listed for completeness/documentation.

Fixes: 6d8a019 ("usb: dwc3: gadget: check for Missed Isoc from event status")
Cc: <stable@vger.kernel.org>
Signed-off-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Link: https://lore.kernel.org/r/db2c80108286cfd108adb05bad52138b78d7c3a7.1650673655.git.Thinh.Nguyen@synopsys.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/dwc3/gadget.c

@@ -3274,6 +3274,7 @@ static int dwc3_gadget_ep_cleanup_completed_request(struct dwc3_ep *dep,
 		const struct dwc3_event_depevt *event,
 		struct dwc3_request *req, int status)
 {
+	int request_status;
 	int ret;
 
 	if (req->request.num_mapped_sgs)
@@ -3294,7 +3295,35 @@ static int dwc3_gadget_ep_cleanup_completed_request(struct dwc3_ep *dep,
 		req->needs_extra_trb = false;
 	}
 
-	dwc3_gadget_giveback(dep, req, status);
+	/*
+	 * The event status only reflects the status of the TRB with IOC set.
+	 * For the requests that don't set interrupt on completion, the driver
+	 * needs to check and return the status of the completed TRBs associated
+	 * with the request. Use the status of the last TRB of the request.
+	 */
+	if (req->request.no_interrupt) {
+		struct dwc3_trb *trb;
+
+		trb = dwc3_ep_prev_trb(dep, dep->trb_dequeue);
+		switch (DWC3_TRB_SIZE_TRBSTS(trb->size)) {
+		case DWC3_TRBSTS_MISSED_ISOC:
+			/* Isoc endpoint only */
+			request_status = -EXDEV;
+			break;
+		case DWC3_TRB_STS_XFER_IN_PROG:
+			/* Applicable when End Transfer with ForceRM=0 */
+		case DWC3_TRBSTS_SETUP_PENDING:
+			/* Control endpoint only */
+		case DWC3_TRBSTS_OK:
+		default:
+			request_status = 0;
+			break;
+		}
+	} else {
+		request_status = status;
+	}
+
+	dwc3_gadget_giveback(dep, req, request_status);
 
 out:
 	return ret;