usb: chipidea: udc: refine ep operation at isr_tr_complete_handler

- delete the warning message at interrupt handler, and adds judgement at
ep_enable, if non-ep0 requests ctrl transfer, it will indicate an error.
- delete hw_test_and_clear_setup_status which is a broken code
- Tested with g_mass_storage, g_ncm, g_ether

Cc: matthieu.castet@parrot.com
Reported-by: Michael Grzeschik <mgr@pengutronix.de>
Acked-by: Michael Grzeschik <mgr@pengutronix.de>
Tested-by: Michael Grzeschik <mgr@pengutronix.de>
Signed-off-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/chipidea/udc.c

@@ -177,19 +177,6 @@ static int hw_ep_get_halt(struct ci_hdrc *ci, int num, int dir)
 	return hw_read(ci, OP_ENDPTCTRL + num, mask) ? 1 : 0;
 }
 
-/**
- * hw_test_and_clear_setup_status: test & clear setup status (execute without
- *                                 interruption)
- * @n: endpoint number
- *
- * This function returns setup status
- */
-static int hw_test_and_clear_setup_status(struct ci_hdrc *ci, int n)
-{
-	n = ep_to_bit(ci, n);
-	return hw_test_and_clear(ci, OP_ENDPTSETUPSTAT, BIT(n));
-}
-
 /**
  * hw_ep_prime: primes endpoint (execute without interruption)
  * @num:     endpoint number
@@ -997,14 +984,10 @@ __acquires(ci->lock)
 			}
 		}
 
-		if (hwep->type != USB_ENDPOINT_XFER_CONTROL ||
-		    !hw_test_and_clear_setup_status(ci, i))
-			continue;
-
-		if (i != 0) {
-			dev_warn(ci->dev, "ctrl traffic at endpoint %d\n", i);
+		/* Only handle setup packet below */
+		if (i != 0 ||
+			!hw_test_and_clear(ci, OP_ENDPTSETUPSTAT, BIT(0)))
 			continue;
-		}
 
 		/*
 		 * Flush data and handshake transactions of previous
@@ -1193,6 +1176,11 @@ static int ep_enable(struct usb_ep *ep,
 
 	hwep->qh.ptr->td.next |= cpu_to_le32(TD_TERMINATE);   /* needed? */
 
+	if (hwep->num != 0 && hwep->type == USB_ENDPOINT_XFER_CONTROL) {
+		dev_err(hwep->ci->dev, "Set control xfer at non-ep0\n");
+		retval = -EINVAL;
+	}
+
 	/*
 	 * Enable endpoints in the HW other than ep0 as ep0
 	 * is always enabled