usb: xhci: Fix TRB transfer length macro used for Event TRB.

Use proper macro while extracting TRB transfer length from
Transfer event TRBs. Adding a macro EVENT_TRB_LEN (bits 0:23)
for the same, and use it instead of TRB_LEN (bits 0:16) in
case of event TRBs.

This patch should be backported to kernels as old as 2.6.31, that
contain the commit b10de14 "USB: xhci:
Bulk transfer support".  This patch will have issues applying to older
kernels.

Signed-off-by: Vivek gautam <gautam.vivek@samsung.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable@vger.kernel.org

drivers/usb/host/xhci-ring.c

@@ -2029,8 +2029,8 @@ static int process_ctrl_td(struct xhci_hcd *xhci, struct xhci_td *td,
 		if (event_trb != ep_ring->dequeue &&
 				event_trb != td->last_trb)
 			td->urb->actual_length =
-				td->urb->transfer_buffer_length
-				- TRB_LEN(le32_to_cpu(event->transfer_len));
+				td->urb->transfer_buffer_length -
+				EVENT_TRB_LEN(le32_to_cpu(event->transfer_len));
 		else
 			td->urb->actual_length = 0;
 
@@ -2062,7 +2062,7 @@ static int process_ctrl_td(struct xhci_hcd *xhci, struct xhci_td *td,
 		/* Maybe the event was for the data stage? */
 			td->urb->actual_length =
 				td->urb->transfer_buffer_length -
-				TRB_LEN(le32_to_cpu(event->transfer_len));
+				EVENT_TRB_LEN(le32_to_cpu(event->transfer_len));
 			xhci_dbg(xhci, "Waiting for status "
 					"stage event\n");
 			return 0;
@@ -2098,7 +2098,7 @@ static int process_isoc_td(struct xhci_hcd *xhci, struct xhci_td *td,
 	/* handle completion code */
 	switch (trb_comp_code) {
 	case COMP_SUCCESS:
-		if (TRB_LEN(le32_to_cpu(event->transfer_len)) == 0) {
+		if (EVENT_TRB_LEN(le32_to_cpu(event->transfer_len)) == 0) {
 			frame->status = 0;
 			break;
 		}
@@ -2143,7 +2143,7 @@ static int process_isoc_td(struct xhci_hcd *xhci, struct xhci_td *td,
 				len += TRB_LEN(le32_to_cpu(cur_trb->generic.field[2]));
 		}
 		len += TRB_LEN(le32_to_cpu(cur_trb->generic.field[2])) -
-			TRB_LEN(le32_to_cpu(event->transfer_len));
+			EVENT_TRB_LEN(le32_to_cpu(event->transfer_len));
 
 		if (trb_comp_code != COMP_STOP_INVAL) {
 			frame->actual_length = len;
@@ -2201,7 +2201,7 @@ static int process_bulk_intr_td(struct xhci_hcd *xhci, struct xhci_td *td,
 	case COMP_SUCCESS:
 		/* Double check that the HW transferred everything. */
 		if (event_trb != td->last_trb ||
-				TRB_LEN(le32_to_cpu(event->transfer_len)) != 0) {
+		    EVENT_TRB_LEN(le32_to_cpu(event->transfer_len)) != 0) {
 			xhci_warn(xhci, "WARN Successful completion "
 					"on short TX\n");
 			if (td->urb->transfer_flags & URB_SHORT_NOT_OK)
@@ -2229,18 +2229,18 @@ static int process_bulk_intr_td(struct xhci_hcd *xhci, struct xhci_td *td,
 				"%d bytes untransferred\n",
 				td->urb->ep->desc.bEndpointAddress,
 				td->urb->transfer_buffer_length,
-				TRB_LEN(le32_to_cpu(event->transfer_len)));
+				EVENT_TRB_LEN(le32_to_cpu(event->transfer_len)));
 	/* Fast path - was this the last TRB in the TD for this URB? */
 	if (event_trb == td->last_trb) {
-		if (TRB_LEN(le32_to_cpu(event->transfer_len)) != 0) {
+		if (EVENT_TRB_LEN(le32_to_cpu(event->transfer_len)) != 0) {
 			td->urb->actual_length =
 				td->urb->transfer_buffer_length -
-				TRB_LEN(le32_to_cpu(event->transfer_len));
+				EVENT_TRB_LEN(le32_to_cpu(event->transfer_len));
 			if (td->urb->transfer_buffer_length <
 					td->urb->actual_length) {
 				xhci_warn(xhci, "HC gave bad length "
 						"of %d bytes left\n",
-					  TRB_LEN(le32_to_cpu(event->transfer_len)));
+					  EVENT_TRB_LEN(le32_to_cpu(event->transfer_len)));
 				td->urb->actual_length = 0;
 				if (td->urb->transfer_flags & URB_SHORT_NOT_OK)
 					*status = -EREMOTEIO;
@@ -2282,7 +2282,7 @@ static int process_bulk_intr_td(struct xhci_hcd *xhci, struct xhci_td *td,
 		if (trb_comp_code != COMP_STOP_INVAL)
 			td->urb->actual_length +=
 				TRB_LEN(le32_to_cpu(cur_trb->generic.field[2])) -
-				TRB_LEN(le32_to_cpu(event->transfer_len));
+				EVENT_TRB_LEN(le32_to_cpu(event->transfer_len));
 	}
 
 	return finish_td(xhci, td, event_trb, event, ep, status, false);
@@ -2370,7 +2370,7 @@ static int handle_tx_event(struct xhci_hcd *xhci,
 	 * transfer type
 	 */
 	case COMP_SUCCESS:
-		if (TRB_LEN(le32_to_cpu(event->transfer_len)) == 0)
+		if (EVENT_TRB_LEN(le32_to_cpu(event->transfer_len)) == 0)
 			break;
 		if (xhci->quirks & XHCI_TRUST_TX_LENGTH)
 			trb_comp_code = COMP_SHORT_TX;

drivers/usb/host/xhci.h

@@ -972,6 +972,10 @@ struct xhci_transfer_event {
 	__le32	flags;
 };
 
+/* Transfer event TRB length bit mask */
+/* bits 0:23 */
+#define	EVENT_TRB_LEN(p)		((p) & 0xffffff)
+
 /** Transfer Event bit fields **/
 #define	TRB_TO_EP_ID(p)	(((p) >> 16) & 0x1f)