xhci: Introduce helper to turn one TRB into a no-op

Useful for turning both transfer and command trbs
into no-ops.

Based on earlier code by Felipe Balbi <felipe.balbi@linux.intel.com>

Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 8b78eee86262754ee32132ccf6dacd1ad752db56..bd00ada6643bb72df35c9ae5b9d14e0b44d28b4e 100644 (file)
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -129,6 +129,21 @@ static void inc_td_cnt(struct urb *urb)
        urb_priv->td_cnt++;
 }
 
+static void trb_to_noop(union xhci_trb *trb, u32 noop_type)
+{
+       if (trb_is_link(trb)) {
+               /* unchain chained link TRBs */
+               trb->link.control &= cpu_to_le32(~TRB_CHAIN);
+       } else {
+               trb->generic.field[0] = 0;
+               trb->generic.field[1] = 0;
+               trb->generic.field[2] = 0;
+               /* Preserve only the cycle bit of this TRB */
+               trb->generic.field[3] &= cpu_to_le32(TRB_CYCLE);
+               trb->generic.field[3] |= cpu_to_le32(TRB_TYPE(noop_type));
+       }
+}
+
 /* Updates trb to point to the next TRB in the ring, and updates seg if the next
  * TRB is in a new segment.  This does not skip over link TRBs, and it does not
  * effect the ring dequeue or enqueue pointers.
@@ -592,18 +607,8 @@ static void td_to_noop(struct xhci_hcd *xhci, struct xhci_ring *ep_ring,
        union xhci_trb *trb             = td->first_trb;
 
        while (1) {
-               if (trb_is_link(trb)) {
-                       /* unchain chained link TRBs */
-                       trb->link.control &= cpu_to_le32(~TRB_CHAIN);
-               } else {
-                       trb->generic.field[0] = 0;
-                       trb->generic.field[1] = 0;
-                       trb->generic.field[2] = 0;
-                       /* Preserve only the cycle bit of this TRB */
-                       trb->generic.field[3] &= cpu_to_le32(TRB_CYCLE);
-                       trb->generic.field[3] |= cpu_to_le32(
-                               TRB_TYPE(TRB_TR_NOOP));
-               }
+               trb_to_noop(trb, TRB_TR_NOOP);
+
                /* flip cycle if asked to */
                if (flip_cycle && trb != td->first_trb && trb != td->last_trb)
                        trb->generic.field[3] ^= cpu_to_le32(TRB_CYCLE);