summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorJohn Youn <John.Youn@synopsys.com>2010-05-11 02:33:00 +0400
committerGreg Kroah-Hartman <gregkh@suse.de>2010-05-21 00:21:44 +0400
commit6c12db90f19727c76990e7f4801c67a148b30111 (patch)
treeae2454143dac5970376cfeb10af008fa03eef7d7
parentb0608690c2deafbca32b45196672bfd74006cf61 (diff)
downloadlinux-6c12db90f19727c76990e7f4801c67a148b30111.tar.xz
USB: xhci: Transfer ring link TRB activation change.
Change transfer ring behavior to not follow/activate link TRBs until active TRBs are queued after it. This change affects the behavior when a TD ends just before a link TRB. Signed-off-by: John Youn <johnyoun@synopsys.com> Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--drivers/usb/host/xhci-ring.c71
1 files changed, 58 insertions, 13 deletions
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 15f02e88f329..803f6810e996 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -112,6 +112,12 @@ static inline int last_trb(struct xhci_hcd *xhci, struct xhci_ring *ring,
return (trb->link.control & TRB_TYPE_BITMASK) == TRB_TYPE(TRB_LINK);
}
+static inline int enqueue_is_link_trb(struct xhci_ring *ring)
+{
+ struct xhci_link_trb *link = &ring->enqueue->link;
+ return ((link->control & TRB_TYPE_BITMASK) == TRB_TYPE(TRB_LINK));
+}
+
/* 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.
@@ -193,20 +199,15 @@ static void inc_enq(struct xhci_hcd *xhci, struct xhci_ring *ring, bool consumer
while (last_trb(xhci, ring, ring->enq_seg, next)) {
if (!consumer) {
if (ring != xhci->event_ring) {
- /* If we're not dealing with 0.95 hardware,
- * carry over the chain bit of the previous TRB
- * (which may mean the chain bit is cleared).
- */
- if (!xhci_link_trb_quirk(xhci)) {
- next->link.control &= ~TRB_CHAIN;
- next->link.control |= chain;
+ if (chain) {
+ next->link.control |= TRB_CHAIN;
+
+ /* Give this link TRB to the hardware */
+ wmb();
+ next->link.control ^= TRB_CYCLE;
+ } else {
+ break;
}
- /* Give this link TRB to the hardware */
- wmb();
- if (next->link.control & TRB_CYCLE)
- next->link.control &= (u32) ~TRB_CYCLE;
- else
- next->link.control |= (u32) TRB_CYCLE;
}
/* Toggle the cycle bit after the last ring segment. */
if (last_trb_on_last_seg(xhci, ring, ring->enq_seg, next)) {
@@ -245,6 +246,13 @@ static int room_on_ring(struct xhci_hcd *xhci, struct xhci_ring *ring,
struct xhci_segment *cur_seg;
unsigned int left_on_ring;
+ /* If we are currently pointing to a link TRB, advance the
+ * enqueue pointer before checking for space */
+ while (last_trb(xhci, ring, enq_seg, enq)) {
+ enq_seg = enq_seg->next;
+ enq = enq_seg->trbs;
+ }
+
/* Check if ring is empty */
if (enq == ring->dequeue) {
/* Can't use link trbs */
@@ -1728,6 +1736,43 @@ static int prepare_ring(struct xhci_hcd *xhci, struct xhci_ring *ep_ring,
xhci_err(xhci, "ERROR no room on ep ring\n");
return -ENOMEM;
}
+
+ if (enqueue_is_link_trb(ep_ring)) {
+ struct xhci_ring *ring = ep_ring;
+ union xhci_trb *next;
+ unsigned long long addr;
+
+ xhci_dbg(xhci, "prepare_ring: pointing to link trb\n");
+ next = ring->enqueue;
+
+ while (last_trb(xhci, ring, ring->enq_seg, next)) {
+
+ /* If we're not dealing with 0.95 hardware,
+ * clear the chain bit.
+ */
+ if (!xhci_link_trb_quirk(xhci))
+ next->link.control &= ~TRB_CHAIN;
+ else
+ next->link.control |= TRB_CHAIN;
+
+ wmb();
+ next->link.control ^= (u32) TRB_CYCLE;
+
+ /* Toggle the cycle bit after the last ring segment. */
+ if (last_trb_on_last_seg(xhci, ring, ring->enq_seg, next)) {
+ ring->cycle_state = (ring->cycle_state ? 0 : 1);
+ if (!in_interrupt()) {
+ xhci_dbg(xhci, "queue_trb: Toggle cycle "
+ "state for ring %p = %i\n",
+ ring, (unsigned int)ring->cycle_state);
+ }
+ }
+ ring->enq_seg = ring->enq_seg->next;
+ ring->enqueue = ring->enq_seg->trbs;
+ next = ring->enqueue;
+ }
+ }
+
return 0;
}