xhci: rework cycle bit checking for new dequeue pointers

[pandora-kernel.git] / drivers / usb / host / xhci-ring.c

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index fa2f7d3..4b6abb6 100644 (file)
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -572,9 +572,12 @@ void xhci_find_new_dequeue_state(struct xhci_hcd *xhci,
        struct xhci_virt_device *dev = xhci->devs[slot_id];
        struct xhci_virt_ep *ep = &dev->eps[ep_index];
        struct xhci_ring *ep_ring;
-       struct xhci_generic_trb *trb;
+       struct xhci_segment *new_seg;
+       union xhci_trb *new_deq;
        dma_addr_t addr;
        u64 hw_dequeue;
+       bool cycle_found = false;
+       bool td_last_trb_found = false;
 
        ep_ring = xhci_triad_to_transfer_ring(xhci, slot_id,
                        ep_index, stream_id);
@@ -598,44 +601,45 @@ void xhci_find_new_dequeue_state(struct xhci_hcd *xhci,
                hw_dequeue = le64_to_cpu(ep_ctx->deq);
        }
 
-       /* Find virtual address and segment of hardware dequeue pointer */
-       state->new_deq_seg = ep_ring->deq_seg;
-       state->new_deq_ptr = ep_ring->dequeue;
-       while (xhci_trb_virt_to_dma(state->new_deq_seg, state->new_deq_ptr)
-                       != (dma_addr_t)(hw_dequeue & ~0xf)) {
-               next_trb(xhci, ep_ring, &state->new_deq_seg,
-                                       &state->new_deq_ptr);
-               if (state->new_deq_ptr == ep_ring->dequeue) {
-                       WARN_ON(1);
-                       return;
-               }
-       }
+       new_seg = ep_ring->deq_seg;
+       new_deq = ep_ring->dequeue;
+       state->new_cycle_state = hw_dequeue & 0x1;
+
        /*
-        * Find cycle state for last_trb, starting at old cycle state of
-        * hw_dequeue. If there is only one segment ring, find_trb_seg() will
-        * return immediately and cannot toggle the cycle state if this search
-        * wraps around, so add one more toggle manually in that case.
+        * We want to find the pointer, segment and cycle state of the new trb
+        * (the one after current TD's last_trb). We know the cycle state at
+        * hw_dequeue, so walk the ring until both hw_dequeue and last_trb are
+        * found.
         */
-       state->new_cycle_state = hw_dequeue & 0x1;
-       if (ep_ring->first_seg == ep_ring->first_seg->next &&
-                       cur_td->last_trb < state->new_deq_ptr)
-               state->new_cycle_state ^= 0x1;
-
-       state->new_deq_ptr = cur_td->last_trb;
-       xhci_dbg(xhci, "Finding segment containing last TRB in TD.\n");
-       state->new_deq_seg = find_trb_seg(state->new_deq_seg,
-                       state->new_deq_ptr, &state->new_cycle_state);
-       if (!state->new_deq_seg) {
-               WARN_ON(1);
-               return;
-       }
+       do {
+               if (!cycle_found && xhci_trb_virt_to_dma(new_seg, new_deq)
+                   == (dma_addr_t)(hw_dequeue & ~0xf)) {
+                       cycle_found = true;
+                       if (td_last_trb_found)
+                               break;
+               }
+               if (new_deq == cur_td->last_trb)
+                       td_last_trb_found = true;
+
+               if (cycle_found &&
+                   TRB_TYPE_LINK_LE32(new_deq->generic.field[3]) &&
+                   new_deq->generic.field[3] & cpu_to_le32(LINK_TOGGLE))
+                       state->new_cycle_state ^= 0x1;
+
+               next_trb(xhci, ep_ring, &new_seg, &new_deq);
+
+               /* Search wrapped around, bail out */
+               if (new_deq == ep->ring->dequeue) {
+                       xhci_err(xhci, "Error: Failed finding new dequeue state\n");
+                       state->new_deq_seg = NULL;
+                       state->new_deq_ptr = NULL;
+                       return;
+               }
+
+       } while (!cycle_found || !td_last_trb_found);
 
-       /* Increment to find next TRB after last_trb. Cycle if appropriate. */
-       trb = &state->new_deq_ptr->generic;
-       if (TRB_TYPE_LINK_LE32(trb->field[3]) &&
-           (trb->field[3] & cpu_to_le32(LINK_TOGGLE)))
-               state->new_cycle_state ^= 0x1;
-       next_trb(xhci, ep_ring, &state->new_deq_seg, &state->new_deq_ptr);
+       state->new_deq_seg = new_seg;
+       state->new_deq_ptr = new_deq;
 
        /* Don't update the ring cycle state for the producer (us). */
        xhci_dbg(xhci, "Cycle state = 0x%x\n", state->new_cycle_state);