4 files changed, 545 insertions, 42 deletions

diff --git a/drivers/usb/host/xhci-hcd.c b/drivers/usb/host/xhci-hcd.c
index e5fbdcdbf676..36e440ce88e5 100644
--- a/drivers/usb/host/xhci-hcd.c
+++ b/drivers/usb/host/xhci-hcd.c
@@ -613,12 +613,70 @@ exit:
         return ret;
 }
 
-/* Remove from hardware lists
- * completions normally happen asynchronously
+/*
+ * Remove the URB's TD from the endpoint ring.  This may cause the HC to stop
+ * USB transfers, potentially stopping in the middle of a TRB buffer.  The HC
+ * should pick up where it left off in the TD, unless a Set Transfer Ring
+ * Dequeue Pointer is issued.
+ *
+ * The TRBs that make up the buffers for the canceled URB will be "removed" from
+ * the ring.  Since the ring is a contiguous structure, they can't be physically
+ * removed.  Instead, there are two options:
+ *
+ *  1) If the HC is in the middle of processing the URB to be canceled, we
+ *     simply move the ring's dequeue pointer past those TRBs using the Set
+ *     Transfer Ring Dequeue Pointer command.  This will be the common case,
+ *     when drivers timeout on the last submitted URB and attempt to cancel.
+ *
+ *  2) If the HC is in the middle of a different TD, we turn the TRBs into a
+ *     series of 1-TRB transfer no-op TDs.  (No-ops shouldn't be chained.)  The
+ *     HC will need to invalidate the any TRBs it has cached after the stop
+ *     endpoint command, as noted in the xHCI 0.95 errata.
+ *
+ *  3) The TD may have completed by the time the Stop Endpoint Command
+ *     completes, so software needs to handle that case too.
+ *
+ * This function should protect against the TD enqueueing code ringing the
+ * doorbell while this code is waiting for a Stop Endpoint command to complete.
+ * It also needs to account for multiple cancellations on happening at the same
+ * time for the same endpoint.
+ *
+ * Note that this function can be called in any context, or so says
+ * usb_hcd_unlink_urb()
  */
 int xhci_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
 {
-        return -ENOSYS;
+        unsigned long flags;
+        int ret;
+        struct xhci_hcd *xhci;
+        struct xhci_td *td;
+        unsigned int ep_index;
+        struct xhci_ring *ep_ring;
+
+        xhci = hcd_to_xhci(hcd);
+        spin_lock_irqsave(&xhci->lock, flags);
+        /* Make sure the URB hasn't completed or been unlinked already */
+        ret = usb_hcd_check_unlink_urb(hcd, urb, status);
+        if (ret || !urb->hcpriv)
+                goto done;
+
+        xhci_dbg(xhci, "Cancel URB 0x%x\n", (unsigned int) urb);
+        ep_index = xhci_get_endpoint_index(&urb->ep->desc);
+        ep_ring = xhci->devs[urb->dev->slot_id]->ep_rings[ep_index];
+        td = (struct xhci_td *) urb->hcpriv;
+
+        ep_ring->cancels_pending++;
+        list_add_tail(&td->cancelled_td_list, &ep_ring->cancelled_td_list);
+        /* Queue a stop endpoint command, but only if this is
+         * the first cancellation to be handled.
+         */
+        if (ep_ring->cancels_pending == 1) {
+                queue_stop_endpoint(xhci, urb->dev->slot_id, ep_index);
+                ring_cmd_db(xhci);
+        }
+done:
+        spin_unlock_irqrestore(&xhci->lock, flags);
+        return ret;
 }
 
 /* Drop an endpoint from a new bandwidth configuration for this device.
diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
index 617db9c37770..e81d10a653ef 100644
--- a/drivers/usb/host/xhci-mem.c
+++ b/drivers/usb/host/xhci-mem.c
@@ -142,6 +142,7 @@ static struct xhci_ring *xhci_ring_alloc(struct xhci_hcd *xhci,
                 return 0;
 
         INIT_LIST_HEAD(&ring->td_list);
+        INIT_LIST_HEAD(&ring->cancelled_td_list);
         if (num_segs == 0)
                 return ring;
 
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index c948288042e2..f967a6df83c7 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -112,6 +112,23 @@ static inline int last_trb(struct xhci_hcd *xhci, struct xhci_ring *ring,
                 return (trb->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.
+ */
+static void next_trb(struct xhci_hcd *xhci,
+                struct xhci_ring *ring,
+                struct xhci_segment **seg,
+                union xhci_trb **trb)
+{
+        if (last_trb(xhci, ring, *seg, *trb)) {
+                *seg = (*seg)->next;
+                *trb = ((*seg)->trbs);
+        } else {
+                *trb = (*trb)++;
+        }
+}
+
 /*
  * See Cycle bit rules. SW is the consumer for the event ring only.
  * Don't make a ring full of link TRBs.  That would be dumb and this would loop.
@@ -250,6 +267,344 @@ void ring_cmd_db(struct xhci_hcd *xhci)
         xhci_readl(xhci, &xhci->dba->doorbell[0]);
 }
 
+static void ring_ep_doorbell(struct xhci_hcd *xhci,
+                unsigned int slot_id,
+                unsigned int ep_index)
+{
+        struct xhci_ring *ep_ring;
+        u32 field;
+        __u32 __iomem *db_addr = &xhci->dba->doorbell[slot_id];
+
+        ep_ring = xhci->devs[slot_id]->ep_rings[ep_index];
+        /* Don't ring the doorbell for this endpoint if there are pending
+         * cancellations because the we don't want to interrupt processing.
+         */
+        if (!ep_ring->cancels_pending && !(ep_ring->state & SET_DEQ_PENDING)) {
+                field = xhci_readl(xhci, db_addr) & DB_MASK;
+                xhci_writel(xhci, field | EPI_TO_DB(ep_index), db_addr);
+                /* Flush PCI posted writes - FIXME Matthew Wilcox says this
+                 * isn't time-critical and we shouldn't make the CPU wait for
+                 * the flush.
+                 */
+                xhci_readl(xhci, db_addr);
+        }
+}
+
+/*
+ * Find the segment that trb is in.  Start searching in start_seg.
+ * If we must move past a segment that has a link TRB with a toggle cycle state
+ * bit set, then we will toggle the value pointed at by cycle_state.
+ */
+static struct xhci_segment *find_trb_seg(
+                struct xhci_segment *start_seg,
+                union xhci_trb  *trb, int *cycle_state)
+{
+        struct xhci_segment *cur_seg = start_seg;
+        struct xhci_generic_trb *generic_trb;
+
+        while (cur_seg->trbs > trb ||
+                        &cur_seg->trbs[TRBS_PER_SEGMENT - 1] < trb) {
+                generic_trb = &cur_seg->trbs[TRBS_PER_SEGMENT - 1].generic;
+                if (TRB_TYPE(generic_trb->field[3]) == TRB_LINK &&
+                                (generic_trb->field[3] & LINK_TOGGLE))
+                        *cycle_state = ~(*cycle_state) & 0x1;
+                cur_seg = cur_seg->next;
+                if (cur_seg == start_seg)
+                        /* Looped over the entire list.  Oops! */
+                        return 0;
+        }
+        return cur_seg;
+}
+
+struct dequeue_state {
+        struct xhci_segment *new_deq_seg;
+        union xhci_trb *new_deq_ptr;
+        int new_cycle_state;
+};
+
+/*
+ * Move the xHC's endpoint ring dequeue pointer past cur_td.
+ * Record the new state of the xHC's endpoint ring dequeue segment,
+ * dequeue pointer, and new consumer cycle state in state.
+ * Update our internal representation of the ring's dequeue pointer.
+ *
+ * We do this in three jumps:
+ *  - First we update our new ring state to be the same as when the xHC stopped.
+ *  - Then we traverse the ring to find the segment that contains
+ *    the last TRB in the TD.  We toggle the xHC's new cycle state when we pass
+ *    any link TRBs with the toggle cycle bit set.
+ *  - Finally we move the dequeue state one TRB further, toggling the cycle bit
+ *    if we've moved it past a link TRB with the toggle cycle bit set.
+ */
+static void find_new_dequeue_state(struct xhci_hcd *xhci,
+                unsigned int slot_id, unsigned int ep_index,
+                struct xhci_td *cur_td, struct dequeue_state *state)
+{
+        struct xhci_virt_device *dev = xhci->devs[slot_id];
+        struct xhci_ring *ep_ring = dev->ep_rings[ep_index];
+        struct xhci_generic_trb *trb;
+
+        state->new_cycle_state = 0;
+        state->new_deq_seg = find_trb_seg(cur_td->start_seg,
+                        ep_ring->stopped_trb,
+                        &state->new_cycle_state);
+        if (!state->new_deq_seg)
+                BUG();
+        /* Dig out the cycle state saved by the xHC during the stop ep cmd */
+        state->new_cycle_state = 0x1 & dev->out_ctx->ep[ep_index].deq[0];
+
+        state->new_deq_ptr = cur_td->last_trb;
+        state->new_deq_seg = find_trb_seg(state->new_deq_seg,
+                        state->new_deq_ptr,
+                        &state->new_cycle_state);
+        if (!state->new_deq_seg)
+                BUG();
+
+        trb = &state->new_deq_ptr->generic;
+        if (TRB_TYPE(trb->field[3]) == TRB_LINK &&
+                                (trb->field[3] & LINK_TOGGLE))
+                state->new_cycle_state = ~(state->new_cycle_state) & 0x1;
+        next_trb(xhci, ep_ring, &state->new_deq_seg, &state->new_deq_ptr);
+
+        /* Don't update the ring cycle state for the producer (us). */
+        ep_ring->dequeue = state->new_deq_ptr;
+        ep_ring->deq_seg = state->new_deq_seg;
+}
+
+void td_to_noop(struct xhci_hcd *xhci, struct xhci_ring *ep_ring,
+                struct xhci_td *cur_td)
+{
+        struct xhci_segment *cur_seg;
+        union xhci_trb *cur_trb;
+
+        for (cur_seg = cur_td->start_seg, cur_trb = cur_td->first_trb;
+                        true;
+                        next_trb(xhci, ep_ring, &cur_seg, &cur_trb)) {
+                if ((cur_trb->generic.field[3] & TRB_TYPE_BITMASK) ==
+                                TRB_TYPE(TRB_LINK)) {
+                        /* Unchain any chained Link TRBs, but
+                         * leave the pointers intact.
+                         */
+                        cur_trb->generic.field[3] &= ~TRB_CHAIN;
+                        xhci_dbg(xhci, "Cancel (unchain) link TRB\n");
+                        xhci_dbg(xhci, "Address = 0x%x (0x%x dma); "
+                                        "in seg 0x%x (0x%x dma)\n",
+                                        (unsigned int) cur_trb,
+                                        trb_virt_to_dma(cur_seg, cur_trb),
+                                        (unsigned int) cur_seg,
+                                        cur_seg->dma);
+                } else {
+                        cur_trb->generic.field[0] = 0;
+                        cur_trb->generic.field[1] = 0;
+                        cur_trb->generic.field[2] = 0;
+                        /* Preserve only the cycle bit of this TRB */
+                        cur_trb->generic.field[3] &= TRB_CYCLE;
+                        cur_trb->generic.field[3] |= TRB_TYPE(TRB_TR_NOOP);
+                        xhci_dbg(xhci, "Cancel TRB 0x%x (0x%x dma) "
+                                        "in seg 0x%x (0x%x dma)\n",
+                                        (unsigned int) cur_trb,
+                                        trb_virt_to_dma(cur_seg, cur_trb),
+                                        (unsigned int) cur_seg,
+                                        cur_seg->dma);
+                }
+                if (cur_trb == cur_td->last_trb)
+                        break;
+        }
+}
+
+static int queue_set_tr_deq(struct xhci_hcd *xhci, int slot_id,
+                unsigned int ep_index, struct xhci_segment *deq_seg,
+                union xhci_trb *deq_ptr, u32 cycle_state);
+
+/*
+ * When we get a command completion for a Stop Endpoint Command, we need to
+ * unlink any cancelled TDs from the ring.  There are two ways to do that:
+ *
+ *  1. If the HW was in the middle of processing the TD that needs to be
+ *     cancelled, then we must move the ring's dequeue pointer past the last TRB
+ *     in the TD with a Set Dequeue Pointer Command.
+ *  2. Otherwise, we turn all the TRBs in the TD into No-op TRBs (with the chain
+ *     bit cleared) so that the HW will skip over them.
+ */
+static void handle_stopped_endpoint(struct xhci_hcd *xhci,
+                union xhci_trb *trb)
+{
+        unsigned int slot_id;
+        unsigned int ep_index;
+        struct xhci_ring *ep_ring;
+        struct list_head *entry;
+        struct xhci_td *cur_td = 0;
+        struct xhci_td *last_unlinked_td;
+
+        struct dequeue_state deq_state;
+#ifdef CONFIG_USB_HCD_STAT
+        ktime_t stop_time = ktime_get();
+#endif
+
+        memset(&deq_state, 0, sizeof(deq_state));
+        slot_id = TRB_TO_SLOT_ID(trb->generic.field[3]);
+        ep_index = TRB_TO_EP_INDEX(trb->generic.field[3]);
+        ep_ring = xhci->devs[slot_id]->ep_rings[ep_index];
+
+        if (list_empty(&ep_ring->cancelled_td_list))
+                return;
+
+        /* Fix up the ep ring first, so HW stops executing cancelled TDs.
+         * We have the xHCI lock, so nothing can modify this list until we drop
+         * it.  We're also in the event handler, so we can't get re-interrupted
+         * if another Stop Endpoint command completes
+         */
+        list_for_each(entry, &ep_ring->cancelled_td_list) {
+                cur_td = list_entry(entry, struct xhci_td, cancelled_td_list);
+                xhci_dbg(xhci, "Cancelling TD starting at 0x%x, 0x%x (dma).\n",
+                                (unsigned int) cur_td->first_trb,
+                                trb_virt_to_dma(cur_td->start_seg, cur_td->first_trb));
+                /*
+                 * If we stopped on the TD we need to cancel, then we have to
+                 * move the xHC endpoint ring dequeue pointer past this TD.
+                 */
+                if (cur_td == ep_ring->stopped_td)
+                        find_new_dequeue_state(xhci, slot_id, ep_index, cur_td,
+                                        &deq_state);
+                else
+                        td_to_noop(xhci, ep_ring, cur_td);
+                /*
+                 * The event handler won't see a completion for this TD anymore,
+                 * so remove it from the endpoint ring's TD list.  Keep it in
+                 * the cancelled TD list for URB completion later.
+                 */
+                list_del(&cur_td->td_list);
+                ep_ring->cancels_pending--;
+        }
+        last_unlinked_td = cur_td;
+
+        /* If necessary, queue a Set Transfer Ring Dequeue Pointer command */
+        if (deq_state.new_deq_ptr && deq_state.new_deq_seg) {
+                xhci_dbg(xhci, "Set TR Deq Ptr cmd, new deq seg = 0x%x (0x%x dma), "
+                                "new deq ptr = 0x%x (0x%x dma), new cycle = %u\n",
+                                (unsigned int) deq_state.new_deq_seg,
+                                deq_state.new_deq_seg->dma,
+                                (unsigned int) deq_state.new_deq_ptr,
+                                trb_virt_to_dma(deq_state.new_deq_seg, deq_state.new_deq_ptr),
+                                deq_state.new_cycle_state);
+                queue_set_tr_deq(xhci, slot_id, ep_index,
+                                deq_state.new_deq_seg,
+                                deq_state.new_deq_ptr,
+                                (u32) deq_state.new_cycle_state);
+                /* Stop the TD queueing code from ringing the doorbell until
+                 * this command completes.  The HC won't set the dequeue pointer
+                 * if the ring is running, and ringing the doorbell starts the
+                 * ring running.
+                 */
+                ep_ring->state |= SET_DEQ_PENDING;
+                ring_cmd_db(xhci);
+        } else {
+                /* Otherwise just ring the doorbell to restart the ring */
+                ring_ep_doorbell(xhci, slot_id, ep_index);
+        }
+
+        /*
+         * Drop the lock and complete the URBs in the cancelled TD list.
+         * New TDs to be cancelled might be added to the end of the list before
+         * we can complete all the URBs for the TDs we already unlinked.
+         * So stop when we've completed the URB for the last TD we unlinked.
+         */
+        do {
+                cur_td = list_entry(ep_ring->cancelled_td_list.next,
+                                struct xhci_td, cancelled_td_list);
+                list_del(&cur_td->cancelled_td_list);
+
+                /* Clean up the cancelled URB */
+#ifdef CONFIG_USB_HCD_STAT
+                hcd_stat_update(xhci->tp_stat, cur_td->urb->actual_length,
+                                ktime_sub(stop_time, cur_td->start_time));
+#endif
+                cur_td->urb->hcpriv = NULL;
+                usb_hcd_unlink_urb_from_ep(xhci_to_hcd(xhci), cur_td->urb);
+
+                xhci_dbg(xhci, "Giveback cancelled URB 0x%x\n",
+                                (unsigned int) cur_td->urb);
+                spin_unlock(&xhci->lock);
+                /* Doesn't matter what we pass for status, since the core will
+                 * just overwrite it (because the URB has been unlinked).
+                 */
+                usb_hcd_giveback_urb(xhci_to_hcd(xhci), cur_td->urb, 0);
+                kfree(cur_td);
+
+                spin_lock(&xhci->lock);
+        } while (cur_td != last_unlinked_td);
+
+        /* Return to the event handler with xhci->lock re-acquired */
+}
+
+/*
+ * When we get a completion for a Set Transfer Ring Dequeue Pointer command,
+ * we need to clear the set deq pending flag in the endpoint ring state, so that
+ * the TD queueing code can ring the doorbell again.  We also need to ring the
+ * endpoint doorbell to restart the ring, but only if there aren't more
+ * cancellations pending.
+ */
+static void handle_set_deq_completion(struct xhci_hcd *xhci,
+                struct xhci_event_cmd *event,
+                union xhci_trb *trb)
+{
+        unsigned int slot_id;
+        unsigned int ep_index;
+        struct xhci_ring *ep_ring;
+        struct xhci_virt_device *dev;
+
+        slot_id = TRB_TO_SLOT_ID(trb->generic.field[3]);
+        ep_index = TRB_TO_EP_INDEX(trb->generic.field[3]);
+        dev = xhci->devs[slot_id];
+        ep_ring = dev->ep_rings[ep_index];
+
+        if (GET_COMP_CODE(event->status) != COMP_SUCCESS) {
+                unsigned int ep_state;
+                unsigned int slot_state;
+
+                switch (GET_COMP_CODE(event->status)) {
+                case COMP_TRB_ERR:
+                        xhci_warn(xhci, "WARN Set TR Deq Ptr cmd invalid because "
+                                        "of stream ID configuration\n");
+                        break;
+                case COMP_CTX_STATE:
+                        xhci_warn(xhci, "WARN Set TR Deq Ptr cmd failed due "
+                                        "to incorrect slot or ep state.\n");
+                        ep_state = dev->out_ctx->ep[ep_index].ep_info;
+                        ep_state &= EP_STATE_MASK;
+                        slot_state = dev->out_ctx->slot.dev_state;
+                        slot_state = GET_SLOT_STATE(slot_state);
+                        xhci_dbg(xhci, "Slot state = %u, EP state = %u\n",
+                                        slot_state, ep_state);
+                        break;
+                case COMP_EBADSLT:
+                        xhci_warn(xhci, "WARN Set TR Deq Ptr cmd failed because "
+                                        "slot %u was not enabled.\n", slot_id);
+                        break;
+                default:
+                        xhci_warn(xhci, "WARN Set TR Deq Ptr cmd with unknown "
+                                        "completion code of %u.\n",
+                                        GET_COMP_CODE(event->status));
+                        break;
+                }
+                /* OK what do we do now?  The endpoint state is hosed, and we
+                 * should never get to this point if the synchronization between
+                 * queueing, and endpoint state are correct.  This might happen
+                 * if the device gets disconnected after we've finished
+                 * cancelling URBs, which might not be an error...
+                 */
+        } else {
+                xhci_dbg(xhci, "Successful Set TR Deq Ptr cmd, deq[0] = 0x%x, "
+                                "deq[1] = 0x%x.\n",
+                                dev->out_ctx->ep[ep_index].deq[0],
+                                dev->out_ctx->ep[ep_index].deq[1]);
+        }
+
+        ep_ring->state &= ~SET_DEQ_PENDING;
+        ring_ep_doorbell(xhci, slot_id, ep_index);
+}
+
+
 static void handle_cmd_completion(struct xhci_hcd *xhci,
                 struct xhci_event_cmd *event)
 {
@@ -290,6 +645,12 @@ static void handle_cmd_completion(struct xhci_hcd *xhci,
                 xhci->devs[slot_id]->cmd_status = GET_COMP_CODE(event->status);
                 complete(&xhci->addr_dev);
                 break;
+        case TRB_TYPE(TRB_STOP_RING):
+                handle_stopped_endpoint(xhci, xhci->cmd_ring->dequeue);
+                break;
+        case TRB_TYPE(TRB_SET_DEQ):
+                handle_set_deq_completion(xhci, event, xhci->cmd_ring->dequeue);
+                break;
         case TRB_TYPE(TRB_CMD_NOOP):
                 ++xhci->noops_handled;
                 break;
@@ -346,11 +707,9 @@ static struct xhci_segment *trb_in_td(
         cur_seg = start_seg;
 
         do {
-                /*
-                 * Last TRB is a link TRB (unless we start inserting links in
-                 * the middle, FIXME if you do)
-                 */
-                end_seg_dma = trb_virt_to_dma(cur_seg, &start_seg->trbs[TRBS_PER_SEGMENT - 2]);
+                /* We may get an event for a Link TRB in the middle of a TD */
+                end_seg_dma = trb_virt_to_dma(cur_seg,
+                                &start_seg->trbs[TRBS_PER_SEGMENT - 1]);
                 /* If the end TRB isn't in this segment, this is set to 0 */
                 end_trb_dma = trb_virt_to_dma(cur_seg, end_trb);
 
@@ -396,7 +755,7 @@ static int handle_tx_event(struct xhci_hcd *xhci,
         dma_addr_t event_dma;
         struct xhci_segment *event_seg;
         union xhci_trb *event_trb;
-        struct urb *urb;
+        struct urb *urb = 0;
         int status = -EINPROGRESS;
 
         xdev = xhci->devs[TRB_TO_SLOT_ID(event->flags)];
@@ -457,6 +816,12 @@ static int handle_tx_event(struct xhci_hcd *xhci,
         case COMP_SUCCESS:
         case COMP_SHORT_TX:
                 break;
+        case COMP_STOP:
+                xhci_dbg(xhci, "Stopped on Transfer TRB\n");
+                break;
+        case COMP_STOP_INVAL:
+                xhci_dbg(xhci, "Stopped on No-op or Link TRB\n");
+                break;
         case COMP_STALL:
                 xhci_warn(xhci, "WARN: Stalled endpoint\n");
                 status = -EPIPE;
@@ -510,11 +875,15 @@ static int handle_tx_event(struct xhci_hcd *xhci,
                 if (event_trb != ep_ring->dequeue) {
                         /* The event was for the status stage */
                         if (event_trb == td->last_trb) {
-                                td->urb->actual_length = td->urb->transfer_buffer_length;
+                                td->urb->actual_length =
+                                        td->urb->transfer_buffer_length;
                         } else {
-                        /* The event was for the data stage */
-                                td->urb->actual_length = td->urb->transfer_buffer_length -
-                                        TRB_LEN(event->transfer_len);
+                        /* Maybe the event was for the data stage? */
+                                if (GET_COMP_CODE(event->transfer_len) != COMP_STOP_INVAL)
+                                        /* We didn't stop on a link TRB in the middle */
+                                        td->urb->actual_length =
+                                                td->urb->transfer_buffer_length -
+                                                TRB_LEN(event->transfer_len);
                         }
                 }
         } else {
@@ -573,29 +942,55 @@ static int handle_tx_event(struct xhci_hcd *xhci,
                                 status = 0;
                         }
                 } else {
-                        /* Slow path - walk the list, starting from the first
-                         * TRB to get the actual length transferred
+                        /* Slow path - walk the list, starting from the dequeue
+                         * pointer, to get the actual length transferred.
                          */
+                        union xhci_trb *cur_trb;
+                        struct xhci_segment *cur_seg;
+
                         td->urb->actual_length = 0;
-                        while (ep_ring->dequeue != event_trb) {
-                                td->urb->actual_length += TRB_LEN(ep_ring->dequeue->generic.field[2]);
-                                inc_deq(xhci, ep_ring, false);
+                        for (cur_trb = ep_ring->dequeue, cur_seg = ep_ring->deq_seg;
+                                        cur_trb != event_trb;
+                                        next_trb(xhci, ep_ring, &cur_seg, &cur_trb)) {
+                                if (TRB_TYPE(cur_trb->generic.field[3]) != TRB_TR_NOOP &&
+                                                TRB_TYPE(cur_trb->generic.field[3]) != TRB_LINK)
+                                        td->urb->actual_length +=
+                                                TRB_LEN(cur_trb->generic.field[2]);
                         }
-                        td->urb->actual_length += TRB_LEN(ep_ring->dequeue->generic.field[2]) -
-                                TRB_LEN(event->transfer_len);
-
+                        /* If the ring didn't stop on a Link or No-op TRB, add
+                         * in the actual bytes transferred from the Normal TRB
+                         */
+                        if (GET_COMP_CODE(event->transfer_len) != COMP_STOP_INVAL)
+                                td->urb->actual_length +=
+                                        TRB_LEN(cur_trb->generic.field[2]) -
+                                        TRB_LEN(event->transfer_len);
                 }
         }
-        /* Update ring dequeue pointer */
-        while (ep_ring->dequeue != td->last_trb)
+        /* The Endpoint Stop Command completion will take care of
+         * any stopped TDs.  A stopped TD may be restarted, so don't update the
+         * ring dequeue pointer or take this TD off any lists yet.
+         */
+        if (GET_COMP_CODE(event->transfer_len) == COMP_STOP_INVAL ||
+                        GET_COMP_CODE(event->transfer_len) == COMP_STOP) {
+                ep_ring->stopped_td = td;
+                ep_ring->stopped_trb = event_trb;
+        } else {
+                /* Update ring dequeue pointer */
+                while (ep_ring->dequeue != td->last_trb)
+                        inc_deq(xhci, ep_ring, false);
                 inc_deq(xhci, ep_ring, false);
-        inc_deq(xhci, ep_ring, false);
 
-        /* Clean up the endpoint's TD list */
-        urb = td->urb;
-        list_del(&td->td_list);
-        kfree(td);
-        urb->hcpriv = NULL;
+                /* Clean up the endpoint's TD list */
+                urb = td->urb;
+                list_del(&td->td_list);
+                /* Was this TD slated to be cancelled but completed anyway? */
+                if (!list_empty(&td->cancelled_td_list)) {
+                        list_del(&td->cancelled_td_list);
+                        ep_ring->cancels_pending--;
+                }
+                kfree(td);
+                urb->hcpriv = NULL;
+        }
 cleanup:
         inc_deq(xhci, xhci->event_ring, true);
         set_hc_event_deq(xhci);
@@ -744,6 +1139,7 @@ int xhci_prepare_transfer(struct xhci_hcd *xhci,
         if (!*td)
                 return -ENOMEM;
         INIT_LIST_HEAD(&(*td)->td_list);
+        INIT_LIST_HEAD(&(*td)->cancelled_td_list);
 
         ret = usb_hcd_link_urb_to_ep(xhci_to_hcd(xhci), urb);
         if (unlikely(ret)) {
@@ -755,6 +1151,8 @@ int xhci_prepare_transfer(struct xhci_hcd *xhci,
         urb->hcpriv = (void *) (*td);
         /* Add this TD to the tail of the endpoint ring's TD list */
         list_add_tail(&(*td)->td_list, &xdev->ep_rings[ep_index]->td_list);
+        (*td)->start_seg = xdev->ep_rings[ep_index]->enq_seg;
+        (*td)->first_trb = xdev->ep_rings[ep_index]->enqueue;
 
         return 0;
 }
@@ -823,19 +1221,13 @@ void giveback_first_trb(struct xhci_hcd *xhci, int slot_id,
                 unsigned int ep_index, int start_cycle,
                 struct xhci_generic_trb *start_trb, struct xhci_td *td)
 {
-        u32 field;
-
         /*
          * Pass all the TRBs to the hardware at once and make sure this write
          * isn't reordered.
          */
         wmb();
         start_trb->field[3] |= start_cycle;
-        field = xhci_readl(xhci, &xhci->dba->doorbell[slot_id]) & DB_MASK;
-        xhci_writel(xhci, field | EPI_TO_DB(ep_index),
-                        &xhci->dba->doorbell[slot_id]);
-        /* Flush PCI posted writes */
-        xhci_readl(xhci, &xhci->dba->doorbell[slot_id]);
+        ring_ep_doorbell(xhci, slot_id, ep_index);
 }
 
 int queue_bulk_sg_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
@@ -1221,3 +1613,36 @@ int queue_configure_endpoint(struct xhci_hcd *xhci, dma_addr_t in_ctx_ptr, u32 s
         return queue_command(xhci, in_ctx_ptr, 0, 0,
                         TRB_TYPE(TRB_CONFIG_EP) | SLOT_ID_FOR_TRB(slot_id));
 }
+
+int queue_stop_endpoint(struct xhci_hcd *xhci, int slot_id,
+                unsigned int ep_index)
+{
+        u32 trb_slot_id = SLOT_ID_FOR_TRB(slot_id);
+        u32 trb_ep_index = EP_ID_FOR_TRB(ep_index);
+        u32 type = TRB_TYPE(TRB_STOP_RING);
+
+        return queue_command(xhci, 0, 0, 0,
+                        trb_slot_id | trb_ep_index | type);
+}
+
+/* Set Transfer Ring Dequeue Pointer command.
+ * This should not be used for endpoints that have streams enabled.
+ */
+static int queue_set_tr_deq(struct xhci_hcd *xhci, int slot_id,
+                unsigned int ep_index, struct xhci_segment *deq_seg,
+                union xhci_trb *deq_ptr, u32 cycle_state)
+{
+        dma_addr_t addr;
+        u32 trb_slot_id = SLOT_ID_FOR_TRB(slot_id);
+        u32 trb_ep_index = EP_ID_FOR_TRB(ep_index);
+        u32 type = TRB_TYPE(TRB_SET_DEQ);
+
+        addr = trb_virt_to_dma(deq_seg, deq_ptr);
+        if (addr == 0)
+                xhci_warn(xhci, "WARN Cannot submit Set TR Deq Ptr\n");
+                xhci_warn(xhci, "WARN deq seg = 0x%x, deq pt = 0x%x\n",
+                                (unsigned int) deq_seg,
+                                (unsigned int) deq_ptr);
+        return queue_command(xhci, (u32) addr | cycle_state, 0, 0,
+                        trb_slot_id | trb_ep_index | type);
+}
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index 06e07616631f..7b7103405c69 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -514,6 +514,7 @@ struct xhci_slot_ctx {
 /* bits 8:26 reserved */
 /* Slot state */
 #define SLOT_STATE      (0x1f << 27)
+#define GET_SLOT_STATE(p)       (((p) & (0x1f << 27)) >> 27)
 
 
 /**
@@ -765,6 +766,11 @@ struct xhci_event_cmd {
 #define TRB_TO_SLOT_ID(p)       (((p) & (0xff<<24)) >> 24)
 #define SLOT_ID_FOR_TRB(p)      (((p) & 0xff) << 24)
 
+/* Stop Endpoint TRB - ep_index to endpoint ID for this TRB */
+#define TRB_TO_EP_INDEX(p)              ((((p) & (0x1f << 16)) >> 16) - 1)
+#define EP_ID_FOR_TRB(p)                ((((p) + 1) & 0x1f) << 16)
+
+
 /* Port Status Change Event TRB fields */
 /* Port ID - bits 31:24 */
 #define GET_PORT_ID(p)          (((p) & (0xff << 24)) >> 24)
@@ -893,12 +899,6 @@ union xhci_trb {
 #define TRB_MAX_BUFF_SHIFT              16
 #define TRB_MAX_BUFF_SIZE       (1 << TRB_MAX_BUFF_SHIFT)
 
-struct xhci_td {
-        struct list_head        td_list;
-        struct urb              *urb;
-        union xhci_trb          *last_trb;
-};
-
 struct xhci_segment {
         union xhci_trb          *trbs;
         /* private to HCD */
@@ -906,6 +906,15 @@ struct xhci_segment {
         dma_addr_t              dma;
 } __attribute__ ((packed));
 
+struct xhci_td {
+        struct list_head        td_list;
+        struct list_head        cancelled_td_list;
+        struct urb              *urb;
+        struct xhci_segment     *start_seg;
+        union xhci_trb          *first_trb;
+        union xhci_trb          *last_trb;
+};
+
 struct xhci_ring {
         struct xhci_segment     *first_seg;
         union  xhci_trb         *enqueue;
@@ -915,6 +924,14 @@ struct xhci_ring {
         struct xhci_segment     *deq_seg;
         unsigned int            deq_updates;
         struct list_head        td_list;
+        /* ----  Related to URB cancellation ---- */
+        struct list_head        cancelled_td_list;
+        unsigned int            cancels_pending;
+        unsigned int            state;
+#define SET_DEQ_PENDING         (1 << 0)
+        /* The TRB that was last reported in a stopped endpoint ring */
+        union xhci_trb          *stopped_trb;
+        struct xhci_td          *stopped_td;
         /*
          * Write the cycle state into the TRB cycle field to give ownership of
          * the TRB to the host controller (if we are the producer), or to check
@@ -1119,6 +1136,8 @@ void handle_event(struct xhci_hcd *xhci);
 void set_hc_event_deq(struct xhci_hcd *xhci);
 int queue_slot_control(struct xhci_hcd *xhci, u32 trb_type, u32 slot_id);
 int queue_address_device(struct xhci_hcd *xhci, dma_addr_t in_ctx_ptr, u32 slot_id);
+int queue_stop_endpoint(struct xhci_hcd *xhci, int slot_id,
+                unsigned int ep_index);
 int queue_ctrl_tx(struct xhci_hcd *xhci, gfp_t mem_flags, struct urb *urb, int slot_id, unsigned int ep_index);
 int queue_bulk_tx(struct xhci_hcd *xhci, gfp_t mem_flags, struct urb *urb, int slot_id, unsigned int ep_index);
 int queue_configure_endpoint(struct xhci_hcd *xhci, dma_addr_t in_ctx_ptr, u32 slot_id);