3 files changed, 120 insertions, 49 deletions

diff --git a/drivers/usb/host/xhci-hcd.c b/drivers/usb/host/xhci-hcd.c
index 057a07e876be..816c39caca1c 100644
--- a/drivers/usb/host/xhci-hcd.c
+++ b/drivers/usb/host/xhci-hcd.c
@@ -1089,6 +1089,8 @@ void xhci_endpoint_reset(struct usb_hcd *hcd,
         unsigned int ep_index;
         unsigned long flags;
         int ret;
+        struct xhci_dequeue_state deq_state;
+        struct xhci_ring *ep_ring;
 
         xhci = hcd_to_xhci(hcd);
         udev = (struct usb_device *) ep->hcpriv;
@@ -1098,11 +1100,33 @@ void xhci_endpoint_reset(struct usb_hcd *hcd,
         if (!ep->hcpriv)
                 return;
         ep_index = xhci_get_endpoint_index(&ep->desc);
+        ep_ring = xhci->devs[udev->slot_id]->ep_rings[ep_index];
+        if (!ep_ring->stopped_td) {
+                xhci_dbg(xhci, "Endpoint 0x%x not halted, refusing to reset.\n",
+                                ep->desc.bEndpointAddress);
+                return;
+        }
 
         xhci_dbg(xhci, "Queueing reset endpoint command\n");
         spin_lock_irqsave(&xhci->lock, flags);
         ret = xhci_queue_reset_ep(xhci, udev->slot_id, ep_index);
+        /*
+         * Can't change the ring dequeue pointer until it's transitioned to the
+         * stopped state, which is only upon a successful reset endpoint
+         * command.  Better hope that last command worked!
+         */
         if (!ret) {
+                xhci_dbg(xhci, "Cleaning up stalled endpoint ring\n");
+                /* We need to move the HW's dequeue pointer past this TD,
+                 * or it will attempt to resend it on the next doorbell ring.
+                 */
+                xhci_find_new_dequeue_state(xhci, udev->slot_id,
+                                ep_index, ep_ring->stopped_td, &deq_state);
+                xhci_dbg(xhci, "Queueing new dequeue state\n");
+                xhci_queue_new_dequeue_state(xhci, ep_ring,
+                                udev->slot_id,
+                                ep_index, &deq_state);
+                kfree(ep_ring->stopped_td);
                 xhci_ring_cmd_db(xhci);
         }
         spin_unlock_irqrestore(&xhci->lock, flags);
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index ea31753c3137..aa88a067148b 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -335,12 +335,6 @@ static struct xhci_segment *find_trb_seg(
         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,
@@ -355,26 +349,30 @@ struct dequeue_state {
  *  - 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,
+void xhci_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_td *cur_td, struct xhci_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;
         struct xhci_ep_ctx *ep_ctx;
+        dma_addr_t addr;
 
         state->new_cycle_state = 0;
+        xhci_dbg(xhci, "Finding segment containing stopped TRB.\n");
         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 */
+        xhci_dbg(xhci, "Finding endpoint context\n");
         ep_ctx = xhci_get_ep_ctx(xhci, dev->out_ctx, ep_index);
         state->new_cycle_state = 0x1 & ep_ctx->deq;
 
         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);
@@ -388,6 +386,12 @@ static void find_new_dequeue_state(struct xhci_hcd *xhci,
         next_trb(xhci, ep_ring, &state->new_deq_seg, &state->new_deq_ptr);
 
         /* Don't update the ring cycle state for the producer (us). */
+        xhci_dbg(xhci, "New dequeue segment = %p (virtual)\n",
+                        state->new_deq_seg);
+        addr = xhci_trb_virt_to_dma(state->new_deq_seg, state->new_deq_ptr);
+        xhci_dbg(xhci, "New dequeue pointer = 0x%llx (DMA)\n",
+                        (unsigned long long) addr);
+        xhci_dbg(xhci, "Setting dequeue pointer in internal ring state.\n");
         ep_ring->dequeue = state->new_deq_ptr;
         ep_ring->deq_seg = state->new_deq_seg;
 }
@@ -437,6 +441,30 @@ 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);
 
+void xhci_queue_new_dequeue_state(struct xhci_hcd *xhci,
+                struct xhci_ring *ep_ring, unsigned int slot_id,
+                unsigned int ep_index, struct xhci_dequeue_state *deq_state)
+{
+        xhci_dbg(xhci, "Set TR Deq Ptr cmd, new deq seg = %p (0x%llx dma), "
+                        "new deq ptr = %p (0x%llx dma), new cycle = %u\n",
+                        deq_state->new_deq_seg,
+                        (unsigned long long)deq_state->new_deq_seg->dma,
+                        deq_state->new_deq_ptr,
+                        (unsigned long long)xhci_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;
+        xhci_ring_cmd_db(xhci);
+}
+
 /*
  * 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:
@@ -457,7 +485,7 @@ static void handle_stopped_endpoint(struct xhci_hcd *xhci,
         struct xhci_td *cur_td = 0;
         struct xhci_td *last_unlinked_td;
 
-        struct dequeue_state deq_state;
+        struct xhci_dequeue_state deq_state;
 #ifdef CONFIG_USB_HCD_STAT
         ktime_t stop_time = ktime_get();
 #endif
@@ -485,7 +513,7 @@ static void handle_stopped_endpoint(struct xhci_hcd *xhci,
                  * 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,
+                        xhci_find_new_dequeue_state(xhci, slot_id, ep_index, cur_td,
                                         &deq_state);
                 else
                         td_to_noop(xhci, ep_ring, cur_td);
@@ -501,24 +529,8 @@ static void handle_stopped_endpoint(struct xhci_hcd *xhci,