xhci: Ensure a command structure points to the correct trb on the command ring
commit ec7e43e2d98173483866fe2e4e690143626b659c upstream.
If a command on the command ring needs to be cancelled before it is handled
it can be turned to a no-op operation when the ring is stopped.
We want to store the command ring enqueue pointer in the command structure
when the command in enqueued for the cancellation case.
Some commands used to store the command ring dequeue pointers instead of enqueue
(these often worked because enqueue happends to equal dequeue quite often)
Other commands correctly used the enqueue pointer but did not check if it pointed
to a valid trb or a link trb, this caused for example stop endpoint command to timeout in
xhci_stop_device() in about 2% of suspend/resume cases.
This should also solve some weird behavior happening in command cancellation cases.
This patch is based on a patch submitted by Sarah Sharp to linux-usb, but
then forgotten:
http://marc.info/?l=linux-usb&m=136269803207465&w=2
This patch should be backported to kernels as old as 3.7, that contain
the commit b92cc66c047ff7cf587b318fe377061a353c120f "xHCI: add aborting
command ring function"
Change-Id: Ic8600211cd5e1605776715a78ec7cdb9ba9f6fe3
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c
index 591d6e5..f7b095d 100644
--- a/drivers/usb/host/xhci-hub.c
+++ b/drivers/usb/host/xhci-hub.c
@@ -287,7 +287,7 @@
if (virt_dev->eps[i].ring && virt_dev->eps[i].ring->dequeue)
xhci_queue_stop_endpoint(xhci, slot_id, i, suspend);
}
- cmd->command_trb = xhci->cmd_ring->enqueue;
+ cmd->command_trb = xhci_find_next_enqueue(xhci->cmd_ring);
list_add_tail(&cmd->cmd_list, &virt_dev->cmd_list);
xhci_queue_stop_endpoint(xhci, slot_id, 0, suspend);
xhci_ring_cmd_db(xhci);
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index ed12739..69752c4 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -122,6 +122,16 @@
return TRB_TYPE_LINK_LE32(link->control);
}
+union xhci_trb *xhci_find_next_enqueue(struct xhci_ring *ring)
+{
+ /* Enqueue pointer can be left pointing to the link TRB,
+ * we must handle that
+ */
+ if (TRB_TYPE_LINK_LE32(ring->enqueue->link.control))
+ return ring->enq_seg->next->trbs;
+ return ring->enqueue;
+}
+
/* 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.
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 1bd4dd1..53b39e1 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -2625,15 +2625,7 @@
if (command) {
cmd_completion = command->completion;
cmd_status = &command->status;
- command->command_trb = xhci->cmd_ring->enqueue;
-
- /* Enqueue pointer can be left pointing to the link TRB,
- * we must handle that
- */
- if (TRB_TYPE_LINK_LE32(command->command_trb->link.control))
- command->command_trb =
- xhci->cmd_ring->enq_seg->next->trbs;
-
+ command->command_trb = xhci_find_next_enqueue(xhci->cmd_ring);
list_add_tail(&command->cmd_list, &virt_dev->cmd_list);
} else {
cmd_completion = &virt_dev->cmd_completion;
@@ -2641,7 +2633,7 @@
}
init_completion(cmd_completion);
- cmd_trb = xhci->cmd_ring->dequeue;
+ cmd_trb = xhci_find_next_enqueue(xhci->cmd_ring);
if (!ctx_change)
ret = xhci_queue_configure_endpoint(xhci, in_ctx->dma,
udev->slot_id, must_succeed);
@@ -3401,14 +3393,7 @@
/* Attempt to submit the Reset Device command to the command ring */
spin_lock_irqsave(&xhci->lock, flags);
- reset_device_cmd->command_trb = xhci->cmd_ring->enqueue;
-
- /* Enqueue pointer can be left pointing to the link TRB,
- * we must handle that
- */
- if (TRB_TYPE_LINK_LE32(reset_device_cmd->command_trb->link.control))
- reset_device_cmd->command_trb =
- xhci->cmd_ring->enq_seg->next->trbs;
+ reset_device_cmd->command_trb = xhci_find_next_enqueue(xhci->cmd_ring);
list_add_tail(&reset_device_cmd->cmd_list, &virt_dev->cmd_list);
ret = xhci_queue_reset_device(xhci, slot_id);
@@ -3612,7 +3597,7 @@
union xhci_trb *cmd_trb;
spin_lock_irqsave(&xhci->lock, flags);
- cmd_trb = xhci->cmd_ring->dequeue;
+ cmd_trb = xhci_find_next_enqueue(xhci->cmd_ring);
ret = xhci_queue_slot_control(xhci, TRB_ENABLE_SLOT, 0);
if (ret) {
spin_unlock_irqrestore(&xhci->lock, flags);
@@ -3739,7 +3724,7 @@
xhci_dbg_ctx(xhci, virt_dev->in_ctx, 2);
spin_lock_irqsave(&xhci->lock, flags);
- cmd_trb = xhci->cmd_ring->dequeue;
+ cmd_trb = xhci_find_next_enqueue(xhci->cmd_ring);
ret = xhci_queue_address_device(xhci, virt_dev->in_ctx->dma,
udev->slot_id);
if (ret) {
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index d06fe0e..a7ff6c9 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1813,6 +1813,7 @@
union xhci_trb *cmd_trb);
void xhci_ring_ep_doorbell(struct xhci_hcd *xhci, unsigned int slot_id,
unsigned int ep_index, unsigned int stream_id);
+union xhci_trb *xhci_find_next_enqueue(struct xhci_ring *ring);
/* xHCI roothub code */
void xhci_set_link_state(struct xhci_hcd *xhci, __le32 __iomem **port_array,
