xhci: Clear the host side toggle manually when endpoint is soft reset

Some devices use a clear endpoint halt request as a soft reset, even if
the endpoint is not halted. This will clear the toggle and sequence on the
device side.

xHCI however refuses to reset a non-halted endpoint, so instead
we need to issue a configure endpoint command on xHCI to clear its host
side toggle and sequence, and get it in sync with the device side.

This is a respin of a old patch that was reverted as it had a stale
endpoint context dequeue value which caused regression.
commit 27082e2654dc ("xhci: Clear the host side toggle manually when
endpoint is 'soft reset'")

Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 86476c6..91a1a82 100644 (file)
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -1829,9 +1829,10 @@ static void xhci_cleanup_halted_endpoint(struct xhci_hcd *xhci,
 
        xhci_queue_reset_ep(xhci, command, slot_id, ep_index, reset_type);
 
-       if (reset_type == EP_HARD_RESET)
+       if (reset_type == EP_HARD_RESET) {
+               ep->ep_state |= EP_HARD_CLEAR_TOGGLE;
                xhci_cleanup_stalled_ring(xhci, ep_index, stream_id, td);
-
+       }
        xhci_ring_cmd_db(xhci);
 }
 

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index f9d8a32..05b22b8 100644 (file)
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -1356,6 +1356,11 @@ static int xhci_urb_enqueue(struct usb_hcd *hcd, struct urb *urb, gfp_t mem_flag
                ret = -EINVAL;
                goto free_priv;
        }
+       if (*ep_state & EP_SOFT_CLEAR_TOGGLE) {
+               xhci_warn(xhci, "Can't enqueue URB while manually clearing toggle\n");
+               ret = -EINVAL;
+               goto free_priv;
+       }
 
        switch (usb_endpoint_type(&urb->ep->desc)) {
 
@@ -2869,33 +2874,103 @@ void xhci_cleanup_stalled_ring(struct xhci_hcd *xhci, unsigned int ep_index,
        }
 }
 
-/* Called when clearing halted device. The core should have sent the control
- * message to clear the device halt condition. The host side of the halt should
- * already be cleared with a reset endpoint command issued when the STALL tx
- * event was received.
+/*
+ * Called after usb core issues a clear halt control message.
+ * The host side of the halt should already be cleared by a reset endpoint
+ * command issued when the STALL event was received.
  *
- * Context: in_interrupt
+ * The reset endpoint command may only be issued to endpoints in the halted
+ * state. For software that wishes to reset the data toggle or sequence number
+ * of an endpoint that isn't in the halted state this function will issue a
+ * configure endpoint command with the Drop and Add bits set for the target
+ * endpoint. Refer to the additional note in xhci spcification section 4.6.8.
  */
 
 static void xhci_endpoint_reset(struct usb_hcd *hcd,
-               struct usb_host_endpoint *ep)
+               struct usb_host_endpoint *host_ep)
 {
        struct xhci_hcd *xhci;
+       struct usb_device *udev;
+       struct xhci_virt_device *vdev;
+       struct xhci_virt_ep *ep;
+       struct xhci_input_control_ctx *ctrl_ctx;
+       struct xhci_command *stop_cmd, *cfg_cmd;
+       unsigned int ep_index;
+       unsigned long flags;
+       u32 ep_flag;
 
        xhci = hcd_to_xhci(hcd);
+       if (!host_ep->hcpriv)
+               return;
+       udev = (struct usb_device *) host_ep->hcpriv;
+       vdev = xhci->devs[udev->slot_id];
+       ep_index = xhci_get_endpoint_index(&host_ep->desc);
+       ep = &vdev->eps[ep_index];
+
+       /* Bail out if toggle is already being cleared by a endpoint reset */
+       if (ep->ep_state & EP_HARD_CLEAR_TOGGLE) {
+               ep->ep_state &= ~EP_HARD_CLEAR_TOGGLE;
+               return;
+       }
+       /* Only interrupt and bulk ep's use data toggle, USB2 spec 5.5.4-> */
+       if (usb_endpoint_xfer_control(&host_ep->desc) ||
+           usb_endpoint_xfer_isoc(&host_ep->desc))
+               return;
+
+       ep_flag = xhci_get_endpoint_flag(&host_ep->desc);
+
+       if (ep_flag == SLOT_FLAG || ep_flag == EP0_FLAG)
+               return;
+
+       stop_cmd = xhci_alloc_command(xhci, true, GFP_NOWAIT);
+       if (!stop_cmd)
+               return;
+
+       cfg_cmd = xhci_alloc_command_with_ctx(xhci, true, GFP_NOWAIT);
+       if (!cfg_cmd)
+               goto cleanup;
+
+       spin_lock_irqsave(&xhci->lock, flags);
+
+       /* block queuing new trbs and ringing ep doorbell */
+       ep->ep_state |= EP_SOFT_CLEAR_TOGGLE;
 
        /*
-        * We might need to implement the config ep cmd in xhci 4.8.1 note:
-        * The Reset Endpoint Command may only be issued to endpoints in the
-        * Halted state. If software wishes reset the Data Toggle or Sequence
-        * Number of an endpoint that isn't in the Halted state, then software
-        * may issue a Configure Endpoint Command with the Drop and Add bits set
-        * for the target endpoint. that is in the Stopped state.
+        * Make sure endpoint ring is empty before resetting the toggle/seq.
+        * Driver is required to synchronously cancel all transfer request.
+        * Stop the endpoint to force xHC to update the output context
         */
 
-       /* For now just print debug to follow the situation */
-       xhci_dbg(xhci, "Endpoint 0x%x ep reset callback called\n",
-                ep->desc.bEndpointAddress);
+       if (!list_empty(&ep->ring->td_list)) {
+               dev_err(&udev->dev, "EP not empty, refuse reset\n");
+               spin_unlock_irqrestore(&xhci->lock, flags);
+               goto cleanup;
+       }
+       xhci_queue_stop_endpoint(xhci, stop_cmd, udev->slot_id, ep_index, 0);
+       xhci_ring_cmd_db(xhci);
+       spin_unlock_irqrestore(&xhci->lock, flags);
+
+       wait_for_completion(stop_cmd->completion);
+
+       spin_lock_irqsave(&xhci->lock, flags);
+
+       /* config ep command clears toggle if add and drop ep flags are set */
+       ctrl_ctx = xhci_get_input_control_ctx(cfg_cmd->in_ctx);
+       xhci_setup_input_ctx_for_config_ep(xhci, cfg_cmd->in_ctx, vdev->out_ctx,
+                                          ctrl_ctx, ep_flag, ep_flag);
+       xhci_endpoint_copy(xhci, cfg_cmd->in_ctx, vdev->out_ctx, ep_index);
+
+       xhci_queue_configure_endpoint(xhci, cfg_cmd, cfg_cmd->in_ctx->dma,
+                                     udev->slot_id, false);
+       xhci_ring_cmd_db(xhci);
+       spin_unlock_irqrestore(&xhci->lock, flags);
+
+       wait_for_completion(cfg_cmd->completion);
+
+       ep->ep_state &= ~EP_SOFT_CLEAR_TOGGLE;
+       xhci_free_command(xhci, cfg_cmd);
+cleanup:
+       xhci_free_command(xhci, stop_cmd);
 }
 
 static int xhci_check_streams_endpoint(struct xhci_hcd *xhci,

diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index e4d7d3d..9f236da 100644 (file)
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -921,6 +921,8 @@ struct xhci_virt_ep {
 #define EP_HAS_STREAMS         (1 << 4)
 /* Transitioning the endpoint to not using streams, don't enqueue URBs */
 #define EP_GETTING_NO_STREAMS  (1 << 5)
+#define EP_HARD_CLEAR_TOGGLE   (1 << 6)
+#define EP_SOFT_CLEAR_TOGGLE   (1 << 7)
        /* ----  Related to URB cancellation ---- */
        struct list_head        cancelled_td_list;
        /* Watchdog timer for stop endpoint command to cancel URBs */