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

Main benefit of this is to get xhci connected USB scanners to work.

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.

Tested-by: Mike Mammarella <mikem@crystalorb.net>
Cc: <stable@vger.kernel.org> # v3.18
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

3 files changed, 94 insertions, 10 deletions

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 88da8d629820..b46b5b98a943 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -1729,7 +1729,7 @@ static void xhci_cleanup_halted_endpoint(struct xhci_hcd *xhci,
         if (!command)
                 return;
 
-        ep->ep_state |= EP_HALTED;
+        ep->ep_state |= EP_HALTED | EP_RECENTLY_HALTED;
         ep->stopped_stream = stream_id;
 
         xhci_queue_reset_ep(xhci, command, slot_id, ep_index);
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index ec8ac1674854..b06d1a53652d 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -1338,6 +1338,12 @@ int xhci_urb_enqueue(struct usb_hcd *hcd, struct urb *urb, gfp_t mem_flags)
                 goto exit;
         }
 
+        /* Reject urb if endpoint is in soft reset, queue must stay empty */
+        if (xhci->devs[slot_id]->eps[ep_index].ep_state & EP_CONFIG_PENDING) {
+                xhci_warn(xhci, "Can't enqueue URB while ep is in soft reset\n");
+                ret = -EINVAL;
+        }
+
         if (usb_endpoint_xfer_isoc(&urb->ep->desc))
                 size = urb->number_of_packets;
         else
@@ -2948,23 +2954,36 @@ void xhci_cleanup_stalled_ring(struct xhci_hcd *xhci,
         }
 }
 
-/* Called when clearing halted device. The core should have sent the control
+/* Called after clearing a halted device. USB 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.
- *
- * Context: in_interrupt
+ * already be cleared with a reset endpoint command issued immediately when the
+ * STALL tx event was received.
  */
 
 void xhci_endpoint_reset(struct usb_hcd *hcd,
                 struct usb_host_endpoint *ep)
 {
         struct xhci_hcd *xhci;
+        struct usb_device *udev;
+        struct xhci_virt_device *virt_dev;
+        struct xhci_virt_ep *virt_ep;
+        struct xhci_input_control_ctx *ctrl_ctx;
+        struct xhci_command *command;
+        unsigned int ep_index, ep_state;
+        unsigned long flags;
+        u32 ep_flag;
 
         xhci = hcd_to_xhci(hcd);
+        udev = (struct usb_device *) ep->hcpriv;
+        if (!ep->hcpriv)
+                return;
+        virt_dev = xhci->devs[udev->slot_id];
+        ep_index = xhci_get_endpoint_index(&ep->desc);
+        virt_ep = &virt_dev->eps[ep_index];
+        ep_state = virt_ep->ep_state;
 
         /*
-         * We might need to implement the config ep cmd in xhci 4.8.1 note:
+         * Implement the config ep command in xhci 4.6.8 additional 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
@@ -2972,9 +2991,72 @@ void xhci_endpoint_reset(struct usb_hcd *hcd,
          * for the target endpoint. that is in the Stopped state.
          */
 
-        /* For now just print debug to follow the situation */
-        xhci_dbg(xhci, "Endpoint 0x%x ep reset callback called\n",
-                 ep->desc.bEndpointAddress);
+        if (ep_state & SET_DEQ_PENDING || ep_state & EP_RECENTLY_HALTED) {
+                virt_ep->ep_state &= ~EP_RECENTLY_HALTED;
+                xhci_dbg(xhci, "ep recently halted, no toggle reset needed\n");
+                return;
+        }
+
+        /* Only interrupt and bulk ep's use Data toggle, USB2 spec 5.5.4-> */
+        if (usb_endpoint_xfer_control(&ep->desc) ||
+            usb_endpoint_xfer_isoc(&ep->desc))
+                return;
+
+        ep_flag = xhci_get_endpoint_flag(&ep->desc);
+
+        if (ep_flag == SLOT_FLAG || ep_flag == EP0_FLAG)
+                return;
+
+        command = xhci_alloc_command(xhci, true, true, GFP_NOWAIT);
+        if (!command) {
+                xhci_err(xhci, "Could not allocate xHCI command structure.\n");
+                return;
+        }
+
+        spin_lock_irqsave(&xhci->lock, flags);
+
+        /* block ringing ep doorbell */
+        virt_ep->ep_state |= EP_CONFIG_PENDING;
+
+        /*
+         * Make sure endpoint ring is empty before resetting the toggle/seq.
+         * Driver is required to synchronously cancel all transfer request.
+         *
+         * xhci 4.6.6 says we can issue a configure endpoint command on a
+         * running endpoint ring as long as it's idle (queue empty)
+         */
+
+        if (!list_empty(&virt_ep->ring->td_list)) {
+                dev_err(&udev->dev, "EP not empty, refuse reset\n");
+                spin_unlock_irqrestore(&xhci->lock, flags);
+                goto cleanup;
+        }
+
+        xhci_dbg(xhci, "Reset toggle/seq for slot %d, ep_index: %d\n",
+                 udev->slot_id, ep_index);
+
+        ctrl_ctx = xhci_get_input_control_ctx(command->in_ctx);
+        if (!ctrl_ctx) {
+                xhci_err(xhci, "Could not get input context, bad type. virt_dev: %p, in_ctx %p\n",
+                         virt_dev, virt_dev->in_ctx);
+                spin_unlock_irqrestore(&xhci->lock, flags);
+                goto cleanup;
+        }
+        xhci_setup_input_ctx_for_config_ep(xhci, command->in_ctx,
+                                           virt_dev->out_ctx, ctrl_ctx,
+                                           ep_flag, ep_flag);
+        xhci_endpoint_copy(xhci, command->in_ctx, virt_dev->out_ctx, ep_index);
+
+        xhci_queue_configure_endpoint(xhci, command, command->in_ctx->dma,
+                                     udev->slot_id, false);
+        xhci_ring_cmd_db(xhci);
+        spin_unlock_irqrestore(&xhci->lock, flags);
+
+        wait_for_completion(command->completion);
+
+cleanup:
+        virt_ep->ep_state &= ~EP_CONFIG_PENDING;
+        xhci_free_command(xhci, command);
 }
 
 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 68956b13b8d1..3b97f0582155 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -864,6 +864,8 @@ 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_RECENTLY_HALTED      (1 << 6)
+#define EP_CONFIG_PENDING       (1 << 7)
         /* ----  Related to URB cancellation ---- */
         struct list_head        cancelled_td_list;
         struct xhci_td          *stopped_td;