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>

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);

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,

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;