usb: xhci: Add Clear_TT_Buffer

USB 2.0 specification chapter 11.17.5 says "as part of endpoint halt
processing for full-/low-speed endpoints connected via a TT, the host
software must use the Clear_TT_Buffer request to the TT to ensure
that the buffer is not in the busy state".

In our case, a full-speed speaker (ConferenceCam) is behind a high-
speed hub (ConferenceCam Connect), sometimes once we get STALL on a
request we may continue to get STALL with the folllowing requests,
like Set_Interface.

Here we invoke usb_hub_clear_tt_buffer() to send Clear_TT_Buffer
request to the hub of the device for the following Set_Interface
requests to the device to get ACK successfully.

Signed-off-by: Jim Lin <jilin@nvidia.com>
Acked-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 feffceb..a52fd96 100644 (file)
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -399,7 +399,7 @@ void xhci_ring_ep_doorbell(struct xhci_hcd *xhci,
         * stream once the endpoint is on the HW schedule.
         */
        if ((ep_state & EP_STOP_CMD_PENDING) || (ep_state & SET_DEQ_PENDING) ||
-           (ep_state & EP_HALTED))
+           (ep_state & EP_HALTED) || (ep_state & EP_CLEARING_TT))
                return;
        writel(DB_VALUE(ep_index, stream_id), db_addr);
        /* The CPU has better things to do at this point than wait for a
@@ -433,6 +433,13 @@ static void ring_doorbell_for_active_rings(struct xhci_hcd *xhci,
        }
 }
 
+void xhci_ring_doorbell_for_active_rings(struct xhci_hcd *xhci,
+               unsigned int slot_id,
+               unsigned int ep_index)
+{
+       ring_doorbell_for_active_rings(xhci, slot_id, ep_index);
+}
+
 /* Get the right ring for the given slot_id, ep_index and stream_id.
  * If the endpoint supports streams, boundary check the URB's stream ID.
  * If the endpoint doesn't support streams, return the singular endpoint ring.
@@ -1794,6 +1801,23 @@ struct xhci_segment *trb_in_td(struct xhci_hcd *xhci,
        return NULL;
 }
 
+static void xhci_clear_hub_tt_buffer(struct xhci_hcd *xhci, struct xhci_td *td,
+               struct xhci_virt_ep *ep)
+{
+       /*
+        * As part of low/full-speed endpoint-halt processing
+        * we must clear the TT buffer (USB 2.0 specification 11.17.5).
+        */
+       if (td->urb->dev->tt && !usb_pipeint(td->urb->pipe) &&
+           (td->urb->dev->tt->hub != xhci_to_hcd(xhci)->self.root_hub) &&
+           !(ep->ep_state & EP_CLEARING_TT)) {
+               ep->ep_state |= EP_CLEARING_TT;
+               td->urb->ep->hcpriv = td->urb->dev;
+               if (usb_hub_clear_tt_buffer(td->urb))
+                       ep->ep_state &= ~EP_CLEARING_TT;
+       }
+}
+
 static void xhci_cleanup_halted_endpoint(struct xhci_hcd *xhci,
                unsigned int slot_id, unsigned int ep_index,
                unsigned int stream_id, struct xhci_td *td,
@@ -1812,6 +1836,7 @@ static void xhci_cleanup_halted_endpoint(struct xhci_hcd *xhci,
        if (reset_type == EP_HARD_RESET) {
                ep->ep_state |= EP_HARD_CLEAR_TOGGLE;
                xhci_cleanup_stalled_ring(xhci, ep_index, stream_id, td);
+               xhci_clear_hub_tt_buffer(xhci, td, ep);
        }
        xhci_ring_cmd_db(xhci);
 }

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 4f92643..ef5702a 100644 (file)
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -5163,6 +5163,26 @@ int xhci_gen_setup(struct usb_hcd *hcd, xhci_get_quirks_t get_quirks)
 }
 EXPORT_SYMBOL_GPL(xhci_gen_setup);
 
+static void xhci_clear_tt_buffer_complete(struct usb_hcd *hcd,
+               struct usb_host_endpoint *ep)
+{
+       struct xhci_hcd *xhci;
+       struct usb_device *udev;
+       unsigned int slot_id;
+       unsigned int ep_index;
+       unsigned long flags;
+
+       xhci = hcd_to_xhci(hcd);
+       udev = (struct usb_device *)ep->hcpriv;
+       slot_id = udev->slot_id;
+       ep_index = xhci_get_endpoint_index(&ep->desc);
+
+       spin_lock_irqsave(&xhci->lock, flags);
+       xhci->devs[slot_id]->eps[ep_index].ep_state &= ~EP_CLEARING_TT;
+       xhci_ring_doorbell_for_active_rings(xhci, slot_id, ep_index);
+       spin_unlock_irqrestore(&xhci->lock, flags);
+}
+
 static const struct hc_driver xhci_hc_driver = {
        .description =          "xhci-hcd",
        .product_desc =         "xHCI Host Controller",
@@ -5224,6 +5244,7 @@ static const struct hc_driver xhci_hc_driver = {
        .enable_usb3_lpm_timeout =      xhci_enable_usb3_lpm_timeout,
        .disable_usb3_lpm_timeout =     xhci_disable_usb3_lpm_timeout,
        .find_raw_port_number = xhci_find_raw_port_number,
+       .clear_tt_buffer_complete = xhci_clear_tt_buffer_complete,
 };
 
 void xhci_init_driver(struct hc_driver *drv,

diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index 7f8b950..34789f4 100644 (file)
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -936,6 +936,8 @@ struct xhci_virt_ep {
 #define EP_GETTING_NO_STREAMS  (1 << 5)
 #define EP_HARD_CLEAR_TOGGLE   (1 << 6)
 #define EP_SOFT_CLEAR_TOGGLE   (1 << 7)
+/* usb_hub_clear_tt_buffer is in progress */
+#define EP_CLEARING_TT         (1 << 8)
        /* ----  Related to URB cancellation ---- */
        struct list_head        cancelled_td_list;
        /* Watchdog timer for stop endpoint command to cancel URBs */
@@ -2102,6 +2104,9 @@ void xhci_handle_command_timeout(struct work_struct *work);
 
 void xhci_ring_ep_doorbell(struct xhci_hcd *xhci, unsigned int slot_id,
                unsigned int ep_index, unsigned int stream_id);
+void xhci_ring_doorbell_for_active_rings(struct xhci_hcd *xhci,
+               unsigned int slot_id,
+               unsigned int ep_index);
 void xhci_cleanup_command_queue(struct xhci_hcd *xhci);
 void inc_deq(struct xhci_hcd *xhci, struct xhci_ring *ring);
 unsigned int count_trbs(u64 addr, u64 len);