1 files changed, 68 insertions, 23 deletions

diff --git a/drivers/usb/host/ehci-q.c b/drivers/usb/host/ehci-q.c
index 68bf81e982d2..e3d2b627bfb3 100644
--- a/drivers/usb/host/ehci-q.c
+++ b/drivers/usb/host/ehci-q.c
@@ -139,6 +139,55 @@ qh_refresh (struct ehci_hcd *ehci, struct ehci_qh *qh)
 
 /*-------------------------------------------------------------------------*/
 
+static void qh_link_async(struct ehci_hcd *ehci, struct ehci_qh *qh);
+
+static void ehci_clear_tt_buffer_complete(struct usb_hcd *hcd,
+                struct usb_host_endpoint *ep)
+{
+        struct ehci_hcd         *ehci = hcd_to_ehci(hcd);
+        struct ehci_qh          *qh = ep->hcpriv;
+        unsigned long           flags;
+
+        spin_lock_irqsave(&ehci->lock, flags);
+        qh->clearing_tt = 0;
+        if (qh->qh_state == QH_STATE_IDLE && !list_empty(&qh->qtd_list)
+                        && HC_IS_RUNNING(hcd->state))
+                qh_link_async(ehci, qh);
+        spin_unlock_irqrestore(&ehci->lock, flags);
+}
+
+static void ehci_clear_tt_buffer(struct ehci_hcd *ehci, struct ehci_qh *qh,
+                struct urb *urb, u32 token)
+{
+
+        /* If an async split transaction gets an error or is unlinked,
+         * the TT buffer may be left in an indeterminate state.  We
+         * have to clear the TT buffer.
+         *
+         * Note: this routine is never called for Isochronous transfers.
+         */
+        if (urb->dev->tt && !usb_pipeint(urb->pipe) && !qh->clearing_tt) {
+#ifdef DEBUG
+                struct usb_device *tt = urb->dev->tt->hub;
+                dev_dbg(&tt->dev,
+                        "clear tt buffer port %d, a%d ep%d t%08x\n",
+                        urb->dev->ttport, urb->dev->devnum,
+                        usb_pipeendpoint(urb->pipe), token);
+#endif /* DEBUG */
+                if (!ehci_is_TDI(ehci)
+                                || urb->dev->tt->hub !=
+                                   ehci_to_hcd(ehci)->self.root_hub) {
+                        if (usb_hub_clear_tt_buffer(urb) == 0)
+                                qh->clearing_tt = 1;
+                } else {
+
+                        /* REVISIT ARC-derived cores don't clear the root
+                         * hub TT buffer in this way...
+                         */
+                }
+        }
+}
+
 static int qtd_copy_status (
         struct ehci_hcd *ehci,
         struct urb *urb,
@@ -195,28 +244,6 @@ static int qtd_copy_status (
                         usb_pipeendpoint (urb->pipe),
                         usb_pipein (urb->pipe) ? "in" : "out",
                         token, status);
-
-                /* if async CSPLIT failed, try cleaning out the TT buffer */
-                if (status != -EPIPE
-                                && urb->dev->tt
-                                && !usb_pipeint(urb->pipe)
-                                && ((token & QTD_STS_MMF) != 0
-                                        || QTD_CERR(token) == 0)
-                                && (!ehci_is_TDI(ehci)
-                                        || urb->dev->tt->hub !=
-                                           ehci_to_hcd(ehci)->self.root_hub)) {
-#ifdef DEBUG
-                        struct usb_device *tt = urb->dev->tt->hub;
-                        dev_dbg (&tt->dev,
-                                "clear tt buffer port %d, a%d ep%d t%08x\n",
-                                urb->dev->ttport, urb->dev->devnum,
-                                usb_pipeendpoint (urb->pipe), token);
-#endif /* DEBUG */
-                        /* REVISIT ARC-derived cores don't clear the root
-                         * hub TT buffer in this way...
-                         */
-                        usb_hub_clear_tt_buffer(urb);
-                }
         }
 
         return status;
@@ -407,9 +434,16 @@ qh_completions (struct ehci_hcd *ehci, struct ehci_qh *qh)
                         /* qh unlinked; token in overlay may be most current */
                         if (state == QH_STATE_IDLE
                                         && cpu_to_hc32(ehci, qtd->qtd_dma)
-                                                == qh->hw_current)
+                                                == qh->hw_current) {
                                 token = hc32_to_cpu(ehci, qh->hw_token);
 
+                                /* An unlink may leave an incomplete
+                                 * async transaction in the TT buffer.
+                                 * We have to clear it.
+                                 */
+                                ehci_clear_tt_buffer(ehci, qh, urb, token);
+                        }
+
                         /* force halt for unlinked or blocked qh, so we'll
                          * patch the qh later and so that completions can't
                          * activate it while we "know" it's stopped.
@@ -435,6 +469,13 @@ halt:
                                         && (qtd->hw_alt_next
                                                 & EHCI_LIST_END(ehci)))
                                 last_status = -EINPROGRESS;
+
+                        /* As part of low/full-speed endpoint-halt processing
+                         * we must clear the TT buffer (11.17.5).
+                         */
+                        if (unlikely(last_status != -EINPROGRESS &&
+                                        last_status != -EREMOTEIO))
+                                ehci_clear_tt_buffer(ehci, qh, urb, token);
                 }
 
                 /* if we're removing something not at the queue head,
@@ -864,6 +905,10 @@ static void qh_link_async (struct ehci_hcd *ehci, struct ehci_qh *qh)
         __hc32          dma = QH_NEXT(ehci, qh->qh_dma);
         struct ehci_qh  *head;
 
+        /* Don't link a QH if there's a Clear-TT-Buffer pending */
+        if (unlikely(qh->clearing_tt))
+                return;
+
         /* (re)start the async schedule? */
         head = ehci->async;
         timer_action_done (ehci, TIMER_ASYNC_OFF);