+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 (