USB: EHCI: update toggle state for linked QHs

This is an update to the "usb-ehci-update-toggle-state-for-linked-qhs"
patch.  Since an HCD's endpoint_reset method can be called in
interrupt context, it mustn't assume that interrupts are enabled or
that it can sleep.

So we revert to the original way of refreshing QHs' toggle bits.  Now
the endpoint_reset method merely clears the toggle flag in the device
structure (as was done before) and starts an async QH unlink.  When the
QH is linked again, after the unlink finishes and an URB is queued,
the qh_refresh() routine will update the QH's toggle bit.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Tested-by: David <david@unsolicited.net>
CC: David Brownell <david-b@pacbell.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

2 files changed, 34 insertions, 20 deletions

diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
index 2b72473544d3..99c75603ec87 100644
--- a/drivers/usb/host/ehci-hcd.c
+++ b/drivers/usb/host/ehci-hcd.c
@@ -1030,12 +1030,14 @@ ehci_endpoint_reset(struct usb_hcd *hcd, struct usb_host_endpoint *ep)
 	struct ehci_hcd		*ehci = hcd_to_ehci(hcd);
 	struct ehci_qh		*qh;
 	int			eptype = usb_endpoint_type(&ep->desc);
+	int			epnum = usb_endpoint_num(&ep->desc);
+	int			is_out = usb_endpoint_dir_out(&ep->desc);
+	unsigned long		flags;
 
 	if (eptype != USB_ENDPOINT_XFER_BULK && eptype != USB_ENDPOINT_XFER_INT)
 		return;
 
- rescan:
-	spin_lock_irq(&ehci->lock);
+	spin_lock_irqsave(&ehci->lock, flags);
 	qh = ep->hcpriv;
 
 	/* For Bulk and Interrupt endpoints we maintain the toggle state
@@ -1044,29 +1046,24 @@ ehci_endpoint_reset(struct usb_hcd *hcd, struct usb_host_endpoint *ep)
 	 * the toggle bit in the QH.
 	 */
 	if (qh) {
+		usb_settoggle(qh->dev, epnum, is_out, 0);
 		if (!list_empty(&qh->qtd_list)) {
 			WARN_ONCE(1, "clear_halt for a busy endpoint\n");
-		} else if (qh->qh_state == QH_STATE_IDLE) {
-			qh->hw_token &= ~cpu_to_hc32(ehci, QTD_TOGGLE);
-		} else {
-			/* It's not safe to write into the overlay area
-			 * while the QH is active.  Unlink it first and
-			 * wait for the unlink to complete.
+		} else if (qh->qh_state == QH_STATE_LINKED) {
+
+			/* The toggle value in the QH can't be updated
+			 * while the QH is active.  Unlink it now;
+			 * re-linking will call qh_refresh().
 			 */
-			if (qh->qh_state == QH_STATE_LINKED) {
-				if (eptype == USB_ENDPOINT_XFER_BULK) {
-					unlink_async(ehci, qh);
-				} else {
-					intr_deschedule(ehci, qh);
-					(void) qh_schedule(ehci, qh);
-				}
+			if (eptype == USB_ENDPOINT_XFER_BULK) {
+				unlink_async(ehci, qh);
+			} else {
+				intr_deschedule(ehci, qh);
+				(void) qh_schedule(ehci, qh);
 			}
-			spin_unlock_irq(&ehci->lock);
-			schedule_timeout_uninterruptible(1);
-			goto rescan;
 		}
 	}
-	spin_unlock_irq(&ehci->lock);
+	spin_unlock_irqrestore(&ehci->lock, flags);
 }
 
 static int ehci_get_frame (struct usb_hcd *hcd)
diff --git a/drivers/usb/host/ehci-q.c b/drivers/usb/host/ehci-q.c
index 3192f683f807..1976b1b3778c 100644
--- a/drivers/usb/host/ehci-q.c
+++ b/drivers/usb/host/ehci-q.c
@@ -93,6 +93,22 @@ qh_update (struct ehci_hcd *ehci, struct ehci_qh *qh, struct ehci_qtd *qtd)
 	qh->hw_qtd_next = QTD_NEXT(ehci, qtd->qtd_dma);
 	qh->hw_alt_next = EHCI_LIST_END(ehci);
 
+	/* Except for control endpoints, we make hardware maintain data
+	 * toggle (like OHCI) ... here (re)initialize the toggle in the QH,
+	 * and set the pseudo-toggle in udev. Only usb_clear_halt() will
+	 * ever clear it.
+	 */
+	if (!(qh->hw_info1 & cpu_to_hc32(ehci, 1 << 14))) {
+		unsigned	is_out, epnum;
+
+		is_out = !(qtd->hw_token & cpu_to_hc32(ehci, 1 << 8));
+		epnum = (hc32_to_cpup(ehci, &qh->hw_info1) >> 8) & 0x0f;
+		if (unlikely (!usb_gettoggle (qh->dev, epnum, is_out))) {
+			qh->hw_token &= ~cpu_to_hc32(ehci, QTD_TOGGLE);
+			usb_settoggle (qh->dev, epnum, is_out, 1);
+		}
+	}
+
 	/* HC must see latest qtd and qh data before we clear ACTIVE+HALT */
 	wmb ();
 	qh->hw_token &= cpu_to_hc32(ehci, QTD_TOGGLE | QTD_STS_PING);
@@ -834,6 +850,7 @@ done:
 	qh->qh_state = QH_STATE_IDLE;
 	qh->hw_info1 = cpu_to_hc32(ehci, info1);
 	qh->hw_info2 = cpu_to_hc32(ehci, info2);
+	usb_settoggle (urb->dev, usb_pipeendpoint (urb->pipe), !is_input, 1);
 	qh_refresh (ehci, qh);
 	return qh;
 }
@@ -864,7 +881,7 @@ static void qh_link_async (struct ehci_hcd *ehci, struct ehci_qh *qh)
 		}
 	}
 
-	/* clear halt and maybe recover from silicon quirk */
+	/* clear halt and/or toggle; and maybe recover from silicon quirk */
 	if (qh->qh_state == QH_STATE_IDLE)
 		qh_refresh (ehci, qh);