USB: EHCI: update toggle state for linked QHs

This patch (as1245) fixes a bug in ehci-hcd.  When an URB is queued
for an endpoint whose QH is already in the LINKED state, the QH
doesn't get refreshed.  As a result, if usb_clear_halt() was called
during the time that the QH was linked but idle, the data toggle value
in the QH doesn't get reset.

The symptom is that after a clear_halt, data gets lost and transfers
time out.  This problem is starting to show up now because the
"ehci-hcd unlink speedups" patch causes QHs with no queued URBs to
remain linked for a suitable time.

The patch utilizes the new endpoint_reset mechanism to fix the
problem.  When an endpoint is reset, the new method forcibly unlinks
the QH (if necessary) and safely updates the toggle value.  This
allows qh_update() to be simplified and avoids using usb_device's
toggle bits in a rather unintuitive way.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: David Brownell <david-b@pacbell.net>
Tested-by: David <david@unsolicited.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/host/ehci-au1xxx.c

@@ -97,6 +97,7 @@ static const struct hc_driver ehci_au1xxx_hc_driver = {
 	.urb_enqueue		= ehci_urb_enqueue,
 	.urb_dequeue		= ehci_urb_dequeue,
 	.endpoint_disable	= ehci_endpoint_disable,
+	.endpoint_reset		= ehci_endpoint_reset,
 
 	/*
 	 * scheduling support

drivers/usb/host/ehci-fsl.c

@@ -309,6 +309,7 @@ static const struct hc_driver ehci_fsl_hc_driver = {
 	.urb_enqueue = ehci_urb_enqueue,
 	.urb_dequeue = ehci_urb_dequeue,
 	.endpoint_disable = ehci_endpoint_disable,
+	.endpoint_reset = ehci_endpoint_reset,
 
 	/*
 	 * scheduling support

drivers/usb/host/ehci-hcd.c

@@ -1024,6 +1024,51 @@ done:
 	return;
 }
 
+static void
+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);
+
+	if (eptype != USB_ENDPOINT_XFER_BULK && eptype != USB_ENDPOINT_XFER_INT)
+		return;
+
+ rescan:
+	spin_lock_irq(&ehci->lock);
+	qh = ep->hcpriv;
+
+	/* For Bulk and Interrupt endpoints we maintain the toggle state
+	 * in the hardware; the toggle bits in udev aren't used at all.
+	 * When an endpoint is reset by usb_clear_halt() we must reset
+	 * the toggle bit in the QH.
+	 */
+	if (qh) {
+		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.
+			 */
+			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);
+				}
+			}
+			spin_unlock_irq(&ehci->lock);
+			schedule_timeout_uninterruptible(1);
+			goto rescan;
+		}
+	}
+	spin_unlock_irq(&ehci->lock);
+}
+
 static int ehci_get_frame (struct usb_hcd *hcd)
 {
 	struct ehci_hcd		*ehci = hcd_to_ehci (hcd);

drivers/usb/host/ehci-ixp4xx.c

@@ -51,6 +51,7 @@ static const struct hc_driver ixp4xx_ehci_hc_driver = {
 	.urb_enqueue		= ehci_urb_enqueue,
 	.urb_dequeue		= ehci_urb_dequeue,
 	.endpoint_disable	= ehci_endpoint_disable,
+	.endpoint_reset		= ehci_endpoint_reset,
 	.get_frame_number	= ehci_get_frame,
 	.hub_status_data	= ehci_hub_status_data,
 	.hub_control		= ehci_hub_control,

drivers/usb/host/ehci-orion.c

@@ -149,6 +149,7 @@ static const struct hc_driver ehci_orion_hc_driver = {
 	.urb_enqueue = ehci_urb_enqueue,
 	.urb_dequeue = ehci_urb_dequeue,
 	.endpoint_disable = ehci_endpoint_disable,
+	.endpoint_reset = ehci_endpoint_reset,
 
 	/*
 	 * scheduling support

drivers/usb/host/ehci-pci.c

@@ -388,6 +388,7 @@ static const struct hc_driver ehci_pci_hc_driver = {
 	.urb_enqueue =		ehci_urb_enqueue,
 	.urb_dequeue =		ehci_urb_dequeue,
 	.endpoint_disable =	ehci_endpoint_disable,
+	.endpoint_reset =	ehci_endpoint_reset,
 
 	/*
 	 * scheduling support

drivers/usb/host/ehci-ppc-of.c

@@ -61,6 +61,7 @@ static const struct hc_driver ehci_ppc_of_hc_driver = {
 	.urb_enqueue		= ehci_urb_enqueue,
 	.urb_dequeue		= ehci_urb_dequeue,
 	.endpoint_disable	= ehci_endpoint_disable,
+	.endpoint_reset		= ehci_endpoint_reset,
 
 	/*
 	 * scheduling support

drivers/usb/host/ehci-ps3.c

@@ -65,6 +65,7 @@ static const struct hc_driver ps3_ehci_hc_driver = {
 	.urb_enqueue		= ehci_urb_enqueue,
 	.urb_dequeue		= ehci_urb_dequeue,
 	.endpoint_disable	= ehci_endpoint_disable,
+	.endpoint_reset		= ehci_endpoint_reset,
 	.get_frame_number	= ehci_get_frame,
 	.hub_status_data	= ehci_hub_status_data,
 	.hub_control		= ehci_hub_control,

drivers/usb/host/ehci-q.c

@@ -93,22 +93,6 @@ 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);
@@ -850,7 +834,6 @@ 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;
 }
@@ -881,7 +864,7 @@ static void qh_link_async (struct ehci_hcd *ehci, struct ehci_qh *qh)
 		}
 	}
 
-	/* clear halt and/or toggle; and maybe recover from silicon quirk */
+	/* clear halt and maybe recover from silicon quirk */
 	if (qh->qh_state == QH_STATE_IDLE)
 		qh_refresh (ehci, qh);