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>

9 files changed, 53 insertions, 18 deletions

diff --git a/drivers/usb/host/ehci-au1xxx.c b/drivers/usb/host/ehci-au1xxx.c
index bf69f4739107..c3a778bd359c 100644
--- a/drivers/usb/host/ehci-au1xxx.c
+++ b/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
diff --git a/drivers/usb/host/ehci-fsl.c b/drivers/usb/host/ehci-fsl.c
index 01c3da34f678..bf86809c5120 100644
--- a/drivers/usb/host/ehci-fsl.c
+++ b/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
diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
index a2ca9cbf2809..2b72473544d3 100644
--- a/drivers/usb/host/ehci-hcd.c
+++ b/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);
diff --git a/drivers/usb/host/ehci-ixp4xx.c b/drivers/usb/host/ehci-ixp4xx.c
index 9c32063a0c2f..a44bb4a94954 100644
--- a/drivers/usb/host/ehci-ixp4xx.c
+++ b/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,
diff --git a/drivers/usb/host/ehci-orion.c b/drivers/usb/host/ehci-orion.c
index 17dc15407a07..770dd9aba62a 100644
--- a/drivers/usb/host/ehci-orion.c
+++ b/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
diff --git a/drivers/usb/host/ehci-pci.c b/drivers/usb/host/ehci-pci.c
index e74948898f76..f3683e1da161 100644
--- a/drivers/usb/host/ehci-pci.c
+++ b/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
diff --git a/drivers/usb/host/ehci-ppc-of.c b/drivers/usb/host/ehci-ppc-of.c
index ef732b704f53..fbd272288fc2 100644
--- a/drivers/usb/host/ehci-ppc-of.c
+++ b/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
diff --git a/drivers/usb/host/ehci-ps3.c b/drivers/usb/host/ehci-ps3.c
index 1ba9f9a8c308..4b4df23efddf 100644
--- a/drivers/usb/host/ehci-ps3.c
+++ b/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,
diff --git a/drivers/usb/host/ehci-q.c b/drivers/usb/host/ehci-q.c
index 1976b1b3778c..3192f683f807 100644
--- a/drivers/usb/host/ehci-q.c
+++ b/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);