3 files changed, 83 insertions, 61 deletions

diff --git a/drivers/usb/host/uhci-debug.c b/drivers/usb/host/uhci-debug.c
index 3faccbd68547..6814783adf91 100644
--- a/drivers/usb/host/uhci-debug.c
+++ b/drivers/usb/host/uhci-debug.c
@@ -189,6 +189,11 @@ static int uhci_show_qh(struct uhci_qh *qh, char *buf, int len, int space)
                                         space, "", nurbs);
         }
 
+        if (qh->udev) {
+                out += sprintf(out, "%*s  Dummy TD\n", space, "");
+                out += uhci_show_td(qh->dummy_td, out, len - (out - buf), 0);
+        }
+
         return out - buf;
 }
 
diff --git a/drivers/usb/host/uhci-hcd.h b/drivers/usb/host/uhci-hcd.h
index 7a9481c09a05..c057956667b5 100644
--- a/drivers/usb/host/uhci-hcd.h
+++ b/drivers/usb/host/uhci-hcd.h
@@ -128,6 +128,7 @@ struct uhci_qh {
         struct usb_device *udev;
         struct list_head queue;         /* Queue of urbps for this QH */
         struct uhci_qh *skel;           /* Skeleton for this QH */
+        struct uhci_td *dummy_td;       /* Dummy TD to end the queue */
 
         unsigned int unlink_frame;      /* When the QH was unlinked */
         int state;                      /* QH_STATE_xxx; see above */
diff --git a/drivers/usb/host/uhci-q.c b/drivers/usb/host/uhci-q.c
index b1b551a3d14e..c4194182dcc4 100644
--- a/drivers/usb/host/uhci-q.c
+++ b/drivers/usb/host/uhci-q.c
@@ -48,10 +48,6 @@ static struct uhci_td *uhci_alloc_td(struct uhci_hcd *uhci)
                 return NULL;
 
         td->dma_handle = dma_handle;
-
-        td->link = UHCI_PTR_TERM;
-        td->buffer = 0;
-
         td->frame = -1;
 
         INIT_LIST_HEAD(&td->list);
@@ -221,6 +217,11 @@ static struct uhci_qh *uhci_alloc_qh(struct uhci_hcd *uhci,
         INIT_LIST_HEAD(&qh->node);
 
         if (udev) {             /* Normal QH */
+                qh->dummy_td = uhci_alloc_td(uhci);
+                if (!qh->dummy_td) {
+                        dma_pool_free(uhci->qh_pool, qh, dma_handle);
+                        return NULL;
+                }
                 qh->state = QH_STATE_IDLE;
                 qh->hep = hep;
                 qh->udev = udev;
@@ -244,6 +245,7 @@ static void uhci_free_qh(struct uhci_hcd *uhci, struct uhci_qh *qh)
         if (qh->udev) {
                 qh->hep->hcpriv = NULL;
                 usb_put_dev(qh->udev);
+                uhci_free_td(uhci, qh->dummy_td);
         }
         dma_pool_free(uhci->qh_pool, qh, qh->dma_handle);
 }
@@ -531,22 +533,20 @@ static int uhci_submit_control(struct uhci_hcd *uhci, struct urb *urb,
         /* The "pipe" thing contains the destination in bits 8--18 */
         destination = (urb->pipe & PIPE_DEVEP_MASK) | USB_PID_SETUP;
 
-        /* 3 errors */
-        status = TD_CTRL_ACTIVE | uhci_maxerr(3);
+        /* 3 errors, dummy TD remains inactive */
+        status = uhci_maxerr(3);
         if (urb->dev->speed == USB_SPEED_LOW)
                 status |= TD_CTRL_LS;
 
         /*
          * Build the TD for the control request setup packet
          */
-        td = uhci_alloc_td(uhci);
-        if (!td)
-                return -ENOMEM;
-
+        td = qh->dummy_td;
         uhci_add_td_to_urb(urb, td);
         uhci_fill_td(td, status, destination | uhci_explen(8),
                         urb->setup_dma);
         plink = &td->link;
+        status |= TD_CTRL_ACTIVE;
 
         /*
          * If direction is "send", change the packet ID from SETUP (0x2D)
@@ -568,7 +568,7 @@ static int uhci_submit_control(struct uhci_hcd *uhci, struct urb *urb,
 
                 td = uhci_alloc_td(uhci);
                 if (!td)
-                        return -ENOMEM;
+                        goto nomem;
                 *plink = cpu_to_le32(td->dma_handle);
 
                 /* Alternate Data0/1 (start with Data1) */
@@ -588,7 +588,7 @@ static int uhci_submit_control(struct uhci_hcd *uhci, struct urb *urb,
          */
         td = uhci_alloc_td(uhci);
         if (!td)
-                return -ENOMEM;
+                goto nomem;
         *plink = cpu_to_le32(td->dma_handle);
 
         /*
@@ -608,6 +608,20 @@ static int uhci_submit_control(struct uhci_hcd *uhci, struct urb *urb,
         uhci_add_td_to_urb(urb, td);
         uhci_fill_td(td, status | TD_CTRL_IOC,
                         destination | uhci_explen(0), 0);
+        plink = &td->link;
+
+        /*
+         * Build the new dummy TD and activate the old one
+         */
+        td = uhci_alloc_td(uhci);
+        if (!td)
+                goto nomem;
+        *plink = cpu_to_le32(td->dma_handle);
+
+        uhci_fill_td(td, 0, USB_PID_OUT | uhci_explen(0), 0);
+        wmb();
+        qh->dummy_td->status |= __constant_cpu_to_le32(TD_CTRL_ACTIVE);
+        qh->dummy_td = td;
 
         /* Low-speed transfers get a different queue, and won't hog the bus.
          * Also, some devices enumerate better without FSBR; the easiest way
@@ -620,8 +634,12 @@ static int uhci_submit_control(struct uhci_hcd *uhci, struct urb *urb,
                 qh->skel = uhci->skel_fs_control_qh;
                 uhci_inc_fsbr(uhci, urb);
         }
-
         return 0;
+
+nomem:
+        /* Remove the dummy TD from the td_list so it doesn't get freed */
+        uhci_remove_td_from_urb(qh->dummy_td);
+        return -ENOMEM;
 }
 
 /*
@@ -761,16 +779,19 @@ static int uhci_submit_common(struct uhci_hcd *uhci, struct urb *urb,
         int maxsze = le16_to_cpu(qh->hep->desc.wMaxPacketSize);
         int len = urb->transfer_buffer_length;
         dma_addr_t data = urb->transfer_dma;
-        __le32 *plink, fake_link;
+        __le32 *plink;
+        unsigned int toggle;
 
         if (len < 0)
                 return -EINVAL;
 
         /* The "pipe" thing contains the destination in bits 8--18 */
         destination = (urb->pipe & PIPE_DEVEP_MASK) | usb_packetid(urb->pipe);
+        toggle = usb_gettoggle(urb->dev, usb_pipeendpoint(urb->pipe),
+                         usb_pipeout(urb->pipe));
 
-        /* 3 errors */
-        status = TD_CTRL_ACTIVE | uhci_maxerr(3);
+        /* 3 errors, dummy TD remains inactive */
+        status = uhci_maxerr(3);
         if (urb->dev->speed == USB_SPEED_LOW)
                 status |= TD_CTRL_LS;
         if (usb_pipein(urb->pipe))
@@ -779,7 +800,8 @@ static int uhci_submit_common(struct uhci_hcd *uhci, struct urb *urb,
         /*
          * Build the DATA TDs
          */
-        plink = &fake_link;
+        plink = NULL;
+        td = qh->dummy_td;
         do {    /* Allow zero length packets */
                 int pktsze = maxsze;
 
@@ -789,24 +811,23 @@ static int uhci_submit_common(struct uhci_hcd *uhci, struct urb *urb,
                                 status &= ~TD_CTRL_SPD;
                 }
 
-                td = uhci_alloc_td(uhci);
-                if (!td)
-                        return -ENOMEM;
-                *plink = cpu_to_le32(td->dma_handle);
-
+                if (plink) {
+                        td = uhci_alloc_td(uhci);
+                        if (!td)
+                                goto nomem;
+                        *plink = cpu_to_le32(td->dma_handle);
+                }
                 uhci_add_td_to_urb(urb, td);
                 uhci_fill_td(td, status,
-                        destination | uhci_explen(pktsze) |
-                        (usb_gettoggle(urb->dev, usb_pipeendpoint(urb->pipe),
-                         usb_pipeout(urb->pipe)) << TD_TOKEN_TOGGLE_SHIFT),
-                        data);
+                                destination | uhci_explen(pktsze) |
+                                        (toggle << TD_TOKEN_TOGGLE_SHIFT),
+                                data);
                 plink = &td->link;
+                status |= TD_CTRL_ACTIVE;
 
                 data += pktsze;
                 len -= maxsze;
-
-                usb_dotoggle(urb->dev, usb_pipeendpoint(urb->pipe),
-                        usb_pipeout(urb->pipe));
+                toggle ^= 1;
         } while (len > 0);
 
         /*
@@ -821,17 +842,17 @@ static int uhci_submit_common(struct uhci_hcd *uhci, struct urb *urb,
                         urb->transfer_buffer_length > 0) {
                 td = uhci_alloc_td(uhci);
                 if (!td)
-                        return -ENOMEM;
+                        goto nomem;
                 *plink = cpu_to_le32(td->dma_handle);
 
                 uhci_add_td_to_urb(urb, td);
-                uhci_fill_td(td, status, destination | uhci_explen(0) |
-                        (usb_gettoggle(urb->dev, usb_pipeendpoint(urb->pipe),
-                         usb_pipeout(urb->pipe)) << TD_TOKEN_TOGGLE_SHIFT),
-                        data);
+                uhci_fill_td(td, status,
+                                destination | uhci_explen(0) |
+                                        (toggle << TD_TOKEN_TOGGLE_SHIFT),
+                                data);
+                plink = &td->link;
 
-                usb_dotoggle(urb->dev, usb_pipeendpoint(urb->pipe),
-                        usb_pipeout(urb->pipe));
+                toggle ^= 1;
         }
 
         /* Set the interrupt-on-completion flag on the last packet.
@@ -842,7 +863,27 @@ static int uhci_submit_common(struct uhci_hcd *uhci, struct urb *urb,
          * flag setting. */
         td->status |= __constant_cpu_to_le32(TD_CTRL_IOC);
 
+        /*
+         * Build the new dummy TD and activate the old one
+         */
+        td = uhci_alloc_td(uhci);
+        if (!td)
+                goto nomem;
+        *plink = cpu_to_le32(td->dma_handle);
+
+        uhci_fill_td(td, 0, USB_PID_OUT | uhci_explen(0), 0);
+        wmb();
+        qh->dummy_td->status |= __constant_cpu_to_le32(TD_CTRL_ACTIVE);
+        qh->dummy_td = td;
+
+        usb_settoggle(urb->dev, usb_pipeendpoint(urb->pipe),
+                        usb_pipeout(urb->pipe), toggle);
         return 0;
+
+nomem:
+        /* Remove the dummy TD from the td_list so it doesn't get freed */
+        uhci_remove_td_from_urb(qh->dummy_td);
+        return -ENOMEM;
 }
 
 /*
@@ -1169,31 +1210,6 @@ static int uhci_urb_enqueue(struct usb_hcd *hcd,
          * become idle, so we can activate it right away. */
         if (qh->queue.next == &urbp->node)
                 uhci_activate_qh(uhci, qh);
-
-        /* If the QH is already active, we have a race with the hardware.
-         * This won't get fixed until dummy TDs are added. */
-        else if (qh->state == QH_STATE_ACTIVE) {
-
-                /* If the URB isn't first on its queue, adjust the link pointer
-                 * of the last TD in the previous URB. */
-                if (urbp->node.prev != &urbp->qh->queue) {
-                        struct urb_priv *purbp = list_entry(urbp->node.prev,
-                                        struct urb_priv, node);
-                        struct uhci_td *ptd = list_entry(purbp->td_list.prev,
-                                        struct uhci_td, list);
-                        struct uhci_td *td = list_entry(urbp->td_list.next,
-                                        struct uhci_td, list);
-
-                        ptd->link = cpu_to_le32(td->dma_handle);
-
-                }
-                if (qh_element(qh) == UHCI_PTR_TERM) {
-                        struct uhci_td *td = list_entry(urbp->td_list.next,
-                                        struct uhci_td, list);
-
-                        qh->element = cpu_to_le32(td->dma_handle);
-                }
-        }
         goto done;
 
 err_submit_failed: