Linux-2.6.12-rc2

[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / drivers / usb / host / uhci-q.c

/*
 * Universal Host Controller Interface driver for USB.
 *
 * Maintainer: Alan Stern <stern@rowland.harvard.edu>
 *
 * (C) Copyright 1999 Linus Torvalds
 * (C) Copyright 1999-2002 Johannes Erdfelt, johannes@erdfelt.com
 * (C) Copyright 1999 Randy Dunlap
 * (C) Copyright 1999 Georg Acher, acher@in.tum.de
 * (C) Copyright 1999 Deti Fliegl, deti@fliegl.de
 * (C) Copyright 1999 Thomas Sailer, sailer@ife.ee.ethz.ch
 * (C) Copyright 1999 Roman Weissgaerber, weissg@vienna.at
 * (C) Copyright 2000 Yggdrasil Computing, Inc. (port of new PCI interface
 *               support from usb-ohci.c by Adam Richter, adam@yggdrasil.com).
 * (C) Copyright 1999 Gregory P. Smith (from usb-ohci.c)
 * (C) Copyright 2004 Alan Stern, stern@rowland.harvard.edu
 */

static int uhci_urb_dequeue(struct usb_hcd *hcd, struct urb *urb);
static void uhci_unlink_generic(struct uhci_hcd *uhci, struct urb *urb);
static void uhci_remove_pending_urbps(struct uhci_hcd *uhci);
static void uhci_free_pending_qhs(struct uhci_hcd *uhci);
static void uhci_free_pending_tds(struct uhci_hcd *uhci);

/*
 * Technically, updating td->status here is a race, but it's not really a
 * problem. The worst that can happen is that we set the IOC bit again
 * generating a spurious interrupt. We could fix this by creating another
 * QH and leaving the IOC bit always set, but then we would have to play
 * games with the FSBR code to make sure we get the correct order in all
 * the cases. I don't think it's worth the effort
 */
static inline void uhci_set_next_interrupt(struct uhci_hcd *uhci)
{
        uhci->term_td->status |= cpu_to_le32(TD_CTRL_IOC); 
}

static inline void uhci_clear_next_interrupt(struct uhci_hcd *uhci)
{
        uhci->term_td->status &= ~cpu_to_le32(TD_CTRL_IOC);
}

static inline void uhci_moveto_complete(struct uhci_hcd *uhci, 
                                        struct urb_priv *urbp)
{
        list_move_tail(&urbp->urb_list, &uhci->complete_list);
}

static struct uhci_td *uhci_alloc_td(struct uhci_hcd *uhci, struct usb_device *dev)
{
        dma_addr_t dma_handle;
        struct uhci_td *td;

        td = dma_pool_alloc(uhci->td_pool, GFP_ATOMIC, &dma_handle);
        if (!td)
                return NULL;

        td->dma_handle = dma_handle;

        td->link = UHCI_PTR_TERM;
        td->buffer = 0;

        td->frame = -1;
        td->dev = dev;

        INIT_LIST_HEAD(&td->list);
        INIT_LIST_HEAD(&td->remove_list);
        INIT_LIST_HEAD(&td->fl_list);

        usb_get_dev(dev);

        return td;
}

static inline void uhci_fill_td(struct uhci_td *td, u32 status,
                u32 token, u32 buffer)
{
        td->status = cpu_to_le32(status);
        td->token = cpu_to_le32(token);
        td->buffer = cpu_to_le32(buffer);
}

/*
 * We insert Isochronous URB's directly into the frame list at the beginning
 */
static void uhci_insert_td_frame_list(struct uhci_hcd *uhci, struct uhci_td *td, unsigned framenum)
{
        framenum &= (UHCI_NUMFRAMES - 1);

        td->frame = framenum;

        /* Is there a TD already mapped there? */
        if (uhci->fl->frame_cpu[framenum]) {
                struct uhci_td *ftd, *ltd;

                ftd = uhci->fl->frame_cpu[framenum];
                ltd = list_entry(ftd->fl_list.prev, struct uhci_td, fl_list);

                list_add_tail(&td->fl_list, &ftd->fl_list);

                td->link = ltd->link;
                wmb();
                ltd->link = cpu_to_le32(td->dma_handle);
        } else {
                td->link = uhci->fl->frame[framenum];
                wmb();
                uhci->fl->frame[framenum] = cpu_to_le32(td->dma_handle);
                uhci->fl->frame_cpu[framenum] = td;
        }
}

static void uhci_remove_td(struct uhci_hcd *uhci, struct uhci_td *td)
{
        /* If it's not inserted, don't remove it */
        if (td->frame == -1 && list_empty(&td->fl_list))
                return;

        if (td->frame != -1 && uhci->fl->frame_cpu[td->frame] == td) {
                if (list_empty(&td->fl_list)) {
                        uhci->fl->frame[td->frame] = td->link;
                        uhci->fl->frame_cpu[td->frame] = NULL;
                } else {
                        struct uhci_td *ntd;

                        ntd = list_entry(td->fl_list.next, struct uhci_td, fl_list);
                        uhci->fl->frame[td->frame] = cpu_to_le32(ntd->dma_handle);
                        uhci->fl->frame_cpu[td->frame] = ntd;
                }
        } else {
                struct uhci_td *ptd;

                ptd = list_entry(td->fl_list.prev, struct uhci_td, fl_list);
                ptd->link = td->link;
        }

        wmb();
        td->link = UHCI_PTR_TERM;

        list_del_init(&td->fl_list);
        td->frame = -1;
}

/*
 * Inserts a td list into qh.
 */
static void uhci_insert_tds_in_qh(struct uhci_qh *qh, struct urb *urb, __le32 breadth)
{
        struct urb_priv *urbp = (struct urb_priv *)urb->hcpriv;
        struct uhci_td *td;
        __le32 *plink;

        /* Ordering isn't important here yet since the QH hasn't been */
        /* inserted into the schedule yet */
        plink = &qh->element;
        list_for_each_entry(td, &urbp->td_list, list) {
                *plink = cpu_to_le32(td->dma_handle) | breadth;
                plink = &td->link;
        }
        *plink = UHCI_PTR_TERM;
}

static void uhci_free_td(struct uhci_hcd *uhci, struct uhci_td *td)
{
        if (!list_empty(&td->list))
                dev_warn(uhci_dev(uhci), "td %p still in list!\n", td);
        if (!list_empty(&td->remove_list))
                dev_warn(uhci_dev(uhci), "td %p still in remove_list!\n", td);
        if (!list_empty(&td->fl_list))
                dev_warn(uhci_dev(uhci), "td %p still in fl_list!\n", td);

        if (td->dev)
                usb_put_dev(td->dev);

        dma_pool_free(uhci->td_pool, td, td->dma_handle);
}

static struct uhci_qh *uhci_alloc_qh(struct uhci_hcd *uhci, struct usb_device *dev)
{
        dma_addr_t dma_handle;
        struct uhci_qh *qh;

        qh = dma_pool_alloc(uhci->qh_pool, GFP_ATOMIC, &dma_handle);
        if (!qh)
                return NULL;

        qh->dma_handle = dma_handle;

        qh->element = UHCI_PTR_TERM;
        qh->link = UHCI_PTR_TERM;

        qh->dev = dev;
        qh->urbp = NULL;

        INIT_LIST_HEAD(&qh->list);
        INIT_LIST_HEAD(&qh->remove_list);

        usb_get_dev(dev);

        return qh;
}

static void uhci_free_qh(struct uhci_hcd *uhci, struct uhci_qh *qh)
{
        if (!list_empty(&qh->list))
                dev_warn(uhci_dev(uhci), "qh %p list not empty!\n", qh);
        if (!list_empty(&qh->remove_list))
                dev_warn(uhci_dev(uhci), "qh %p still in remove_list!\n", qh);

        if (qh->dev)
                usb_put_dev(qh->dev);

        dma_pool_free(uhci->qh_pool, qh, qh->dma_handle);
}

/*
 * Append this urb's qh after the last qh in skelqh->list
 *
 * Note that urb_priv.queue_list doesn't have a separate queue head;
 * it's a ring with every element "live".
 */
static void uhci_insert_qh(struct uhci_hcd *uhci, struct uhci_qh *skelqh, struct urb *urb)
{
        struct urb_priv *urbp = (struct urb_priv *)urb->hcpriv;
        struct urb_priv *turbp;
        struct uhci_qh *lqh;

        /* Grab the last QH */
        lqh = list_entry(skelqh->list.prev, struct uhci_qh, list);

        /* Point to the next skelqh */
        urbp->qh->link = lqh->link;
        wmb();                          /* Ordering is important */

        /*
         * Patch QHs for previous endpoint's queued URBs?  HC goes
         * here next, not to the next skelqh it now points to.
         *
         *    lqh --> td ... --> qh ... --> td --> qh ... --> td
         *     |                 |                 |
         *     v                 v                 v
         *     +<----------------+-----------------+
         *     v
         *    newqh --> td ... --> td
         *     |
         *     v
         *    ...
         *
         * The HC could see (and use!) any of these as we write them.
         */
        lqh->link = cpu_to_le32(urbp->qh->dma_handle) | UHCI_PTR_QH;
        if (lqh->urbp) {
                list_for_each_entry(turbp, &lqh->urbp->queue_list, queue_list)
                        turbp->qh->link = lqh->link;
        }

        list_add_tail(&urbp->qh->list, &skelqh->list);
}

/*
 * Start removal of QH from schedule; it finishes next frame.
 * TDs should be unlinked before this is called.
 */
static void uhci_remove_qh(struct uhci_hcd *uhci, struct uhci_qh *qh)
{
        struct uhci_qh *pqh;
        __le32 newlink;

        if (!qh)
                return;

        /*
         * Only go through the hoops if it's actually linked in
         */
        if (!list_empty(&qh->list)) {

                /* If our queue is nonempty, make the next URB the head */
                if (!list_empty(&qh->urbp->queue_list)) {
                        struct urb_priv *nurbp;

                        nurbp = list_entry(qh->urbp->queue_list.next,
                                        struct urb_priv, queue_list);
                        nurbp->queued = 0;
                        list_add(&nurbp->qh->list, &qh->list);
                        newlink = cpu_to_le32(nurbp->qh->dma_handle) | UHCI_PTR_QH;
                } else
                        newlink = qh->link;

                /* Fix up the previous QH's queue to link to either
                 * the new head of this queue or the start of the
                 * next endpoint's queue. */
                pqh = list_entry(qh->list.prev, struct uhci_qh, list);
                pqh->link = newlink;
                if (pqh->urbp) {
                        struct urb_priv *turbp;

                        list_for_each_entry(turbp, &pqh->urbp->queue_list,
                                        queue_list)
                                turbp->qh->link = newlink;
                }
                wmb();

                /* Leave qh->link in case the HC is on the QH now, it will */
                /* continue the rest of the schedule */
                qh->element = UHCI_PTR_TERM;

                list_del_init(&qh->list);
        }

        list_del_init(&qh->urbp->queue_list);
        qh->urbp = NULL;

        uhci_get_current_frame_number(uhci);
        if (uhci->frame_number + uhci->is_stopped != uhci->qh_remove_age) {
                uhci_free_pending_qhs(uhci);
                uhci->qh_remove_age = uhci->frame_number;
        }

        /* Check to see if the remove list is empty. Set the IOC bit */
        /* to force an interrupt so we can remove the QH */
        if (list_empty(&uhci->qh_remove_list))
                uhci_set_next_interrupt(uhci);

        list_add(&qh->remove_list, &uhci->qh_remove_list);
}

static int uhci_fixup_toggle(struct urb *urb, unsigned int toggle)
{
        struct urb_priv *urbp = (struct urb_priv *)urb->hcpriv;
        struct uhci_td *td;

        list_for_each_entry(td, &urbp->td_list, list) {
                if (toggle)
                        td->token |= cpu_to_le32(TD_TOKEN_TOGGLE);
                else
                        td->token &= ~cpu_to_le32(TD_TOKEN_TOGGLE);

                toggle ^= 1;
        }

        return toggle;
}

/* This function will append one URB's QH to another URB's QH. This is for */
/* queuing interrupt, control or bulk transfers */
static void uhci_append_queued_urb(struct uhci_hcd *uhci, struct urb *eurb, struct urb *urb)
{
        struct urb_priv *eurbp, *urbp, *furbp, *lurbp;
        struct uhci_td *lltd;

        eurbp = eurb->hcpriv;
        urbp = urb->hcpriv;

        /* Find the first URB in the queue */
        furbp = eurbp;
        if (eurbp->queued) {
                list_for_each_entry(furbp, &eurbp->queue_list, queue_list)
                        if (!furbp->queued)
                                break;
        }

        lurbp = list_entry(furbp->queue_list.prev, struct urb_priv, queue_list);

        lltd = list_entry(lurbp->td_list.prev, struct uhci_td, list);

        /* Control transfers always start with toggle 0 */
        if (!usb_pipecontrol(urb->pipe))
                usb_settoggle(urb->dev, usb_pipeendpoint(urb->pipe),
                                usb_pipeout(urb->pipe),
                                uhci_fixup_toggle(urb,
                                        uhci_toggle(td_token(lltd)) ^ 1));

        /* All qh's in the queue need to link to the next queue */
        urbp->qh->link = eurbp->qh->link;

        wmb();                  /* Make sure we flush everything */

        lltd->link = cpu_to_le32(urbp->qh->dma_handle) | UHCI_PTR_QH;

        list_add_tail(&urbp->queue_list, &furbp->queue_list);

        urbp->queued = 1;
}

static void uhci_delete_queued_urb(struct uhci_hcd *uhci, struct urb *urb)
{
        struct urb_priv *urbp, *nurbp, *purbp, *turbp;
        struct uhci_td *pltd;
        unsigned int toggle;

        urbp = urb->hcpriv;

        if (list_empty(&urbp->queue_list))
                return;

        nurbp = list_entry(urbp->queue_list.next, struct urb_priv, queue_list);

        /*
         * Fix up the toggle for the following URBs in the queue.
         * Only needed for bulk and interrupt: control and isochronous
         * endpoints don't propagate toggles between messages.
         */
        if (usb_pipebulk(urb->pipe) || usb_pipeint(urb->pipe)) {
                if (!urbp->queued)
                        /* We just set the toggle in uhci_unlink_generic */
                        toggle = usb_gettoggle(urb->dev,
                                        usb_pipeendpoint(urb->pipe),
                                        usb_pipeout(urb->pipe));
                else {
                        /* If we're in the middle of the queue, grab the */
                        /* toggle from the TD previous to us */
                        purbp = list_entry(urbp->queue_list.prev,
                                        struct urb_priv, queue_list);
                        pltd = list_entry(purbp->td_list.prev,
                                        struct uhci_td, list);
                        toggle = uhci_toggle(td_token(pltd)) ^ 1;
                }

                list_for_each_entry(turbp, &urbp->queue_list, queue_list) {
                        if (!turbp->queued)
                                break;
                        toggle = uhci_fixup_toggle(turbp->urb, toggle);
                }

                usb_settoggle(urb->dev, usb_pipeendpoint(urb->pipe),
                                usb_pipeout(urb->pipe), toggle);
        }

        if (urbp->queued) {
                /* We're somewhere in the middle (or end).  The case where
                 * we're at the head is handled in uhci_remove_qh(). */
                purbp = list_entry(urbp->queue_list.prev, struct urb_priv,
                                queue_list);

                pltd = list_entry(purbp->td_list.prev, struct uhci_td, list);
                if (nurbp->queued)
                        pltd->link = cpu_to_le32(nurbp->qh->dma_handle) | UHCI_PTR_QH;
                else
                        /* The next URB happens to be the beginning, so */
                        /*  we're the last, end the chain */
                        pltd->link = UHCI_PTR_TERM;
        }

        /* urbp->queue_list is handled in uhci_remove_qh() */
}

static struct urb_priv *uhci_alloc_urb_priv(struct uhci_hcd *uhci, struct urb *urb)
{
        struct urb_priv *urbp;

        urbp = kmem_cache_alloc(uhci_up_cachep, SLAB_ATOMIC);
        if (!urbp)
                return NULL;

        memset((void *)urbp, 0, sizeof(*urbp));

        urbp->inserttime = jiffies;
        urbp->fsbrtime = jiffies;
        urbp->urb = urb;
        
        INIT_LIST_HEAD(&urbp->td_list);
        INIT_LIST_HEAD(&urbp->queue_list);
        INIT_LIST_HEAD(&urbp->urb_list);

        list_add_tail(&urbp->urb_list, &uhci->urb_list);

        urb->hcpriv = urbp;

        return urbp;
}

static void uhci_add_td_to_urb(struct urb *urb, struct uhci_td *td)
{
        struct urb_priv *urbp = (struct urb_priv *)urb->hcpriv;

        td->urb = urb;

        list_add_tail(&td->list, &urbp->td_list);
}

static void uhci_remove_td_from_urb(struct uhci_td *td)
{
        if (list_empty(&td->list))
                return;

        list_del_init(&td->list);

        td->urb = NULL;
}

static void uhci_destroy_urb_priv(struct uhci_hcd *uhci, struct urb *urb)
{
        struct uhci_td *td, *tmp;
        struct urb_priv *urbp;

        urbp = (struct urb_priv *)urb->hcpriv;
        if (!urbp)
                return;

        if (!list_empty(&urbp->urb_list))
                dev_warn(uhci_dev(uhci), "urb %p still on uhci->urb_list "
                                "or uhci->remove_list!\n", urb);

        uhci_get_current_frame_number(uhci);
        if (uhci->frame_number + uhci->is_stopped != uhci->td_remove_age) {
                uhci_free_pending_tds(uhci);
                uhci->td_remove_age = uhci->frame_number;
        }

        /* Check to see if the remove list is empty. Set the IOC bit */
        /* to force an interrupt so we can remove the TD's*/
        if (list_empty(&uhci->td_remove_list))
                uhci_set_next_interrupt(uhci);

        list_for_each_entry_safe(td, tmp, &urbp->td_list, list) {
                uhci_remove_td_from_urb(td);
                uhci_remove_td(uhci, td);
                list_add(&td->remove_list, &uhci->td_remove_list);
        }

        urb->hcpriv = NULL;
        kmem_cache_free(uhci_up_cachep, urbp);
}

static void uhci_inc_fsbr(struct uhci_hcd *uhci, struct urb *urb)
{
        struct urb_priv *urbp = (struct urb_priv *)urb->hcpriv;

        if ((!(urb->transfer_flags & URB_NO_FSBR)) && !urbp->fsbr) {
                urbp->fsbr = 1;
                if (!uhci->fsbr++ && !uhci->fsbrtimeout)
                        uhci->skel_term_qh->link = cpu_to_le32(uhci->skel_fs_control_qh->dma_handle) | UHCI_PTR_QH;
        }
}

static void uhci_dec_fsbr(struct uhci_hcd *uhci, struct urb *urb)
{
        struct urb_priv *urbp = (struct urb_priv *)urb->hcpriv;

        if ((!(urb->transfer_flags & URB_NO_FSBR)) && urbp->fsbr) {
                urbp->fsbr = 0;
                if (!--uhci->fsbr)
                        uhci->fsbrtimeout = jiffies + FSBR_DELAY;
        }
}

/*
 * Map status to standard result codes
 *
 * <status> is (td_status(td) & 0xF60000), a.k.a.
 * uhci_status_bits(td_status(td)).
 * Note: <status> does not include the TD_CTRL_NAK bit.
 * <dir_out> is True for output TDs and False for input TDs.
 */
static int uhci_map_status(int status, int dir_out)
{
        if (!status)
                return 0;
        if (status & TD_CTRL_BITSTUFF)                  /* Bitstuff error */
                return -EPROTO;
        if (status & TD_CTRL_CRCTIMEO) {                /* CRC/Timeout */
                if (dir_out)
                        return -EPROTO;
                else
                        return -EILSEQ;
        }
        if (status & TD_CTRL_BABBLE)                    /* Babble */
                return -EOVERFLOW;
        if (status & TD_CTRL_DBUFERR)                   /* Buffer error */
                return -ENOSR;
        if (status & TD_CTRL_STALLED)                   /* Stalled */
                return -EPIPE;
        WARN_ON(status & TD_CTRL_ACTIVE);               /* Active */
        return 0;
}

/*
 * Control transfers
 */
static int uhci_submit_control(struct uhci_hcd *uhci, struct urb *urb, struct urb *eurb)
{
        struct urb_priv *urbp = (struct urb_priv *)urb->hcpriv;
        struct uhci_td *td;
        struct uhci_qh *qh, *skelqh;
        unsigned long destination, status;
        int maxsze = usb_maxpacket(urb->dev, urb->pipe, usb_pipeout(urb->pipe));
        int len = urb->transfer_buffer_length;
        dma_addr_t data = urb->transfer_dma;

        /* 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);
        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, urb->dev);
        if (!td)
                return -ENOMEM;

        uhci_add_td_to_urb(urb, td);
        uhci_fill_td(td, status, destination | uhci_explen(7),
                urb->setup_dma);

        /*
         * If direction is "send", change the packet ID from SETUP (0x2D)
         * to OUT (0xE1).  Else change it from SETUP to IN (0x69) and
         * set Short Packet Detect (SPD) for all data packets.
         */
        if (usb_pipeout(urb->pipe))
                destination ^= (USB_PID_SETUP ^ USB_PID_OUT);
        else {
                destination ^= (USB_PID_SETUP ^ USB_PID_IN);
                status |= TD_CTRL_SPD;
        }

        /*
         * Build the DATA TD's
         */
        while (len > 0) {
                int pktsze = len;

                if (pktsze > maxsze)
                        pktsze = maxsze;

                td = uhci_alloc_td(uhci, urb->dev);
                if (!td)
                        return -ENOMEM;

                /* Alternate Data0/1 (start with Data1) */
                destination ^= TD_TOKEN_TOGGLE;
        
                uhci_add_td_to_urb(urb, td);
                uhci_fill_td(td, status, destination | uhci_explen(pktsze - 1),
                        data);

                data += pktsze;
                len -= pktsze;
        }

        /*
         * Build the final TD for control status 
         */
        td = uhci_alloc_td(uhci, urb->dev);
        if (!td)
                return -ENOMEM;

        /*
         * It's IN if the pipe is an output pipe or we're not expecting
         * data back.
         */
        destination &= ~TD_TOKEN_PID_MASK;
        if (usb_pipeout(urb->pipe) || !urb->transfer_buffer_length)
                destination |= USB_PID_IN;
        else
                destination |= USB_PID_OUT;

        destination |= TD_TOKEN_TOGGLE;         /* End in Data1 */

        status &= ~TD_CTRL_SPD;

        uhci_add_td_to_urb(urb, td);
        uhci_fill_td(td, status | TD_CTRL_IOC,
                destination | uhci_explen(UHCI_NULL_DATA_SIZE), 0);

        qh = uhci_alloc_qh(uhci, urb->dev);
        if (!qh)
                return -ENOMEM;

        urbp->qh = qh;
        qh->urbp = urbp;

        uhci_insert_tds_in_qh(qh, urb, UHCI_PTR_BREADTH);

        /* Low-speed transfers get a different queue, and won't hog the bus.
         * Also, some devices enumerate better without FSBR; the easiest way
         * to do that is to put URBs on the low-speed queue while the device
         * is in the DEFAULT state. */
        if (urb->dev->speed == USB_SPEED_LOW ||
                        urb->dev->state == USB_STATE_DEFAULT)
                skelqh = uhci->skel_ls_control_qh;
        else {
                skelqh = uhci->skel_fs_control_qh;
                uhci_inc_fsbr(uhci, urb);
        }

        if (eurb)
                uhci_append_queued_urb(uhci, eurb, urb);
        else
                uhci_insert_qh(uhci, skelqh, urb);

        return -EINPROGRESS;
}

/*
 * If control-IN transfer was short, the status packet wasn't sent.
 * This routine changes the element pointer in the QH to point at the
 * status TD.  It's safe to do this even while the QH is live, because
 * the hardware only updates the element pointer following a successful
 * transfer.  The inactive TD for the short packet won't cause an update,
 * so the pointer won't get overwritten.  The next time the controller
 * sees this QH, it will send the status packet.
 */
static int usb_control_retrigger_status(struct uhci_hcd *uhci, struct urb *urb)
{
        struct urb_priv *urbp = (struct urb_priv *)urb->hcpriv;
        struct uhci_td *td;

        urbp->short_control_packet = 1;

        td = list_entry(urbp->td_list.prev, struct uhci_td, list);
        urbp->qh->element = cpu_to_le32(td->dma_handle);

        return -EINPROGRESS;
}


static int uhci_result_control(struct uhci_hcd *uhci, struct urb *urb)
{
        struct list_head *tmp, *head;
        struct urb_priv *urbp = urb->hcpriv;
        struct uhci_td *td;
        unsigned int status;
        int ret = 0;

        if (list_empty(&urbp->td_list))
                return -EINVAL;

        head = &urbp->td_list;

        if (urbp->short_control_packet) {
                tmp = head->prev;
                goto status_stage;
        }

        tmp = head->next;
        td = list_entry(tmp, struct uhci_td, list);

        /* The first TD is the SETUP stage, check the status, but skip */
        /*  the count */
        status = uhci_status_bits(td_status(td));
        if (status & TD_CTRL_ACTIVE)
                return -EINPROGRESS;

        if (status)
                goto td_error;

        urb->actual_length = 0;

        /* The rest of the TD's (but the last) are data */
        tmp = tmp->next;
        while (tmp != head && tmp->next != head) {
                unsigned int ctrlstat;

                td = list_entry(tmp, struct uhci_td, list);
                tmp = tmp->next;

                ctrlstat = td_status(td);
                status = uhci_status_bits(ctrlstat);
                if (status & TD_CTRL_ACTIVE)
                        return -EINPROGRESS;

                urb->actual_length += uhci_actual_length(ctrlstat);

                if (status)
                        goto td_error;

                /* Check to see if we received a short packet */
                if (uhci_actual_length(ctrlstat) <
                                uhci_expected_length(td_token(td))) {
                        if (urb->transfer_flags & URB_SHORT_NOT_OK) {
                                ret = -EREMOTEIO;
                                goto err;
                        }

                        if (uhci_packetid(td_token(td)) == USB_PID_IN)
                                return usb_control_retrigger_status(uhci, urb);
                        else
                                return 0;
                }
        }

status_stage:
        td = list_entry(tmp, struct uhci_td, list);

        /* Control status stage */
        status = td_status(td);

#ifdef I_HAVE_BUGGY_APC_BACKUPS
        /* APC BackUPS Pro kludge */
        /* It tries to send all of the descriptor instead of the amount */
        /*  we requested */
        if (status & TD_CTRL_IOC &&     /* IOC is masked out by uhci_status_bits */
            status & TD_CTRL_ACTIVE &&
            status & TD_CTRL_NAK)
                return 0;
#endif

        status = uhci_status_bits(status);
        if (status & TD_CTRL_ACTIVE)
                return -EINPROGRESS;

        if (status)
                goto td_error;

        return 0;

td_error:
        ret = uhci_map_status(status, uhci_packetout(td_token(td)));

err:
        if ((debug == 1 && ret != -EPIPE) || debug > 1) {
                /* Some debugging code */
                dev_dbg(uhci_dev(uhci), "%s: failed with status %x\n",
                                __FUNCTION__, status);

                if (errbuf) {
                        /* Print the chain for debugging purposes */
                        uhci_show_qh(urbp->qh, errbuf, ERRBUF_LEN, 0);

                        lprintk(errbuf);
                }
        }

        return ret;
}

/*
 * Common submit for bulk and interrupt
 */
static int uhci_submit_common(struct uhci_hcd *uhci, struct urb *urb, struct urb *eurb, struct uhci_qh *skelqh)
{
        struct uhci_td *td;
        struct uhci_qh *qh;
        unsigned long destination, status;
        int maxsze = usb_maxpacket(urb->dev, urb->pipe, usb_pipeout(urb->pipe));
        int len = urb->transfer_buffer_length;
        struct urb_priv *urbp = (struct urb_priv *)urb->hcpriv;
        dma_addr_t data = urb->transfer_dma;

        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);

        status = uhci_maxerr(3) | TD_CTRL_ACTIVE;
        if (urb->dev->speed == USB_SPEED_LOW)
                status |= TD_CTRL_LS;
        if (usb_pipein(urb->pipe))
                status |= TD_CTRL_SPD;

        /*
         * Build the DATA TD's
         */
        do {    /* Allow zero length packets */
                int pktsze = maxsze;

                if (pktsze >= len) {
                        pktsze = len;
                        if (!(urb->transfer_flags & URB_SHORT_NOT_OK))
                                status &= ~TD_CTRL_SPD;
                }

                td = uhci_alloc_td(uhci, urb->dev);
                if (!td)
                        return -ENOMEM;

                uhci_add_td_to_urb(urb, td);
                uhci_fill_td(td, status, destination | uhci_explen(pktsze - 1) |
                        (usb_gettoggle(urb->dev, usb_pipeendpoint(urb->pipe),
                         usb_pipeout(urb->pipe)) << TD_TOKEN_TOGGLE_SHIFT),
                        data);

                data += pktsze;
                len -= maxsze;

                usb_dotoggle(urb->dev, usb_pipeendpoint(urb->pipe),
                        usb_pipeout(urb->pipe));
        } while (len > 0);

        /*
         * URB_ZERO_PACKET means adding a 0-length packet, if direction
         * is OUT and the transfer_length was an exact multiple of maxsze,
         * hence (len = transfer_length - N * maxsze) == 0
         * however, if transfer_length == 0, the zero packet was already
         * prepared above.
         */
        if (usb_pipeout(urb->pipe) && (urb->transfer_flags & URB_ZERO_PACKET) &&
            !len && urb->transfer_buffer_length) {
                td = uhci_alloc_td(uhci, urb->dev);
                if (!td)
                        return -ENOMEM;

                uhci_add_td_to_urb(urb, td);
                uhci_fill_td(td, status, destination | uhci_explen(UHCI_NULL_DATA_SIZE) |
                        (usb_gettoggle(urb->dev, usb_pipeendpoint(urb->pipe),
                         usb_pipeout(urb->pipe)) << TD_TOKEN_TOGGLE_SHIFT),
                        data);

                usb_dotoggle(urb->dev, usb_pipeendpoint(urb->pipe),
                        usb_pipeout(urb->pipe));
        }

        /* Set the interrupt-on-completion flag on the last packet.
         * A more-or-less typical 4 KB URB (= size of one memory page)
         * will require about 3 ms to transfer; that's a little on the
         * fast side but not enough to justify delaying an interrupt
         * more than 2 or 3 URBs, so we will ignore the URB_NO_INTERRUPT
         * flag setting. */
        td->status |= cpu_to_le32(TD_CTRL_IOC);

        qh = uhci_alloc_qh(uhci, urb->dev);
        if (!qh)
                return -ENOMEM;

        urbp->qh = qh;
        qh->urbp = urbp;

        /* Always breadth first */
        uhci_insert_tds_in_qh(qh, urb, UHCI_PTR_BREADTH);

        if (eurb)
                uhci_append_queued_urb(uhci, eurb, urb);
        else
                uhci_insert_qh(uhci, skelqh, urb);

        return -EINPROGRESS;
}

/*
 * Common result for bulk and interrupt
 */
static int uhci_result_common(struct uhci_hcd *uhci, struct urb *urb)
{
        struct urb_priv *urbp = urb->hcpriv;
        struct uhci_td *td;
        unsigned int status = 0;
        int ret = 0;

        urb->actual_length = 0;

        list_for_each_entry(td, &urbp->td_list, list) {
                unsigned int ctrlstat = td_status(td);

                status = uhci_status_bits(ctrlstat);
                if (status & TD_CTRL_ACTIVE)
                        return -EINPROGRESS;

                urb->actual_length += uhci_actual_length(ctrlstat);

                if (status)
                        goto td_error;

                if (uhci_actual_length(ctrlstat) <
                                uhci_expected_length(td_token(td))) {
                        if (urb->transfer_flags & URB_SHORT_NOT_OK) {
                                ret = -EREMOTEIO;
                                goto err;
                        } else
                                return 0;
                }
        }

        return 0;

td_error:
        ret = uhci_map_status(status, uhci_packetout(td_token(td)));

err:
        /* 
         * Enable this chunk of code if you want to see some more debugging.
         * But be careful, it has the tendancy to starve out khubd and prevent
         * disconnects from happening successfully if you have a slow debug
         * log interface (like a serial console.
         */
#if 0
        if ((debug == 1 && ret != -EPIPE) || debug > 1) {
                /* Some debugging code */
                dev_dbg(uhci_dev(uhci), "%s: failed with status %x\n",
                                __FUNCTION__, status);

                if (errbuf) {
                        /* Print the chain for debugging purposes */
                        uhci_show_qh(urbp->qh, errbuf, ERRBUF_LEN, 0);

                        lprintk(errbuf);
                }
        }
#endif
        return ret;
}

static inline int uhci_submit_bulk(struct uhci_hcd *uhci, struct urb *urb, struct urb *eurb)
{
        int ret;

        /* Can't have low-speed bulk transfers */
        if (urb->dev->speed == USB_SPEED_LOW)
                return -EINVAL;

        ret = uhci_submit_common(uhci, urb, eurb, uhci->skel_bulk_qh);
        if (ret == -EINPROGRESS)
                uhci_inc_fsbr(uhci, urb);

        return ret;
}

static inline int uhci_submit_interrupt(struct uhci_hcd *uhci, struct urb *urb, struct urb *eurb)
{
        /* USB 1.1 interrupt transfers only involve one packet per interval;
         * that's the uhci_submit_common() "breadth first" policy.  Drivers
         * can submit urbs of any length, but longer ones might need many
         * intervals to complete.
         */
        return uhci_submit_common(uhci, urb, eurb, uhci->skelqh[__interval_to_skel(urb->interval)]);
}

/*
 * Isochronous transfers
 */
static int isochronous_find_limits(struct uhci_hcd *uhci, struct urb *urb, unsigned int *start, unsigned int *end)
{
        struct urb *last_urb = NULL;
        struct urb_priv *up;
        int ret = 0;

        list_for_each_entry(up, &uhci->urb_list, urb_list) {
                struct urb *u = up->urb;

                /* look for pending URB's with identical pipe handle */
                if ((urb->pipe == u->pipe) && (urb->dev == u->dev) &&
                    (u->status == -EINPROGRESS) && (u != urb)) {
                        if (!last_urb)
                                *start = u->start_frame;
                        last_urb = u;
                }
        }

        if (last_urb) {
                *end = (last_urb->start_frame + last_urb->number_of_packets *
                                last_urb->interval) & (UHCI_NUMFRAMES-1);
                ret = 0;
        } else
                ret = -1;       /* no previous urb found */

        return ret;
}

static int isochronous_find_start(struct uhci_hcd *uhci, struct urb *urb)
{
        int limits;
        unsigned int start = 0, end = 0;

        if (urb->number_of_packets > 900)       /* 900? Why? */
                return -EFBIG;

        limits = isochronous_find_limits(uhci, urb, &start, &end);

        if (urb->transfer_flags & URB_ISO_ASAP) {
                if (limits) {
                        uhci_get_current_frame_number(uhci);
                        urb->start_frame = (uhci->frame_number + 10)
                                        & (UHCI_NUMFRAMES - 1);
                } else
                        urb->start_frame = end;
        } else {
                urb->start_frame &= (UHCI_NUMFRAMES - 1);
                /* FIXME: Sanity check */
        }

        return 0;
}

/*
 * Isochronous transfers
 */
static int uhci_submit_isochronous(struct uhci_hcd *uhci, struct urb *urb)
{
        struct uhci_td *td;
        int i, ret, frame;
        int status, destination;

        status = TD_CTRL_ACTIVE | TD_CTRL_IOS;
        destination = (urb->pipe & PIPE_DEVEP_MASK) | usb_packetid(urb->pipe);

        ret = isochronous_find_start(uhci, urb);
        if (ret)
                return ret;

        frame = urb->start_frame;
        for (i = 0; i < urb->number_of_packets; i++, frame += urb->interval) {
                if (!urb->iso_frame_desc[i].length)
                        continue;

                td = uhci_alloc_td(uhci, urb->dev);
                if (!td)
                        return -ENOMEM;

                uhci_add_td_to_urb(urb, td);
                uhci_fill_td(td, status, destination | uhci_explen(urb->iso_frame_desc[i].length - 1),
                        urb->transfer_dma + urb->iso_frame_desc[i].offset);

                if (i + 1 >= urb->number_of_packets)
                        td->status |= cpu_to_le32(TD_CTRL_IOC);

                uhci_insert_td_frame_list(uhci, td, frame);
        }

        return -EINPROGRESS;
}

static int uhci_result_isochronous(struct uhci_hcd *uhci, struct urb *urb)
{
        struct uhci_td *td;
        struct urb_priv *urbp = (struct urb_priv *)urb->hcpriv;
        int status;
        int i, ret = 0;

        urb->actual_length = 0;

        i = 0;
        list_for_each_entry(td, &urbp->td_list, list) {
                int actlength;
                unsigned int ctrlstat = td_status(td);

                if (ctrlstat & TD_CTRL_ACTIVE)
                        return -EINPROGRESS;

                actlength = uhci_actual_length(ctrlstat);
                urb->iso_frame_desc[i].actual_length = actlength;
                urb->actual_length += actlength;

                status = uhci_map_status(uhci_status_bits(ctrlstat),
                                usb_pipeout(urb->pipe));
                urb->iso_frame_desc[i].status = status;
                if (status) {
                        urb->error_count++;
                        ret = status;
                }

                i++;
        }

        return ret;
}

static struct urb *uhci_find_urb_ep(struct uhci_hcd *uhci, struct urb *urb)
{
        struct urb_priv *up;

        /* We don't match Isoc transfers since they are special */
        if (usb_pipeisoc(urb->pipe))
                return NULL;

        list_for_each_entry(up, &uhci->urb_list, urb_list) {
                struct urb *u = up->urb;

                if (u->dev == urb->dev && u->status == -EINPROGRESS) {
                        /* For control, ignore the direction */
                        if (usb_pipecontrol(urb->pipe) &&
                            (u->pipe & ~USB_DIR_IN) == (urb->pipe & ~USB_DIR_IN))
                                return u;
                        else if (u->pipe == urb->pipe)
                                return u;
                }
        }

        return NULL;
}

static int uhci_urb_enqueue(struct usb_hcd *hcd,
                struct usb_host_endpoint *ep,
                struct urb *urb, int mem_flags)
{
        int ret;
        struct uhci_hcd *uhci = hcd_to_uhci(hcd);
        unsigned long flags;
        struct urb *eurb;
        int bustime;

        spin_lock_irqsave(&uhci->lock, flags);

        ret = urb->status;
        if (ret != -EINPROGRESS)                /* URB already unlinked! */
                goto out;

        eurb = uhci_find_urb_ep(uhci, urb);

        if (!uhci_alloc_urb_priv(uhci, urb)) {
                ret = -ENOMEM;
                goto out;
        }

        switch (usb_pipetype(urb->pipe)) {
        case PIPE_CONTROL:
                ret = uhci_submit_control(uhci, urb, eurb);
                break;
        case PIPE_INTERRUPT:
                if (!eurb) {
                        bustime = usb_check_bandwidth(urb->dev, urb);
                        if (bustime < 0)
                                ret = bustime;
                        else {
                                ret = uhci_submit_interrupt(uhci, urb, eurb);
                                if (ret == -EINPROGRESS)
                                        usb_claim_bandwidth(urb->dev, urb, bustime, 0);
                        }
                } else {        /* inherit from parent */
                        urb->bandwidth = eurb->bandwidth;
                        ret = uhci_submit_interrupt(uhci, urb, eurb);
                }
                break;
        case PIPE_BULK:
                ret = uhci_submit_bulk(uhci, urb, eurb);
                break;
        case PIPE_ISOCHRONOUS:
                bustime = usb_check_bandwidth(urb->dev, urb);
                if (bustime < 0) {
                        ret = bustime;
                        break;
                }

                ret = uhci_submit_isochronous(uhci, urb);
                if (ret == -EINPROGRESS)
                        usb_claim_bandwidth(urb->dev, urb, bustime, 1);
                break;
        }

        if (ret != -EINPROGRESS) {
                /* Submit failed, so delete it from the urb_list */
                struct urb_priv *urbp = urb->hcpriv;

                list_del_init(&urbp->urb_list);
                uhci_destroy_urb_priv(uhci, urb);
        } else
                ret = 0;

out:
        spin_unlock_irqrestore(&uhci->lock, flags);
        return ret;
}

/*
 * Return the result of a transfer
 */
static void uhci_transfer_result(struct uhci_hcd *uhci, struct urb *urb)
{
        int ret = -EINPROGRESS;
        struct urb_priv *urbp;

        spin_lock(&urb->lock);

        urbp = (struct urb_priv *)urb->hcpriv;

        if (urb->status != -EINPROGRESS)        /* URB already dequeued */
                goto out;

        switch (usb_pipetype(urb->pipe)) {
        case PIPE_CONTROL:
                ret = uhci_result_control(uhci, urb);
                break;
        case PIPE_BULK:
        case PIPE_INTERRUPT:
                ret = uhci_result_common(uhci, urb);
                break;
        case PIPE_ISOCHRONOUS:
                ret = uhci_result_isochronous(uhci, urb);
                break;
        }

        if (ret == -EINPROGRESS)
                goto out;
        urb->status = ret;

        switch (usb_pipetype(urb->pipe)) {
        case PIPE_CONTROL:
        case PIPE_BULK:
        case PIPE_ISOCHRONOUS:
                /* Release bandwidth for Interrupt or Isoc. transfers */
                if (urb->bandwidth)
                        usb_release_bandwidth(urb->dev, urb, 1);
                uhci_unlink_generic(uhci, urb);
                break;
        case PIPE_INTERRUPT:
                /* Release bandwidth for Interrupt or Isoc. transfers */
                /* Make sure we don't release if we have a queued URB */
                if (list_empty(&urbp->queue_list) && urb->bandwidth)
                        usb_release_bandwidth(urb->dev, urb, 0);
                else
                        /* bandwidth was passed on to queued URB, */
                        /* so don't let usb_unlink_urb() release it */
                        urb->bandwidth = 0;
                uhci_unlink_generic(uhci, urb);
                break;
        default:
                dev_info(uhci_dev(uhci), "%s: unknown pipe type %d "
                                "for urb %p\n",
                                __FUNCTION__, usb_pipetype(urb->pipe), urb);
        }

        /* Move it from uhci->urb_list to uhci->complete_list */
        uhci_moveto_complete(uhci, urbp);

out:
        spin_unlock(&urb->lock);
}

static void uhci_unlink_generic(struct uhci_hcd *uhci, struct urb *urb)
{
        struct list_head *head;
        struct uhci_td *td;
        struct urb_priv *urbp = (struct urb_priv *)urb->hcpriv;
        int prevactive = 0;

        uhci_dec_fsbr(uhci, urb);       /* Safe since it checks */

        /*
         * Now we need to find out what the last successful toggle was
         * so we can update the local data toggle for the next transfer
         *
         * There are 2 ways the last successful completed TD is found:
         *
         * 1) The TD is NOT active and the actual length < expected length
         * 2) The TD is NOT active and it's the last TD in the chain
         *
         * and a third way the first uncompleted TD is found:
         *
         * 3) The TD is active and the previous TD is NOT active
         *
         * Control and Isochronous ignore the toggle, so this is safe
         * for all types
         *
         * FIXME: The toggle fixups won't be 100% reliable until we
         * change over to using a single queue for each endpoint and
         * stop the queue before unlinking.
         */
        head = &urbp->td_list;
        list_for_each_entry(td, head, list) {
                unsigned int ctrlstat = td_status(td);

                if (!(ctrlstat & TD_CTRL_ACTIVE) &&
                                (uhci_actual_length(ctrlstat) <
                                 uhci_expected_length(td_token(td)) ||
                                td->list.next == head))
                        usb_settoggle(urb->dev, uhci_endpoint(td_token(td)),
                                uhci_packetout(td_token(td)),
                                uhci_toggle(td_token(td)) ^ 1);
                else if ((ctrlstat & TD_CTRL_ACTIVE) && !prevactive)
                        usb_settoggle(urb->dev, uhci_endpoint(td_token(td)),
                                uhci_packetout(td_token(td)),
                                uhci_toggle(td_token(td)));

                prevactive = ctrlstat & TD_CTRL_ACTIVE;
        }

        uhci_delete_queued_urb(uhci, urb);

        /* The interrupt loop will reclaim the QH's */
        uhci_remove_qh(uhci, urbp->qh);
        urbp->qh = NULL;
}

static int uhci_urb_dequeue(struct usb_hcd *hcd, struct urb *urb)
{
        struct uhci_hcd *uhci = hcd_to_uhci(hcd);
        unsigned long flags;
        struct urb_priv *urbp;

        spin_lock_irqsave(&uhci->lock, flags);
        urbp = urb->hcpriv;
        if (!urbp)                      /* URB was never linked! */
                goto done;
        list_del_init(&urbp->urb_list);

        uhci_unlink_generic(uhci, urb);

        uhci_get_current_frame_number(uhci);
        if (uhci->frame_number + uhci->is_stopped != uhci->urb_remove_age) {
                uhci_remove_pending_urbps(uhci);
                uhci->urb_remove_age = uhci->frame_number;
        }

        /* If we're the first, set the next interrupt bit */
        if (list_empty(&uhci->urb_remove_list))
                uhci_set_next_interrupt(uhci);
        list_add_tail(&urbp->urb_list, &uhci->urb_remove_list);

done:
        spin_unlock_irqrestore(&uhci->lock, flags);
        return 0;
}

static int uhci_fsbr_timeout(struct uhci_hcd *uhci, struct urb *urb)
{
        struct urb_priv *urbp = (struct urb_priv *)urb->hcpriv;
        struct list_head *head;
        struct uhci_td *td;
        int count = 0;

        uhci_dec_fsbr(uhci, urb);

        urbp->fsbr_timeout = 1;

        /*
         * Ideally we would want to fix qh->element as well, but it's
         * read/write by the HC, so that can introduce a race. It's not
         * really worth the hassle
         */

        head = &urbp->td_list;
        list_for_each_entry(td, head, list) {
                /*
                 * Make sure we don't do the last one (since it'll have the
                 * TERM bit set) as well as we skip every so many TD's to
                 * make sure it doesn't hog the bandwidth
                 */
                if (td->list.next != head && (count % DEPTH_INTERVAL) ==
                                (DEPTH_INTERVAL - 1))
                        td->link |= UHCI_PTR_DEPTH;

                count++;
        }

        return 0;
}

static void uhci_free_pending_qhs(struct uhci_hcd *uhci)
{
        struct uhci_qh *qh, *tmp;

        list_for_each_entry_safe(qh, tmp, &uhci->qh_remove_list, remove_list) {
                list_del_init(&qh->remove_list);

                uhci_free_qh(uhci, qh);
        }
}

static void uhci_free_pending_tds(struct uhci_hcd *uhci)
{
        struct uhci_td *td, *tmp;

        list_for_each_entry_safe(td, tmp, &uhci->td_remove_list, remove_list) {
                list_del_init(&td->remove_list);

                uhci_free_td(uhci, td);
        }
}

static void
uhci_finish_urb(struct usb_hcd *hcd, struct urb *urb, struct pt_regs *regs)
__releases(uhci->lock)
__acquires(uhci->lock)
{
        struct uhci_hcd *uhci = hcd_to_uhci(hcd);

        uhci_destroy_urb_priv(uhci, urb);

        spin_unlock(&uhci->lock);
        usb_hcd_giveback_urb(hcd, urb, regs);
        spin_lock(&uhci->lock);
}

static void uhci_finish_completion(struct uhci_hcd *uhci, struct pt_regs *regs)
{
        struct urb_priv *urbp, *tmp;

        list_for_each_entry_safe(urbp, tmp, &uhci->complete_list, urb_list) {
                struct urb *urb = urbp->urb;

                list_del_init(&urbp->urb_list);
                uhci_finish_urb(uhci_to_hcd(uhci), urb, regs);
        }
}

static void uhci_remove_pending_urbps(struct uhci_hcd *uhci)
{

        /* Splice the urb_remove_list onto the end of the complete_list */
        list_splice_init(&uhci->urb_remove_list, uhci->complete_list.prev);
}

/* Process events in the schedule, but only in one thread at a time */
static void uhci_scan_schedule(struct uhci_hcd *uhci, struct pt_regs *regs)
{
        struct urb_priv *urbp, *tmp;

        /* Don't allow re-entrant calls */
        if (uhci->scan_in_progress) {
                uhci->need_rescan = 1;
                return;
        }
        uhci->scan_in_progress = 1;
 rescan:
        uhci->need_rescan = 0;

        uhci_get_current_frame_number(uhci);

        if (uhci->frame_number + uhci->is_stopped != uhci->qh_remove_age)
                uhci_free_pending_qhs(uhci);
        if (uhci->frame_number + uhci->is_stopped != uhci->td_remove_age)
                uhci_free_pending_tds(uhci);
        if (uhci->frame_number + uhci->is_stopped != uhci->urb_remove_age)
                uhci_remove_pending_urbps(uhci);

        /* Walk the list of pending URBs to see which ones completed
         * (must be _safe because uhci_transfer_result() dequeues URBs) */
        list_for_each_entry_safe(urbp, tmp, &uhci->urb_list, urb_list) {
                struct urb *urb = urbp->urb;

                /* Checks the status and does all of the magic necessary */
                uhci_transfer_result(uhci, urb);
        }
        uhci_finish_completion(uhci, regs);

        /* If the controller is stopped, we can finish these off right now */
        if (uhci->is_stopped) {
                uhci_free_pending_qhs(uhci);
                uhci_free_pending_tds(uhci);
                uhci_remove_pending_urbps(uhci);
        }

        if (uhci->need_rescan)
                goto rescan;
        uhci->scan_in_progress = 0;

        if (list_empty(&uhci->urb_remove_list) &&
            list_empty(&uhci->td_remove_list) &&
            list_empty(&uhci->qh_remove_list))
                uhci_clear_next_interrupt(uhci);
        else
                uhci_set_next_interrupt(uhci);

        /* Wake up anyone waiting for an URB to complete */
        wake_up_all(&uhci->waitqh);
}