/*
   * 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 2004-2007 Alan Stern, stern@rowland.harvard.edu

   */

  
  /*
   * 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 void uhci_set_next_interrupt(struct uhci_hcd *uhci)

  {

  	if (uhci->is_stopped)

  		mod_timer(&uhci_to_hcd(uhci)->rh_timer, jiffies);

  	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);
  }

  
  /*
   * Full-Speed Bandwidth Reclamation (FSBR).
   * We turn on FSBR whenever a queue that wants it is advancing,
   * and leave it on for a short time thereafter.
   */
  static void uhci_fsbr_on(struct uhci_hcd *uhci)
  {

  	struct uhci_qh *lqh;

  	/* The terminating skeleton QH always points back to the first
  	 * FSBR QH.  Make the last async QH point to the terminating
  	 * skeleton QH. */

  	uhci->fsbr_is_on = 1;

  	lqh = list_entry(uhci->skel_async_qh->node.prev,
  			struct uhci_qh, node);

  	lqh->link = LINK_TO_QH(uhci->skel_term_qh);

  }
  
  static void uhci_fsbr_off(struct uhci_hcd *uhci)
  {

  	struct uhci_qh *lqh;

  	/* Remove the link from the last async QH to the terminating
  	 * skeleton QH. */

  	uhci->fsbr_is_on = 0;

  	lqh = list_entry(uhci->skel_async_qh->node.prev,
  			struct uhci_qh, node);

  	lqh->link = UHCI_PTR_TERM;

  }
  
  static void uhci_add_fsbr(struct uhci_hcd *uhci, struct urb *urb)
  {
  	struct urb_priv *urbp = urb->hcpriv;
  
  	if (!(urb->transfer_flags & URB_NO_FSBR))
  		urbp->fsbr = 1;
  }

  static void uhci_urbp_wants_fsbr(struct uhci_hcd *uhci, struct urb_priv *urbp)

  {

  	if (urbp->fsbr) {

  		uhci->fsbr_is_wanted = 1;

  		if (!uhci->fsbr_is_on)
  			uhci_fsbr_on(uhci);

  		else if (uhci->fsbr_expiring) {
  			uhci->fsbr_expiring = 0;
  			del_timer(&uhci->fsbr_timer);
  		}
  	}
  }
  
  static void uhci_fsbr_timeout(unsigned long _uhci)
  {
  	struct uhci_hcd *uhci = (struct uhci_hcd *) _uhci;
  	unsigned long flags;
  
  	spin_lock_irqsave(&uhci->lock, flags);
  	if (uhci->fsbr_expiring) {
  		uhci->fsbr_expiring = 0;
  		uhci_fsbr_off(uhci);

  	}

  	spin_unlock_irqrestore(&uhci->lock, flags);

  }

  static struct uhci_td *uhci_alloc_td(struct uhci_hcd *uhci)

  {
  	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->frame = -1;

  
  	INIT_LIST_HEAD(&td->list);

  	INIT_LIST_HEAD(&td->fl_list);

  	return td;
  }

  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!
  ", td);
  	if (!list_empty(&td->fl_list))
  		dev_WARN(uhci_dev(uhci), "td %p still in fl_list!
  ", td);

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

  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);
  }

  static void uhci_add_td_to_urbp(struct uhci_td *td, struct urb_priv *urbp)
  {
  	list_add_tail(&td->list, &urbp->td_list);
  }
  
  static void uhci_remove_td_from_urbp(struct uhci_td *td)
  {
  	list_del_init(&td->list);
  }

  /*

   * We insert Isochronous URBs directly into the frame list at the beginning

   */

  static inline void uhci_insert_td_in_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->frame_cpu[framenum]) {

  		struct uhci_td *ftd, *ltd;

  		ftd = uhci->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 = LINK_TO_TD(td);

  	} else {

  		td->link = uhci->frame[framenum];

  		wmb();

  		uhci->frame[framenum] = LINK_TO_TD(td);

  		uhci->frame_cpu[framenum] = td;

  	}
  }

  static inline void uhci_remove_td_from_frame_list(struct uhci_hcd *uhci,

  		struct uhci_td *td)

  {
  	/* If it's not inserted, don't remove it */

  	if (td->frame == -1) {
  		WARN_ON(!list_empty(&td->fl_list));

  		return;

  	}

  	if (uhci->frame_cpu[td->frame] == td) {

  		if (list_empty(&td->fl_list)) {

  			uhci->frame[td->frame] = td->link;
  			uhci->frame_cpu[td->frame] = NULL;

  		} else {
  			struct uhci_td *ntd;
  
  			ntd = list_entry(td->fl_list.next, struct uhci_td, fl_list);

  			uhci->frame[td->frame] = LINK_TO_TD(ntd);

  			uhci->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;
  	}

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

  static inline void uhci_remove_tds_from_frame(struct uhci_hcd *uhci,
  		unsigned int framenum)
  {
  	struct uhci_td *ftd, *ltd;
  
  	framenum &= (UHCI_NUMFRAMES - 1);
  
  	ftd = uhci->frame_cpu[framenum];
  	if (ftd) {
  		ltd = list_entry(ftd->fl_list.prev, struct uhci_td, fl_list);
  		uhci->frame[framenum] = ltd->link;
  		uhci->frame_cpu[framenum] = NULL;
  
  		while (!list_empty(&ftd->fl_list))
  			list_del_init(ftd->fl_list.prev);
  	}
  }

  /*
   * Remove all the TDs for an Isochronous URB from the frame list
   */
  static void uhci_unlink_isochronous_tds(struct uhci_hcd *uhci, struct urb *urb)

  {
  	struct urb_priv *urbp = (struct urb_priv *) urb->hcpriv;
  	struct uhci_td *td;
  
  	list_for_each_entry(td, &urbp->td_list, list)

  		uhci_remove_td_from_frame_list(uhci, td);

  }

  static struct uhci_qh *uhci_alloc_qh(struct uhci_hcd *uhci,
  		struct usb_device *udev, struct usb_host_endpoint *hep)

  {
  	dma_addr_t dma_handle;
  	struct uhci_qh *qh;
  
  	qh = dma_pool_alloc(uhci->qh_pool, GFP_ATOMIC, &dma_handle);
  	if (!qh)
  		return NULL;

  	memset(qh, 0, sizeof(*qh));

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

  	INIT_LIST_HEAD(&qh->queue);
  	INIT_LIST_HEAD(&qh->node);

  	if (udev) {		/* Normal QH */

  		qh->type = usb_endpoint_type(&hep->desc);

  		if (qh->type != USB_ENDPOINT_XFER_ISOC) {
  			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;
  		hep->hcpriv = qh;

  		if (qh->type == USB_ENDPOINT_XFER_INT ||
  				qh->type == USB_ENDPOINT_XFER_ISOC)
  			qh->load = usb_calc_bus_time(udev->speed,
  					usb_endpoint_dir_in(&hep->desc),
  					qh->type == USB_ENDPOINT_XFER_ISOC,
  					le16_to_cpu(hep->desc.wMaxPacketSize))
  				/ 1000 + 1;

  	} else {		/* Skeleton QH */
  		qh->state = QH_STATE_ACTIVE;

  		qh->type = -1;

  	}

  	return qh;
  }
  
  static void uhci_free_qh(struct uhci_hcd *uhci, struct uhci_qh *qh)
  {

  	WARN_ON(qh->state != QH_STATE_IDLE && qh->udev);

  	if (!list_empty(&qh->queue))
  		dev_WARN(uhci_dev(uhci), "qh %p list not empty!
  ", qh);

  	list_del(&qh->node);
  	if (qh->udev) {
  		qh->hep->hcpriv = NULL;

  		if (qh->dummy_td)
  			uhci_free_td(uhci, qh->dummy_td);

  	}

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

   * When a queue is stopped and a dequeued URB is given back, adjust
   * the previous TD link (if the URB isn't first on the queue) or
   * save its toggle value (if it is first and is currently executing).

   *
   * Returns 0 if the URB should not yet be given back, 1 otherwise.

   */

  static int uhci_cleanup_queue(struct uhci_hcd *uhci, struct uhci_qh *qh,

  		struct urb *urb)

  {

  	struct urb_priv *urbp = urb->hcpriv;

  	struct uhci_td *td;

  	int ret = 1;

  	/* Isochronous pipes don't use toggles and their TD link pointers

  	 * get adjusted during uhci_urb_dequeue().  But since their queues
  	 * cannot truly be stopped, we have to watch out for dequeues
  	 * occurring after the nominal unlink frame. */
  	if (qh->type == USB_ENDPOINT_XFER_ISOC) {
  		ret = (uhci->frame_number + uhci->is_stopped !=
  				qh->unlink_frame);

  		goto done;

  	}

  
  	/* If the URB isn't first on its queue, adjust the link pointer
  	 * of the last TD in the previous URB.  The toggle doesn't need
  	 * to be saved since this URB can't be executing yet. */
  	if (qh->queue.next != &urbp->node) {
  		struct urb_priv *purbp;
  		struct uhci_td *ptd;
  
  		purbp = list_entry(urbp->node.prev, struct urb_priv, node);
  		WARN_ON(list_empty(&purbp->td_list));
  		ptd = list_entry(purbp->td_list.prev, struct uhci_td,
  				list);
  		td = list_entry(urbp->td_list.prev, struct uhci_td,
  				list);
  		ptd->link = td->link;

  		goto done;

  	}

  	/* If the QH element pointer is UHCI_PTR_TERM then then currently
  	 * executing URB has already been unlinked, so this one isn't it. */

  	if (qh_element(qh) == UHCI_PTR_TERM)

  		goto done;

  	qh->element = UHCI_PTR_TERM;

  	/* Control pipes don't have to worry about toggles */

  	if (qh->type == USB_ENDPOINT_XFER_CONTROL)

  		goto done;

  	/* Save the next toggle value */

  	WARN_ON(list_empty(&urbp->td_list));
  	td = list_entry(urbp->td_list.next, struct uhci_td, list);
  	qh->needs_fixup = 1;
  	qh->initial_toggle = uhci_toggle(td_token(td));

  
  done:

  	return ret;

  }
  
  /*
   * Fix up the data toggles for URBs in a queue, when one of them
   * terminates early (short transfer, error, or dequeued).
   */
  static void uhci_fixup_toggles(struct uhci_qh *qh, int skip_first)
  {
  	struct urb_priv *urbp = NULL;
  	struct uhci_td *td;
  	unsigned int toggle = qh->initial_toggle;
  	unsigned int pipe;
  
  	/* Fixups for a short transfer start with the second URB in the
  	 * queue (the short URB is the first). */
  	if (skip_first)
  		urbp = list_entry(qh->queue.next, struct urb_priv, node);
  
  	/* When starting with the first URB, if the QH element pointer is
  	 * still valid then we know the URB's toggles are okay. */
  	else if (qh_element(qh) != UHCI_PTR_TERM)
  		toggle = 2;
  
  	/* Fix up the toggle for the URBs in the queue.  Normally this
  	 * loop won't run more than once: When an error or short transfer
  	 * occurs, the queue usually gets emptied. */

  	urbp = list_prepare_entry(urbp, &qh->queue, node);

  	list_for_each_entry_continue(urbp, &qh->queue, node) {
  
  		/* If the first TD has the right toggle value, we don't
  		 * need to change any toggles in this URB */
  		td = list_entry(urbp->td_list.next, struct uhci_td, list);
  		if (toggle > 1 || uhci_toggle(td_token(td)) == toggle) {

  			td = list_entry(urbp->td_list.prev, struct uhci_td,

  					list);
  			toggle = uhci_toggle(td_token(td)) ^ 1;
  
  		/* Otherwise all the toggles in the URB have to be switched */
  		} else {
  			list_for_each_entry(td, &urbp->td_list, list) {

  				td->token ^= cpu_to_le32(

  							TD_TOKEN_TOGGLE);
  				toggle ^= 1;
  			}
  		}
  	}
  
  	wmb();
  	pipe = list_entry(qh->queue.next, struct urb_priv, node)->urb->pipe;
  	usb_settoggle(qh->udev, usb_pipeendpoint(pipe),
  			usb_pipeout(pipe), toggle);
  	qh->needs_fixup = 0;
  }
  
  /*

   * Link an Isochronous QH into its skeleton's list

   */

  static inline void link_iso(struct uhci_hcd *uhci, struct uhci_qh *qh)
  {
  	list_add_tail(&qh->node, &uhci->skel_iso_qh->node);
  
  	/* Isochronous QHs aren't linked by the hardware */
  }
  
  /*
   * Link a high-period interrupt QH into the schedule at the end of its
   * skeleton's list
   */
  static void link_interrupt(struct uhci_hcd *uhci, struct uhci_qh *qh)

  {

  	struct uhci_qh *pqh;

  	list_add_tail(&qh->node, &uhci->skelqh[qh->skel]->node);
  
  	pqh = list_entry(qh->node.prev, struct uhci_qh, node);
  	qh->link = pqh->link;
  	wmb();
  	pqh->link = LINK_TO_QH(qh);
  }
  
  /*
   * Link a period-1 interrupt or async QH into the schedule at the
   * correct spot in the async skeleton's list, and update the FSBR link
   */
  static void link_async(struct uhci_hcd *uhci, struct uhci_qh *qh)
  {

  	struct uhci_qh *pqh;

  	__le32 link_to_new_qh;

  
  	/* Find the predecessor QH for our new one and insert it in the list.
  	 * The list of QHs is expected to be short, so linear search won't
  	 * take too long. */
  	list_for_each_entry_reverse(pqh, &uhci->skel_async_qh->node, node) {
  		if (pqh->skel <= qh->skel)
  			break;
  	}
  	list_add(&qh->node, &pqh->node);

  
  	/* Link it into the schedule */

  	qh->link = pqh->link;

  	wmb();

  	link_to_new_qh = LINK_TO_QH(qh);
  	pqh->link = link_to_new_qh;
  
  	/* If this is now the first FSBR QH, link the terminating skeleton
  	 * QH to it. */
  	if (pqh->skel < SKEL_FSBR && qh->skel >= SKEL_FSBR)
  		uhci->skel_term_qh->link = link_to_new_qh;

  }
  
  /*
   * Put a QH on the schedule in both hardware and software
   */
  static void uhci_activate_qh(struct uhci_hcd *uhci, struct uhci_qh *qh)
  {

  	WARN_ON(list_empty(&qh->queue));

  	/* Set the element pointer if it isn't set already.
  	 * This isn't needed for Isochronous queues, but it doesn't hurt. */
  	if (qh_element(qh) == UHCI_PTR_TERM) {
  		struct urb_priv *urbp = list_entry(qh->queue.next,
  				struct urb_priv, node);
  		struct uhci_td *td = list_entry(urbp->td_list.next,
  				struct uhci_td, list);

  		qh->element = LINK_TO_TD(td);

  	}

  	/* Treat the queue as if it has just advanced */
  	qh->wait_expired = 0;
  	qh->advance_jiffies = jiffies;

  	if (qh->state == QH_STATE_ACTIVE)
  		return;
  	qh->state = QH_STATE_ACTIVE;

  	/* Move the QH from its old list to the correct spot in the appropriate

  	 * skeleton's list */

  	if (qh == uhci->next_qh)
  		uhci->next_qh = list_entry(qh->node.next, struct uhci_qh,
  				node);

  	list_del(&qh->node);
  
  	if (qh->skel == SKEL_ISO)
  		link_iso(uhci, qh);
  	else if (qh->skel < SKEL_ASYNC)
  		link_interrupt(uhci, qh);
  	else
  		link_async(uhci, qh);
  }
  
  /*
   * Unlink a high-period interrupt QH from the schedule
   */
  static void unlink_interrupt(struct uhci_hcd *uhci, struct uhci_qh *qh)
  {
  	struct uhci_qh *pqh;

  	pqh = list_entry(qh->node.prev, struct uhci_qh, node);

  	pqh->link = qh->link;
  	mb();
  }
  
  /*
   * Unlink a period-1 interrupt or async QH from the schedule
   */
  static void unlink_async(struct uhci_hcd *uhci, struct uhci_qh *qh)
  {

  	struct uhci_qh *pqh;

  	__le32 link_to_next_qh = qh->link;
  
  	pqh = list_entry(qh->node.prev, struct uhci_qh, node);

  	pqh->link = link_to_next_qh;

  
  	/* If this was the old first FSBR QH, link the terminating skeleton
  	 * QH to the next (new first FSBR) QH. */
  	if (pqh->skel < SKEL_FSBR && qh->skel >= SKEL_FSBR)
  		uhci->skel_term_qh->link = link_to_next_qh;

  	mb();

  }
  
  /*

   * Take a QH off the hardware schedule

   */

  static void uhci_unlink_qh(struct uhci_hcd *uhci, struct uhci_qh *qh)

  {

  	if (qh->state == QH_STATE_UNLINKING)

  		return;

  	WARN_ON(qh->state != QH_STATE_ACTIVE || !qh->udev);
  	qh->state = QH_STATE_UNLINKING;

  	/* Unlink the QH from the schedule and record when we did it */

  	if (qh->skel == SKEL_ISO)
  		;
  	else if (qh->skel < SKEL_ASYNC)
  		unlink_interrupt(uhci, qh);
  	else
  		unlink_async(uhci, qh);

  
  	uhci_get_current_frame_number(uhci);

  	qh->unlink_frame = uhci->frame_number;

  	/* Force an interrupt so we know when the QH is fully unlinked */
  	if (list_empty(&uhci->skel_unlink_qh->node))

  		uhci_set_next_interrupt(uhci);

  	/* Move the QH from its old list to the end of the unlinking list */

  	if (qh == uhci->next_qh)
  		uhci->next_qh = list_entry(qh->node.next, struct uhci_qh,
  				node);

  	list_move_tail(&qh->node, &uhci->skel_unlink_qh->node);

  }

  /*
   * When we and the controller are through with a QH, it becomes IDLE.
   * This happens when a QH has been off the schedule (on the unlinking
   * list) for more than one frame, or when an error occurs while adding
   * the first URB onto a new QH.
   */
  static void uhci_make_qh_idle(struct uhci_hcd *uhci, struct uhci_qh *qh)

  {

  	WARN_ON(qh->state == QH_STATE_ACTIVE);

  	if (qh == uhci->next_qh)
  		uhci->next_qh = list_entry(qh->node.next, struct uhci_qh,
  				node);

  	list_move(&qh->node, &uhci->idle_qh_list);
  	qh->state = QH_STATE_IDLE;

  	/* Now that the QH is idle, its post_td isn't being used */
  	if (qh->post_td) {
  		uhci_free_td(uhci, qh->post_td);
  		qh->post_td = NULL;
  	}

  	/* If anyone is waiting for a QH to become idle, wake them up */
  	if (uhci->num_waiting)
  		wake_up_all(&uhci->waitqh);

  }

  /*
   * Find the highest existing bandwidth load for a given phase and period.
   */
  static int uhci_highest_load(struct uhci_hcd *uhci, int phase, int period)
  {
  	int highest_load = uhci->load[phase];
  
  	for (phase += period; phase < MAX_PHASE; phase += period)
  		highest_load = max_t(int, highest_load, uhci->load[phase]);
  	return highest_load;
  }
  
  /*
   * Set qh->phase to the optimal phase for a periodic transfer and
   * check whether the bandwidth requirement is acceptable.
   */
  static int uhci_check_bandwidth(struct uhci_hcd *uhci, struct uhci_qh *qh)
  {
  	int minimax_load;
  
  	/* Find the optimal phase (unless it is already set) and get
  	 * its load value. */
  	if (qh->phase >= 0)
  		minimax_load = uhci_highest_load(uhci, qh->phase, qh->period);
  	else {
  		int phase, load;
  		int max_phase = min_t(int, MAX_PHASE, qh->period);
  
  		qh->phase = 0;
  		minimax_load = uhci_highest_load(uhci, qh->phase, qh->period);
  		for (phase = 1; phase < max_phase; ++phase) {
  			load = uhci_highest_load(uhci, phase, qh->period);
  			if (load < minimax_load) {
  				minimax_load = load;
  				qh->phase = phase;
  			}
  		}
  	}
  
  	/* Maximum allowable periodic bandwidth is 90%, or 900 us per frame */
  	if (minimax_load + qh->load > 900) {
  		dev_dbg(uhci_dev(uhci), "bandwidth allocation failed: "
  				"period %d, phase %d, %d + %d us
  ",
  				qh->period, qh->phase, minimax_load, qh->load);
  		return -ENOSPC;
  	}
  	return 0;
  }
  
  /*
   * Reserve a periodic QH's bandwidth in the schedule
   */
  static void uhci_reserve_bandwidth(struct uhci_hcd *uhci, struct uhci_qh *qh)
  {
  	int i;
  	int load = qh->load;
  	char *p = "??";
  
  	for (i = qh->phase; i < MAX_PHASE; i += qh->period) {
  		uhci->load[i] += load;
  		uhci->total_load += load;
  	}
  	uhci_to_hcd(uhci)->self.bandwidth_allocated =
  			uhci->total_load / MAX_PHASE;
  	switch (qh->type) {
  	case USB_ENDPOINT_XFER_INT:
  		++uhci_to_hcd(uhci)->self.bandwidth_int_reqs;
  		p = "INT";
  		break;
  	case USB_ENDPOINT_XFER_ISOC:
  		++uhci_to_hcd(uhci)->self.bandwidth_isoc_reqs;
  		p = "ISO";
  		break;
  	}
  	qh->bandwidth_reserved = 1;
  	dev_dbg(uhci_dev(uhci),
  			"%s dev %d ep%02x-%s, period %d, phase %d, %d us
  ",
  			"reserve", qh->udev->devnum,
  			qh->hep->desc.bEndpointAddress, p,
  			qh->period, qh->phase, load);
  }
  
  /*
   * Release a periodic QH's bandwidth reservation
   */
  static void uhci_release_bandwidth(struct uhci_hcd *uhci, struct uhci_qh *qh)
  {
  	int i;
  	int load = qh->load;
  	char *p = "??";
  
  	for (i = qh->phase; i < MAX_PHASE; i += qh->period) {
  		uhci->load[i] -= load;
  		uhci->total_load -= load;
  	}
  	uhci_to_hcd(uhci)->self.bandwidth_allocated =
  			uhci->total_load / MAX_PHASE;
  	switch (qh->type) {
  	case USB_ENDPOINT_XFER_INT:
  		--uhci_to_hcd(uhci)->self.bandwidth_int_reqs;
  		p = "INT";
  		break;
  	case USB_ENDPOINT_XFER_ISOC:
  		--uhci_to_hcd(uhci)->self.bandwidth_isoc_reqs;
  		p = "ISO";
  		break;
  	}
  	qh->bandwidth_reserved = 0;
  	dev_dbg(uhci_dev(uhci),
  			"%s dev %d ep%02x-%s, period %d, phase %d, %d us
  ",
  			"release", qh->udev->devnum,
  			qh->hep->desc.bEndpointAddress, p,
  			qh->period, qh->phase, load);
  }

  static inline struct urb_priv *uhci_alloc_urb_priv(struct uhci_hcd *uhci,
  		struct urb *urb)

  {
  	struct urb_priv *urbp;

  	urbp = kmem_cache_zalloc(uhci_up_cachep, GFP_ATOMIC);

  	if (!urbp)
  		return NULL;

  	urbp->urb = urb;

  	urb->hcpriv = urbp;

  	INIT_LIST_HEAD(&urbp->node);

  	INIT_LIST_HEAD(&urbp->td_list);

  	return urbp;
  }

  static void uhci_free_urb_priv(struct uhci_hcd *uhci,
  		struct urb_priv *urbp)

  {
  	struct uhci_td *td, *tmp;

  	if (!list_empty(&urbp->node))
  		dev_WARN(uhci_dev(uhci), "urb %p still on QH's list!
  ",

  				urbp->urb);

  	list_for_each_entry_safe(td, tmp, &urbp->td_list, list) {

  		uhci_remove_td_from_urbp(td);
  		uhci_free_td(uhci, td);

  	}

  	kmem_cache_free(uhci_up_cachep, urbp);
  }

  /*
   * 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;

  	return 0;
  }
  
  /*
   * Control transfers
   */

  static int uhci_submit_control(struct uhci_hcd *uhci, struct urb *urb,
  		struct uhci_qh *qh)

  {

  	struct uhci_td *td;

  	unsigned long destination, status;

  	int maxsze = le16_to_cpu(qh->hep->desc.wMaxPacketSize);

  	int len = urb->transfer_buffer_length;
  	dma_addr_t data = urb->transfer_dma;

  	__le32 *plink;

  	struct urb_priv *urbp = urb->hcpriv;

  	int skel;

  
  	/* The "pipe" thing contains the destination in bits 8--18 */
  	destination = (urb->pipe & PIPE_DEVEP_MASK) | USB_PID_SETUP;

  	/* 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 = qh->dummy_td;

  	uhci_add_td_to_urbp(td, urbp);

  	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)
  	 * to OUT (0xE1).  Else change it from SETUP to IN (0x69) and
  	 * set Short Packet Detect (SPD) for all data packets.

  	 *
  	 * 0-length transfers always get treated as "send".

  	 */

  	if (usb_pipeout(urb->pipe) || len == 0)

  		destination ^= (USB_PID_SETUP ^ USB_PID_OUT);
  	else {
  		destination ^= (USB_PID_SETUP ^ USB_PID_IN);
  		status |= TD_CTRL_SPD;
  	}
  
  	/*

  	 * Build the DATA TDs

  	 */
  	while (len > 0) {

  		int pktsze = maxsze;
  
  		if (len <= pktsze) {		/* The last data packet */
  			pktsze = len;
  			status &= ~TD_CTRL_SPD;
  		}

  		td = uhci_alloc_td(uhci);

  		if (!td)

  			goto nomem;

  		*plink = LINK_TO_TD(td);

  
  		/* Alternate Data0/1 (start with Data1) */
  		destination ^= TD_TOKEN_TOGGLE;
  	

  		uhci_add_td_to_urbp(td, urbp);

  		uhci_fill_td(td, status, destination | uhci_explen(pktsze),

  				data);
  		plink = &td->link;

  
  		data += pktsze;
  		len -= pktsze;
  	}
  
  	/*
  	 * Build the final TD for control status 
  	 */

  	td = uhci_alloc_td(uhci);

  	if (!td)

  		goto nomem;

  	*plink = LINK_TO_TD(td);

  	/* Change direction for the status transaction */
  	destination ^= (USB_PID_IN ^ USB_PID_OUT);

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

  	uhci_add_td_to_urbp(td, urbp);

  	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 = LINK_TO_TD(td);

  
  	uhci_fill_td(td, 0, USB_PID_OUT | uhci_explen(0), 0);
  	wmb();

  	qh->dummy_td->status |= 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
  	 * to do that is to put URBs on the low-speed queue while the device

  	 * isn't in the CONFIGURED state. */

  	if (urb->dev->speed == USB_SPEED_LOW ||

  			urb->dev->state != USB_STATE_CONFIGURED)

  		skel = SKEL_LS_CONTROL;

  	else {

  		skel = SKEL_FS_CONTROL;

  		uhci_add_fsbr(uhci, urb);

  	}

  	if (qh->state != QH_STATE_ACTIVE)
  		qh->skel = skel;

  	return 0;

  
  nomem:
  	/* Remove the dummy TD from the td_list so it doesn't get freed */

  	uhci_remove_td_from_urbp(qh->dummy_td);

  	return -ENOMEM;

  }
  
  /*

   * Common submit for bulk and interrupt
   */

  static int uhci_submit_common(struct uhci_hcd *uhci, struct urb *urb,
  		struct uhci_qh *qh)

  {
  	struct uhci_td *td;

  	unsigned long destination, status;

  	int maxsze = le16_to_cpu(qh->hep->desc.wMaxPacketSize);

  	int len = urb->transfer_buffer_length;

  	dma_addr_t data = urb->transfer_dma;

  	__le32 *plink;

  	struct urb_priv *urbp = urb->hcpriv;

  	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, dummy TD remains inactive */
  	status = uhci_maxerr(3);

  	if (urb->dev->speed == USB_SPEED_LOW)
  		status |= TD_CTRL_LS;
  	if (usb_pipein(urb->pipe))
  		status |= TD_CTRL_SPD;
  
  	/*

  	 * Build the DATA TDs

  	 */

  	plink = NULL;
  	td = qh->dummy_td;

  	do {	/* Allow zero length packets */
  		int pktsze = maxsze;

  		if (len <= pktsze) {		/* The last packet */

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

  		if (plink) {
  			td = uhci_alloc_td(uhci);
  			if (!td)
  				goto nomem;

  			*plink = LINK_TO_TD(td);

  		}

  		uhci_add_td_to_urbp(td, urbp);

  		uhci_fill_td(td, status,

  				destination | uhci_explen(pktsze) |
  					(toggle << TD_TOKEN_TOGGLE_SHIFT),
  				data);

  		plink = &td->link;

  		status |= TD_CTRL_ACTIVE;

  
  		data += pktsze;
  		len -= maxsze;

  		toggle ^= 1;

  	} 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 ((urb->transfer_flags & URB_ZERO_PACKET) &&
  			usb_pipeout(urb->pipe) && len == 0 &&
  			urb->transfer_buffer_length > 0) {

  		td = uhci_alloc_td(uhci);

  		if (!td)

  			goto nomem;

  		*plink = LINK_TO_TD(td);

  		uhci_add_td_to_urbp(td, urbp);

  		uhci_fill_td(td, status,
  				destination | uhci_explen(0) |
  					(toggle << TD_TOKEN_TOGGLE_SHIFT),
  				data);
  		plink = &td->link;

  		toggle ^= 1;

  	}
  
  	/* 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);

  	/*
  	 * Build the new dummy TD and activate the old one
  	 */
  	td = uhci_alloc_td(uhci);
  	if (!td)
  		goto nomem;

  	*plink = LINK_TO_TD(td);

  
  	uhci_fill_td(td, 0, USB_PID_OUT | uhci_explen(0), 0);
  	wmb();

  	qh->dummy_td->status |= 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_urbp(qh->dummy_td);

  	return -ENOMEM;

  }

  static int uhci_submit_bulk(struct uhci_hcd *uhci, struct urb *urb,

  		struct uhci_qh *qh)

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

  	if (qh->state != QH_STATE_ACTIVE)
  		qh->skel = SKEL_BULK;

  	ret = uhci_submit_common(uhci, urb, qh);
  	if (ret == 0)

  		uhci_add_fsbr(uhci, urb);

  	return ret;
  }

  static int uhci_submit_interrupt(struct uhci_hcd *uhci, struct urb *urb,

  		struct uhci_qh *qh)

  {

  	int ret;

  	/* USB 1.1 interrupt transfers only involve one packet per interval.
  	 * Drivers can submit URBs of any length, but longer ones will need
  	 * multiple intervals to complete.

  	 */

  	if (!qh->bandwidth_reserved) {
  		int exponent;

  		/* Figure out which power-of-two queue to use */
  		for (exponent = 7; exponent >= 0; --exponent) {
  			if ((1 << exponent) <= urb->interval)
  				break;
  		}
  		if (exponent < 0)
  			return -EINVAL;

  		/* If the slot is full, try a lower period */
  		do {
  			qh->period = 1 << exponent;
  			qh->skel = SKEL_INDEX(exponent);
  
  			/* For now, interrupt phase is fixed by the layout
  			 * of the QH lists.
  			 */
  			qh->phase = (qh->period / 2) & (MAX_PHASE - 1);
  			ret = uhci_check_bandwidth(uhci, qh);
  		} while (ret != 0 && --exponent >= 0);

  		if (ret)
  			return ret;
  	} else if (qh->period > urb->interval)
  		return -EINVAL;		/* Can't decrease the period */
  
  	ret = uhci_submit_common(uhci, urb, qh);
  	if (ret == 0) {
  		urb->interval = qh->period;
  		if (!qh->bandwidth_reserved)
  			uhci_reserve_bandwidth(uhci, qh);
  	}
  	return ret;

  }
  
  /*

   * Fix up the data structures following a short transfer
   */
  static int uhci_fixup_short_transfer(struct uhci_hcd *uhci,

  		struct uhci_qh *qh, struct urb_priv *urbp)

  {
  	struct uhci_td *td;

  	struct list_head *tmp;
  	int ret;

  
  	td = list_entry(urbp->td_list.prev, struct uhci_td, list);
  	if (qh->type == USB_ENDPOINT_XFER_CONTROL) {

  
  		/* When a control transfer is short, we have to restart
  		 * the queue at the status stage transaction, which is
  		 * the last TD. */

  		WARN_ON(list_empty(&urbp->td_list));

  		qh->element = LINK_TO_TD(td);

  		tmp = td->list.prev;

  		ret = -EINPROGRESS;

  	} else {

  
  		/* When a bulk/interrupt transfer is short, we have to
  		 * fix up the toggles of the following URBs on the queue
  		 * before restarting the queue at the next URB. */

  		qh->initial_toggle = uhci_toggle(td_token(qh->post_td)) ^ 1;

  		uhci_fixup_toggles(qh, 1);

  		if (list_empty(&urbp->td_list))
  			td = qh->post_td;

  		qh->element = td->link;

  		tmp = urbp->td_list.prev;
  		ret = 0;

  	}

  	/* Remove all the TDs we skipped over, from tmp back to the start */
  	while (tmp != &urbp->td_list) {
  		td = list_entry(tmp, struct uhci_td, list);
  		tmp = tmp->prev;

  		uhci_remove_td_from_urbp(td);
  		uhci_free_td(uhci, td);

  	}

  	return ret;
  }
  
  /*
   * Common result for control, bulk, and interrupt
   */
  static int uhci_result_common(struct uhci_hcd *uhci, struct urb *urb)
  {
  	struct urb_priv *urbp = urb->hcpriv;
  	struct uhci_qh *qh = urbp->qh;

  	struct uhci_td *td, *tmp;

  	unsigned status;
  	int ret = 0;

  	list_for_each_entry_safe(td, tmp, &urbp->td_list, list) {

  		unsigned int ctrlstat;
  		int len;

  		ctrlstat = td_status(td);
  		status = uhci_status_bits(ctrlstat);
  		if (status & TD_CTRL_ACTIVE)
  			return -EINPROGRESS;
  
  		len = uhci_actual_length(ctrlstat);
  		urb->actual_length += len;
  
  		if (status) {
  			ret = uhci_map_status(status,
  					uhci_packetout(td_token(td)));
  			if ((debug == 1 && ret != -EPIPE) || debug > 1) {
  				/* Some debugging code */

  				dev_dbg(&urb->dev->dev,

  						"%s: failed with status %x
  ",

  						__func__, status);

  
  				if (debug > 1 && errbuf) {
  					/* Print the chain for debugging */

  					uhci_show_qh(uhci, urbp->qh, errbuf,

  							ERRBUF_LEN, 0);
  					lprintk(errbuf);
  				}
  			}

  		/* Did we receive a short packet? */

  		} else if (len < uhci_expected_length(td_token(td))) {

  			/* For control transfers, go to the status TD if
  			 * this isn't already the last data TD */
  			if (qh->type == USB_ENDPOINT_XFER_CONTROL) {
  				if (td->list.next != urbp->td_list.prev)
  					ret = 1;
  			}
  
  			/* For bulk and interrupt, this may be an error */
  			else if (urb->transfer_flags & URB_SHORT_NOT_OK)

  				ret = -EREMOTEIO;

  
  			/* Fixup needed only if this isn't the URB's last TD */
  			else if (&td->list != urbp->td_list.prev)

  				ret = 1;
  		}

  		uhci_remove_td_from_urbp(td);

  		if (qh->post_td)

  			uhci_free_td(uhci, qh->post_td);

  		qh->post_td = td;

  		if (ret != 0)
  			goto err;
  	}
  	return ret;
  
  err:
  	if (ret < 0) {

  		/* Note that the queue has stopped and save
  		 * the next toggle value */
  		qh->element = UHCI_PTR_TERM;
  		qh->is_stopped = 1;
  		qh->needs_fixup = (qh->type != USB_ENDPOINT_XFER_CONTROL);
  		qh->initial_toggle = uhci_toggle(td_token(td)) ^
  				(ret == -EREMOTEIO);
  
  	} else		/* Short packet received */

  		ret = uhci_fixup_short_transfer(uhci, qh, urbp);

  	return ret;
  }
  
  /*

   * Isochronous transfers
   */

  static int uhci_submit_isochronous(struct uhci_hcd *uhci, struct urb *urb,
  		struct uhci_qh *qh)

  {

  	struct uhci_td *td = NULL;	/* Since urb->number_of_packets > 0 */
  	int i, frame;
  	unsigned long destination, status;
  	struct urb_priv *urbp = (struct urb_priv *) urb->hcpriv;

  	/* Values must not be too big (could overflow below) */
  	if (urb->interval >= UHCI_NUMFRAMES ||
  			urb->number_of_packets >= UHCI_NUMFRAMES)

  		return -EFBIG;

  	/* Check the period and figure out the starting frame number */

  	if (!qh->bandwidth_reserved) {
  		qh->period = urb->interval;

  		if (urb->transfer_flags & URB_ISO_ASAP) {

  			qh->phase = -1;		/* Find the best phase */
  			i = uhci_check_bandwidth(uhci, qh);
  			if (i)
  				return i;
  
  			/* Allow a little time to allocate the TDs */

  			uhci_get_current_frame_number(uhci);

  			frame = uhci->frame_number + 10;
  
  			/* Move forward to the first frame having the
  			 * correct phase */
  			urb->start_frame = frame + ((qh->phase - frame) &
  					(qh->period - 1));

  		} else {

  			i = urb->start_frame - uhci->last_iso_frame;

  			if (i <= 0 || i >= UHCI_NUMFRAMES)
  				return -EINVAL;

  			qh->phase = urb->start_frame & (qh->period - 1);
  			i = uhci_check_bandwidth(uhci, qh);
  			if (i)
  				return i;

  		}

  	} else if (qh->period != urb->interval) {
  		return -EINVAL;		/* Can't change the period */

  	} else {
  		/* Find the next unused frame */

  		if (list_empty(&qh->queue)) {

  			frame = qh->iso_frame;

  		} else {
  			struct urb *lurb;

  			lurb = list_entry(qh->queue.prev,

  					struct urb_priv, node)->urb;

  			frame = lurb->start_frame +
  					lurb->number_of_packets *
  					lurb->interval;

  		}

  		if (urb->transfer_flags & URB_ISO_ASAP) {
  			/* Skip some frames if necessary to insure
  			 * the start frame is in the future.
  			 */
  			uhci_get_current_frame_number(uhci);
  			if (uhci_frame_before_eq(frame, uhci->frame_number)) {
  				frame = uhci->frame_number + 1;
  				frame += ((qh->phase - frame) &
  					(qh->period - 1));
  			}
  		}	/* Otherwise pick up where the last URB leaves off */
  		urb->start_frame = frame;

  	}

  	/* Make sure we won't have to go too far into the future */

  	if (uhci_frame_before_eq(uhci->last_iso_frame + UHCI_NUMFRAMES,

  			urb->start_frame + urb->number_of_packets *
  				urb->interval))
  		return -EFBIG;
  
  	status = TD_CTRL_ACTIVE | TD_CTRL_IOS;
  	destination = (urb->pipe & PIPE_DEVEP_MASK) | usb_packetid(urb->pipe);

  	for (i = 0; i < urb->number_of_packets; i++) {

  		td = uhci_alloc_td(uhci);

  		if (!td)
  			return -ENOMEM;

  		uhci_add_td_to_urbp(td, urbp);

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

  	}

  	/* Set the interrupt-on-completion flag on the last packet. */

  	td->status |= cpu_to_le32(TD_CTRL_IOC);

  	/* Add the TDs to the frame list */

  	frame = urb->start_frame;
  	list_for_each_entry(td, &urbp->td_list, list) {

  		uhci_insert_td_in_frame_list(uhci, td, frame);

  		frame += qh->period;
  	}
  
  	if (list_empty(&qh->queue)) {
  		qh->iso_packet_desc = &urb->iso_frame_desc[0];
  		qh->iso_frame = urb->start_frame;

  	}

  	qh->skel = SKEL_ISO;

  	if (!qh->bandwidth_reserved)
  		uhci_reserve_bandwidth(uhci, qh);

  	return 0;

  }
  
  static int uhci_result_isochronous(struct uhci_hcd *uhci, struct urb *urb)
  {

  	struct uhci_td *td, *tmp;
  	struct urb_priv *urbp = urb->hcpriv;
  	struct uhci_qh *qh = urbp->qh;

  	list_for_each_entry_safe(td, tmp, &urbp->td_list, list) {
  		unsigned int ctrlstat;
  		int status;

  		int actlength;

  		if (uhci_frame_before_eq(uhci->cur_iso_frame, qh->iso_frame))

  			return -EINPROGRESS;

  		uhci_remove_tds_from_frame(uhci, qh->iso_frame);
  
  		ctrlstat = td_status(td);
  		if (ctrlstat & TD_CTRL_ACTIVE) {
  			status = -EXDEV;	/* TD was added too late? */
  		} else {
  			status = uhci_map_status(uhci_status_bits(ctrlstat),
  					usb_pipeout(urb->pipe));
  			actlength = uhci_actual_length(ctrlstat);
  
  			urb->actual_length += actlength;
  			qh->iso_packet_desc->actual_length = actlength;
  			qh->iso_packet_desc->status = status;
  		}

  		if (status)

  			urb->error_count++;

  		uhci_remove_td_from_urbp(td);
  		uhci_free_td(uhci, td);
  		qh->iso_frame += qh->period;
  		++qh->iso_packet_desc;

  	}

  	return 0;

  }

  static int uhci_urb_enqueue(struct usb_hcd *hcd,

  		struct urb *urb, gfp_t mem_flags)

  {
  	int ret;
  	struct uhci_hcd *uhci = hcd_to_uhci(hcd);
  	unsigned long flags;

  	struct urb_priv *urbp;
  	struct uhci_qh *qh;

  
  	spin_lock_irqsave(&uhci->lock, flags);

  	ret = usb_hcd_link_urb_to_ep(hcd, urb);
  	if (ret)
  		goto done_not_linked;

  	ret = -ENOMEM;
  	urbp = uhci_alloc_urb_priv(uhci, urb);
  	if (!urbp)
  		goto done;

  	if (urb->ep->hcpriv)
  		qh = urb->ep->hcpriv;

  	else {

  		qh = uhci_alloc_qh(uhci, urb->dev, urb->ep);

  		if (!qh)
  			goto err_no_qh;

  	}

  	urbp->qh = qh;

  	switch (qh->type) {
  	case USB_ENDPOINT_XFER_CONTROL:

  		ret = uhci_submit_control(uhci, urb, qh);
  		break;

  	case USB_ENDPOINT_XFER_BULK:

  		ret = uhci_submit_bulk(uhci, urb, qh);

  		break;

  	case USB_ENDPOINT_XFER_INT:

  		ret = uhci_submit_interrupt(uhci, urb, qh);

  		break;

  	case USB_ENDPOINT_XFER_ISOC:

  		urb->error_count = 0;

  		ret = uhci_submit_isochronous(uhci, urb, qh);

  		break;
  	}

  	if (ret != 0)
  		goto err_submit_failed;

  	/* Add this URB to the QH */

  	list_add_tail(&urbp->node, &qh->queue);

  	/* If the new URB is the first and only one on this QH then either
  	 * the QH is new and idle or else it's unlinked and waiting to

  	 * become idle, so we can activate it right away.  But only if the
  	 * queue isn't stopped. */

  	if (qh->queue.next == &urbp->node && !qh->is_stopped) {

  		uhci_activate_qh(uhci, qh);

  		uhci_urbp_wants_fsbr(uhci, urbp);

  	}

  	goto done;
  
  err_submit_failed:
  	if (qh->state == QH_STATE_IDLE)
  		uhci_make_qh_idle(uhci, qh);	/* Reclaim unused QH */

  err_no_qh:
  	uhci_free_urb_priv(uhci, urbp);

  done:

  	if (ret)
  		usb_hcd_unlink_urb_from_ep(hcd, urb);
  done_not_linked:

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

  static int uhci_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)

  {
  	struct uhci_hcd *uhci = hcd_to_uhci(hcd);
  	unsigned long flags;

  	struct uhci_qh *qh;

  	int rc;

  
  	spin_lock_irqsave(&uhci->lock, flags);

  	rc = usb_hcd_check_unlink_urb(hcd, urb, status);
  	if (rc)

  		goto done;

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

  
  	/* Remove Isochronous TDs from the frame list ASAP */

  	if (qh->type == USB_ENDPOINT_XFER_ISOC) {

  		uhci_unlink_isochronous_tds(uhci, urb);

  		mb();
  
  		/* If the URB has already started, update the QH unlink time */
  		uhci_get_current_frame_number(uhci);
  		if (uhci_frame_before_eq(urb->start_frame, uhci->frame_number))
  			qh->unlink_frame = uhci->frame_number;
  	}
  
  	uhci_unlink_qh(uhci, qh);

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

  	return rc;

  }

  /*

   * Finish unlinking an URB and give it back

   */

  static void uhci_giveback_urb(struct uhci_hcd *uhci, struct uhci_qh *qh,

  		struct urb *urb, int status)

  __releases(uhci->lock)
  __acquires(uhci->lock)

  {

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

  	if (qh->type == USB_ENDPOINT_XFER_CONTROL) {

  		/* Subtract off the length of the SETUP packet from
  		 * urb->actual_length.
  		 */
  		urb->actual_length -= min_t(u32, 8, urb->actual_length);

  	}

  	/* When giving back the first URB in an Isochronous queue,
  	 * reinitialize the QH's iso-related members for the next URB. */

  	else if (qh->type == USB_ENDPOINT_XFER_ISOC &&

  			urbp->node.prev == &qh->queue &&
  			urbp->node.next != &qh->queue) {
  		struct urb *nurb = list_entry(urbp->node.next,
  				struct urb_priv, node)->urb;
  
  		qh->iso_packet_desc = &nurb->iso_frame_desc[0];
  		qh->iso_frame = nurb->start_frame;

  	}

  	/* Take the URB off the QH's queue.  If the queue is now empty,
  	 * this is a perfect time for a toggle fixup. */
  	list_del_init(&urbp->node);
  	if (list_empty(&qh->queue) && qh->needs_fixup) {
  		usb_settoggle(urb->dev, usb_pipeendpoint(urb->pipe),
  				usb_pipeout(urb->pipe), qh->initial_toggle);
  		qh->needs_fixup = 0;
  	}

  	uhci_free_urb_priv(uhci, urbp);

  	usb_hcd_unlink_urb_from_ep(uhci_to_hcd(uhci), urb);

  	spin_unlock(&uhci->lock);

  	usb_hcd_giveback_urb(uhci_to_hcd(uhci), urb, status);

  	spin_lock(&uhci->lock);

  	/* If the queue is now empty, we can unlink the QH and give up its
  	 * reserved bandwidth. */
  	if (list_empty(&qh->queue)) {
  		uhci_unlink_qh(uhci, qh);

  		if (qh->bandwidth_reserved)
  			uhci_release_bandwidth(uhci, qh);

  	}

  }

  /*

   * Scan the URBs in a QH's queue

   */

  #define QH_FINISHED_UNLINKING(qh)			\
  		(qh->state == QH_STATE_UNLINKING &&	\
  		uhci->frame_number + uhci->is_stopped != qh->unlink_frame)

  static void uhci_scan_qh(struct uhci_hcd *uhci, struct uhci_qh *qh)

  {

  	struct urb_priv *urbp;

  	struct urb *urb;
  	int status;

  	while (!list_empty(&qh->queue)) {
  		urbp = list_entry(qh->queue.next, struct urb_priv, node);
  		urb = urbp->urb;

  		if (qh->type == USB_ENDPOINT_XFER_ISOC)

  			status = uhci_result_isochronous(uhci, urb);

  		else

  			status = uhci_result_common(uhci, urb);

  		if (status == -EINPROGRESS)
  			break;

  		/* Dequeued but completed URBs can't be given back unless
  		 * the QH is stopped or has finished unlinking. */

  		if (urb->unlinked) {

  			if (QH_FINISHED_UNLINKING(qh))
  				qh->is_stopped = 1;
  			else if (!qh->is_stopped)
  				return;
  		}

  		uhci_giveback_urb(uhci, qh, urb, status);

  		if (status < 0)

  			break;
  	}

  	/* If the QH is neither stopped nor finished unlinking (normal case),
  	 * our work here is done. */

  	if (QH_FINISHED_UNLINKING(qh))
  		qh->is_stopped = 1;
  	else if (!qh->is_stopped)

  		return;

  	/* Otherwise give back each of the dequeued URBs */

  restart:

  	list_for_each_entry(urbp, &qh->queue, node) {
  		urb = urbp->urb;

  		if (urb->unlinked) {

  
  			/* Fix up the TD links and save the toggles for
  			 * non-Isochronous queues.  For Isochronous queues,
  			 * test for too-recent dequeues. */
  			if (!uhci_cleanup_queue(uhci, qh, urb)) {
  				qh->is_stopped = 0;
  				return;
  			}

  			uhci_giveback_urb(uhci, qh, urb, 0);

  			goto restart;
  		}
  	}
  	qh->is_stopped = 0;

  	/* There are no more dequeued URBs.  If there are still URBs on the
  	 * queue, the QH can now be re-activated. */
  	if (!list_empty(&qh->queue)) {
  		if (qh->needs_fixup)
  			uhci_fixup_toggles(qh, 0);

  
  		/* If the first URB on the queue wants FSBR but its time
  		 * limit has expired, set the next TD to interrupt on
  		 * completion before reactivating the QH. */
  		urbp = list_entry(qh->queue.next, struct urb_priv, node);
  		if (urbp->fsbr && qh->wait_expired) {
  			struct uhci_td *td = list_entry(urbp->td_list.next,
  					struct uhci_td, list);
  
  			td->status |= __cpu_to_le32(TD_CTRL_IOC);
  		}

  		uhci_activate_qh(uhci, qh);

  	}

  	/* The queue is empty.  The QH can become idle if it is fully
  	 * unlinked. */
  	else if (QH_FINISHED_UNLINKING(qh))
  		uhci_make_qh_idle(uhci, qh);

  }

  /*

   * Check for queues that have made some forward progress.
   * Returns 0 if the queue is not Isochronous, is ACTIVE, and
   * has not advanced since last examined; 1 otherwise.

   *
   * Early Intel controllers have a bug which causes qh->element sometimes
   * not to advance when a TD completes successfully.  The queue remains
   * stuck on the inactive completed TD.  We detect such cases and advance
   * the element pointer by hand.

   */
  static int uhci_advance_check(struct uhci_hcd *uhci, struct uhci_qh *qh)
  {
  	struct urb_priv *urbp = NULL;
  	struct uhci_td *td;
  	int ret = 1;
  	unsigned status;
  
  	if (qh->type == USB_ENDPOINT_XFER_ISOC)

  		goto done;

  
  	/* Treat an UNLINKING queue as though it hasn't advanced.
  	 * This is okay because reactivation will treat it as though
  	 * it has advanced, and if it is going to become IDLE then
  	 * this doesn't matter anyway.  Furthermore it's possible
  	 * for an UNLINKING queue not to have any URBs at all, or
  	 * for its first URB not to have any TDs (if it was dequeued
  	 * just as it completed).  So it's not easy in any case to
  	 * test whether such queues have advanced. */
  	if (qh->state != QH_STATE_ACTIVE) {
  		urbp = NULL;
  		status = 0;
  
  	} else {
  		urbp = list_entry(qh->queue.next, struct urb_priv, node);
  		td = list_entry(urbp->td_list.next, struct uhci_td, list);
  		status = td_status(td);
  		if (!(status & TD_CTRL_ACTIVE)) {
  
  			/* We're okay, the queue has advanced */
  			qh->wait_expired = 0;
  			qh->advance_jiffies = jiffies;

  			goto done;

  		}
  		ret = 0;
  	}
  
  	/* The queue hasn't advanced; check for timeout */

  	if (qh->wait_expired)
  		goto done;
  
  	if (time_after(jiffies, qh->advance_jiffies + QH_WAIT_TIMEOUT)) {

  
  		/* Detect the Intel bug and work around it */

  		if (qh->post_td && qh_element(qh) == LINK_TO_TD(qh->post_td)) {

  			qh->element = qh->post_td->link;
  			qh->advance_jiffies = jiffies;

  			ret = 1;
  			goto done;

  		}

  		qh->wait_expired = 1;
  
  		/* If the current URB wants FSBR, unlink it temporarily
  		 * so that we can safely set the next TD to interrupt on
  		 * completion.  That way we'll know as soon as the queue
  		 * starts moving again. */
  		if (urbp && urbp->fsbr && !(status & TD_CTRL_IOC))
  			uhci_unlink_qh(uhci, qh);

  
  	} else {
  		/* Unmoving but not-yet-expired queues keep FSBR alive */
  		if (urbp)
  			uhci_urbp_wants_fsbr(uhci, urbp);

  	}

  
  done:

  	return ret;
  }
  
  /*

   * Process events in the schedule, but only in one thread at a time
   */

  static void uhci_scan_schedule(struct uhci_hcd *uhci)

  {

  	int i;
  	struct uhci_qh *qh;

  
  	/* 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->fsbr_is_wanted = 0;

  	uhci_clear_next_interrupt(uhci);

  	uhci_get_current_frame_number(uhci);

  	uhci->cur_iso_frame = uhci->frame_number;

  	/* Go through all the QH queues and process the URBs in each one */
  	for (i = 0; i < UHCI_NUM_SKELQH - 1; ++i) {
  		uhci->next_qh = list_entry(uhci->skelqh[i]->node.next,
  				struct uhci_qh, node);
  		while ((qh = uhci->next_qh) != uhci->skelqh[i]) {
  			uhci->next_qh = list_entry(qh->node.next,
  					struct uhci_qh, node);

  
  			if (uhci_advance_check(uhci, qh)) {

  				uhci_scan_qh(uhci, qh);

  				if (qh->state == QH_STATE_ACTIVE) {
  					uhci_urbp_wants_fsbr(uhci,
  	list_entry(qh->queue.next, struct urb_priv, node));
  				}

  			}

  		}

  	}

  	uhci->last_iso_frame = uhci->cur_iso_frame;

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

  	if (uhci->fsbr_is_on && !uhci->fsbr_is_wanted &&
  			!uhci->fsbr_expiring) {
  		uhci->fsbr_expiring = 1;
  		mod_timer(&uhci->fsbr_timer, jiffies + FSBR_OFF_DELAY);
  	}