uhci-q.c

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/*
 * Universal Host Controller Interface driver for USB.
 *
 * Maintainer: Alan Stern <[e-mail]>
 *
 * (C) Copyright 1999 Linus Torvalds
 * (C) Copyright 1999-2002 Johannes Erdfelt, [e-mail]
 * (C) Copyright 1999 Randy Dunlap
 * (C) Copyright 1999 Georg Acher, [e-mail]
 * (C) Copyright 1999 Deti Fliegl, [e-mail]
 * (C) Copyright 1999 Thomas Sailer, [e-mail]
 * (C) Copyright 1999 Roman Weissgaerber, [e-mail]
 * (C) Copyright 2000 Yggdrasil Computing, Inc. (port of new PCI interface
 *               support from usb-ohci.c by Adam Richter, [e-mail]).
 * (C) Copyright 1999 Gregory P. Smith (from usb-ohci.c)
 * (C) Copyright 2004-2007 Alan Stern, [e-mail]
 */


/*
 * 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!\n", td);
	if (!list_empty(&td->fl_list))
		dev_warn(uhci_dev(uhci), "td %p still in fl_list!\n", 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 = hep->desc.bmAttributes & USB_ENDPOINT_XFERTYPE_MASK;
		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!\n", 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 ^= __constant_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);