uhci-q.c

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		qh->iso_status = 0;
	}

	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++;
			qh->iso_status = status;
		}

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

static int uhci_urb_enqueue(struct usb_hcd *hcd,
		struct usb_host_endpoint *hep,
		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 = urb->status;
	if (ret != -EINPROGRESS)		/* URB already unlinked! */
		goto done;

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

	if (hep->hcpriv)
		qh = (struct uhci_qh *) hep->hcpriv;
	else {
		qh = uhci_alloc_qh(uhci, urb->dev, hep);
		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 */
	urbp->qh = 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:
	spin_unlock_irqrestore(&uhci->lock, flags);
	return ret;
}

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;
	struct uhci_qh *qh;

	spin_lock_irqsave(&uhci->lock, flags);
	urbp = urb->hcpriv;
	if (!urbp)			/* URB was never linked! */
		goto done;
	qh = urbp->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 0;
}

/*
 * Finish unlinking an URB and give it back
 */
static void uhci_giveback_urb(struct uhci_hcd *uhci, struct uhci_qh *qh,
		struct urb *urb)
__releases(uhci->lock)
__acquires(uhci->lock)
{
	struct urb_priv *urbp = (struct urb_priv *) urb->hcpriv;

	/* When giving back the first URB in an Isochronous queue,
	 * reinitialize the QH's iso-related members for the next URB. */
	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;
		qh->iso_status = 0;
	}

	/* 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);

	spin_unlock(&uhci->lock);
	usb_hcd_giveback_urb(uhci_to_hcd(uhci), urb);
	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;

		spin_lock(&urb->lock);
		if (urb->status == -EINPROGRESS)	/* Not dequeued */
			urb->status = status;
		else
			status = ECONNRESET;		/* Not -ECONNRESET */
		spin_unlock(&urb->lock);

		/* Dequeued but completed URBs can't be given back unless
		 * the QH is stopped or has finished unlinking. */
		if (status == ECONNRESET) {
			if (QH_FINISHED_UNLINKING(qh))
				qh->is_stopped = 1;
			else if (!qh->is_stopped)
				return;
		}

		uhci_giveback_urb(uhci, qh, urb);
		if (status < 0 && qh->type != USB_ENDPOINT_XFER_ISOC)
			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->status != -EINPROGRESS) {

			/* 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);
			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);
	}

	if (list_empty(&uhci->skel_unlink_qh->node))
		uhci_clear_next_interrupt(uhci);
	else
		uhci_set_next_interrupt(uhci);
}