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UHCI: implement new semantics for URB_ISO_ASAP
This patch (as1613) updates the isochronous scheduling in uhci-hcd to match the new semantics for URB_ISO_ASAP. The amount of code alteration is smaller than it looks because of a change in the indentation level. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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4005ad4390
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c44b225077
1 changed files with 34 additions and 35 deletions
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@ -1256,7 +1256,8 @@ static int uhci_submit_isochronous(struct uhci_hcd *uhci, struct urb *urb,
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struct uhci_qh *qh)
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{
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struct uhci_td *td = NULL; /* Since urb->number_of_packets > 0 */
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int i, frame;
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int i;
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unsigned frame, next;
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unsigned long destination, status;
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struct urb_priv *urbp = (struct urb_priv *) urb->hcpriv;
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@ -1265,37 +1266,29 @@ static int uhci_submit_isochronous(struct uhci_hcd *uhci, struct urb *urb,
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urb->number_of_packets >= UHCI_NUMFRAMES)
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return -EFBIG;
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uhci_get_current_frame_number(uhci);
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/* Check the period and figure out the starting frame number */
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if (!qh->bandwidth_reserved) {
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qh->period = urb->interval;
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if (urb->transfer_flags & URB_ISO_ASAP) {
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qh->phase = -1; /* Find the best phase */
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i = uhci_check_bandwidth(uhci, qh);
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if (i)
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return i;
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qh->phase = -1; /* Find the best phase */
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i = uhci_check_bandwidth(uhci, qh);
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if (i)
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return i;
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/* Allow a little time to allocate the TDs */
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uhci_get_current_frame_number(uhci);
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frame = uhci->frame_number + 10;
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/* Allow a little time to allocate the TDs */
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next = uhci->frame_number + 10;
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frame = qh->phase;
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/* Move forward to the first frame having the
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* correct phase */
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urb->start_frame = frame + ((qh->phase - frame) &
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(qh->period - 1));
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} else {
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i = urb->start_frame - uhci->last_iso_frame;
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if (i <= 0 || i >= UHCI_NUMFRAMES)
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return -EINVAL;
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qh->phase = urb->start_frame & (qh->period - 1);
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i = uhci_check_bandwidth(uhci, qh);
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if (i)
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return i;
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}
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/* Round up to the first available slot */
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frame += (next - frame + qh->period - 1) & -qh->period;
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} else if (qh->period != urb->interval) {
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return -EINVAL; /* Can't change the period */
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} else {
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next = uhci->frame_number + 2;
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/* Find the next unused frame */
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if (list_empty(&qh->queue)) {
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frame = qh->iso_frame;
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@ -1308,25 +1301,31 @@ static int uhci_submit_isochronous(struct uhci_hcd *uhci, struct urb *urb,
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lurb->number_of_packets *
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lurb->interval;
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}
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if (urb->transfer_flags & URB_ISO_ASAP) {
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/* Skip some frames if necessary to insure
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* the start frame is in the future.
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/* Fell behind? */
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if (uhci_frame_before_eq(frame, next)) {
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/* USB_ISO_ASAP: Round up to the first available slot */
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if (urb->transfer_flags & URB_ISO_ASAP)
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frame += (next - frame + qh->period - 1) &
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-qh->period;
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/*
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* Not ASAP: Use the next slot in the stream. If
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* the entire URB falls before the threshold, fail.
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*/
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uhci_get_current_frame_number(uhci);
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if (uhci_frame_before_eq(frame, uhci->frame_number)) {
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frame = uhci->frame_number + 1;
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frame += ((qh->phase - frame) &
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(qh->period - 1));
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}
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} /* Otherwise pick up where the last URB leaves off */
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urb->start_frame = frame;
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else if (!uhci_frame_before_eq(next,
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frame + (urb->number_of_packets - 1) *
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qh->period))
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return -EXDEV;
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}
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}
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/* Make sure we won't have to go too far into the future */
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if (uhci_frame_before_eq(uhci->last_iso_frame + UHCI_NUMFRAMES,
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urb->start_frame + urb->number_of_packets *
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urb->interval))
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frame + urb->number_of_packets * urb->interval))
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return -EFBIG;
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urb->start_frame = frame;
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status = TD_CTRL_ACTIVE | TD_CTRL_IOS;
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destination = (urb->pipe & PIPE_DEVEP_MASK) | usb_packetid(urb->pipe);
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