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UHCI: implement new semantics for URB_ISO_ASAP

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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>
This commit is contained in:
Alan Stern 2012-10-01 10:32:09 -04:00 committed by Greg Kroah-Hartman
parent 4005ad4390
commit c44b225077
1 changed files with 34 additions and 35 deletions
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69
drivers/usb/host/uhci-q.c
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@ -1256,7 +1256,8 @@ static int uhci_submit_isochronous(struct uhci_hcd *uhci, struct urb *urb,
struct uhci_qh *qh) struct uhci_qh *qh)
{ {
struct uhci_td *td = NULL; /* Since urb->number_of_packets > 0 */ struct uhci_td *td = NULL; /* Since urb->number_of_packets > 0 */
int i, frame; int i;
unsigned frame, next;
unsigned long destination, status; unsigned long destination, status;
struct urb_priv *urbp = (struct urb_priv *) urb->hcpriv; struct urb_priv *urbp = (struct urb_priv *) urb->hcpriv;
@ -1265,37 +1266,29 @@ static int uhci_submit_isochronous(struct uhci_hcd *uhci, struct urb *urb,
urb->number_of_packets >= UHCI_NUMFRAMES) urb->number_of_packets >= UHCI_NUMFRAMES)
return -EFBIG; return -EFBIG;
uhci_get_current_frame_number(uhci);
/* Check the period and figure out the starting frame number */ /* Check the period and figure out the starting frame number */
if (!qh->bandwidth_reserved) { if (!qh->bandwidth_reserved) {
qh->period = urb->interval; qh->period = urb->interval;
if (urb->transfer_flags & URB_ISO_ASAP) { qh->phase = -1; /* Find the best phase */
qh->phase = -1; /* Find the best phase */ i = uhci_check_bandwidth(uhci, qh);
i = uhci_check_bandwidth(uhci, qh); if (i)
if (i) return i;
return i;
/* Allow a little time to allocate the TDs */ /* Allow a little time to allocate the TDs */
uhci_get_current_frame_number(uhci); next = uhci->frame_number + 10;
frame = uhci->frame_number + 10; frame = qh->phase;
/* Move forward to the first frame having the /* Round up to the first available slot */
* correct phase */ frame += (next - frame + qh->period - 1) & -qh->period;
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) { } else if (qh->period != urb->interval) {
return -EINVAL; /* Can't change the period */ return -EINVAL; /* Can't change the period */
} else { } else {
next = uhci->frame_number + 2;
/* Find the next unused frame */ /* Find the next unused frame */
if (list_empty(&qh->queue)) { if (list_empty(&qh->queue)) {
frame = qh->iso_frame; frame = qh->iso_frame;
@ -1308,25 +1301,31 @@ static int uhci_submit_isochronous(struct uhci_hcd *uhci, struct urb *urb,
lurb->number_of_packets * lurb->number_of_packets *
lurb->interval; lurb->interval;
} }
if (urb->transfer_flags & URB_ISO_ASAP) {
/* Skip some frames if necessary to insure /* Fell behind? */
* the start frame is in the future. if (uhci_frame_before_eq(frame, next)) {
/* USB_ISO_ASAP: Round up to the first available slot */
if (urb->transfer_flags & URB_ISO_ASAP)
frame += (next - frame + qh->period - 1) &
-qh->period;
/*
* Not ASAP: Use the next slot in the stream. If
* the entire URB falls before the threshold, fail.
*/ */
uhci_get_current_frame_number(uhci); else if (!uhci_frame_before_eq(next,
if (uhci_frame_before_eq(frame, uhci->frame_number)) { frame + (urb->number_of_packets - 1) *
frame = uhci->frame_number + 1; qh->period))
frame += ((qh->phase - frame) & return -EXDEV;
(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 */ /* Make sure we won't have to go too far into the future */
if (uhci_frame_before_eq(uhci->last_iso_frame + UHCI_NUMFRAMES, if (uhci_frame_before_eq(uhci->last_iso_frame + UHCI_NUMFRAMES,
urb->start_frame + urb->number_of_packets * frame + urb->number_of_packets * urb->interval))
urb->interval))
return -EFBIG; return -EFBIG;
urb->start_frame = frame;
status = TD_CTRL_ACTIVE | TD_CTRL_IOS; status = TD_CTRL_ACTIVE | TD_CTRL_IOS;
destination = (urb->pipe & PIPE_DEVEP_MASK) | usb_packetid(urb->pipe); destination = (urb->pipe & PIPE_DEVEP_MASK) | usb_packetid(urb->pipe);