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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>
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_td *td = NULL; /* Since urb->number_of_packets > 0 */
int i, frame;
int i;
unsigned frame, next;
unsigned long destination, status;
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)
return -EFBIG;
uhci_get_current_frame_number(uhci);
/* 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;
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;
/* Allow a little time to allocate the TDs */
next = uhci->frame_number + 10;
frame = qh->phase;
/* 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;
}
/* Round up to the first available slot */
frame += (next - frame + qh->period - 1) & -qh->period;
} else if (qh->period != urb->interval) {
return -EINVAL; /* Can't change the period */
} else {
next = uhci->frame_number + 2;
/* Find the next unused frame */
if (list_empty(&qh->queue)) {
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->interval;
}
if (urb->transfer_flags & URB_ISO_ASAP) {
/* Skip some frames if necessary to insure
* the start frame is in the future.
/* Fell behind? */
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);
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;
else if (!uhci_frame_before_eq(next,
frame + (urb->number_of_packets - 1) *
qh->period))
return -EXDEV;
}
}
/* 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))
frame + urb->number_of_packets * urb->interval))
return -EFBIG;
urb->start_frame = frame;
status = TD_CTRL_ACTIVE | TD_CTRL_IOS;
destination = (urb->pipe & PIPE_DEVEP_MASK) | usb_packetid(urb->pipe);