The old microframe scheduler was terribly hard to follow and (it seemed
to me) that it had some bugs in it.
Let's re-write it in a simpler, easier-to-read way. Hopefully this will
work better.
Note: no known problems are fixed by this patch, and in fact I can see
very little impact of the microframe scheduler overall.
Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
---
drivers/usb/dwc2/hcd_queue.c | 72 ++++++++++++++++++++------------------------
1 file changed, 32 insertions(+), 40 deletions(-)
diff --git a/drivers/usb/dwc2/hcd_queue.c b/drivers/usb/dwc2/hcd_queue.c
index 7d8d06cfe3c1..d6c24decee08 100644
--- a/drivers/usb/dwc2/hcd_queue.c
+++ b/drivers/usb/dwc2/hcd_queue.c
@@ -359,57 +359,49 @@ static int dwc2_find_single_uframe(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh)
*/
static int dwc2_find_multi_uframe(struct dwc2_hsotg *hsotg, struct dwc2_qh *qh)
{
- unsigned short utime = qh->usecs;
- unsigned short xtime;
- int t_left;
+ int utime;
int i;
int j;
- int k;
for (i = 0; i < 8; i++) {
if (hsotg->frame_usecs[i] <= 0)
continue;
- /*
- * we need n consecutive slots so use j as a start slot
- * j plus j+1 must be enough time (for now)
- */
- xtime = hsotg->frame_usecs[i];
- for (j = i + 1; j < 8; j++) {
+ for (utime = qh->usecs, j = i; utime > 0 && j < 8; j++) {
+ /* Give the available time from this uframe */
+ utime -= hsotg->frame_usecs[j];
+
/*
- * if we add this frame remaining time to xtime we may
- * be OK, if not we need to test j for a complete frame
+ * Except for first frame, we can't continue past this
+ * frame if it wasn't full, so bail now. We might still
+ * be successful the above subtract made utime <= 0.
*/
- if (xtime + hsotg->frame_usecs[j] < utime) {
- if (hsotg->frame_usecs[j] <
- max_uframe_usecs[j])
- continue;
- }
- if (xtime >= utime) {
- t_left = utime;
- for (k = i; k < 8; k++) {
- t_left -= hsotg->frame_usecs[k];
- if (t_left <= 0) {
- qh->frame_usecs[k] +=
- hsotg->frame_usecs[k]
- + t_left;
- hsotg->frame_usecs[k] = -t_left;
- return i;
- } else {
- qh->frame_usecs[k] +=
- hsotg->frame_usecs[k];
- hsotg->frame_usecs[k] = 0;
- }
- }
- }
- /* add the frame time to x time */
- xtime += hsotg->frame_usecs[j];
- /* we must have a fully available next frame or break */
- if (xtime < utime &&
- hsotg->frame_usecs[j] == max_uframe_usecs[j])
- continue;
+ if ((i != j) &&
+ (hsotg->frame_usecs[j] < max_uframe_usecs[j]))
+ break;
+ }
+
+ /* If utime > 0 after above loop, try a different start (i) */
+ if (utime > 0)
+ continue;
+
+ dev_dbg(hsotg->dev, "Assigned %d us starting at i=%d + %d us\n",
+ qh->usecs, i,
+ max_uframe_usecs[i] - hsotg->frame_usecs[i]);
+
+ /* We've got success, so allocate */
+ for (utime = qh->usecs, j = i; utime > 0 && j < 8; j++) {
+ qh->frame_usecs[i] = min_t(u16, utime,
+ hsotg->frame_usecs[j]);
+ utime -= qh->frame_usecs[i];
+ hsotg->frame_usecs[j] -= qh->frame_usecs[i];
}
+
+ return i;
}
+
+ dev_dbg(hsotg->dev, "Failed to assign %d us\n", qh->usecs);
+
return -ENOSPC;
}
--
2.6.0.rc2.230.g3dd15c0
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