1 files changed, 39 insertions, 13 deletions

diff --git a/drivers/usb/host/ehci-sched.c b/drivers/usb/host/ehci-sched.c
index 2abf8543f08..c787af2ba4b 100644
--- a/drivers/usb/host/ehci-sched.c
+++ b/drivers/usb/host/ehci-sched.c
@@ -36,6 +36,27 @@
 
 static int ehci_get_frame (struct usb_hcd *hcd);
 
+#ifdef CONFIG_PCI
+
+static unsigned ehci_read_frame_index(struct ehci_hcd *ehci)
+{
+	unsigned uf;
+
+	/*
+	 * The MosChip MCS9990 controller updates its microframe counter
+	 * a little before the frame counter, and occasionally we will read
+	 * the invalid intermediate value.  Avoid problems by checking the
+	 * microframe number (the low-order 3 bits); if they are 0 then
+	 * re-read the register to get the correct value.
+	 */
+	uf = ehci_readl(ehci, &ehci->regs->frame_index);
+	if (unlikely(ehci->frame_index_bug && ((uf & 7) == 0)))
+		uf = ehci_readl(ehci, &ehci->regs->frame_index);
+	return uf;
+}
+
+#endif
+
 /*-------------------------------------------------------------------------*/
 
 /*
@@ -482,7 +503,7 @@ static int enable_periodic (struct ehci_hcd *ehci)
 	ehci_to_hcd(ehci)->state = HC_STATE_RUNNING;
 
 	/* make sure ehci_work scans these */
-	ehci->next_uframe = ehci_readl(ehci, &ehci->regs->frame_index)
+	ehci->next_uframe = ehci_read_frame_index(ehci)
 		% (ehci->periodic_size << 3);
 	if (unlikely(ehci->broken_periodic))
 		ehci->last_periodic_enable = ktime_get_real();
@@ -1409,7 +1430,7 @@ iso_stream_schedule (
 		goto fail;
 	}
 
-	now = ehci_readl(ehci, &ehci->regs->frame_index) & (mod - 1);
+	now = ehci_read_frame_index(ehci) & (mod - 1);
 
 	/* Typical case: reuse current schedule, stream is still active.
 	 * Hopefully there are no gaps from the host falling behind
@@ -1455,30 +1476,36 @@ iso_stream_schedule (
 	 * jump until after the queue is primed.
 	 */
 	else {
+		int done = 0;
 		start = SCHEDULE_SLOP + (now & ~0x07);
 
 		/* NOTE:  assumes URB_ISO_ASAP, to limit complexity/bugs */
 
-		/* find a uframe slot with enough bandwidth */
-		next = start + period;
-		for (; start < next; start++) {
-
+		/* find a uframe slot with enough bandwidth.
+		 * Early uframes are more precious because full-speed
+		 * iso IN transfers can't use late uframes,
+		 * and therefore they should be allocated last.
+		 */
+		next = start;
+		start += period;
+		do {
+			start--;
 			/* check schedule: enough space? */
 			if (stream->highspeed) {
 				if (itd_slot_ok(ehci, mod, start,
 						stream->usecs, period))
-					break;
+					done = 1;
 			} else {
 				if ((start % 8) >= 6)
 					continue;
 				if (sitd_slot_ok(ehci, mod, stream,
 						start, sched, period))
-					break;
+					done = 1;
 			}
-		}
+		} while (start > next && !done);
 
 		/* no room in the schedule */
-		if (start == next) {
+		if (!done) {
 			ehci_dbg(ehci, "iso resched full %p (now %d max %d)\n",
 				urb, now, now + mod);
 			status = -ENOSPC;
@@ -2276,7 +2303,7 @@ scan_periodic (struct ehci_hcd *ehci)
 	 */
 	now_uframe = ehci->next_uframe;
 	if (HC_IS_RUNNING(ehci_to_hcd(ehci)->state)) {
-		clock = ehci_readl(ehci, &ehci->regs->frame_index);
+		clock = ehci_read_frame_index(ehci);
 		clock_frame = (clock >> 3) & (ehci->periodic_size - 1);
 	} else  {
 		clock = now_uframe + mod - 1;
@@ -2455,8 +2482,7 @@ restart:
 					|| ehci->periodic_sched == 0)
 				break;
 			ehci->next_uframe = now_uframe;
-			now = ehci_readl(ehci, &ehci->regs->frame_index) &
-					(mod - 1);
+			now = ehci_read_frame_index(ehci) & (mod - 1);
 			if (now_uframe == now)
 				break;