1 files changed, 46 insertions, 23 deletions

diff --git a/drivers/usb/host/ehci-sched.c b/drivers/usb/host/ehci-sched.c
index 6c9fbe352f7..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
+
 /*-------------------------------------------------------------------------*/
 
 /*
@@ -172,7 +193,7 @@ periodic_usecs (struct ehci_hcd *ehci, unsigned frame, unsigned uframe)
                 }
         }
 #ifdef  DEBUG
-        if (usecs > 100)
+        if (usecs > ehci->uframe_periodic_max)
                 ehci_err (ehci, "uframe %d sched overrun: %d usecs\n",
                         frame * 8 + uframe, usecs);
 #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();
@@ -709,11 +730,8 @@ static int check_period (
         if (uframe >= 8)
                 return 0;
 
-        /*
-         * 80% periodic == 100 usec/uframe available
-         * convert "usecs we need" to "max already claimed"
-         */
-        usecs = 100 - usecs;
+        /* convert "usecs we need" to "max already claimed" */
+        usecs = ehci->uframe_periodic_max - usecs;
 
         /* we "know" 2 and 4 uframe intervals were rejected; so
          * for period 0, check _every_ microframe in the schedule.
@@ -1286,9 +1304,9 @@ itd_slot_ok (
 {
         uframe %= period;
         do {
-                /* can't commit more than 80% periodic == 100 usec */
+                /* can't commit more than uframe_periodic_max usec */
                 if (periodic_usecs (ehci, uframe >> 3, uframe & 0x7)
-                                > (100 - usecs))
+                                > (ehci->uframe_periodic_max - usecs))
                         return 0;
 
                 /* we know urb->interval is 2^N uframes */
@@ -1345,7 +1363,7 @@ sitd_slot_ok (
 #endif
 
                 /* check starts (OUT uses more than one) */
-                max_used = 100 - stream->usecs;
+                max_used = ehci->uframe_periodic_max - stream->usecs;
                 for (tmp = stream->raw_mask & 0xff; tmp; tmp >>= 1, uf++) {
                         if (periodic_usecs (ehci, frame, uf) > max_used)
                                 return 0;
@@ -1354,7 +1372,7 @@ sitd_slot_ok (
                 /* for IN, check CSPLIT */
                 if (stream->c_usecs) {
                         uf = uframe & 7;
-                        max_used = 100 - stream->c_usecs;
+                        max_used = ehci->uframe_periodic_max - stream->c_usecs;
                         do {
                                 tmp = 1 << uf;
                                 tmp <<= 8;
@@ -1412,7 +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
@@ -1458,30 +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;
@@ -2279,7 +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;
@@ -2458,8 +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;