1 files changed, 84 insertions, 68 deletions

diff --git a/drivers/usb/host/ehci-sched.c b/drivers/usb/host/ehci-sched.c
index 80d99bce2b38..8a8e08a51ba3 100644
--- a/drivers/usb/host/ehci-sched.c
+++ b/drivers/usb/host/ehci-sched.c
@@ -119,7 +119,8 @@ periodic_usecs (struct ehci_hcd *ehci, unsigned frame, unsigned uframe)
                         q = &q->fstn->fstn_next;
                         break;
                 case Q_TYPE_ITD:
-                        usecs += q->itd->usecs [uframe];
+                        if (q->itd->hw_transaction[uframe])
+                                usecs += q->itd->stream->usecs;
                         hw_p = &q->itd->hw_next;
                         q = &q->itd->itd_next;
                         break;
@@ -211,7 +212,7 @@ static inline void carryover_tt_bandwidth(unsigned short tt_usecs[8])
  * low/fullspeed transfer can "carry over" from one uframe to the next,
  * since the TT just performs downstream transfers in sequence.
  *
- * For example two seperate 100 usec transfers can start in the same uframe,
+ * For example two separate 100 usec transfers can start in the same uframe,
  * and the second one would "carry over" 75 usecs into the next uframe.
  */
 static void
@@ -1536,7 +1537,6 @@ itd_link_urb (
                 uframe = next_uframe & 0x07;
                 frame = next_uframe >> 3;
 
-                itd->usecs [uframe] = stream->usecs;
                 itd_patch(ehci, itd, iso_sched, packet, uframe);
 
                 next_uframe += stream->interval;
@@ -1565,6 +1565,16 @@ itd_link_urb (
 
 #define ISO_ERRS (EHCI_ISOC_BUF_ERR | EHCI_ISOC_BABBLE | EHCI_ISOC_XACTERR)
 
+/* Process and recycle a completed ITD.  Return true iff its urb completed,
+ * and hence its completion callback probably added things to the hardware
+ * schedule.
+ *
+ * Note that we carefully avoid recycling this descriptor until after any
+ * completion callback runs, so that it won't be reused quickly.  That is,
+ * assuming (a) no more than two urbs per frame on this endpoint, and also
+ * (b) only this endpoint's completions submit URBs.  It seems some silicon
+ * corrupts things if you reuse completed descriptors very quickly...
+ */
 static unsigned
 itd_complete (
         struct ehci_hcd *ehci,
@@ -1577,6 +1587,7 @@ itd_complete (
         int                                     urb_index = -1;
         struct ehci_iso_stream                  *stream = itd->stream;
         struct usb_device                       *dev;
+        unsigned                                retval = false;
 
         /* for each uframe with a packet */
         for (uframe = 0; uframe < 8; uframe++) {
@@ -1610,30 +1621,21 @@ itd_complete (
                 }
         }
 
-        usb_put_urb (urb);
-        itd->urb = NULL;
-        itd->stream = NULL;
-        list_move (&itd->itd_list, &stream->free_list);
-        iso_stream_put (ehci, stream);
-
         /* handle completion now? */
         if (likely ((urb_index + 1) != urb->number_of_packets))
-                return 0;
+                goto done;
 
         /* ASSERT: it's really the last itd for this urb
         list_for_each_entry (itd, &stream->td_list, itd_list)
                 BUG_ON (itd->urb == urb);
          */
 
-        /* give urb back to the driver ... can be out-of-order */
+        /* give urb back to the driver; completion often (re)submits */
         dev = urb->dev;
         ehci_urb_done(ehci, urb, 0);
+        retval = true;
         urb = NULL;
-
-        /* defer stopping schedule; completion can submit */
         ehci->periodic_sched--;
-        if (unlikely (!ehci->periodic_sched))
-                (void) disable_periodic (ehci);
         ehci_to_hcd(ehci)->self.bandwidth_isoc_reqs--;
 
         if (unlikely (list_empty (&stream->td_list))) {
@@ -1645,8 +1647,15 @@ itd_complete (
                         (stream->bEndpointAddress & USB_DIR_IN) ? "in" : "out");
         }
         iso_stream_put (ehci, stream);
+        /* OK to recycle this ITD now that its completion callback ran. */
+done:
+        usb_put_urb(urb);
+        itd->urb = NULL;
+        itd->stream = NULL;
+        list_move(&itd->itd_list, &stream->free_list);
+        iso_stream_put(ehci, stream);
 
-        return 1;
+        return retval;
 }
 
 /*-------------------------------------------------------------------------*/
@@ -1712,8 +1721,6 @@ done:
         return status;
 }
 
-#ifdef CONFIG_USB_EHCI_SPLIT_ISO
-
 /*-------------------------------------------------------------------------*/
 
 /*
@@ -1950,6 +1957,16 @@ sitd_link_urb (
 #define SITD_ERRS (SITD_STS_ERR | SITD_STS_DBE | SITD_STS_BABBLE \
                                 | SITD_STS_XACT | SITD_STS_MMF)
 
+/* Process and recycle a completed SITD.  Return true iff its urb completed,
+ * and hence its completion callback probably added things to the hardware
+ * schedule.
+ *
+ * Note that we carefully avoid recycling this descriptor until after any
+ * completion callback runs, so that it won't be reused quickly.  That is,
+ * assuming (a) no more than two urbs per frame on this endpoint, and also
+ * (b) only this endpoint's completions submit URBs.  It seems some silicon
+ * corrupts things if you reuse completed descriptors very quickly...
+ */
 static unsigned
 sitd_complete (
         struct ehci_hcd         *ehci,
@@ -1961,6 +1978,7 @@ sitd_complete (
         int                                     urb_index = -1;
         struct ehci_iso_stream                  *stream = sitd->stream;
         struct usb_device                       *dev;
+        unsigned                                retval = false;
 
         urb_index = sitd->index;
         desc = &urb->iso_frame_desc [urb_index];
@@ -1981,32 +1999,23 @@ sitd_complete (
                 desc->status = 0;
                 desc->actual_length = desc->length - SITD_LENGTH (t);
         }
-
-        usb_put_urb (urb);
-        sitd->urb = NULL;
-        sitd->stream = NULL;
-        list_move (&sitd->sitd_list, &stream->free_list);
         stream->depth -= stream->interval << 3;
-        iso_stream_put (ehci, stream);
 
         /* handle completion now? */
         if ((urb_index + 1) != urb->number_of_packets)
-                return 0;
+                goto done;
 
         /* ASSERT: it's really the last sitd for this urb
         list_for_each_entry (sitd, &stream->td_list, sitd_list)
                 BUG_ON (sitd->urb == urb);
          */
 
-        /* give urb back to the driver */
+        /* give urb back to the driver; completion often (re)submits */
         dev = urb->dev;
         ehci_urb_done(ehci, urb, 0);
+        retval = true;
         urb = NULL;
-
-        /* defer stopping schedule; completion can submit */
         ehci->periodic_sched--;
-        if (!ehci->periodic_sched)
-                (void) disable_periodic (ehci);
         ehci_to_hcd(ehci)->self.bandwidth_isoc_reqs--;
 
         if (list_empty (&stream->td_list)) {
@@ -2018,8 +2027,15 @@ sitd_complete (
                         (stream->bEndpointAddress & USB_DIR_IN) ? "in" : "out");
         }
         iso_stream_put (ehci, stream);
+        /* OK to recycle this SITD now that its completion callback ran. */
+done:
+        usb_put_urb(urb);
+        sitd->urb = NULL;
+        sitd->stream = NULL;
+        list_move(&sitd->sitd_list, &stream->free_list);
+        iso_stream_put(ehci, stream);
 
-        return 1;
+        return retval;
 }
 
 
@@ -2082,26 +2098,6 @@ done:
         return status;
 }
 
-#else
-
-static inline int
-sitd_submit (struct ehci_hcd *ehci, struct urb *urb, gfp_t mem_flags)
-{
-        ehci_dbg (ehci, "split iso support is disabled\n");
-        return -ENOSYS;
-}
-
-static inline unsigned
-sitd_complete (
-        struct ehci_hcd         *ehci,
-        struct ehci_sitd        *sitd
-) {
-        ehci_err (ehci, "sitd_complete %p?\n", sitd);
-        return 0;
-}
-
-#endif /* USB_EHCI_SPLIT_ISO */
-
 /*-------------------------------------------------------------------------*/
 
 static void
@@ -2127,17 +2123,9 @@ scan_periodic (struct ehci_hcd *ehci)
         for (;;) {
                 union ehci_shadow       q, *q_p;
                 __hc32                  type, *hw_p;
-                unsigned                uframes;
+                unsigned                incomplete = false;
 
-                /* don't scan past the live uframe */
                 frame = now_uframe >> 3;
-                if (frame == (clock >> 3))
-                        uframes = now_uframe & 0x07;
-                else {
-                        /* safe to scan the whole frame at once */
-                        now_uframe |= 0x07;
-                        uframes = 8;
-                }
 
 restart:
                 /* scan each element in frame's queue for completions */
@@ -2175,12 +2163,15 @@ restart:
                                 q = q.fstn->fstn_next;
                                 break;
                         case Q_TYPE_ITD:
-                                /* skip itds for later in the frame */
+                                /* If this ITD is still active, leave it for
+                                 * later processing ... check the next entry.
+                                 */
                                 rmb ();
-                                for (uf = live ? uframes : 8; uf < 8; uf++) {
+                                for (uf = 0; uf < 8 && live; uf++) {
                                         if (0 == (q.itd->hw_transaction [uf]
                                                         & ITD_ACTIVE(ehci)))
                                                 continue;
+                                        incomplete = true;
                                         q_p = &q.itd->itd_next;
                                         hw_p = &q.itd->hw_next;
                                         type = Q_NEXT_TYPE(ehci,
@@ -2188,10 +2179,12 @@ restart:
                                         q = *q_p;
                                         break;
                                 }
-                                if (uf != 8)
+                                if (uf < 8 && live)
                                         break;
 
-                                /* this one's ready ... HC won't cache the
+                                /* Take finished ITDs out of the schedule
+                                 * and process them:  recycle, maybe report
+                                 * URB completion.  HC won't cache the
                                  * pointer for much longer, if at all.
                                  */
                                 *q_p = q.itd->itd_next;
@@ -2202,8 +2195,12 @@ restart:
                                 q = *q_p;
                                 break;
                         case Q_TYPE_SITD:
+                                /* If this SITD is still active, leave it for
+                                 * later processing ... check the next entry.
+                                 */
                                 if ((q.sitd->hw_results & SITD_ACTIVE(ehci))
                                                 && live) {
+                                        incomplete = true;
                                         q_p = &q.sitd->sitd_next;
                                         hw_p = &q.sitd->hw_next;
                                         type = Q_NEXT_TYPE(ehci,
@@ -2211,6 +2208,11 @@ restart:
                                         q = *q_p;
                                         break;
                                 }
+
+                                /* Take finished SITDs out of the schedule
+                                 * and process them:  recycle, maybe report
+                                 * URB completion.
+                                 */
                                 *q_p = q.sitd->sitd_next;
                                 *hw_p = q.sitd->hw_next;
                                 type = Q_NEXT_TYPE(ehci, q.sitd->hw_next);
@@ -2226,11 +2228,24 @@ restart:
                         }
 
                         /* assume completion callbacks modify the queue */
-                        if (unlikely (modified))
-                                goto restart;
+                        if (unlikely (modified)) {
+                                if (likely(ehci->periodic_sched > 0))
+                                        goto restart;
+                                /* maybe we can short-circuit this scan! */
+                                disable_periodic(ehci);
+                                now_uframe = clock;
+                                break;
+                        }
                 }
 
-                /* stop when we catch up to the HC */
+                /* If we can tell we caught up to the hardware, stop now.
+                 * We can't advance our scan without collecting the ISO
+                 * transfers that are still pending in this frame.
+                 */
+                if (incomplete && HC_IS_RUNNING(ehci_to_hcd(ehci)->state)) {
+                        ehci->next_uframe = now_uframe;
+                        break;
+                }
 
                 // FIXME:  this assumes we won't get lapped when
                 // latencies climb; that should be rare, but...
@@ -2243,7 +2258,8 @@ restart:
                 if (now_uframe == clock) {
                         unsigned        now;
 
-                        if (!HC_IS_RUNNING (ehci_to_hcd(ehci)->state))
+                        if (!HC_IS_RUNNING (ehci_to_hcd(ehci)->state)
+                                        || ehci->periodic_sched == 0)
                                 break;
                         ehci->next_uframe = now_uframe;
                         now = ehci_readl(ehci, &ehci->regs->frame_index) % mod;