1 files changed, 84 insertions, 68 deletions

diff --git a/drivers/usb/host/ehci-sched.c b/drivers/usb/host/ehci-sched.c
index 80d99bc..8a8e08a 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;