1 files changed, 75 insertions, 33 deletions

diff --git a/drivers/usb/host/ehci-q.c b/drivers/usb/host/ehci-q.c
index 2e49de820b1..b85b54160cd 100644
--- a/drivers/usb/host/ehci-q.c
+++ b/drivers/usb/host/ehci-q.c
@@ -242,7 +242,8 @@ __acquires(ehci->lock)
 	if (unlikely(urb->unlinked)) {
 		COUNT(ehci->stats.unlink);
 	} else {
-		if (likely(status == -EINPROGRESS))
+		/* report non-error and short read status as zero */
+		if (status == -EINPROGRESS || status == -EREMOTEIO)
 			status = 0;
 		COUNT(ehci->stats.complete);
 	}
@@ -250,7 +251,7 @@ __acquires(ehci->lock)
 #ifdef EHCI_URB_TRACE
 	ehci_dbg (ehci,
 		"%s %s urb %p ep%d%s status %d len %d/%d\n",
-		__FUNCTION__, urb->dev->devpath, urb,
+		__func__, urb->dev->devpath, urb,
 		usb_pipeendpoint (urb->pipe),
 		usb_pipein (urb->pipe) ? "in" : "out",
 		status,
@@ -283,9 +284,8 @@ qh_completions (struct ehci_hcd *ehci, struct ehci_qh *qh)
 	int			last_status = -EINPROGRESS;
 	int			stopped;
 	unsigned		count = 0;
-	int			do_status = 0;
 	u8			state;
-	u32			halt = HALT_BIT(ehci);
+	__le32			halt = HALT_BIT(ehci);
 
 	if (unlikely (list_empty (&qh->qtd_list)))
 		return count;
@@ -309,7 +309,6 @@ qh_completions (struct ehci_hcd *ehci, struct ehci_qh *qh)
 		struct ehci_qtd	*qtd;
 		struct urb	*urb;
 		u32		token = 0;
-		int		qtd_status;
 
 		qtd = list_entry (entry, struct ehci_qtd, qtd_list);
 		urb = qtd->urb;
@@ -336,11 +335,20 @@ qh_completions (struct ehci_hcd *ehci, struct ehci_qh *qh)
 		/* always clean up qtds the hc de-activated */
 		if ((token & QTD_STS_ACTIVE) == 0) {
 
+			/* on STALL, error, and short reads this urb must
+			 * complete and all its qtds must be recycled.
+			 */
 			if ((token & QTD_STS_HALT) != 0) {
 				stopped = 1;
 
 			/* magic dummy for some short reads; qh won't advance.
 			 * that silicon quirk can kick in with this dummy too.
+			 *
+			 * other short reads won't stop the queue, including
+			 * control transfers (status stage handles that) or
+			 * most other single-qtd reads ... the queue stops if
+			 * URB_SHORT_NOT_OK was set so the driver submitting
+			 * the urbs could clean it up.
 			 */
 			} else if (IS_SHORT_READ (token)
 					&& !(qtd->hw_alt_next
@@ -354,28 +362,21 @@ qh_completions (struct ehci_hcd *ehci, struct ehci_qh *qh)
 				&& HC_IS_RUNNING (ehci_to_hcd(ehci)->state))) {
 			break;
 
+		/* scan the whole queue for unlinks whenever it stops */
 		} else {
 			stopped = 1;
 
-			if (unlikely (!HC_IS_RUNNING (ehci_to_hcd(ehci)->state)))
+			/* cancel everything if we halt, suspend, etc */
+			if (!HC_IS_RUNNING(ehci_to_hcd(ehci)->state))
 				last_status = -ESHUTDOWN;
 
-			/* ignore active urbs unless some previous qtd
-			 * for the urb faulted (including short read) or
-			 * its urb was canceled.  we may patch qh or qtds.
+			/* this qtd is active; skip it unless a previous qtd
+			 * for its urb faulted, or its urb was canceled.
 			 */
-			if (likely(last_status == -EINPROGRESS &&
-					!urb->unlinked))
-				continue;
-
-			/* issue status after short control reads */
-			if (unlikely (do_status != 0)
-					&& QTD_PID (token) == 0 /* OUT */) {
-				do_status = 0;
+			else if (last_status == -EINPROGRESS && !urb->unlinked)
 				continue;
-			}
 
-			/* token in overlay may be most current */
+			/* qh unlinked; token in overlay may be most current */
 			if (state == QH_STATE_IDLE
 					&& cpu_to_hc32(ehci, qtd->qtd_dma)
 						== qh->hw_current)
@@ -392,21 +393,32 @@ halt:
 			}
 		}
 
-		/* remove it from the queue */
-		qtd_status = qtd_copy_status(ehci, urb, qtd->length, token);
-		if (unlikely(qtd_status == -EREMOTEIO)) {
-			do_status = (!urb->unlinked &&
-					usb_pipecontrol(urb->pipe));
-			qtd_status = 0;
+		/* unless we already know the urb's status, collect qtd status
+		 * and update count of bytes transferred.  in common short read
+		 * cases with only one data qtd (including control transfers),
+		 * queue processing won't halt.  but with two or more qtds (for
+		 * example, with a 32 KB transfer), when the first qtd gets a
+		 * short read the second must be removed by hand.
+		 */
+		if (last_status == -EINPROGRESS) {
+			last_status = qtd_copy_status(ehci, urb,
+					qtd->length, token);
+			if (last_status == -EREMOTEIO
+					&& (qtd->hw_alt_next
+						& EHCI_LIST_END(ehci)))
+				last_status = -EINPROGRESS;
 		}
-		if (likely(last_status == -EINPROGRESS))
-			last_status = qtd_status;
 
+		/* if we're removing something not at the queue head,
+		 * patch the hardware queue pointer.
+		 */
 		if (stopped && qtd->qtd_list.prev != &qh->qtd_list) {
 			last = list_entry (qtd->qtd_list.prev,
 					struct ehci_qtd, qtd_list);
 			last->hw_next = qtd->hw_next;
 		}
+
+		/* remove qtd; it's recycled after possible urb completion */
 		list_del (&qtd->qtd_list);
 		last = qtd;
 	}
@@ -431,7 +443,15 @@ halt:
 			qh_refresh(ehci, qh);
 			break;
 		case QH_STATE_LINKED:
-			/* should be rare for periodic transfers,
+			/* We won't refresh a QH that's linked (after the HC
+			 * stopped the queue).  That avoids a race:
+			 *  - HC reads first part of QH;
+			 *  - CPU updates that first part and the token;
+			 *  - HC reads rest of that QH, including token
+			 * Result:  HC gets an inconsistent image, and then
+			 * DMAs to/from the wrong memory (corrupting it).
+			 *
+			 * That should be rare for interrupt transfers,
 			 * except maybe high bandwidth ...
 			 */
 			if ((cpu_to_hc32(ehci, QH_SMASK)
@@ -549,6 +569,12 @@ qh_urb_transaction (
 		this_qtd_len = qtd_fill(ehci, qtd, buf, len, token, maxpacket);
 		len -= this_qtd_len;
 		buf += this_qtd_len;
+
+		/*
+		 * short reads advance to a "magic" dummy instead of the next
+		 * qtd ... that forces the queue to stop, for manual cleanup.
+		 * (this will usually be overridden later.)
+		 */
 		if (is_input)
 			qtd->hw_alt_next = ehci->async->hw_alt_next;
 
@@ -568,8 +594,10 @@ qh_urb_transaction (
 		list_add_tail (&qtd->qtd_list, head);
 	}
 
-	/* unless the bulk/interrupt caller wants a chance to clean
-	 * up after short reads, hc should advance qh past this urb
+	/*
+	 * unless the caller requires manual cleanup after short reads,
+	 * have the alt_next mechanism keep the queue running after the
+	 * last data qtd (the only one, for control and most other cases).
 	 */
 	if (likely ((urb->transfer_flags & URB_SHORT_NOT_OK) == 0
 				|| usb_pipecontrol (urb->pipe)))
@@ -657,6 +685,14 @@ qh_make (
 	type = usb_pipetype (urb->pipe);
 	maxp = usb_maxpacket (urb->dev, urb->pipe, !is_input);
 
+	/* 1024 byte maxpacket is a hardware ceiling.  High bandwidth
+	 * acts like up to 3KB, but is built from smaller packets.
+	 */
+	if (max_packet(maxp) > 1024) {
+		ehci_dbg(ehci, "bogus qh maxpacket %d\n", max_packet(maxp));
+		goto done;
+	}
+
 	/* Compute interrupt scheduling parameters just once, and save.
 	 * - allowing for high bandwidth, how many nsec/uframe are used?
 	 * - split transactions need a second CSPLIT uframe; same question
@@ -757,7 +793,13 @@ qh_make (
 			info2 |= (EHCI_TUNE_MULT_HS << 30);
 		} else if (type == PIPE_BULK) {
 			info1 |= (EHCI_TUNE_RL_HS << 28);
-			info1 |= 512 << 16;	/* usb2 fixed maxpacket */
+			/* The USB spec says that high speed bulk endpoints
+			 * always use 512 byte maxpacket.  But some device
+			 * vendors decided to ignore that, and MSFT is happy
+			 * to help them do so.  So now people expect to use
+			 * such nonconformant devices with Linux too; sigh.
+			 */
+			info1 |= max_packet(maxp) << 16;
 			info2 |= (EHCI_TUNE_MULT_HS << 30);
 		} else {		/* PIPE_INTERRUPT */
 			info1 |= max_packet (maxp) << 16;
@@ -841,7 +883,7 @@ static struct ehci_qh *qh_append_tds (
 )
 {
 	struct ehci_qh		*qh = NULL;
-	u32			qh_addr_mask = cpu_to_hc32(ehci, 0x7f);
+	__hc32			qh_addr_mask = cpu_to_hc32(ehci, 0x7f);
 
 	qh = (struct ehci_qh *) *ptr;
 	if (unlikely (qh == NULL)) {
@@ -932,7 +974,7 @@ submit_async (
 #ifdef EHCI_URB_TRACE
 	ehci_dbg (ehci,
 		"%s %s urb %p ep%d%s len %d, qtd %p [qh %p]\n",
-		__FUNCTION__, urb->dev->devpath, urb,
+		__func__, urb->dev->devpath, urb,
 		epnum & 0x0f, (epnum & USB_DIR_IN) ? "in" : "out",
 		urb->transfer_buffer_length,
 		qtd, urb->ep->hcpriv);