Implement better error recovery for Transaction Translators, TTs,

found in High Speed USB HUBs which translate from High Speed USB into
FULL or LOW speed USB. In some rare cases SPLIT transactions might get
lost, which might leave the TT in an unknown state. Whenever we detect
such an error try to issue either a clear TT buffer request, or if
that is not possible reset the whole TT.

MFC after:	1 week

1 files changed, 26 insertions, 8 deletions

diff --git a/sys/dev/usb/usb_transfer.c b/sys/dev/usb/usb_transfer.c
index 562ebb0..0a3a782 100644
--- a/sys/dev/usb/usb_transfer.c
+++ b/sys/dev/usb/usb_transfer.c
@@ -2432,7 +2432,9 @@ usbd_transfer_enqueue(struct usb_xfer_queue *pq, struct usb_xfer *xfer)
 void
 usbd_transfer_done(struct usb_xfer *xfer, usb_error_t error)
 {
-	USB_BUS_LOCK_ASSERT(xfer->xroot->bus, MA_OWNED);
+	struct usb_xfer_root *info = xfer->xroot;
+
+	USB_BUS_LOCK_ASSERT(info->bus, MA_OWNED);
 
 	DPRINTF("err=%s\n", usbd_errstr(error));
 
@@ -2446,10 +2448,10 @@ usbd_transfer_done(struct usb_xfer *xfer, usb_error_t error)
 		xfer->flags_int.control_act = 0;
 		return;
 	}
-	/* only set transfer error if not already set */
-	if (!xfer->error) {
+	/* only set transfer error, if not already set */
+	if (xfer->error == USB_ERR_NORMAL_COMPLETION)
 		xfer->error = error;
-	}
+
 	/* stop any callouts */
 	usb_callout_stop(&xfer->timeout_handle);
 
@@ -2461,14 +2463,14 @@ usbd_transfer_done(struct usb_xfer *xfer, usb_error_t error)
 	usbd_transfer_dequeue(xfer);
 
 #if USB_HAVE_BUSDMA
-	if (mtx_owned(xfer->xroot->xfer_mtx)) {
+	if (mtx_owned(info->xfer_mtx)) {
 		struct usb_xfer_queue *pq;
 
 		/*
 		 * If the private USB lock is not locked, then we assume
 		 * that the BUS-DMA load stage has been passed:
 		 */
-		pq = &xfer->xroot->dma_q;
+		pq = &info->dma_q;
 
 		if (pq->curr == xfer) {
 			/* start the next BUS-DMA load, if any */
@@ -2478,10 +2480,10 @@ usbd_transfer_done(struct usb_xfer *xfer, usb_error_t error)
 #endif
 	/* keep some statistics */
 	if (xfer->error) {
-		xfer->xroot->bus->stats_err.uds_requests
+		info->bus->stats_err.uds_requests
 		    [xfer->endpoint->edesc->bmAttributes & UE_XFERTYPE]++;
 	} else {
-		xfer->xroot->bus->stats_ok.uds_requests
+		info->bus->stats_ok.uds_requests
 		    [xfer->endpoint->edesc->bmAttributes & UE_XFERTYPE]++;
 	}
 
@@ -2847,6 +2849,22 @@ usbd_callback_wrapper_sub(struct usb_xfer *xfer)
 		/* end of control transfer, if any */
 		xfer->flags_int.control_act = 0;
 
+#if USB_HAVE_TT_SUPPORT
+		switch (xfer->error) {
+		case USB_ERR_NORMAL_COMPLETION:
+		case USB_ERR_SHORT_XFER:
+		case USB_ERR_STALLED:
+		case USB_ERR_CANCELLED:
+			/* nothing to do */
+			break;
+		default:
+			/* try to reset the TT, if any */
+			USB_BUS_LOCK(bus);
+			uhub_tt_buffer_reset_async_locked(xfer->xroot->udev, xfer->endpoint);
+			USB_BUS_UNLOCK(bus);
+			break;
+		}
+#endif
 		/* check if we should block the execution queue */
 		if ((xfer->error != USB_ERR_CANCELLED) &&
 		    (xfer->flags.pipe_bof)) {