usb: wusbcore: add support for isoc out transfers

This patch adds support for isochronous out transfers to the HWA.  The
primary changes are:

1.  Add a isoc_pack_desc_urb field to struct wa_seg.  This urb is used
to send the isochronous packet info message to the HWA which describes
the isoc data segment(s) that will be sent as the payload of the
transfer request.

2.  Use the URB iso_frame_desc field to populate the isochronous packet
info message and data segments sent to the HWA.

3.  After the data is sent and transfer result is returned from the
HWA, read the isoc packet status message from the HWA.  The contents of
the isoc packet status message are used to set the iso_frame_desc
status and actual_length fields in the original isoc URB.  This feature
required the addition of a some state tracking variables in struct wahc
so the dti_urb knows what type of packet it expects to receive next.

Signed-off-by: Thomas Pugliese <thomas.pugliese@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2 files changed, 406 insertions, 102 deletions

diff --git a/drivers/usb/wusbcore/wa-hc.h b/drivers/usb/wusbcore/wa-hc.h
index ab399343757..b44aca3f25d 100644
--- a/drivers/usb/wusbcore/wa-hc.h
+++ b/drivers/usb/wusbcore/wa-hc.h
@@ -122,6 +122,11 @@ struct wa_rpipe {
 };
 
 
+enum wa_dti_state {
+	WA_DTI_TRANSFER_RESULT_PENDING,
+	WA_DTI_ISOC_PACKET_STATUS_PENDING
+};
+
 /**
  * Instance of a HWA Host Controller
  *
@@ -181,6 +186,15 @@ struct wahc {
 	spinlock_t rpipe_bm_lock;	/* protect rpipe_bm */
 	struct mutex rpipe_mutex;	/* assigning resources to endpoints */
 
+	/*
+	 * dti_state is used to track the state of the dti_urb.  When dti_state
+	 * is WA_DTI_ISOC_PACKET_STATUS_PENDING, dti_isoc_xfer_in_progress and
+	 * dti_isoc_xfer_seg identify which xfer the incoming isoc packet status
+	 * refers to.
+	 */
+	enum wa_dti_state dti_state;
+	u32 dti_isoc_xfer_in_progress;
+	u8  dti_isoc_xfer_seg;
 	struct urb *dti_urb;		/* URB for reading xfer results */
 	struct urb *buf_in_urb;		/* URB for reading data in */
 	struct edc dti_edc;		/* DTI error density counter */
@@ -247,6 +261,7 @@ static inline void wa_init(struct wahc *wa)
 {
 	edc_init(&wa->nep_edc);
 	atomic_set(&wa->notifs_queued, 0);
+	wa->dti_state = WA_DTI_TRANSFER_RESULT_PENDING;
 	wa_rpipe_init(wa);
 	edc_init(&wa->dti_edc);
 	INIT_LIST_HEAD(&wa->xfer_list);
diff --git a/drivers/usb/wusbcore/wa-xfer.c b/drivers/usb/wusbcore/wa-xfer.c
index 13faac0ea99..e097da30a26 100644
--- a/drivers/usb/wusbcore/wa-xfer.c
+++ b/drivers/usb/wusbcore/wa-xfer.c
@@ -115,6 +115,7 @@ static void wa_xfer_delayed_run(struct wa_rpipe *);
  */
 struct wa_seg {
 	struct urb tr_urb;		/* transfer request urb. */
+	struct urb *isoc_pack_desc_urb;	/* for isoc packet descriptor. */
 	struct urb *dto_urb;		/* for data output. */
 	struct list_head list_node;	/* for rpipe->req_list */
 	struct wa_xfer *xfer;		/* out xfer */
@@ -122,7 +123,6 @@ struct wa_seg {
 	enum wa_seg_status status;
 	ssize_t result;			/* bytes xfered or error */
 	struct wa_xfer_hdr xfer_hdr;
-	u8 xfer_extra[];		/* xtra space for xfer_hdr_ctl */
 };
 
 static inline void wa_seg_init(struct wa_seg *seg)
@@ -169,7 +169,7 @@ static inline void wa_xfer_init(struct wa_xfer *xfer)
 /*
  * Destroy a transfer structure
  *
- * Note that freeing xfer->seg[cnt]->urb will free the containing
+ * Note that freeing xfer->seg[cnt]->tr_urb will free the containing
  * xfer->seg[cnt] memory that was allocated by __wa_xfer_setup_segs.
  */
 static void wa_xfer_destroy(struct kref *_xfer)
@@ -178,12 +178,14 @@ static void wa_xfer_destroy(struct kref *_xfer)
 	if (xfer->seg) {
 		unsigned cnt;
 		for (cnt = 0; cnt < xfer->segs; cnt++) {
-			if (xfer->seg[cnt]) {
-				if (xfer->seg[cnt]->dto_urb) {
-					kfree(xfer->seg[cnt]->dto_urb->sg);
-					usb_free_urb(xfer->seg[cnt]->dto_urb);
+			struct wa_seg *seg = xfer->seg[cnt];
+			if (seg) {
+				usb_free_urb(seg->isoc_pack_desc_urb);
+				if (seg->dto_urb) {
+					kfree(seg->dto_urb->sg);
+					usb_free_urb(seg->dto_urb);
 				}
-				usb_free_urb(&xfer->seg[cnt]->tr_urb);
+				usb_free_urb(&seg->tr_urb);
 			}
 		}
 		kfree(xfer->seg);
@@ -291,7 +293,8 @@ static unsigned __wa_xfer_is_done(struct wa_xfer *xfer)
 				goto out;
 			}
 			urb->actual_length += seg->result;
-			if (seg->result < xfer->seg_size
+			if (!(usb_pipeisoc(xfer->urb->pipe))
+				&& seg->result < xfer->seg_size
 			    && cnt != xfer->segs-1)
 				found_short = 1;
 			dev_dbg(dev, "xfer %p ID %08X#%u: DONE short %d "
@@ -429,39 +432,53 @@ static ssize_t __wa_xfer_setup_sizes(struct wa_xfer *xfer,
 		result = sizeof(struct wa_xfer_bi);
 		break;
 	case USB_ENDPOINT_XFER_ISOC:
-		dev_err(dev, "FIXME: ISOC not implemented\n");
-		result = -ENOSYS;
-		goto error;
+		if (usb_pipeout(urb->pipe)) {
+			*pxfer_type = WA_XFER_TYPE_ISO;
+			result = sizeof(struct wa_xfer_hwaiso);
+		} else {
+			dev_err(dev, "FIXME: ISOC IN not implemented\n");
+			result = -ENOSYS;
+			goto error;
+		}
+		break;
 	default:
 		/* never happens */
 		BUG();
 		result = -EINVAL;	/* shut gcc up */
-	};
+	}
 	xfer->is_inbound = urb->pipe & USB_DIR_IN ? 1 : 0;
 	xfer->is_dma = urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP ? 1 : 0;
-	xfer->seg_size = le16_to_cpu(rpipe->descr.wBlocks)
-		* 1 << (xfer->wa->wa_descr->bRPipeBlockSize - 1);
-	/* Compute the segment size and make sure it is a multiple of
-	 * the maxpktsize (WUSB1.0[8.3.3.1])...not really too much of
-	 * a check (FIXME) */
+
 	maxpktsize = le16_to_cpu(rpipe->descr.wMaxPacketSize);
-	if (xfer->seg_size < maxpktsize) {
-		dev_err(dev, "HW BUG? seg_size %zu smaller than maxpktsize "
-			"%zu\n", xfer->seg_size, maxpktsize);
-		result = -EINVAL;
-		goto error;
-	}
-	xfer->seg_size = (xfer->seg_size / maxpktsize) * maxpktsize;
-	xfer->segs = DIV_ROUND_UP(urb->transfer_buffer_length, xfer->seg_size);
-	if (xfer->segs >= WA_SEGS_MAX) {
-		dev_err(dev, "BUG? ops, number of segments %d bigger than %d\n",
-			(int)(urb->transfer_buffer_length / xfer->seg_size),
-			WA_SEGS_MAX);
-		result = -EINVAL;
-		goto error;
+	if ((rpipe->descr.bmAttribute & 0x3) == USB_ENDPOINT_XFER_ISOC) {
+		xfer->seg_size = maxpktsize;
+		xfer->segs = urb->number_of_packets;
+	} else {
+		xfer->seg_size = le16_to_cpu(rpipe->descr.wBlocks)
+			* 1 << (xfer->wa->wa_descr->bRPipeBlockSize - 1);
+		/* Compute the segment size and make sure it is a multiple of
+		 * the maxpktsize (WUSB1.0[8.3.3.1])...not really too much of
+		 * a check (FIXME) */
+		if (xfer->seg_size < maxpktsize) {
+			dev_err(dev,
+				"HW BUG? seg_size %zu smaller than maxpktsize %zu\n",
+				xfer->seg_size, maxpktsize);
+			result = -EINVAL;
+			goto error;
+		}
+		xfer->seg_size = (xfer->seg_size / maxpktsize) * maxpktsize;
+		xfer->segs = DIV_ROUND_UP(urb->transfer_buffer_length,
+						xfer->seg_size);
+		if (xfer->segs >= WA_SEGS_MAX) {
+			dev_err(dev, "BUG? oops, number of segments %d bigger than %d\n",
+				(urb->transfer_buffer_length/xfer->seg_size),
+				WA_SEGS_MAX);
+			result = -EINVAL;
+			goto error;
+		}
+		if (xfer->segs == 0 && *pxfer_type == WA_XFER_TYPE_CTL)
+			xfer->segs = 1;
 	}
-	if (xfer->segs == 0 && *pxfer_type == WA_XFER_TYPE_CTL)
-		xfer->segs = 1;
 error:
 	return result;
 }
@@ -491,8 +508,26 @@ static void __wa_xfer_setup_hdr0(struct wa_xfer *xfer,
 	}
 	case WA_XFER_TYPE_BI:
 		break;
-	case WA_XFER_TYPE_ISO:
-		printk(KERN_ERR "FIXME: ISOC not implemented\n");
+	case WA_XFER_TYPE_ISO: {
+		struct wa_xfer_hwaiso *xfer_iso =
+			container_of(xfer_hdr0, struct wa_xfer_hwaiso, hdr);
+		struct wa_xfer_packet_info_hwaiso *packet_desc =
+			((void *)xfer_iso) + xfer_hdr_size;
+		struct usb_iso_packet_descriptor *iso_frame_desc =
+			&(xfer->urb->iso_frame_desc[0]);
+		/* populate the isoc section of the transfer request. */
+		xfer_iso->dwNumOfPackets = cpu_to_le32(1);
+		/*
+		 * populate isoc packet descriptor.  This assumes 1
+		 * packet per segment.
+		 */
+		packet_desc->wLength = cpu_to_le16(sizeof(*packet_desc) +
+			sizeof(packet_desc->PacketLength[0]));
+		packet_desc->bPacketType = WA_XFER_ISO_PACKET_INFO;
+		packet_desc->PacketLength[0] =
+			cpu_to_le16(iso_frame_desc->length);
+		break;
+	}
 	default:
 		BUG();
 	};
@@ -570,6 +605,72 @@ static void wa_seg_dto_cb(struct urb *urb)
 }
 
 /*
+ * Callback for the isoc packet descriptor phase of the segment request
+ *
+ * Check wa_seg_tr_cb(); most comments also apply here because this
+ * function does almost the same thing and they work closely
+ * together.
+ *
+ * If the seg request has failed but this phase has succeeded,
+ * wa_seg_tr_cb() has already failed the segment and moved the
+ * status to WA_SEG_ERROR, so this will go through 'case 0' and
+ * effectively do nothing.
+ */
+static void wa_seg_iso_pack_desc_cb(struct urb *urb)
+{
+	struct wa_seg *seg = urb->context;
+	struct wa_xfer *xfer = seg->xfer;
+	struct wahc *wa;
+	struct device *dev;
+	struct wa_rpipe *rpipe;
+	unsigned long flags;
+	unsigned rpipe_ready = 0;
+	u8 done = 0;
+
+	switch (urb->status) {
+	case 0:
+		spin_lock_irqsave(&xfer->lock, flags);
+		wa = xfer->wa;
+		dev = &wa->usb_iface->dev;
+		dev_dbg(dev, "iso xfer %p#%u: packet descriptor done\n",
+			xfer, seg->index);
+		if (xfer->is_inbound && seg->status < WA_SEG_PENDING)
+			seg->status = WA_SEG_PENDING;
+		spin_unlock_irqrestore(&xfer->lock, flags);
+		break;
+	case -ECONNRESET:	/* URB unlinked; no need to do anything */
+	case -ENOENT:		/* as it was done by the who unlinked us */
+		break;
+	default:		/* Other errors ... */
+		spin_lock_irqsave(&xfer->lock, flags);
+		wa = xfer->wa;
+		dev = &wa->usb_iface->dev;
+		rpipe = xfer->ep->hcpriv;
+		pr_err_ratelimited("iso xfer %p#%u: packet descriptor error %d\n",
+				xfer, seg->index, urb->status);
+		if (edc_inc(&wa->nep_edc, EDC_MAX_ERRORS,
+			    EDC_ERROR_TIMEFRAME)){
+			dev_err(dev, "DTO: URB max acceptable errors exceeded, resetting device\n");
+			wa_reset_all(wa);
+		}
+		if (seg->status != WA_SEG_ERROR) {
+			usb_unlink_urb(seg->dto_urb);
+			seg->status = WA_SEG_ERROR;
+			seg->result = urb->status;
+			xfer->segs_done++;
+			__wa_xfer_abort(xfer);
+			rpipe_ready = rpipe_avail_inc(rpipe);
+			done = __wa_xfer_is_done(xfer);
+		}
+		spin_unlock_irqrestore(&xfer->lock, flags);
+		if (done)
+			wa_xfer_completion(xfer);
+		if (rpipe_ready)
+			wa_xfer_delayed_run(rpipe);
+	}
+}
+
+/*
  * Callback for the segment request
  *
  * If successful transition state (unless already transitioned or
@@ -583,7 +684,7 @@ static void wa_seg_dto_cb(struct urb *urb)
  * We have to check before setting the status to WA_SEG_PENDING
  * because sometimes the xfer result callback arrives before this
  * callback (geeeeeeze), so it might happen that we are already in
- * another state. As well, we don't set it if the transfer is inbound,
+ * another state. As well, we don't set it if the transfer is not inbound,
  * as in that case, wa_seg_dto_cb will do it when the OUT data phase
  * finishes.
  */
@@ -603,8 +704,11 @@ static void wa_seg_tr_cb(struct urb *urb)
 		spin_lock_irqsave(&xfer->lock, flags);
 		wa = xfer->wa;
 		dev = &wa->usb_iface->dev;
-		dev_dbg(dev, "xfer %p#%u: request done\n", xfer, seg->index);
-		if (xfer->is_inbound && seg->status < WA_SEG_PENDING)
+		dev_dbg(dev, "xfer %p ID 0x%08X#%u: request done\n",
+			xfer, wa_xfer_id(xfer), seg->index);
+		if (xfer->is_inbound &&
+			seg->status < WA_SEG_PENDING &&
+			!(usb_pipeisoc(xfer->urb->pipe)))
 			seg->status = WA_SEG_PENDING;
 		spin_unlock_irqrestore(&xfer->lock, flags);
 		break;
@@ -626,6 +730,7 @@ static void wa_seg_tr_cb(struct urb *urb)
 				"exceeded, resetting device\n");
 			wa_reset_all(wa);
 		}
+		usb_unlink_urb(seg->isoc_pack_desc_urb);
 		usb_unlink_urb(seg->dto_urb);
 		seg->status = WA_SEG_ERROR;
 		seg->result = urb->status;
@@ -724,6 +829,25 @@ static struct scatterlist *wa_xfer_create_subset_sg(struct scatterlist *in_sg,
 }
 
 /*
+ * Populate DMA buffer info for the isoc dto urb.
+ */
+static void __wa_populate_dto_urb_iso(struct wa_xfer *xfer,
+	struct wa_seg *seg,	int curr_iso_frame)
+{
+	/*
+	 * dto urb buffer address and size pulled from
+	 * iso_frame_desc.
+	 */
+	seg->dto_urb->transfer_dma = xfer->urb->transfer_dma +
+		xfer->urb->iso_frame_desc[curr_iso_frame].offset;
+	seg->dto_urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
+	seg->dto_urb->sg = NULL;
+	seg->dto_urb->num_sgs = 0;
+	seg->dto_urb->transfer_buffer_length =
+		xfer->urb->iso_frame_desc[curr_iso_frame].length;
+}
+
+/*
  * Populate buffer ptr and size, DMA buffer or SG list for the dto urb.
  */
 static int __wa_populate_dto_urb(struct wa_xfer *xfer,
@@ -788,7 +912,7 @@ static int __wa_xfer_setup_segs(struct wa_xfer *xfer, size_t xfer_hdr_size)
 	struct usb_device *usb_dev = xfer->wa->usb_dev;
 	const struct usb_endpoint_descriptor *dto_epd = xfer->wa->dto_epd;
 	struct wa_seg *seg;
-	size_t buf_itr, buf_size, buf_itr_size;
+	size_t buf_itr, buf_size, buf_itr_size, iso_pkt_descr_size = 0;
 
 	result = -ENOMEM;
 	xfer->seg = kcalloc(xfer->segs, sizeof(xfer->seg[0]), GFP_ATOMIC);
@@ -796,6 +920,17 @@ static int __wa_xfer_setup_segs(struct wa_xfer *xfer, size_t xfer_hdr_size)
 		goto error_segs_kzalloc;
 	buf_itr = 0;
 	buf_size = xfer->urb->transfer_buffer_length;
+
+	if (usb_pipeisoc(xfer->urb->pipe)) {
+		/*
+		 * This calculation assumes one isoc packet per xfer segment.
+		 * It will need to be updated if this changes.
+		 */
+		iso_pkt_descr_size = sizeof(struct wa_xfer_packet_info_hwaiso) +
+			sizeof(__le16);
+		alloc_size += iso_pkt_descr_size;
+	}
+
 	for (cnt = 0; cnt < xfer->segs; cnt++) {
 		seg = xfer->seg[cnt] = kmalloc(alloc_size, GFP_ATOMIC);
 		if (seg == NULL)
@@ -820,16 +955,40 @@ static int __wa_xfer_setup_segs(struct wa_xfer *xfer, size_t xfer_hdr_size)
 						dto_epd->bEndpointAddress),
 				NULL, 0, wa_seg_dto_cb, seg);
 
-			/* fill in the xfer buffer information. */
-			result = __wa_populate_dto_urb(xfer, seg,
-						buf_itr, buf_itr_size);
+			if (usb_pipeisoc(xfer->urb->pipe)) {
+				/* iso packet descriptor. */
+				seg->isoc_pack_desc_urb =
+						usb_alloc_urb(0, GFP_ATOMIC);
+				if (seg->isoc_pack_desc_urb == NULL)
+					goto error_iso_pack_desc_alloc;
+				/*
+				 * The buffer for the isoc packet descriptor
+				 * after the transfer request header in the
+				 * segment object memory buffer.
+				 */
+				usb_fill_bulk_urb(
+					seg->isoc_pack_desc_urb, usb_dev,
+					usb_sndbulkpipe(usb_dev,
+						dto_epd->bEndpointAddress),
+					(void *)(&seg->xfer_hdr) +
+						xfer_hdr_size,
+					iso_pkt_descr_size,
+					wa_seg_iso_pack_desc_cb, seg);
 
-			if (result < 0)
-				goto error_seg_outbound_populate;
+				/* fill in the xfer buffer information. */
+				__wa_populate_dto_urb_iso(xfer, seg, cnt);
+			} else {
+				/* fill in the xfer buffer information. */
+				result = __wa_populate_dto_urb(xfer, seg,
+							buf_itr, buf_itr_size);
+				if (result < 0)
+					goto error_seg_outbound_populate;
+
+				buf_itr += buf_itr_size;
+				buf_size -= buf_itr_size;
+			}
 		}
 		seg->status = WA_SEG_READY;
-		buf_itr += buf_itr_size;
-		buf_size -= buf_itr_size;
 	}
 	return 0;
 
@@ -838,6 +997,7 @@ static int __wa_xfer_setup_segs(struct wa_xfer *xfer, size_t xfer_hdr_size)
 	 * Use the fact that cnt is left at were it failed.  The remaining
 	 * segments will be cleaned up by wa_xfer_destroy.
 	 */
+error_iso_pack_desc_alloc:
 error_seg_outbound_populate:
 	usb_free_urb(xfer->seg[cnt]->dto_urb);
 error_dto_alloc:
@@ -881,21 +1041,50 @@ static int __wa_xfer_setup(struct wa_xfer *xfer, struct urb *urb)
 	wa_xfer_id_init(xfer);
 	__wa_xfer_setup_hdr0(xfer, xfer_hdr0, xfer_type, xfer_hdr_size);
 
-	/* Fill remainig headers */
+	/* Fill remaining headers */
 	xfer_hdr = xfer_hdr0;
-	transfer_size = urb->transfer_buffer_length;
-	xfer_hdr0->dwTransferLength = transfer_size > xfer->seg_size ?
-		xfer->seg_size : transfer_size;
-	transfer_size -=  xfer->seg_size;
-	for (cnt = 1; cnt < xfer->segs; cnt++) {
-		xfer_hdr = &xfer->seg[cnt]->xfer_hdr;
-		memcpy(xfer_hdr, xfer_hdr0, xfer_hdr_size);
-		xfer_hdr->bTransferSegment = cnt;
-		xfer_hdr->dwTransferLength = transfer_size > xfer->seg_size ?
-			cpu_to_le32(xfer->seg_size)
-			: cpu_to_le32(transfer_size);
-		xfer->seg[cnt]->status = WA_SEG_READY;
+	if (xfer_type == WA_XFER_TYPE_ISO) {
+		xfer_hdr0->dwTransferLength =
+			cpu_to_le32(xfer->urb->iso_frame_desc[0].length);
+		for (cnt = 1; cnt < xfer->segs; cnt++) {
+			struct usb_iso_packet_descriptor *iso_frame_desc =
+				&(xfer->urb->iso_frame_desc[cnt]);
+			struct wa_xfer_packet_info_hwaiso *packet_desc;
+
+			xfer_hdr = &xfer->seg[cnt]->xfer_hdr;
+			packet_desc = ((void *)xfer_hdr) + xfer_hdr_size;
+			/*
+			 * Copy values from the 0th header and isoc packet
+			 * descriptor.  Segment specific values are set below.
+			 */
+			memcpy(xfer_hdr, xfer_hdr0,
+				xfer_hdr_size + sizeof(*packet_desc));
+			xfer_hdr->bTransferSegment = cnt;
+			xfer_hdr->dwTransferLength =
+				cpu_to_le32(iso_frame_desc->length);
+			/* populate isoc packet descriptor length. */
+			packet_desc->PacketLength[0] =
+				cpu_to_le16(iso_frame_desc->length);
+
+			xfer->seg[cnt]->status = WA_SEG_READY;
+		}
+	} else {
+		transfer_size = urb->transfer_buffer_length;
+		xfer_hdr0->dwTransferLength = transfer_size > xfer->seg_size ?
+			cpu_to_le32(xfer->seg_size) :
+			cpu_to_le32(transfer_size);
 		transfer_size -=  xfer->seg_size;
+		for (cnt = 1; cnt < xfer->segs; cnt++) {
+			xfer_hdr = &xfer->seg[cnt]->xfer_hdr;
+			memcpy(xfer_hdr, xfer_hdr0, xfer_hdr_size);
+			xfer_hdr->bTransferSegment = cnt;
+			xfer_hdr->dwTransferLength =
+				transfer_size > xfer->seg_size ?
+					cpu_to_le32(xfer->seg_size)
+					: cpu_to_le32(transfer_size);
+			xfer->seg[cnt]->status = WA_SEG_READY;
+			transfer_size -=  xfer->seg_size;
+		}
 	}
 	xfer_hdr->bTransferSegment |= 0x80;	/* this is the last segment */
 	result = 0;
@@ -916,16 +1105,25 @@ static int __wa_seg_submit(struct wa_rpipe *rpipe, struct wa_xfer *xfer,
 	/* submit the transfer request. */
 	result = usb_submit_urb(&seg->tr_urb, GFP_ATOMIC);
 	if (result < 0) {
-		printk(KERN_ERR "xfer %p#%u: REQ submit failed: %d\n",
-		       xfer, seg->index, result);
+		pr_err("%s: xfer %p#%u: REQ submit failed: %d\n",
+		       __func__, xfer, seg->index, result);
 		goto error_seg_submit;
 	}
+	/* submit the isoc packet descriptor if present. */
+	if (seg->isoc_pack_desc_urb) {
+		result = usb_submit_urb(seg->isoc_pack_desc_urb, GFP_ATOMIC);
+		if (result < 0) {
+			pr_err("%s: xfer %p#%u: ISO packet descriptor submit failed: %d\n",
+			       __func__, xfer, seg->index, result);
+			goto error_iso_pack_desc_submit;
+		}
+	}
 	/* submit the out data if this is an out request. */
 	if (seg->dto_urb) {
 		result = usb_submit_urb(seg->dto_urb, GFP_ATOMIC);
 		if (result < 0) {
-			printk(KERN_ERR "xfer %p#%u: DTO submit failed: %d\n",
-			       xfer, seg->index, result);
+			pr_err("%s: xfer %p#%u: DTO submit failed: %d\n",
+			       __func__, xfer, seg->index, result);
 			goto error_dto_submit;
 		}
 	}
@@ -934,6 +1132,8 @@ static int __wa_seg_submit(struct wa_rpipe *rpipe, struct wa_xfer *xfer,
 	return 0;
 
 error_dto_submit:
+	usb_unlink_urb(seg->isoc_pack_desc_urb);
+error_iso_pack_desc_submit:
 	usb_unlink_urb(&seg->tr_urb);
 error_seg_submit:
 	seg->status = WA_SEG_ERROR;
@@ -1565,7 +1765,12 @@ static void wa_xfer_result_chew(struct wahc *wa, struct wa_xfer *xfer,
 	/* FIXME: we ignore warnings, tally them for stats */
 	if (usb_status & 0x40) 		/* Warning?... */
 		usb_status = 0;		/* ... pass */
-	if (xfer->is_inbound) {	/* IN data phase: read to buffer */
+	if (usb_pipeisoc(xfer->urb->pipe)) {
+		/* set up WA state to read the isoc packet status next. */
+		wa->dti_isoc_xfer_in_progress = wa_xfer_id(xfer);
+		wa->dti_isoc_xfer_seg = seg_idx;
+		wa->dti_state = WA_DTI_ISOC_PACKET_STATUS_PENDING;
+	} else if (xfer->is_inbound) {	/* IN data phase: read to buffer */
 		seg->status = WA_SEG_DTI_PENDING;
 		BUG_ON(wa->buf_in_urb->status == -EINPROGRESS);
 		/* this should always be 0 before a resubmit. */
@@ -1694,6 +1899,85 @@ segment_aborted:
 }
 
 /*
+ * Process a isochronous packet status message
+ *
+ * inbound transfers: need to schedule a buf_in_urb read
+ */
+static void wa_process_iso_packet_status(struct wahc *wa, struct urb *urb)
+{
+	struct device *dev = &wa->usb_iface->dev;
+	struct wa_xfer_packet_status_hwaiso *packet_status;
+	struct wa_xfer *xfer;
+	unsigned long flags;
+	struct wa_seg *seg;
+	struct wa_rpipe *rpipe;
+	unsigned done = 0;
+	unsigned rpipe_ready = 0;
+	const int expected_size = sizeof(*packet_status) +
+				sizeof(packet_status->PacketStatus[0]);
+
+	/* We have a xfer result buffer; check it */
+	dev_dbg(dev, "DTI: isoc packet status %d bytes at %p\n",
+		urb->actual_length, urb->transfer_buffer);
+	if (urb->actual_length != expected_size) {
+		dev_err(dev, "DTI Error: isoc packet status--bad urb length (%d bytes vs %zu needed)\n",
+			urb->actual_length, expected_size);
+		goto error_parse_buffer;
+	}
+	packet_status = (struct wa_xfer_packet_status_hwaiso *)(wa->dti_buf);
+	if (le16_to_cpu(packet_status->wLength) != expected_size) {
+		dev_err(dev, "DTI Error: isoc packet status--bad length %u\n",
+			le16_to_cpu(packet_status->wLength));
+		goto error_parse_buffer;
+	}
+	if (packet_status->bPacketType != WA_XFER_ISO_PACKET_STATUS) {
+		dev_err(dev, "DTI Error: isoc packet status--bad type 0x%02x\n",
+			packet_status->bPacketType);
+		goto error_parse_buffer;
+	}
+	xfer = wa_xfer_get_by_id(wa, wa->dti_isoc_xfer_in_progress);
+	if (xfer == NULL) {
+		dev_err(dev, "DTI Error: isoc packet status--unknown xfer 0x%08x\n",
+			wa->dti_isoc_xfer_in_progress);
+		goto error_parse_buffer;
+	}
+	spin_lock_irqsave(&xfer->lock, flags);
+	if (unlikely(wa->dti_isoc_xfer_seg >= xfer->segs))
+		goto error_bad_seg;
+	seg = xfer->seg[wa->dti_isoc_xfer_seg];
+	rpipe = xfer->ep->hcpriv;
+
+	/* set urb isoc packet status and length. */
+	xfer->urb->iso_frame_desc[seg->index].status =
+		wa_xfer_status_to_errno(
+		le16_to_cpu(packet_status->PacketStatus[0].PacketStatus));
+	xfer->urb->iso_frame_desc[seg->index].actual_length =
+		le16_to_cpu(packet_status->PacketStatus[0].PacketLength);
+
+	if (!xfer->is_inbound) {
+		/* OUT transfer, complete it -- */
+		seg->status = WA_SEG_DONE;
+		xfer->segs_done++;
+		rpipe_ready = rpipe_avail_inc(rpipe);
+		done = __wa_xfer_is_done(xfer);
+	}
+	spin_unlock_irqrestore(&xfer->lock, flags);
+	wa->dti_state = WA_DTI_TRANSFER_RESULT_PENDING;
+	if (done)
+		wa_xfer_completion(xfer);
+	if (rpipe_ready)
+		wa_xfer_delayed_run(rpipe);
+	wa_xfer_put(xfer);
+	return;
+
+error_bad_seg:
+	spin_unlock_irqrestore(&xfer->lock, flags);
+	wa_xfer_put(xfer);
+error_parse_buffer:
+	return;
+}
+
+/*
  * Callback for the IN data phase
  *
  * If successful transition state; otherwise, take a note of the
@@ -1799,51 +2083,56 @@ static void wa_dti_cb(struct urb *urb)
 	int result;
 	struct wahc *wa = urb->context;
 	struct device *dev = &wa->usb_iface->dev;
-	struct wa_xfer_result *xfer_result;
 	u32 xfer_id;
-	struct wa_xfer *xfer;
 	u8 usb_status;
 
 	BUG_ON(wa->dti_urb != urb);
 	switch (wa->dti_urb->status) {
 	case 0:
-		/* We have a xfer result buffer; check it */
-		dev_dbg(dev, "DTI: xfer result %d bytes at %p\n",
-			urb->actual_length, urb->transfer_buffer);
-		if (wa->dti_urb->actual_length != sizeof(*xfer_result)) {
-			dev_err(dev, "DTI Error: xfer result--bad size "
-				"xfer result (%d bytes vs %zu needed)\n",
-				urb->actual_length, sizeof(*xfer_result));
-			break;
-		}
-		xfer_result = (struct wa_xfer_result *)(wa->dti_buf);
-		if (xfer_result->hdr.bLength != sizeof(*xfer_result)) {
-			dev_err(dev, "DTI Error: xfer result--"
-				"bad header length %u\n",
-				xfer_result->hdr.bLength);
-			break;
-		}
-		if (xfer_result->hdr.bNotifyType != WA_XFER_RESULT) {
-			dev_err(dev, "DTI Error: xfer result--"
-				"bad header type 0x%02x\n",
-				xfer_result->hdr.bNotifyType);
-			break;
-		}
-		usb_status = xfer_result->bTransferStatus & 0x3f;
-		if (usb_status == WA_XFER_STATUS_NOT_FOUND)
-			/* taken care of already */
-			break;
-		xfer_id = le32_to_cpu(xfer_result->dwTransferID);
-		xfer = wa_xfer_get_by_id(wa, xfer_id);
-		if (xfer == NULL) {
-			/* FIXME: transaction might have been cancelled */
-			dev_err(dev, "DTI Error: xfer result--"
-				"unknown xfer 0x%08x (status 0x%02x)\n",
-				xfer_id, usb_status);
-			break;
+		if (wa->dti_state == WA_DTI_TRANSFER_RESULT_PENDING) {
+			struct wa_xfer_result *xfer_result;
+			struct wa_xfer *xfer;
+
+			/* We have a xfer result buffer; check it */
+			dev_dbg(dev, "DTI: xfer result %d bytes at %p\n",
+				urb->actual_length, urb->transfer_buffer);
+			if (urb->actual_length != sizeof(*xfer_result)) {
+				dev_err(dev, "DTI Error: xfer result--bad size xfer result (%d bytes vs %zu needed)\n",
+					urb->actual_length,
+					sizeof(*xfer_result));
+				break;
+			}
+			xfer_result = (struct wa_xfer_result *)(wa->dti_buf);
+			if (xfer_result->hdr.bLength != sizeof(*xfer_result)) {
+				dev_err(dev, "DTI Error: xfer result--bad header length %u\n",
+					xfer_result->hdr.bLength);
+				break;
+			}
+			if (xfer_result->hdr.bNotifyType != WA_XFER_RESULT) {
+				dev_err(dev, "DTI Error: xfer result--bad header type 0x%02x\n",
+					xfer_result->hdr.bNotifyType);
+				break;
+			}
+			usb_status = xfer_result->bTransferStatus & 0x3f;
+			if (usb_status == WA_XFER_STATUS_NOT_FOUND)
+				/* taken care of already */
+				break;
+			xfer_id = le32_to_cpu(xfer_result->dwTransferID);
+			xfer = wa_xfer_get_by_id(wa, xfer_id);
+			if (xfer == NULL) {
+				/* FIXME: transaction not found. */
+				dev_err(dev, "DTI Error: xfer result--unknown xfer 0x%08x (status 0x%02x)\n",
+					xfer_id, usb_status);
+				break;
+			}
+			wa_xfer_result_chew(wa, xfer, xfer_result);
+			wa_xfer_put(xfer);
+		} else if (wa->dti_state == WA_DTI_ISOC_PACKET_STATUS_PENDING) {
+			wa_process_iso_packet_status(wa, urb);
+		} else {
+			dev_err(dev, "DTI Error: unexpected EP state = %d\n",
+				wa->dti_state);
 		}
-		wa_xfer_result_chew(wa, xfer, xfer_result);
-		wa_xfer_put(xfer);
 		break;
 	case -ENOENT:		/* (we killed the URB)...so, no broadcast */
 	case -ESHUTDOWN:	/* going away! */