usb: wusbcore: use multiple urbs for HWA iso transfer result frame reads

Submit multiple concurrent urbs for HWA isochronous transfer result data
frame reads.  This keeps the read pipeline full and significantly
improves performance in cases where the frame reads cannot be combined
because they are not contiguous or multiples of the max packet size.

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

3 files changed, 134 insertions, 74 deletions

diff --git a/drivers/usb/wusbcore/wa-hc.c b/drivers/usb/wusbcore/wa-hc.c
index 368360f..252c7bd 100644
--- a/drivers/usb/wusbcore/wa-hc.c
+++ b/drivers/usb/wusbcore/wa-hc.c
@@ -75,8 +75,6 @@ void __wa_destroy(struct wahc *wa)
 	if (wa->dti_urb) {
 		usb_kill_urb(wa->dti_urb);
 		usb_put_urb(wa->dti_urb);
-		usb_kill_urb(wa->buf_in_urb);
-		usb_put_urb(wa->buf_in_urb);
 	}
 	kfree(wa->dti_buf);
 	wa_nep_destroy(wa);
diff --git a/drivers/usb/wusbcore/wa-hc.h b/drivers/usb/wusbcore/wa-hc.h
index 7510960..f2a8d29 100644
--- a/drivers/usb/wusbcore/wa-hc.h
+++ b/drivers/usb/wusbcore/wa-hc.h
@@ -125,7 +125,8 @@ struct wa_rpipe {
 
 enum wa_dti_state {
 	WA_DTI_TRANSFER_RESULT_PENDING,
-	WA_DTI_ISOC_PACKET_STATUS_PENDING
+	WA_DTI_ISOC_PACKET_STATUS_PENDING,
+	WA_DTI_BUF_IN_DATA_PENDING
 };
 
 enum wa_quirks {
@@ -146,6 +147,8 @@ enum wa_vendor_specific_requests {
 	WA_REQ_ALEREON_FEATURE_SET = 0x01,
 	WA_REQ_ALEREON_FEATURE_CLEAR = 0x00,
 };
+
+#define WA_MAX_BUF_IN_URBS	4
 /**
  * Instance of a HWA Host Controller
  *
@@ -216,7 +219,9 @@ struct wahc {
 	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 */
+					/* URBs for reading data in */
+	struct urb buf_in_urbs[WA_MAX_BUF_IN_URBS];
+	int active_buf_in_urbs;		/* number of buf_in_urbs active. */
 	struct edc dti_edc;		/* DTI error density counter */
 	void *dti_buf;
 	size_t dti_buf_size;
@@ -286,6 +291,8 @@ static inline void wa_rpipe_init(struct wahc *wa)
 
 static inline void wa_init(struct wahc *wa)
 {
+	int index;
+
 	edc_init(&wa->nep_edc);
 	atomic_set(&wa->notifs_queued, 0);
 	wa->dti_state = WA_DTI_TRANSFER_RESULT_PENDING;
@@ -299,6 +306,10 @@ static inline void wa_init(struct wahc *wa)
 	INIT_WORK(&wa->xfer_error_work, wa_process_errored_transfers_run);
 	wa->dto_in_use = 0;
 	atomic_set(&wa->xfer_id_count, 1);
+	/* init the buf in URBs */
+	for (index = 0; index < WA_MAX_BUF_IN_URBS; ++index)
+		usb_init_urb(&(wa->buf_in_urbs[index]));
+	wa->active_buf_in_urbs = 0;
 }
 
 /**
diff --git a/drivers/usb/wusbcore/wa-xfer.c b/drivers/usb/wusbcore/wa-xfer.c
index f930bbb..c8e2a47 100644
--- a/drivers/usb/wusbcore/wa-xfer.c
+++ b/drivers/usb/wusbcore/wa-xfer.c
@@ -2159,9 +2159,9 @@ static void wa_complete_remaining_xfer_segs(struct wa_xfer *xfer,
 	}
 }
 
-/* Populate the wa->buf_in_urb based on the current isoc transfer state. */
-static int __wa_populate_buf_in_urb_isoc(struct wahc *wa, struct wa_xfer *xfer,
-	struct wa_seg *seg)
+/* Populate the given urb based on the current isoc transfer state. */
+static int __wa_populate_buf_in_urb_isoc(struct wahc *wa,
+	struct urb *buf_in_urb, struct wa_xfer *xfer, struct wa_seg *seg)
 {
 	int urb_start_frame = seg->isoc_frame_index + seg->isoc_frame_offset;
 	int seg_index, total_len = 0, urb_frame_index = urb_start_frame;
@@ -2171,7 +2171,7 @@ static int __wa_populate_buf_in_urb_isoc(struct wahc *wa, struct wa_xfer *xfer,
 	int next_frame_contiguous;
 	struct usb_iso_packet_descriptor *iso_frame;
 
-	BUG_ON(wa->buf_in_urb->status == -EINPROGRESS);
+	BUG_ON(buf_in_urb->status == -EINPROGRESS);
 
 	/*
 	 * If the current frame actual_length is contiguous with the next frame
@@ -2201,68 +2201,68 @@ static int __wa_populate_buf_in_urb_isoc(struct wahc *wa, struct wa_xfer *xfer,
 			&& ((iso_frame->actual_length % dti_packet_size) == 0));
 
 	/* this should always be 0 before a resubmit. */
-	wa->buf_in_urb->num_mapped_sgs	= 0;
-	wa->buf_in_urb->transfer_dma = xfer->urb->transfer_dma +
+	buf_in_urb->num_mapped_sgs	= 0;
+	buf_in_urb->transfer_dma = xfer->urb->transfer_dma +
 		iso_frame_desc[urb_start_frame].offset;
-	wa->buf_in_urb->transfer_buffer_length = total_len;
-	wa->buf_in_urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
-	wa->buf_in_urb->transfer_buffer = NULL;
-	wa->buf_in_urb->sg = NULL;
-	wa->buf_in_urb->num_sgs = 0;
-	wa->buf_in_urb->context = seg;
+	buf_in_urb->transfer_buffer_length = total_len;
+	buf_in_urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
+	buf_in_urb->transfer_buffer = NULL;
+	buf_in_urb->sg = NULL;
+	buf_in_urb->num_sgs = 0;
+	buf_in_urb->context = seg;
 
 	/* return the number of frames included in this URB. */
 	return seg_index - seg->isoc_frame_index;
 }
 
-/* Populate the wa->buf_in_urb based on the current transfer state. */
-static int wa_populate_buf_in_urb(struct wahc *wa, struct wa_xfer *xfer,
+/* Populate the given urb based on the current transfer state. */
+static int wa_populate_buf_in_urb(struct urb *buf_in_urb, struct wa_xfer *xfer,
 	unsigned int seg_idx, unsigned int bytes_transferred)
 {
 	int result = 0;
 	struct wa_seg *seg = xfer->seg[seg_idx];
 
-	BUG_ON(wa->buf_in_urb->status == -EINPROGRESS);
+	BUG_ON(buf_in_urb->status == -EINPROGRESS);
 	/* this should always be 0 before a resubmit. */
-	wa->buf_in_urb->num_mapped_sgs	= 0;
+	buf_in_urb->num_mapped_sgs	= 0;
 
 	if (xfer->is_dma) {
-		wa->buf_in_urb->transfer_dma = xfer->urb->transfer_dma
+		buf_in_urb->transfer_dma = xfer->urb->transfer_dma
 			+ (seg_idx * xfer->seg_size);
-		wa->buf_in_urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
-		wa->buf_in_urb->transfer_buffer = NULL;
-		wa->buf_in_urb->sg = NULL;
-		wa->buf_in_urb->num_sgs = 0;
+		buf_in_urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
+		buf_in_urb->transfer_buffer = NULL;
+		buf_in_urb->sg = NULL;
+		buf_in_urb->num_sgs = 0;
 	} else {
 		/* do buffer or SG processing. */
-		wa->buf_in_urb->transfer_flags &= ~URB_NO_TRANSFER_DMA_MAP;
+		buf_in_urb->transfer_flags &= ~URB_NO_TRANSFER_DMA_MAP;
 
 		if (xfer->urb->transfer_buffer) {
-			wa->buf_in_urb->transfer_buffer =
+			buf_in_urb->transfer_buffer =
 				xfer->urb->transfer_buffer
 				+ (seg_idx * xfer->seg_size);
-			wa->buf_in_urb->sg = NULL;
-			wa->buf_in_urb->num_sgs = 0;
+			buf_in_urb->sg = NULL;
+			buf_in_urb->num_sgs = 0;
 		} else {
 			/* allocate an SG list to store seg_size bytes
 				and copy the subset of the xfer->urb->sg
 				that matches the buffer subset we are
 				about to read. */
-			wa->buf_in_urb->sg = wa_xfer_create_subset_sg(
+			buf_in_urb->sg = wa_xfer_create_subset_sg(
 				xfer->urb->sg,
 				seg_idx * xfer->seg_size,
 				bytes_transferred,
-				&(wa->buf_in_urb->num_sgs));
+				&(buf_in_urb->num_sgs));
 
-			if (!(wa->buf_in_urb->sg)) {
-				wa->buf_in_urb->num_sgs	= 0;
+			if (!(buf_in_urb->sg)) {
+				buf_in_urb->num_sgs	= 0;
 				result = -ENOMEM;
 			}
-			wa->buf_in_urb->transfer_buffer = NULL;
+			buf_in_urb->transfer_buffer = NULL;
 		}
 	}
-	wa->buf_in_urb->transfer_buffer_length = bytes_transferred;
-	wa->buf_in_urb->context = seg;
+	buf_in_urb->transfer_buffer_length = bytes_transferred;
+	buf_in_urb->context = seg;
 
 	return result;
 }
@@ -2287,6 +2287,7 @@ static void wa_xfer_result_chew(struct wahc *wa, struct wa_xfer *xfer,
 	u8 usb_status;
 	unsigned rpipe_ready = 0;
 	unsigned bytes_transferred = le32_to_cpu(xfer_result->dwTransferLength);
+	struct urb *buf_in_urb = &(wa->buf_in_urbs[0]);
 
 	spin_lock_irqsave(&xfer->lock, flags);
 	seg_idx = xfer_result->bTransferSegment & 0x7f;
@@ -2337,13 +2338,16 @@ static void wa_xfer_result_chew(struct wahc *wa, struct wa_xfer *xfer,
 			&& (bytes_transferred > 0)) {
 		/* IN data phase: read to buffer */
 		seg->status = WA_SEG_DTI_PENDING;
-		result = wa_populate_buf_in_urb(wa, xfer, seg_idx,
+		result = wa_populate_buf_in_urb(buf_in_urb, xfer, seg_idx,
 			bytes_transferred);
 		if (result < 0)
 			goto error_buf_in_populate;
-		result = usb_submit_urb(wa->buf_in_urb, GFP_ATOMIC);
-		if (result < 0)
+		++(wa->active_buf_in_urbs);
+		result = usb_submit_urb(buf_in_urb, GFP_ATOMIC);
+		if (result < 0) {
+			--(wa->active_buf_in_urbs);
 			goto error_submit_buf_in;
+		}
 	} else {
 		/* OUT data phase or no data, complete it -- */
 		seg->result = bytes_transferred;
@@ -2367,8 +2371,8 @@ error_submit_buf_in:
 		dev_err(dev, "xfer %p#%u: can't submit DTI data phase: %d\n",
 			xfer, seg_idx, result);
 	seg->result = result;
-	kfree(wa->buf_in_urb->sg);
-	wa->buf_in_urb->sg = NULL;
+	kfree(buf_in_urb->sg);
+	buf_in_urb->sg = NULL;
 error_buf_in_populate:
 	__wa_xfer_abort(xfer);
 	seg->status = WA_SEG_ERROR;
@@ -2477,16 +2481,16 @@ static int wa_process_iso_packet_status(struct wahc *wa, struct urb *urb)
 	for (seg_index = 0; seg_index < seg->isoc_frame_count; ++seg_index) {
 		struct usb_iso_packet_descriptor *iso_frame_desc =
 			xfer->urb->iso_frame_desc;
-		const int urb_frame_index =
+		const int xfer_frame_index =
 			seg->isoc_frame_offset + seg_index;
 
-		iso_frame_desc[urb_frame_index].status =
+		iso_frame_desc[xfer_frame_index].status =
 			wa_xfer_status_to_errno(
 			le16_to_cpu(status_array[seg_index].PacketStatus));
-		iso_frame_desc[urb_frame_index].actual_length =
+		iso_frame_desc[xfer_frame_index].actual_length =
 			le16_to_cpu(status_array[seg_index].PacketLength);
 		/* track the number of frames successfully transferred. */
-		if (iso_frame_desc[urb_frame_index].actual_length > 0) {
+		if (iso_frame_desc[xfer_frame_index].actual_length > 0) {
 			/* save the starting frame index for buf_in_urb. */
 			if (!data_frame_count)
 				first_frame_index = seg_index;
@@ -2495,21 +2499,53 @@ static int wa_process_iso_packet_status(struct wahc *wa, struct urb *urb)
 	}
 
 	if (xfer->is_inbound && data_frame_count) {
-		int result, urb_frame_count;
+		int result, total_frames_read = 0, urb_index = 0;
+		struct urb *buf_in_urb;
 
+		/* IN data phase: read to buffer */
+		seg->status = WA_SEG_DTI_PENDING;
+
+		/* start with the first frame with data. */
 		seg->isoc_frame_index = first_frame_index;
-		/* submit a read URB for the first frame with data. */
-		urb_frame_count = __wa_populate_buf_in_urb_isoc(wa, xfer, seg);
-		/* advance index to start of next read URB. */
-		seg->isoc_frame_index += urb_frame_count;
+		/* submit up to WA_MAX_BUF_IN_URBS read URBs. */
+		do {
+			int urb_frame_index, urb_frame_count;
+			struct usb_iso_packet_descriptor *iso_frame_desc;
+
+			buf_in_urb = &(wa->buf_in_urbs[urb_index]);
+			urb_frame_count = __wa_populate_buf_in_urb_isoc(wa,
+				buf_in_urb, xfer, seg);
+			/* advance frame index to start of next read URB. */
+			seg->isoc_frame_index += urb_frame_count;
+			total_frames_read += urb_frame_count;
+
+			++(wa->active_buf_in_urbs);
+			result = usb_submit_urb(buf_in_urb, GFP_ATOMIC);
+
+			/* skip 0-byte frames. */
+			urb_frame_index =
+				seg->isoc_frame_offset + seg->isoc_frame_index;
+			iso_frame_desc =
+				&(xfer->urb->iso_frame_desc[urb_frame_index]);
+			while ((seg->isoc_frame_index <
+						seg->isoc_frame_count) &&
+				 (iso_frame_desc->actual_length == 0)) {
+				++(seg->isoc_frame_index);
+				++iso_frame_desc;
+			}
+			++urb_index;
+
+		} while ((result == 0) && (urb_index < WA_MAX_BUF_IN_URBS)
+				&& (seg->isoc_frame_index <
+						seg->isoc_frame_count));
 
-		result = usb_submit_urb(wa->buf_in_urb, GFP_ATOMIC);
 		if (result < 0) {
+			--(wa->active_buf_in_urbs);
 			dev_err(dev, "DTI Error: Could not submit buf in URB (%d)",
 				result);
 			wa_reset_all(wa);
-		} else if (data_frame_count > urb_frame_count)
-			/* If we need to read multiple frames, set DTI busy. */
+		} else if (data_frame_count > total_frames_read)
+			/* If we need to read more frames, set DTI busy. */
 			dti_busy = 1;
 	} else {
 		/* OUT transfer or no more IN data, complete it -- */
@@ -2517,7 +2553,10 @@ static int wa_process_iso_packet_status(struct wahc *wa, struct urb *urb)
 		done = __wa_xfer_mark_seg_as_done(xfer, seg, WA_SEG_DONE);
 	}
 	spin_unlock_irqrestore(&xfer->lock, flags);
-	wa->dti_state = WA_DTI_TRANSFER_RESULT_PENDING;
+	if (dti_busy)
+		wa->dti_state = WA_DTI_BUF_IN_DATA_PENDING;
+	else
+		wa->dti_state = WA_DTI_TRANSFER_RESULT_PENDING;
 	if (done)
 		wa_xfer_completion(xfer);
 	if (rpipe_ready)
@@ -2551,7 +2590,7 @@ static void wa_buf_in_cb(struct urb *urb)
 	struct wa_rpipe *rpipe;
 	unsigned rpipe_ready = 0, isoc_data_frame_count = 0;
 	unsigned long flags;
-	int resubmit_dti = 0;
+	int resubmit_dti = 0, active_buf_in_urbs;
 	u8 done = 0;
 
 	/* free the sg if it was used. */
@@ -2561,6 +2600,8 @@ static void wa_buf_in_cb(struct urb *urb)
 	spin_lock_irqsave(&xfer->lock, flags);
 	wa = xfer->wa;
 	dev = &wa->usb_iface->dev;
+	--(wa->active_buf_in_urbs);
+	active_buf_in_urbs = wa->active_buf_in_urbs;
 
 	if (usb_pipeisoc(xfer->urb->pipe)) {
 		struct usb_iso_packet_descriptor *iso_frame_desc =
@@ -2596,12 +2637,14 @@ static void wa_buf_in_cb(struct urb *urb)
 			int result, urb_frame_count;
 
 			/* submit a read URB for the next frame with data. */
-			urb_frame_count = __wa_populate_buf_in_urb_isoc(wa,
+			urb_frame_count = __wa_populate_buf_in_urb_isoc(wa, urb,
 				 xfer, seg);
 			/* advance index to start of next read URB. */
 			seg->isoc_frame_index += urb_frame_count;
-			result = usb_submit_urb(wa->buf_in_urb, GFP_ATOMIC);
+			++(wa->active_buf_in_urbs);
+			result = usb_submit_urb(urb, GFP_ATOMIC);
 			if (result < 0) {
+				--(wa->active_buf_in_urbs);
 				dev_err(dev, "DTI Error: Could not submit buf in URB (%d)",
 					result);
 				wa_reset_all(wa);
@@ -2615,7 +2658,7 @@ static void wa_buf_in_cb(struct urb *urb)
 			 */
 			  resubmit_dti = (isoc_data_frame_count ==
 							urb_frame_count);
-		} else {
+		} else if (active_buf_in_urbs == 0) {
 			rpipe = xfer->ep->hcpriv;
 			dev_dbg(dev,
 				"xfer %p 0x%08X#%u: data in done (%zu bytes)\n",
@@ -2635,7 +2678,12 @@ static void wa_buf_in_cb(struct urb *urb)
 	case -ENOENT:		/* as it was done by the who unlinked us */
 		break;
 	default:		/* Other errors ... */
-		resubmit_dti = 1;
+		/*
+		 * Error on data buf read.  Only resubmit DTI if it hasn't
+		 * already been done by previously hitting this error or by a
+		 * successful completion of the previous buf_in_urb.
+		 */
+		resubmit_dti = wa->dti_state != WA_DTI_TRANSFER_RESULT_PENDING;
 		spin_lock_irqsave(&xfer->lock, flags);
 		rpipe = xfer->ep->hcpriv;
 		if (printk_ratelimit())
@@ -2650,8 +2698,11 @@ static void wa_buf_in_cb(struct urb *urb)
 		}
 		seg->result = urb->status;
 		rpipe_ready = rpipe_avail_inc(rpipe);
-		__wa_xfer_abort(xfer);
-		done = __wa_xfer_mark_seg_as_done(xfer, seg, WA_SEG_ERROR);
+		if (active_buf_in_urbs == 0)
+			done = __wa_xfer_mark_seg_as_done(xfer, seg,
+				WA_SEG_ERROR);
+		else
+			__wa_xfer_abort(xfer);
 		spin_unlock_irqrestore(&xfer->lock, flags);
 		if (done)
 			wa_xfer_completion(xfer);
@@ -2660,7 +2711,11 @@ static void wa_buf_in_cb(struct urb *urb)
 	}
 
 	if (resubmit_dti) {
-		int result = usb_submit_urb(wa->dti_urb, GFP_ATOMIC);
+		int result;
+
+		wa->dti_state = WA_DTI_TRANSFER_RESULT_PENDING;
+
+		result = usb_submit_urb(wa->dti_urb, GFP_ATOMIC);
 		if (result < 0) {
 			dev_err(dev, "DTI Error: Could not submit DTI URB (%d)\n",
 				result);
@@ -2794,7 +2849,7 @@ int wa_dti_start(struct wahc *wa)
 {
 	const struct usb_endpoint_descriptor *dti_epd = wa->dti_epd;
 	struct device *dev = &wa->usb_iface->dev;
-	int result = -ENOMEM;
+	int result = -ENOMEM, index;
 
 	if (wa->dti_urb != NULL)	/* DTI URB already started */
 		goto out;
@@ -2810,15 +2865,14 @@ int wa_dti_start(struct wahc *wa)
 		wa->dti_buf, wa->dti_buf_size,
 		wa_dti_cb, wa);
 
-	wa->buf_in_urb = usb_alloc_urb(0, GFP_KERNEL);
-	if (wa->buf_in_urb == NULL) {
-		dev_err(dev, "Can't allocate BUF-IN URB\n");
-		goto error_buf_in_urb_alloc;
+	/* init the buf in URBs */
+	for (index = 0; index < WA_MAX_BUF_IN_URBS; ++index) {
+		usb_fill_bulk_urb(
+			&(wa->buf_in_urbs[index]), wa->usb_dev,
+			usb_rcvbulkpipe(wa->usb_dev,
+				0x80 | dti_epd->bEndpointAddress),
+			NULL, 0, wa_buf_in_cb, wa);
 	}
-	usb_fill_bulk_urb(
-		wa->buf_in_urb, wa->usb_dev,
-		usb_rcvbulkpipe(wa->usb_dev, 0x80 | dti_epd->bEndpointAddress),
-		NULL, 0, wa_buf_in_cb, wa);
 	result = usb_submit_urb(wa->dti_urb, GFP_KERNEL);
 	if (result < 0) {
 		dev_err(dev, "DTI Error: Could not submit DTI URB (%d) resetting\n",
@@ -2829,9 +2883,6 @@ out:
 	return 0;
 
 error_dti_urb_submit:
-	usb_put_urb(wa->buf_in_urb);
-	wa->buf_in_urb = NULL;
-error_buf_in_urb_alloc:
 	usb_put_urb(wa->dti_urb);
 	wa->dti_urb = NULL;
 error_dti_urb_alloc: