[PATCH] usb: cdnsp: : add scatter gather support for ISOC endpoint

[Pawel Laszczak]

Patch implements scatter gather support for isochronous endpoint.
This fix is forced by 'commit e81e7f9a0eb9
("usb: gadget: uvc: add scatter gather support")'.
After this fix CDNSP driver stop working with UVC class.

cc: <stable@xxxxxxxxxxxxxxx>
Fixes: 3d82904559f4 ("usb: cdnsp: cdns3 Add main part of Cadence USBSSP DRD Driver")
Signed-off-by: Pawel Laszczak <pawell@xxxxxxxxxxx>
---
 drivers/usb/cdns3/cdnsp-gadget.c |   2 +-
 drivers/usb/cdns3/cdnsp-gadget.h |   4 +-
 drivers/usb/cdns3/cdnsp-ring.c   | 110 +++++++++++++++++--------------
 3 files changed, 63 insertions(+), 53 deletions(-)

diff --git a/drivers/usb/cdns3/cdnsp-gadget.c b/drivers/usb/cdns3/cdnsp-gadget.c
index a8640516c895..e81dca0e62a8 100644
--- a/drivers/usb/cdns3/cdnsp-gadget.c
+++ b/drivers/usb/cdns3/cdnsp-gadget.c
@@ -382,7 +382,7 @@ int cdnsp_ep_enqueue(struct cdnsp_ep *pep, struct cdnsp_request *preq)
 		ret = cdnsp_queue_bulk_tx(pdev, preq);
 		break;
 	case USB_ENDPOINT_XFER_ISOC:
-		ret = cdnsp_queue_isoc_tx_prepare(pdev, preq);
+		ret = cdnsp_queue_isoc_tx(pdev, preq);
 	}
 
 	if (ret)
diff --git a/drivers/usb/cdns3/cdnsp-gadget.h b/drivers/usb/cdns3/cdnsp-gadget.h
index f740fa6089d8..e1b5801fdddf 100644
--- a/drivers/usb/cdns3/cdnsp-gadget.h
+++ b/drivers/usb/cdns3/cdnsp-gadget.h
@@ -1532,8 +1532,8 @@ void cdnsp_queue_stop_endpoint(struct cdnsp_device *pdev,
 			       unsigned int ep_index);
 int cdnsp_queue_ctrl_tx(struct cdnsp_device *pdev, struct cdnsp_request *preq);
 int cdnsp_queue_bulk_tx(struct cdnsp_device *pdev, struct cdnsp_request *preq);
-int cdnsp_queue_isoc_tx_prepare(struct cdnsp_device *pdev,
-				struct cdnsp_request *preq);
+int cdnsp_queue_isoc_tx(struct cdnsp_device *pdev,
+			struct cdnsp_request *preq);
 void cdnsp_queue_configure_endpoint(struct cdnsp_device *pdev,
 				    dma_addr_t in_ctx_ptr);
 void cdnsp_queue_reset_ep(struct cdnsp_device *pdev, unsigned int ep_index);
diff --git a/drivers/usb/cdns3/cdnsp-ring.c b/drivers/usb/cdns3/cdnsp-ring.c
index b23e543b3a3d..07f6068342d4 100644
--- a/drivers/usb/cdns3/cdnsp-ring.c
+++ b/drivers/usb/cdns3/cdnsp-ring.c
@@ -1333,6 +1333,20 @@ static int cdnsp_handle_tx_event(struct cdnsp_device *pdev,
 					 ep_ring->dequeue, td->last_trb,
 					 ep_trb_dma);
 
+		desc = td->preq->pep->endpoint.desc;
+
+		if (ep_seg) {
+			ep_trb = &ep_seg->trbs[(ep_trb_dma - ep_seg->dma)
+					       / sizeof(*ep_trb)];
+
+			trace_cdnsp_handle_transfer(ep_ring,
+					(struct cdnsp_generic_trb *)ep_trb);
+
+			if (pep->skip && usb_endpoint_xfer_isoc(desc) &&
+			    td->last_trb != ep_trb)
+				return -EAGAIN;
+		}
+
 		/*
 		 * Skip the Force Stopped Event. The event_trb(ep_trb_dma)
 		 * of FSE is not in the current TD pointed by ep_ring->dequeue
@@ -1347,7 +1361,6 @@ static int cdnsp_handle_tx_event(struct cdnsp_device *pdev,
 			goto cleanup;
 		}
 
-		desc = td->preq->pep->endpoint.desc;
 		if (!ep_seg) {
 			if (!pep->skip || !usb_endpoint_xfer_isoc(desc)) {
 				/* Something is busted, give up! */
@@ -1374,12 +1387,6 @@ static int cdnsp_handle_tx_event(struct cdnsp_device *pdev,
 			goto cleanup;
 		}
 
-		ep_trb = &ep_seg->trbs[(ep_trb_dma - ep_seg->dma)
-				       / sizeof(*ep_trb)];
-
-		trace_cdnsp_handle_transfer(ep_ring,
-					    (struct cdnsp_generic_trb *)ep_trb);
-
 		if (cdnsp_trb_is_noop(ep_trb))
 			goto cleanup;
 
@@ -1726,11 +1733,6 @@ static unsigned int count_sg_trbs_needed(struct cdnsp_request *preq)
 	return num_trbs;
 }
 
-static unsigned int count_isoc_trbs_needed(struct cdnsp_request *preq)
-{
-	return cdnsp_count_trbs(preq->request.dma, preq->request.length);
-}
-
 static void cdnsp_check_trb_math(struct cdnsp_request *preq, int running_total)
 {
 	if (running_total != preq->request.length)
@@ -2192,28 +2194,48 @@ static unsigned int
 }
 
 /* Queue function isoc transfer */
-static int cdnsp_queue_isoc_tx(struct cdnsp_device *pdev,
-			       struct cdnsp_request *preq)
+int cdnsp_queue_isoc_tx(struct cdnsp_device *pdev,
+			struct cdnsp_request *preq)
 {
-	int trb_buff_len, td_len, td_remain_len, ret;
+	unsigned int trb_buff_len, td_len, td_remain_len, block_len;
 	unsigned int burst_count, last_burst_pkt;
 	unsigned int total_pkt_count, max_pkt;
 	struct cdnsp_generic_trb *start_trb;
+	struct scatterlist *sg = NULL;
 	bool more_trbs_coming = true;
 	struct cdnsp_ring *ep_ring;
+	unsigned int num_sgs = 0;
 	int running_total = 0;
 	u32 field, length_field;
+	u64 addr, send_addr;
 	int start_cycle;
 	int trbs_per_td;
-	u64 addr;
-	int i;
+	int i, sent_len, ret;
 
 	ep_ring = preq->pep->ring;
+
+	td_len = preq->request.length;
+
+	if (preq->request.num_sgs) {
+		num_sgs = preq->request.num_sgs;
+		sg = preq->request.sg;
+		addr = (u64)sg_dma_address(sg);
+		block_len = sg_dma_len(sg);
+		trbs_per_td = count_sg_trbs_needed(preq);
+	} else {
+		addr = (u64)preq->request.dma;
+		block_len = td_len;
+		trbs_per_td = count_trbs_needed(preq);
+	}
+
+	ret = cdnsp_prepare_transfer(pdev, preq, trbs_per_td);
+	if (ret)
+		return ret;
+
 	start_trb = &ep_ring->enqueue->generic;
 	start_cycle = ep_ring->cycle_state;
-	td_len = preq->request.length;
-	addr = (u64)preq->request.dma;
 	td_remain_len = td_len;
+	send_addr = addr;
 
 	max_pkt = usb_endpoint_maxp(preq->pep->endpoint.desc);
 	total_pkt_count = DIV_ROUND_UP(td_len, max_pkt);
@@ -2225,11 +2247,6 @@ static int cdnsp_queue_isoc_tx(struct cdnsp_device *pdev,
 	burst_count = cdnsp_get_burst_count(pdev, preq, total_pkt_count);
 	last_burst_pkt = cdnsp_get_last_burst_packet_count(pdev, preq,
 							   total_pkt_count);
-	trbs_per_td = count_isoc_trbs_needed(preq);
-
-	ret = cdnsp_prepare_transfer(pdev, preq, trbs_per_td);
-	if (ret)
-		goto cleanup;
 
 	/*
 	 * Set isoc specific data for the first TRB in a TD.
@@ -2248,6 +2265,7 @@ static int cdnsp_queue_isoc_tx(struct cdnsp_device *pdev,
 
 		/* Calculate TRB length. */
 		trb_buff_len = TRB_BUFF_LEN_UP_TO_BOUNDARY(addr);
+		trb_buff_len = min(trb_buff_len, block_len);
 		if (trb_buff_len > td_remain_len)
 			trb_buff_len = td_remain_len;
 
@@ -2256,7 +2274,8 @@ static int cdnsp_queue_isoc_tx(struct cdnsp_device *pdev,
 					       trb_buff_len, td_len, preq,
 					       more_trbs_coming, 0);
 
-		length_field = TRB_LEN(trb_buff_len) | TRB_INTR_TARGET(0);
+		length_field = TRB_LEN(trb_buff_len) | TRB_TD_SIZE(remainder) |
+			TRB_INTR_TARGET(0);
 
 		/* Only first TRB is isoc, overwrite otherwise. */
 		if (i) {
@@ -2281,12 +2300,27 @@ static int cdnsp_queue_isoc_tx(struct cdnsp_device *pdev,
 		}
 
 		cdnsp_queue_trb(pdev, ep_ring, more_trbs_coming,
-				lower_32_bits(addr), upper_32_bits(addr),
+				lower_32_bits(send_addr), upper_32_bits(send_addr),
 				length_field, field);
 
 		running_total += trb_buff_len;
 		addr += trb_buff_len;
 		td_remain_len -= trb_buff_len;
+
+		sent_len = trb_buff_len;
+		while (sg && sent_len >= block_len) {
+			/* New sg entry */
+			--num_sgs;
+			sent_len -= block_len;
+			if (num_sgs != 0) {
+				sg = sg_next(sg);
+				block_len = sg_dma_len(sg);
+				addr = (u64)sg_dma_address(sg);
+				addr += sent_len;
+			}
+		}
+		block_len -= sent_len;
+		send_addr = addr;
 	}
 
 	/* Check TD length */
@@ -2324,30 +2358,6 @@ static int cdnsp_queue_isoc_tx(struct cdnsp_device *pdev,
 	return ret;
 }
 
-int cdnsp_queue_isoc_tx_prepare(struct cdnsp_device *pdev,
-				struct cdnsp_request *preq)
-{
-	struct cdnsp_ring *ep_ring;
-	u32 ep_state;
-	int num_trbs;
-	int ret;
-
-	ep_ring = preq->pep->ring;
-	ep_state = GET_EP_CTX_STATE(preq->pep->out_ctx);
-	num_trbs = count_isoc_trbs_needed(preq);
-
-	/*
-	 * Check the ring to guarantee there is enough room for the whole
-	 * request. Do not insert any td of the USB Request to the ring if the
-	 * check failed.
-	 */
-	ret = cdnsp_prepare_ring(pdev, ep_ring, ep_state, num_trbs, GFP_ATOMIC);
-	if (ret)
-		return ret;
-
-	return cdnsp_queue_isoc_tx(pdev, preq);
-}
-
 /****		Command Ring Operations		****/
 /*
  * Generic function for queuing a command TRB on the command ring.
-- 
2.25.1