1 files changed, 78 insertions, 33 deletions

diff --git a/drivers/rapidio/devices/tsi721_dma.c b/drivers/rapidio/devices/tsi721_dma.c
index 91245f5dbe81..9b60b1f3261c 100644
--- a/drivers/rapidio/devices/tsi721_dma.c
+++ b/drivers/rapidio/devices/tsi721_dma.c
@@ -304,35 +304,17 @@ struct tsi721_tx_desc *tsi721_desc_get(struct tsi721_bdma_chan *bdma_chan)
 }
 
 static int
-tsi721_fill_desc(struct tsi721_bdma_chan *bdma_chan,
-	struct tsi721_tx_desc *desc, struct scatterlist *sg,
+tsi721_desc_fill_init(struct tsi721_tx_desc *desc, struct scatterlist *sg,
 	enum dma_rtype rtype, u32 sys_size)
 {
 	struct tsi721_dma_desc *bd_ptr = desc->hw_desc;
 	u64 rio_addr;
 
-	if (sg_dma_len(sg) > TSI721_DMAD_BCOUNT1 + 1) {
-		dev_err(bdma_chan->dchan.device->dev,
-			"SG element is too large\n");
-		return -EINVAL;
-	}
-
-	dev_dbg(bdma_chan->dchan.device->dev,
-		"desc: 0x%llx, addr: 0x%llx len: 0x%x\n",
-		(u64)desc->txd.phys, (unsigned long long)sg_dma_address(sg),
-		sg_dma_len(sg));
-
-	dev_dbg(bdma_chan->dchan.device->dev,
-		"bd_ptr = %p did=%d raddr=0x%llx\n",
-		bd_ptr, desc->destid, desc->rio_addr);
-
 	/* Initialize DMA descriptor */
 	bd_ptr->type_id = cpu_to_le32((DTYPE1 << 29) |
 					(rtype << 19) | desc->destid);
-	if (desc->interrupt)
-		bd_ptr->type_id |= cpu_to_le32(TSI721_DMAD_IOF);
 	bd_ptr->bcount = cpu_to_le32(((desc->rio_addr & 0x3) << 30) |
-					(sys_size << 26) | sg_dma_len(sg));
+				     (sys_size << 26));
 	rio_addr = (desc->rio_addr >> 2) |
 				((u64)(desc->rio_addr_u & 0x3) << 62);
 	bd_ptr->raddr_lo = cpu_to_le32(rio_addr & 0xffffffff);
@@ -346,6 +328,20 @@ tsi721_fill_desc(struct tsi721_bdma_chan *bdma_chan,
 	return 0;
 }
 
+static int
+tsi721_desc_fill_end(struct tsi721_tx_desc *desc)
+{
+	struct tsi721_dma_desc *bd_ptr = desc->hw_desc;
+
+	/* Update DMA descriptor */
+	if (desc->interrupt)
+		bd_ptr->type_id |= cpu_to_le32(TSI721_DMAD_IOF);
+	bd_ptr->bcount |= cpu_to_le32(desc->bcount & TSI721_DMAD_BCOUNT1);
+
+	return 0;
+}
+
+
 static void tsi721_dma_chain_complete(struct tsi721_bdma_chan *bdma_chan,
 				      struct tsi721_tx_desc *desc)
 {
@@ -674,6 +670,7 @@ struct dma_async_tx_descriptor *tsi721_prep_rio_sg(struct dma_chan *dchan,
 	unsigned int i;
 	u32 sys_size = dma_to_mport(dchan->device)->sys_size;
 	enum dma_rtype rtype;
+	dma_addr_t next_addr = -1;
 
 	if (!sgl || !sg_len) {
 		dev_err(dchan->device->dev, "%s: No SG list\n", __func__);
@@ -704,36 +701,84 @@ struct dma_async_tx_descriptor *tsi721_prep_rio_sg(struct dma_chan *dchan,
 	for_each_sg(sgl, sg, sg_len, i) {
 		int err;
 
-		dev_dbg(dchan->device->dev, "%s: sg #%d\n", __func__, i);
+		if (sg_dma_len(sg) > TSI721_BDMA_MAX_BCOUNT) {
+			dev_err(dchan->device->dev,
+				"%s: SG entry %d is too large\n", __func__, i);
+			goto err_desc_put;
+		}
+
+		/*
+		 * If this sg entry forms contiguous block with previous one,
+		 * try to merge it into existing DMA descriptor
+		 */
+		if (desc) {
+			if (next_addr == sg_dma_address(sg) &&
+			    desc->bcount + sg_dma_len(sg) <=
+						TSI721_BDMA_MAX_BCOUNT) {
+				/* Adjust byte count of the descriptor */
+				desc->bcount += sg_dma_len(sg);
+				goto entry_done;
+			}
+
+			/*
+			 * Finalize this descriptor using total
+			 * byte count value.
+			 */
+			tsi721_desc_fill_end(desc);
+			dev_dbg(dchan->device->dev, "%s: desc final len: %d\n",
+				__func__, desc->bcount);
+		}
+
+		/*
+		 * Obtain and initialize a new descriptor
+		 */
 		desc = tsi721_desc_get(bdma_chan);
 		if (!desc) {
 			dev_err(dchan->device->dev,
-				"Not enough descriptors available\n");
-			goto err_desc_get;
+				"%s: Failed to get new descriptor for SG %d\n",
+				__func__, i);
+			goto err_desc_put;
 		}
 
-		if (sg_is_last(sg))
-			desc->interrupt = (flags & DMA_PREP_INTERRUPT) != 0;
-		else
-			desc->interrupt = false;
-
 		desc->destid = rext->destid;
 		desc->rio_addr = rio_addr;
 		desc->rio_addr_u = 0;
+		desc->bcount = sg_dma_len(sg);
+
+		dev_dbg(dchan->device->dev,
+			"sg%d desc: 0x%llx, addr: 0x%llx len: %d\n",
+			i, (u64)desc->txd.phys,
+			(unsigned long long)sg_dma_address(sg),
+			sg_dma_len(sg));
+
+		dev_dbg(dchan->device->dev,
+			"bd_ptr = %p did=%d raddr=0x%llx\n",
+			desc->hw_desc, desc->destid, desc->rio_addr);
 
-		err = tsi721_fill_desc(bdma_chan, desc, sg, rtype, sys_size);
+		err = tsi721_desc_fill_init(desc, sg, rtype, sys_size);
 		if (err) {
 			dev_err(dchan->device->dev,
 				"Failed to build desc: %d\n", err);
-			goto err_desc_get;
+			goto err_desc_put;
 		}
 
-		rio_addr += sg_dma_len(sg);
+		next_addr = sg_dma_address(sg);
 
 		if (!first)
 			first = desc;
 		else
 			list_add_tail(&desc->desc_node, &first->tx_list);
+
+entry_done:
+		if (sg_is_last(sg)) {
+			desc->interrupt = (flags & DMA_PREP_INTERRUPT) != 0;
+			tsi721_desc_fill_end(desc);
+			dev_dbg(dchan->device->dev, "%s: desc final len: %d\n",
+				__func__, desc->bcount);
+		} else {
+			rio_addr += sg_dma_len(sg);
+			next_addr += sg_dma_len(sg);
+		}
 	}
 
 	first->txd.cookie = -EBUSY;
@@ -741,7 +786,7 @@ struct dma_async_tx_descriptor *tsi721_prep_rio_sg(struct dma_chan *dchan,
 
 	return &first->txd;
 
-err_desc_get:
+err_desc_put:
 	tsi721_desc_put(bdma_chan, first);
 	return NULL;
 }
@@ -792,7 +837,7 @@ int tsi721_register_dma(struct tsi721_device *priv)
 		if (i == TSI721_DMACH_MAINT)
 			continue;
 
-		bdma_chan->bd_num = 64;
+		bdma_chan->bd_num = TSI721_BDMA_BD_RING_SZ;
 		bdma_chan->regs = priv->regs + TSI721_DMAC_BASE(i);
 
 		bdma_chan->dchan.device = &mport->dma;