[PATCH v5 3/3] dma: imx-sdma: reorg code to make code clean

[Robin Gong <b38343@freescale.com>]

Code reorg for transfer prepare and bus width check to make code
cleaner.

Signed-off-by: Robin Gong <b38343@freescale.com>
---
 drivers/dma/imx-sdma.c | 127 +++++++++++++++++++++++--------------------------
 1 file changed, 60 insertions(+), 67 deletions(-)

diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c
index 377bb18..f2dee57 100644
--- a/drivers/dma/imx-sdma.c
+++ b/drivers/dma/imx-sdma.c
@@ -1026,6 +1026,52 @@ static void sdma_free_chan_resources(struct dma_chan *chan)
 	clk_disable(sdma->clk_ahb);
 }
 
+static int sdma_transfer_init(struct sdma_channel *sdmac,
+			      enum dma_transfer_direction direction)
+{
+	int ret = 0;
+
+	sdmac->status = DMA_IN_PROGRESS;
+	sdmac->buf_tail = 0;
+	sdmac->flags = 0;
+	sdmac->direction = direction;
+
+	ret = sdma_load_context(sdmac);
+	if (ret)
+		return ret;
+
+	sdmac->chn_count = 0;
+
+	return ret;
+}
+
+static int check_bd_buswidth(struct sdma_buffer_descriptor *bd,
+			     struct sdma_channel *sdmac, int count,
+			     dma_addr_t dma_dst, dma_addr_t dma_src)
+{
+	int ret = 0;
+
+	switch (sdmac->word_size) {
+	case DMA_SLAVE_BUSWIDTH_4_BYTES:
+		bd->mode.command = 0;
+		if ((count | dma_dst | dma_src) & 3)
+			ret = -EINVAL;
+		break;
+	case DMA_SLAVE_BUSWIDTH_2_BYTES:
+		bd->mode.command = 2;
+		if ((count | dma_dst | dma_src) & 1)
+			ret = -EINVAL;
+		break;
+	case DMA_SLAVE_BUSWIDTH_1_BYTE:
+		 bd->mode.command = 1;
+		 break;
+	default:
+		 return -EINVAL;
+	}
+
+	return ret;
+}
+
 static struct dma_async_tx_descriptor *sdma_prep_memcpy(
 		struct dma_chan *chan, dma_addr_t dma_dst,
 		dma_addr_t dma_src, size_t len, unsigned long flags)
@@ -1034,7 +1080,7 @@ static struct dma_async_tx_descriptor *sdma_prep_memcpy(
 	struct sdma_engine *sdma = sdmac->sdma;
 	int channel = sdmac->channel;
 	size_t count;
-	int i = 0, param, ret;
+	int i = 0, param;
 	struct sdma_buffer_descriptor *bd;
 
 	if (!chan || !len || sdmac->status == DMA_IN_PROGRESS)
@@ -1046,21 +1092,12 @@ static struct dma_async_tx_descriptor *sdma_prep_memcpy(
 		goto err_out;
 	}
 
-	sdmac->status = DMA_IN_PROGRESS;
-
-	sdmac->buf_tail = 0;
-
 	dev_dbg(sdma->dev, "memcpy: %pad->%pad, len=%zu, channel=%d.\n",
 		&dma_src, &dma_dst, len, channel);
 
-	sdmac->direction = DMA_MEM_TO_MEM;
-
-	ret = sdma_load_context(sdmac);
-	if (ret)
+	if (sdma_transfer_init(sdmac, DMA_MEM_TO_MEM))
 		goto err_out;
 
-	sdmac->chn_count = 0;
-
 	do {
 		count = min_t(size_t, len, SDMA_BD_MAX_CNT);
 		bd = &sdmac->bd[i];
@@ -1068,28 +1105,8 @@ static struct dma_async_tx_descriptor *sdma_prep_memcpy(
 		bd->ext_buffer_addr = dma_dst;
 		bd->mode.count = count;
 
-		if (sdmac->word_size > DMA_SLAVE_BUSWIDTH_4_BYTES) {
-			ret =  -EINVAL;
+		if (check_bd_buswidth(bd, sdmac, count, dma_dst, dma_src))
 			goto err_out;
-		}
-
-		switch (sdmac->word_size) {
-		case DMA_SLAVE_BUSWIDTH_4_BYTES:
-			bd->mode.command = 0;
-			if ((count | dma_dst | dma_src) & 3)
-				return NULL;
-			break;
-		case DMA_SLAVE_BUSWIDTH_2_BYTES:
-			bd->mode.command = 2;
-			if ((count | dma_dst | dma_src) & 1)
-				return NULL;
-			break;
-		case DMA_SLAVE_BUSWIDTH_1_BYTE:
-			bd->mode.command = 1;
-			break;
-		default:
-			return NULL;
-		}
 
 		dma_src += count;
 		dma_dst += count;
@@ -1141,21 +1158,10 @@ static struct dma_async_tx_descriptor *sdma_prep_sg(
 
 	if (sdmac->status == DMA_IN_PROGRESS)
 		return NULL;
-	sdmac->status = DMA_IN_PROGRESS;
-
-	sdmac->flags = 0;
-
-	sdmac->buf_tail = 0;
 
 	dev_dbg(sdma->dev, "setting up %d entries for channel %d.\n",
 			src_nents, channel);
 
-	sdmac->direction = direction;
-
-	ret = sdma_load_context(sdmac);
-	if (ret)
-		goto err_out;
-
 	if (src_nents > NUM_BD) {
 		dev_err(sdma->dev, "SDMA channel %d: maximum number of sg exceeded: %d > %d\n",
 				channel, src_nents, NUM_BD);
@@ -1163,7 +1169,9 @@ static struct dma_async_tx_descriptor *sdma_prep_sg(
 		goto err_out;
 	}
 
-	sdmac->chn_count = 0;
+	if (sdma_transfer_init(sdmac, direction))
+		goto err_out;
+
 	for_each_sg(src_sg, sg_src, src_nents, i) {
 		struct sdma_buffer_descriptor *bd = &sdmac->bd[i];
 		int param;
@@ -1187,30 +1195,15 @@ static struct dma_async_tx_descriptor *sdma_prep_sg(
 		bd->mode.count = count;
 		sdmac->chn_count += count;
 
-		if (sdmac->word_size > DMA_SLAVE_BUSWIDTH_4_BYTES) {
-			ret =  -EINVAL;
+		if (direction == DMA_MEM_TO_MEM)
+			ret = check_bd_buswidth(bd, sdmac, count,
+						sg_dst->dma_address,
+						sg_src->dma_address);
+		else
+			ret = check_bd_buswidth(bd, sdmac, count, 0,
+						sg_src->dma_address);
+		if (ret)
 			goto err_out;
-		}
-
-		switch (sdmac->word_size) {
-		case DMA_SLAVE_BUSWIDTH_4_BYTES:
-			bd->mode.command = 0;
-			if ((count | sg_src->dma_address | (sg_dst &&
-				(sg_dst->dma_address))) & 3)
-				return NULL;
-			break;
-		case DMA_SLAVE_BUSWIDTH_2_BYTES:
-			bd->mode.command = 2;
-			if ((count | sg_src->dma_address |
-				(sg_dst && (sg_dst->dma_address))) & 1)
-				return NULL;
-			break;
-		case DMA_SLAVE_BUSWIDTH_1_BYTE:
-			bd->mode.command = 1;
-			break;
-		default:
-			return NULL;
-		}
 
 		param = BD_DONE | BD_EXTD | BD_CONT;
 
-- 
1.9.1