[PATCH v2 2/4] dmaengine: rcar-dmac: Add for_each_rcar_dmac_chan() helper

[Geert Uytterhoeven]

Add and helper macro for iterating over all DMAC channels, taking into
account the channel mask.  Use it where appropriate, to simplify code.

Restore "reverse Christmas tree" order of local variables while adding a
new variable.

Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
---
v2:
  - Put the full loop control of for_each_rcar_dmac_chan() on a single
    line, to improve readability.
---
 drivers/dma/sh/rcar-dmac.c | 22 ++++++++++------------
 1 file changed, 10 insertions(+), 12 deletions(-)

diff --git a/drivers/dma/sh/rcar-dmac.c b/drivers/dma/sh/rcar-dmac.c
index a57705356e8bb796..537550b4121bbc22 100644
--- a/drivers/dma/sh/rcar-dmac.c
+++ b/drivers/dma/sh/rcar-dmac.c
@@ -209,6 +209,10 @@ struct rcar_dmac {
 
 #define to_rcar_dmac(d)		container_of(d, struct rcar_dmac, engine)
 
+#define for_each_rcar_dmac_chan(i, chan, dmac)						\
+	for (i = 0, chan = &(dmac)->channels[0]; i < (dmac)->n_channels; i++, chan++)	\
+		if (!((dmac)->channels_mask & BIT(i))) continue; else
+
 /*
  * struct rcar_dmac_of_data - This driver's OF data
  * @chan_offset_base: DMAC channels base offset
@@ -817,15 +821,11 @@ static void rcar_dmac_chan_reinit(struct rcar_dmac_chan *chan)
 
 static void rcar_dmac_stop_all_chan(struct rcar_dmac *dmac)
 {
+	struct rcar_dmac_chan *chan;
 	unsigned int i;
 
 	/* Stop all channels. */
-	for (i = 0; i < dmac->n_channels; ++i) {
-		struct rcar_dmac_chan *chan = &dmac->channels[i];
-
-		if (!(dmac->channels_mask & BIT(i)))
-			continue;
-
+	for_each_rcar_dmac_chan(i, chan, dmac) {
 		/* Stop and reinitialize the channel. */
 		spin_lock_irq(&chan->lock);
 		rcar_dmac_chan_halt(chan);
@@ -1828,9 +1828,10 @@ static int rcar_dmac_probe(struct platform_device *pdev)
 		DMA_SLAVE_BUSWIDTH_2_BYTES | DMA_SLAVE_BUSWIDTH_4_BYTES |
 		DMA_SLAVE_BUSWIDTH_8_BYTES | DMA_SLAVE_BUSWIDTH_16_BYTES |
 		DMA_SLAVE_BUSWIDTH_32_BYTES | DMA_SLAVE_BUSWIDTH_64_BYTES;
+	const struct rcar_dmac_of_data *data;
+	struct rcar_dmac_chan *chan;
 	struct dma_device *engine;
 	struct rcar_dmac *dmac;
-	const struct rcar_dmac_of_data *data;
 	unsigned int i;
 	int ret;
 
@@ -1916,11 +1917,8 @@ static int rcar_dmac_probe(struct platform_device *pdev)
 
 	INIT_LIST_HEAD(&engine->channels);
 
-	for (i = 0; i < dmac->n_channels; ++i) {
-		if (!(dmac->channels_mask & BIT(i)))
-			continue;
-
-		ret = rcar_dmac_chan_probe(dmac, &dmac->channels[i], data, i);
+	for_each_rcar_dmac_chan(i, chan, dmac) {
+		ret = rcar_dmac_chan_probe(dmac, chan, data, i);
 		if (ret < 0)
 			goto error;
 	}
-- 
2.25.1