[PATCH] mtd: nand: tango: Enforce DMA direction type

On Mon, 20 Feb 2017 13:30:25 +0100
Marc Gonzalez [off-list ref] wrote:

On 13/02/2017 10:45, Boris Brezillon wrote:

quoted

do_dma() use an integer to pass the DMA data direction information and
pass the same value to dmaengine_prep_slave_sg().

Currently, DMA_{FROM,TO}_DEVICE match DMA_{DEV_TO_MEM,MEM_TO_DEV}
definitions so it works fine, but assuming this will always be the case
is not safe.

Enforce enum dma_data_direction type in the function prototype and make
the enum dma_data_direction -> enum dma_transfer_direction conversion
explicit.

Reported-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Boris Brezillon <redacted>
---
 drivers/mtd/nand/tango_nand.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/mtd/nand/tango_nand.c b/drivers/mtd/nand/tango_nand.c
index 4a5e948c62df..9a0e2f85d865 100644
--- a/drivers/mtd/nand/tango_nand.c
+++ b/drivers/mtd/nand/tango_nand.c

@@ -223,8 +223,8 @@ static void tango_dma_callback(void *arg)
 	complete(arg);
 }
 
-static int do_dma(struct tango_nfc *nfc, int dir, int cmd, const void *buf,
-		  int len, int page)
+static int do_dma(struct tango_nfc *nfc, enum dma_data_direction dir, int cmd,
+		  const void *buf, int len, int page)
 {
 	void __iomem *addr = nfc->reg_base + NFC_STATUS;
 	struct dma_chan *chan = nfc->chan;

@@ -238,7 +238,10 @@ static int do_dma(struct tango_nfc *nfc, int dir, int cmd, const void *buf,
 	if (dma_map_sg(chan->device->dev, &sg, 1, dir) != 1)
 		return -EIO;
 
-	desc = dmaengine_prep_slave_sg(chan, &sg, 1, dir, DMA_PREP_INTERRUPT);
+	desc = dmaengine_prep_slave_sg(chan, &sg, 1,
+				       dir == DMA_FROM_DEVICE ?
+				       DMA_DEV_TO_MEM : DMA_MEM_TO_DEV,
+				       DMA_PREP_INTERRUPT);
 	if (!desc)
 		goto dma_unmap;
 
  

How about evaluating the ternary conditional into a temp var?

Works for me.