[PATCH/RFC] spi: sh-msiof: Fix FIFO size to 64 word from 256 word

[Yoshihiro Kaneko <ykaneko0929@gmail.com>]

From: Koji Matsuoka <koji.matsuoka.xm@renesas.com>

The upper limit of Tx/Rx FIFO size is 64 word by the
specification of H/W. This patch corrects to 64 word from 256 word.

Signed-off-by: Koji Matsuoka <koji.matsuoka.xm@renesas.com>
Signed-off-by: Yoshihiro Kaneko <ykaneko0929@gmail.com>
---

This patch is based on the for-next branch of Mark Brown's spi tree.

 drivers/spi/spi-sh-msiof.c | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/drivers/spi/spi-sh-msiof.c b/drivers/spi/spi-sh-msiof.c
index d3370a6..a7629f8 100644
--- a/drivers/spi/spi-sh-msiof.c
+++ b/drivers/spi/spi-sh-msiof.c
@@ -48,8 +48,8 @@ struct sh_msiof_spi_priv {
 	const struct sh_msiof_chipdata *chipdata;
 	struct sh_msiof_spi_info *info;
 	struct completion done;
-	int tx_fifo_size;
-	int rx_fifo_size;
+	unsigned int tx_fifo_size;
+	unsigned int rx_fifo_size;
 	void *tx_dma_page;
 	void *rx_dma_page;
 	dma_addr_t tx_dma_addr;
@@ -95,8 +95,6 @@ struct sh_msiof_spi_priv {
 #define MDR2_WDLEN1(i)	(((i) - 1) << 16) /* Word Count (1-64/256 (SH, A1))) */
 #define MDR2_GRPMASK1	0x00000001 /* Group Output Mask 1 (SH, A1) */
 
-#define MAX_WDLEN	256U
-
 /* TSCR and RSCR */
 #define SCR_BRPS_MASK	    0x1f00 /* Prescaler Setting (1-32) */
 #define SCR_BRPS(i)	(((i) - 1) << 8)
@@ -850,7 +848,12 @@ static int sh_msiof_transfer_one(struct spi_master *master,
 		 *  DMA supports 32-bit words only, hence pack 8-bit and 16-bit
 		 *  words, with byte resp. word swapping.
 		 */
-		unsigned int l = min(len, MAX_WDLEN * 4);
+		unsigned int l = 0;
+
+		if (tx_buf)
+			l = min(len, p->tx_fifo_size * 4);
+		if (rx_buf)
+			l = min(len, p->rx_fifo_size * 4);
 
 		if (bits <= 8) {
 			if (l & 3)
@@ -963,7 +966,7 @@ static const struct sh_msiof_chipdata sh_data = {
 
 static const struct sh_msiof_chipdata r8a779x_data = {
 	.tx_fifo_size = 64,
-	.rx_fifo_size = 256,
+	.rx_fifo_size = 64,
 	.master_flags = SPI_MASTER_MUST_TX,
 };
 
-- 
1.9.1