[PATCH] spi: s3c64xx: Use DMA mode from fifo size

Jaewon Kim jaewon02.kim at samsung.com
Tue Mar 26 20:30:41 PDT 2024


The SPI data size is smaller than FIFO, it operates in PIO mode,
and if it is larger than FIFO mode, DMA mode is selected.

If the data size is the same as the FIFO size, it operates in PIO mode
and data is separated into two transfer. In order to prevent,
DMA mode must be used from the case of FIFO and data size.

Fixes: 1ee806718d5e ("spi: s3c64xx: support interrupt based pio mode")
Signed-off-by: Jaewon Kim <jaewon02.kim at samsung.com>
---
 drivers/spi/spi-s3c64xx.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c
index 9fcbe040cb2f..81ed5fddf83e 100644
--- a/drivers/spi/spi-s3c64xx.c
+++ b/drivers/spi/spi-s3c64xx.c
@@ -430,7 +430,7 @@ static bool s3c64xx_spi_can_dma(struct spi_controller *host,
 	struct s3c64xx_spi_driver_data *sdd = spi_controller_get_devdata(host);
 
 	if (sdd->rx_dma.ch && sdd->tx_dma.ch)
-		return xfer->len > sdd->fifo_depth;
+		return xfer->len >= sdd->fifo_depth;
 
 	return false;
 }
@@ -826,11 +826,11 @@ static int s3c64xx_spi_transfer_one(struct spi_controller *host,
 			return status;
 	}
 
-	if (!is_polling(sdd) && (xfer->len > fifo_len) &&
+	if (!is_polling(sdd) && xfer->len >= fifo_len &&
 	    sdd->rx_dma.ch && sdd->tx_dma.ch) {
 		use_dma = 1;
 
-	} else if (xfer->len >= fifo_len) {
+	} else if (xfer->len > fifo_len) {
 		tx_buf = xfer->tx_buf;
 		rx_buf = xfer->rx_buf;
 		origin_len = xfer->len;
-- 
2.43.2




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