spi: s3c64xx: Use DMA mode from fifo size

[ Upstream commit a3d3eab627bbbb0cb175910cf8d0f7022628a642 ]

If the SPI data size is smaller than FIFO, it operates in PIO mode,
and if it is larger than FIFO size, it oerates in DMA mode.

If the SPI data size is equal to fifo, it operates in PIO mode and it is
separated to 2 transfers. To prevent it, it must operate in DMA mode
from the case where the data size and the fifo size are the same.

Fixes: 1ee806718d5e ("spi: s3c64xx: support interrupt based pio mode")
Signed-off-by: Jaewon Kim <jaewon02.kim@samsung.com>
Reviewed-by: Sam Protsenko <semen.protsenko@linaro.org>
Link: https://lore.kernel.org/r/20240329085840.65856-1-jaewon02.kim@samsung.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c
index e059fb9db1da1802bd0978536c895308f68dfa99..652eadbefe24caeb0210b7d5553be0b8b33babc5 100644 (file)
--- a/drivers/spi/spi-s3c64xx.c
+++ b/drivers/spi/spi-s3c64xx.c
@@ -424,7 +424,7 @@ 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;
 }
@@ -783,10 +783,9 @@ 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) {
                tx_buf = xfer->tx_buf;
                rx_buf = xfer->rx_buf;