[PATCH] tty: serial: samsung_tty: set dma burst_size to 1

[PATCH] tty: serial: samsung_tty: set dma burst_size to 1

[Chanho Park]

The src_maxburst and dst_maxburst have been changed to 1 but the settings
of the UCON register aren't changed yet. They should be changed as well
according to the dmaengine slave config.

Fixes: aa2f80e752c7 ("serial: samsung: fix maxburst parameter for DMA transactions")
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Chanho Park <chanho61.park@samsung.com>
---
 drivers/tty/serial/samsung_tty.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/tty/serial/samsung_tty.c b/drivers/tty/serial/samsung_tty.c
index 679789bf856d..2b9c56c77676 100644
--- a/drivers/tty/serial/samsung_tty.c
+++ b/drivers/tty/serial/samsung_tty.c
@@ -383,8 +383,7 @@ static void enable_tx_dma(struct s3c24xx_uart_port *ourport)
 	/* Enable tx dma mode */
 	ucon = rd_regl(port, S3C2410_UCON);
 	ucon &= ~(S3C64XX_UCON_TXBURST_MASK | S3C64XX_UCON_TXMODE_MASK);
-	ucon |= (dma_get_cache_alignment() >= 16) ?
-		S3C64XX_UCON_TXBURST_16 : S3C64XX_UCON_TXBURST_1;
+	ucon |= S3C64XX_UCON_TXBURST_1;
 	ucon |= S3C64XX_UCON_TXMODE_DMA;
 	wr_regl(port,  S3C2410_UCON, ucon);
 
@@ -680,7 +679,7 @@ static void enable_rx_dma(struct s3c24xx_uart_port *ourport)
 			S3C64XX_UCON_DMASUS_EN |
 			S3C64XX_UCON_TIMEOUT_EN |
 			S3C64XX_UCON_RXMODE_MASK);
-	ucon |= S3C64XX_UCON_RXBURST_16 |
+	ucon |= S3C64XX_UCON_RXBURST_1 |
 			0xf << S3C64XX_UCON_TIMEOUT_SHIFT |
 			S3C64XX_UCON_EMPTYINT_EN |
 			S3C64XX_UCON_TIMEOUT_EN |
-- 
2.36.1


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Re: [PATCH] tty: serial: samsung_tty: set dma burst_size to 1

[Krzysztof Kozlowski]

On 27/06/2022 08:51, Chanho Park wrote:
> The src_maxburst and dst_maxburst have been changed to 1 but the settings
> of the UCON register aren't changed yet. They should be changed as well
> according to the dmaengine slave config.
> 
> Fixes: aa2f80e752c7 ("serial: samsung: fix maxburst parameter for DMA transactions")
> Cc: Marek Szyprowski <m.szyprowski@samsung.com>
> Signed-off-by: Chanho Park <chanho61.park@samsung.com>
> ---
>  drivers/tty/serial/samsung_tty.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)


Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>


Best regards,
Krzysztof

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