Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit aa2f80e7 authored by Marek Szyprowski's avatar Marek Szyprowski Committed by Greg Kroah-Hartman
Browse files

serial: samsung: fix maxburst parameter for DMA transactions 



The best granularity of residue that DMA engine can report is in the BURST
units, so the serial driver must use MAXBURST = 1 and DMA_SLAVE_BUSWIDTH_1_BYTE
if it relies on exact number of bytes transferred by DMA engine.

Fixes: 62c37eed ("serial: samsung: add dma reqest/release functions")
Signed-off-by: default avatarMarek Szyprowski <m.szyprowski@samsung.com>
Acked-by: default avatarKrzysztof Kozlowski <krzk@kernel.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 2ccdb55e

drivers/tty/serial/samsung.c

+2 −5
Original line number Diff line number Diff line
@@ -862,14 +862,11 @@ static int s3c24xx_serial_request_dma(struct s3c24xx_uart_port *p) 
	dma->rx_conf.direction		= DMA_DEV_TO_MEM;

	dma->rx_conf.src_addr_width	= DMA_SLAVE_BUSWIDTH_1_BYTE;

	dma->rx_conf.src_addr		= p->port.mapbase + S3C2410_URXH;

	dma->rx_conf.src_maxburst	= 16;

	dma->rx_conf.src_maxburst	= 1;



	dma->tx_conf.direction		= DMA_MEM_TO_DEV;

	dma->tx_conf.dst_addr_width	= DMA_SLAVE_BUSWIDTH_1_BYTE;

	dma->tx_conf.dst_addr		= p->port.mapbase + S3C2410_UTXH;

	if (dma_get_cache_alignment() >= 16)

		dma->tx_conf.dst_maxburst = 16;

	else

	dma->tx_conf.dst_maxburst	= 1;



	dma->rx_chan = dma_request_chan(p->port.dev, "rx");