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authorMarek Szyprowski <m.szyprowski@samsung.com>2018-05-10 08:41:13 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-05-14 13:41:05 +0200
commitaa2f80e752c75e593b3820f42c416ed9458fa73e (patch)
tree8f2bebb6d17d2e10017e3304e1654ea478999825 /drivers/tty
parent2ccdb55e52a126aa51a64a2244d8b60c16f370cc (diff)
downloadlinux-aa2f80e752c75e593b3820f42c416ed9458fa73e.tar.bz2
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: 62c37eedb74c ("serial: samsung: add dma reqest/release functions") Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Acked-by: Krzysztof Kozlowski <krzk@kernel.org> Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty')
-rw-r--r--drivers/tty/serial/samsung.c7
1 files changed, 2 insertions, 5 deletions
diff --git a/drivers/tty/serial/samsung.c b/drivers/tty/serial/samsung.c
index 3f2f8c118ce0..64e96926f1ad 100644
--- a/drivers/tty/serial/samsung.c
+++ b/drivers/tty/serial/samsung.c
@@ -862,15 +862,12 @@ 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->tx_conf.dst_maxburst = 1;
dma->rx_chan = dma_request_chan(p->port.dev, "rx");