From: Peng Fan <peng.fan@nxp.com> commit 596fd8dffb745afcebc0ec6968e17fe29f02044c upstream. The dmaengine_prep_slave_sg needs to use sg count returned by dma_map_sg, not use sport->dma_tx_nents, because the return value of dma_map_sg is not always same with "nents". Fixes: b4cdc8f61beb ("serial: imx: add DMA support for imx6q") Signed-off-by: Peng Fan <peng.fan@nxp.com> Link: https://lore.kernel.org/r/1573108875-26530-1-git-send-email-peng.fan@nxp.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> --- drivers/tty/serial/imx.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index 989ca7d..672e979 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -624,7 +624,7 @@ static void imx_uart_dma_tx(struct imx_port *sport) dev_err(dev, "DMA mapping error for TX.\n"); return; } - desc = dmaengine_prep_slave_sg(chan, sgl, sport->dma_tx_nents, + desc = dmaengine_prep_slave_sg(chan, sgl, ret, DMA_MEM_TO_DEV, DMA_PREP_INTERRUPT); if (!desc) { dma_unmap_sg(dev, sgl, sport->dma_tx_nents, -- 1.8.3