[PATCH V2] tty: serial: imx: use the sg count from dma_map_sg

[Peng Fan]

From: Peng Fan <peng.fan@xxxxxxx>

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@xxxxxxx>
---

V2:
 Update commit log
 Drop assigning ret to sport->dma_tx_nents, it is wrong.

 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 87c58f9f6390..f1ddb2cae31e 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -619,7 +619,7 @@ 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,
-- 
2.16.4