[PATCH] tty/serial: at91: maxburst was missing for dma transfers

[Ludovic Desroches]

Maxburst was not set when doing the dma slave configuration. This value
is checked by the recently introduced xdmac. It causes an error when
doing the slave configuration and so prevents from using dma.

Signed-off-by: Ludovic Desroches <ludovic.desroches at atmel.com>
Cc: <stable at vger.kernel.org> # 3.12 and later
---
 drivers/tty/serial/atmel_serial.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index 4e959c4..6afce7e 100644
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -880,6 +880,7 @@ static int atmel_prepare_tx_dma(struct uart_port *port)
 	config.direction = DMA_MEM_TO_DEV;
 	config.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
 	config.dst_addr = port->mapbase + ATMEL_US_THR;
+	config.dst_maxburst = 1;
 
 	ret = dmaengine_slave_config(atmel_port->chan_tx,
 				     &config);
@@ -1059,6 +1060,7 @@ static int atmel_prepare_rx_dma(struct uart_port *port)
 	config.direction = DMA_DEV_TO_MEM;
 	config.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
 	config.src_addr = port->mapbase + ATMEL_US_RHR;
+	config.src_maxburst = 1;
 
 	ret = dmaengine_slave_config(atmel_port->chan_rx,
 				     &config);
-- 
2.2.0