Merge branch 'linux-linaro-lsk-v4.4' into linux-linaro-lsk-v4.4-android

[firefly-linux-kernel-4.4.55.git] / drivers / tty / serial / atmel_serial.c

diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index e0b89b961e1b10fa7901e7c95c8f91c4220a5007..a0f911641b04a04430dc22f940e07575f519ae8d 100644 (file)
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -470,6 +470,14 @@ static void atmel_stop_tx(struct uart_port *port)
                /* disable PDC transmit */
                atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_TXTDIS);
        }
+
+       /*
+        * Disable the transmitter.
+        * This is mandatory when DMA is used, otherwise the DMA buffer
+        * is fully transmitted.
+        */
+       atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXDIS);
+
        /* Disable interrupts */
        atmel_uart_writel(port, ATMEL_US_IDR, atmel_port->tx_done_mask);
 
@@ -502,6 +510,9 @@ static void atmel_start_tx(struct uart_port *port)
 
        /* Enable interrupts */
        atmel_uart_writel(port, ATMEL_US_IER, atmel_port->tx_done_mask);
+
+       /* re-enable the transmitter */
+       atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXEN);
 }
 
 /*