atmel_serial: fix flow control bug

Fix the following problem, related to hardware flow control (CTS/RTS):
Transmitting while CTS line is asserted in DMA mode, due to not checking
for tx-stopped condition.

We found these problems while testing the UARTs with hardware
flow-control.

Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
Cc: "Andrew Victor" <avictor.za@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/serial/atmel_serial.c b/drivers/serial/atmel_serial.c
index d5efd6c..89362d7 100644 (file)
--- a/drivers/serial/atmel_serial.c
+++ b/drivers/serial/atmel_serial.c
@@ -579,7 +579,7 @@ static void atmel_tx_dma(struct uart_port *port)
        /* disable PDC transmit */
        UART_PUT_PTCR(port, ATMEL_PDC_TXTDIS);
 
-       if (!uart_circ_empty(xmit)) {
+       if (!uart_circ_empty(xmit) && !uart_tx_stopped(port)) {
                dma_sync_single_for_device(port->dev,
                                           pdc->dma_addr,
                                           pdc->dma_size,