tty/serial: atmel: fix RS485 half duplex with DMA
When using DMA, half duplex doesn't work properly because rx is not stopped
before starting tx. Ensure we call atmel_stop_rx() in the DMA case.
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index 8570163..f887c1d 100644
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -487,19 +487,21 @@
{
struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
- if (atmel_use_pdc_tx(port)) {
- if (atmel_uart_readl(port, ATMEL_PDC_PTSR) & ATMEL_PDC_TXTEN)
- /* The transmitter is already running. Yes, we
- really need this.*/
- return;
+ if (atmel_use_pdc_tx(port) && (atmel_uart_readl(port, ATMEL_PDC_PTSR)
+ & ATMEL_PDC_TXTEN))
+ /* The transmitter is already running. Yes, we
+ really need this.*/
+ return;
+ if (atmel_use_pdc_tx(port) || atmel_use_dma_tx(port))
if ((port->rs485.flags & SER_RS485_ENABLED) &&
!(port->rs485.flags & SER_RS485_RX_DURING_TX))
atmel_stop_rx(port);
+ if (atmel_use_pdc_tx(port))
/* re-enable PDC transmit */
atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_TXTEN);
- }
+
/* Enable interrupts */
atmel_uart_writel(port, ATMEL_US_IER, atmel_port->tx_done_mask);
}