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path: root/drivers/tty/serial/atmel_serial.c
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Diffstat (limited to 'drivers/tty/serial/atmel_serial.c')
-rw-r--r--drivers/tty/serial/atmel_serial.c22
1 files changed, 16 insertions, 6 deletions
diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index 168b10cad47b..fabbe76203bb 100644
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -481,6 +481,14 @@ 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);
@@ -513,6 +521,9 @@ 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);
}
/*
@@ -798,6 +809,11 @@ static void atmel_complete_tx_dma(void *arg)
*/
if (!uart_circ_empty(xmit))
atmel_tasklet_schedule(atmel_port, &atmel_port->tasklet_tx);
+ else if ((port->rs485.flags & SER_RS485_ENABLED) &&
+ !(port->rs485.flags & SER_RS485_RX_DURING_TX)) {
+ /* DMA done, stop TX, start RX for RS485 */
+ atmel_start_rx(port);
+ }
spin_unlock_irqrestore(&port->lock, flags);
}
@@ -900,12 +916,6 @@ static void atmel_tx_dma(struct uart_port *port)
desc->callback = atmel_complete_tx_dma;
desc->callback_param = atmel_port;
atmel_port->cookie_tx = dmaengine_submit(desc);
-
- } else {
- if (port->rs485.flags & SER_RS485_ENABLED) {
- /* DMA done, stop TX, start RX for RS485 */
- atmel_start_rx(port);
- }
}
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)