[PATCH 4.9 50/72] tty/serial: atmel: fix TX path in atmel_console_write()

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Nicolas Ferre <nicolas.ferre@xxxxxxxxxxxxx>

commit 497e1e16f45c70574dc9922c7f75c642c2162119 upstream.

A side effect of 89d8232411a8 ("tty/serial: atmel_serial: BUG: stop DMA
from transmitting in stop_tx") is that the console can be called with
TX path disabled. Then the system would hang trying to push charecters
out in atmel_console_putchar().

Signed-off-by: Nicolas Ferre <nicolas.ferre@xxxxxxxxxxxxx>
Fixes: 89d8232411a8 ("tty/serial: atmel_serial: BUG: stop DMA from transmitting in stop_tx")
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/tty/serial/atmel_serial.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -2476,6 +2476,9 @@ static void atmel_console_write(struct c
 	pdc_tx = atmel_uart_readl(port, ATMEL_PDC_PTSR) & ATMEL_PDC_TXTEN;
 	atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_TXTDIS);
 
+	/* Make sure that tx path is actually able to send characters */
+	atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXEN);
+
 	uart_console_write(port, s, count, atmel_console_putchar);
 
 	/*