[PATCH] 16C950 UART enable Hardware Flow Control

[Denis Ahrens <denis@xxxxxxx>]

From: Denis Ahrens <denis@xxxxxxx>

Enable Automatic RTS/CTS flow control for the 16C950 UART in Enhanced Mode
like described in the Data Sheet Revision 1.2 page 28 and 29.

Without this change normal console output works, but everything putting
a little more pressure on the UART simply overruns the FIFO.

Signed-off-by: Denis Ahrens <denis@xxxxxxx>
---

diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index f77bf820b7a3..024235946f4d 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -2168,7 +2168,9 @@ int serial8250_do_startup(struct uart_port *port)
                serial_port_out(port, UART_LCR, 0);
                serial_icr_write(up, UART_CSR, 0); /* Reset the UART */
                serial_port_out(port, UART_LCR, UART_LCR_CONF_MODE_B);
-               serial_port_out(port, UART_EFR, UART_EFR_ECB);
+               serial_port_out(port, UART_EFR, UART_EFR_ECB |
+                                               UART_EFR_RTS |
+                                               UART_EFR_CTS);
                serial_port_out(port, UART_LCR, 0);
        }