tty: serial: 8250: 8250_core: NXP SC16C2552 workaround

NXP SC16C2552 requires that we always write a reset to the RX FIFO and
TX FIFO whenever we enable the FIFOs

Cc: xe-kernel@external.cisco.com
Signed-off-by: Steve Shih <sshih@cisco.com>
Signed-off-by: David Singleton <davsingl@cisco.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index 1bfb6fd..1731b98 100644 (file)
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -83,7 +83,8 @@ static const struct serial8250_config uart_config[] = {
                .name           = "16550A",
                .fifo_size      = 16,
                .tx_loadsz      = 16,
-               .fcr            = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
+               .fcr            = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10 |
+                                 UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT,
                .rxtrig_bytes   = {1, 4, 8, 14},
                .flags          = UART_CAP_FIFO,
        },