new file mode 100644
@@ -0,0 +1,54 @@
+From 4d3c17975c7814884a721fe693b3adf5c426d759 Mon Sep 17 00:00:00 2001
+From: Hauke Mehrtens <hauke@hauke-m.de>
+Date: Tue, 10 Nov 2015 22:18:39 +0100
+Subject: [RFC] serial: core: add support for boot console with arbitrary
+ baud rates
+
+The Arduino Yun uses a baud rate of 250000 by default. The serial is
+going over the Atmel ATmega and is used to connect to this chip.
+Without this patch Linux wants to switch the console to 9600 Baud.
+
+With this patch Linux will use the configured baud rate and not a
+default one specified in uart_register_driver().
+
+Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
+[rebased to 4.14, slightly reworded commit message]
+Signed-off-by: Sungbo Eo <mans0n@gorani.run>
+---
+ drivers/tty/serial/serial_core.c | 6 +++++-
+ include/linux/console.h | 1 +
+ 2 files changed, 6 insertions(+), 1 deletions(-)
+
+--- a/drivers/tty/serial/serial_core.c
++++ b/drivers/tty/serial/serial_core.c
+@@ -232,6 +232,8 @@ static int uart_port_startup(struct tty_
+ if (retval == 0) {
+ if (uart_console(uport) && uport->cons->cflag) {
+ tty->termios.c_cflag = uport->cons->cflag;
++ tty->termios.c_ospeed = uport->cons->baud;
++ tty->termios.c_ispeed = uport->cons->baud;
+ uport->cons->cflag = 0;
+ }
+ /*
+@@ -2072,8 +2074,10 @@ uart_set_options(struct uart_port *port,
+ * Allow the setting of the UART parameters with a NULL console
+ * too:
+ */
+- if (co)
++ if (co) {
+ co->cflag = termios.c_cflag;
++ co->baud = baud;
++ }
+
+ return 0;
+ }
+--- a/include/linux/console.h
++++ b/include/linux/console.h
+@@ -145,6 +145,7 @@ struct console {
+ short flags;
+ short index;
+ int cflag;
++ int baud;
+ void *data;
+ struct console *next;
+ };
Commit 1bfbf2de6df9 ("ar71xx: serial: core: add support for boot console with arbitrary baud rates") added support for arbitrary baud rates which enabled 250000 baud rate for Yun. But the patch was not ported to kernel 4.9, and since then the kernel set its baud rate to 9600. This commit ports the patch to kernel 4.14, thereby restoring the serial console of Yun. Cc: Hauke Mehrtens <hauke@hauke-m.de> Signed-off-by: Sungbo Eo <mans0n@gorani.run> --- ...support-for-boot-console-with-arbitr.patch | 54 +++++++++++++++++++ 1 file changed, 54 insertions(+) create mode 100644 target/linux/ar71xx/patches-4.14/821-serial-core-add-support-for-boot-console-with-arbitr.patch