ARM: meson: serial: add MesonX SoC on-chip uart driver

The SoC has four fully functional UARTs which use the same programming
model. They are named UART_A, UART_B, UART_C and UART_AO (Always-On)
which cannot be powered off.

Signed-off-by: Carlo Caione <carlo@caione.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/Kconfig

@@ -200,6 +200,24 @@ config SERIAL_KS8695_CONSOLE
 	  receives all kernel messages and warnings and which allows
 	  logins in single user mode).
 
+config SERIAL_MESON
+	tristate "Meson serial port support"
+	depends on ARCH_MESON
+	select SERIAL_CORE
+	help
+	  This enables the driver for the on-chip UARTs of the Amlogic
+	  MesonX processors.
+
+config SERIAL_MESON_CONSOLE
+	bool "Support for console on meson"
+	depends on SERIAL_MESON=y
+	select SERIAL_CORE_CONSOLE
+	help
+	  Say Y here if you wish to use a Amlogic MesonX UART as the
+	  system console (the system console is the device which
+	  receives all kernel messages and warnings and which allows
+	  logins in single user mode) as /dev/ttyAMLx.
+
 config SERIAL_CLPS711X
 	tristate "CLPS711X serial port support"
 	depends on ARCH_CLPS711X || COMPILE_TEST

drivers/tty/serial/Makefile

@@ -48,6 +48,7 @@ obj-$(CONFIG_SERIAL_MPC52xx) += mpc52xx_uart.o
 obj-$(CONFIG_SERIAL_ICOM) += icom.o
 obj-$(CONFIG_SERIAL_M32R_SIO) += m32r_sio.o
 obj-$(CONFIG_SERIAL_MPSC) += mpsc.o
+obj-$(CONFIG_SERIAL_MESON) += meson_uart.o
 obj-$(CONFIG_SERIAL_SB1250_DUART) += sb1250-duart.o
 obj-$(CONFIG_ETRAX_SERIAL) += crisv10.o
 obj-$(CONFIG_SERIAL_SCCNXP) += sccnxp.o

include/uapi/linux/serial_core.h

@@ -244,4 +244,7 @@
 /* SC16IS74xx */
 #define PORT_SC16IS7XX   108
 
+/* MESON */
+#define PORT_MESON	109
+
 #endif /* _UAPILINUX_SERIAL_CORE_H */