tty/serial: add generic serial earlycon
This introduces generic earlycon infrastructure for serial devices
based on the 8250 earlycon. This allows for supporting earlycon option
with other serial devices. The earlycon output is enabled at the time
early_params are processed.
Only architectures that have fixmap support or have functional ioremap
when early_params are processed are supported. This is the same
restriction that the 8250 driver had.
Signed-off-by: Rob Herring <robh@kernel.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index 30530e4..9fb6028 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -7,6 +7,13 @@
menu "Serial drivers"
depends on HAS_IOMEM
+config SERIAL_EARLYCON
+ bool
+ help
+ Support for early consoles with the earlycon parameter. This enables
+ the console before standard serial driver is probed. The console is
+ enabled when early_param is processed.
+
source "drivers/tty/serial/8250/Kconfig"
comment "Non-8250 serial port support"