tty/serial: add arm/arm64 semihosting earlycon
Add earlycon support for the arm/arm64 semihosting debug serial
interface. This allows enabling a debug console when early_params are
processed. This is based on the arm64 earlyprintk smh support and is
intended to replace it.
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 4290d05..988fa2b 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -73,6 +73,16 @@
your boot loader (lilo or loadlin) about how to pass options to the
kernel at boot time.)
+config SERIAL_EARLYCON_ARM_SEMIHOST
+ bool "Early console using ARM semihosting"
+ depends on ARM64 || ARM
+ select SERIAL_EARLYCON
+ help
+ Support for early debug console using ARM semihosting. This enables
+ the console before standard serial driver is probed. This is enabled
+ with "earlycon=smh" on the kernel command line. The console is
+ enabled when early_param is processed.
+
config SERIAL_SB1250_DUART
tristate "BCM1xxx on-chip DUART serial support"
depends on SIBYTE_SB1xxx_SOC=y