tty: New RISC-V SBI console driver
The RISC-V ISA defines a simple console that is availiable via SBI calls
on all systems. The SBI console is designed to be availiable at all
times, so while it's most natural to use this as an early printk target
it's also possible to use this as the system console when there isn't a
better one availiable.
This patch adds support for the RISC-V SBI console via the HVC
infastructure. It's entirely independent from our early printk support,
which results in early boot messages appearing twice over the SBI
console. As far as I can tell that's the fault of our early printk
support (we should support earlycon) as opposed to this driver.
There is one checkpatch.pl warning here: to check the MAINTAINERS file.
They're all matched by the "K: riscv" line.
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/tty/hvc/Kconfig b/drivers/tty/hvc/Kconfig
index fec457e..e7cc617 100644
--- a/drivers/tty/hvc/Kconfig
+++ b/drivers/tty/hvc/Kconfig
@@ -97,6 +97,16 @@
the HVC driver. If you don't have JTAG, then you probably don't
want this option.
+config HVC_RISCV_SBI
+ bool "RISC-V SBI console support"
+ depends on RISCV
+ select HVC_DRIVER
+ help
+ This enables support for console output via RISC-V SBI calls, which
+ is normally used only during boot to output printk.
+
+ If you don't know what do to here, say Y.
+
config HVCS
tristate "IBM Hypervisor Virtual Console Server support"
depends on PPC_PSERIES && HVC_CONSOLE
