powerpc: udbg-based backend for hvc_console
This adds a new backend for the hvc console based on the low-level
udbg callbacks. This effectively implements a working runtime console
in terms of the simple udbg primitives. This is kind of a hack -
since udbg isn't something you really want to be using routinely - but
it's really useful during bringup.
This can be used to quickly implement a userspace-usable console while
you're working on a proper driver for whatever console I/O device the
hardware has. Or, it can be used to avoid writing a full blown
tty/console driver entirely for quick-and-dirty I/O hardware that will
later be replaced by something else.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig
index 43b35d0..19e255c 100644
--- a/drivers/char/Kconfig
+++ b/drivers/char/Kconfig
@@ -631,6 +631,12 @@
help
Xen virtual console device driver
+config HVC_UDBG
+ bool "udbg based fake hypervisor console"
+ depends on PPC && EXPERIMENTAL
+ select HVC_DRIVER
+ default n
+
config VIRTIO_CONSOLE
tristate "Virtio console"
depends on VIRTIO