powerpc/powernv: Support for OPAL console

This adds a udbg and an hvc console backend for supporting a console
using the OPAL console interfaces.

On OPAL v1 we have hvc0 mapped to whatever console the system was
configured for (network or hvsi serial port) via the service
processor.

On OPAL v2 we have hvcN mapped to the Nth console provided by OPAL
which generally corresponds to:

	hvc0 : network console (raw protocol)
	hvc1 : serial port S1 (hvsi)
	hvc2 : serial port S2 (hvsi)

Note: At this point, early debug console only works with OPAL v1
and shouldn't be enabled in a normal kernel.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 31 insertions, 0 deletions

diff --git a/arch/powerpc/Kconfig.debug b/arch/powerpc/Kconfig.debug
index 06eb62b0fd90..1b8a9c905cf7 100644
--- a/arch/powerpc/Kconfig.debug
+++ b/arch/powerpc/Kconfig.debug
@@ -265,8 +265,27 @@ config PPC_EARLY_DEBUG_PS3GELIC
           Select this to enable early debugging for the PlayStation3 via
           UDP broadcasts sent out through the Ethernet port.
 
+config PPC_EARLY_DEBUG_OPAL_RAW
+        bool "OPAL raw console"
+        depends on HVC_OPAL
+        help
+          Select this to enable early debugging for the PowerNV platform
+          using a "raw" console
+
+config PPC_EARLY_DEBUG_OPAL_HVSI
+        bool "OPAL hvsi console"
+        depends on HVC_OPAL
+        help
+          Select this to enable early debugging for the PowerNV platform
+          using an "hvsi" console
+
 endchoice
 
+config PPC_EARLY_DEBUG_OPAL
+        def_bool y
+        depends on PPC_EARLY_DEBUG_OPAL_RAW || PPC_EARLY_DEBUG_OPAL_HVSI
+
+
 config PPC_EARLY_DEBUG_HVSI_VTERMNO
         hex "vterm number to use with early debug HVSI"
         depends on PPC_EARLY_DEBUG_LPAR_HVSI
@@ -275,6 +294,18 @@ config PPC_EARLY_DEBUG_HVSI_VTERMNO
           You probably want 0x30000000 for your first serial port and
           0x30000001 for your second one
 
+config PPC_EARLY_DEBUG_OPAL_VTERMNO
+        hex "vterm number to use with OPAL early debug"
+        depends on PPC_EARLY_DEBUG_OPAL
+        default "0"
+        help
+          This correspond to which /dev/hvcN you want to use for early
+          debug.
+
+          On OPAL v1 (takeover) this should always be 0
+          On OPAL v2, this will be 0 for network console and 1 or 2 for
+          the machine built-in serial ports.
+
 config PPC_EARLY_DEBUG_44x_PHYSLOW
         hex "Low 32 bits of early debug UART physical address"
         depends on PPC_EARLY_DEBUG_44x