[POWERPC] Add PMI driver for cell blade

This adds driver code for the PMI device found in future IBM products.
PMI stands for "Platform Management Interrupt" and is a way to
communicate with the BMC (Baseboard Management Controller).
It provides bidirectional communication with a low latency.

Signed-off-by: Christian Krafft <krafft@de.ibm.com>
Acked-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
Acked-by: Heiko J Schick <schickhj@de.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 340d9be..6dfbd52 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -620,6 +620,15 @@
 	tristate "Firmware flash interface"
 	depends on PPC64 && RTAS_PROC
 
+config PPC_PMI
+	tristate "Support for PMI"
+	depends PPC_IBM_CELL_BLADE
+	help
+	  PMI (Platform Management Interrupt) is a way to
+	  communicate with the BMC (Baseboard Mangement Controller).
+	  It is used in some IBM Cell blades.
+	default m
+
 config MMIO_NVRAM
 	bool
 	default n