powerpc: Add support for using doorbells for SMP IPI

The e500mc supports the new msgsnd/doorbell mechanisms that were added in
the Power ISA 2.05 architecture.  We use the normal level doorbell for
doing SMP IPIs at this point.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/include/asm/cputable.h b/arch/powerpc/include/asm/cputable.h
index 4911104..fca1611 100644
--- a/arch/powerpc/include/asm/cputable.h
+++ b/arch/powerpc/include/asm/cputable.h
@@ -145,6 +145,7 @@
 #define CPU_FTR_USE_TB			ASM_CONST(0x0000000000000040)
 #define CPU_FTR_L2CSR			ASM_CONST(0x0000000000000080)
 #define CPU_FTR_601			ASM_CONST(0x0000000000000100)
+#define CPU_FTR_DBELL			ASM_CONST(0x0000000000000200)
 #define CPU_FTR_CAN_NAP			ASM_CONST(0x0000000000000400)
 #define CPU_FTR_L3CR			ASM_CONST(0x0000000000000800)
 #define CPU_FTR_L3_DISABLE_NAP		ASM_CONST(0x0000000000001000)
@@ -373,7 +374,8 @@
 	    CPU_FTR_NODSISRALIGN | CPU_FTR_NOEXECUTE)
 #define CPU_FTRS_E500MC	(CPU_FTR_MAYBE_CAN_DOZE | CPU_FTR_USE_TB | \
 	    CPU_FTR_MAYBE_CAN_NAP | CPU_FTR_NODSISRALIGN | \
-	    CPU_FTR_L2CSR | CPU_FTR_LWSYNC | CPU_FTR_NOEXECUTE)
+	    CPU_FTR_L2CSR | CPU_FTR_LWSYNC | CPU_FTR_NOEXECUTE | \
+	    CPU_FTR_DBELL)
 #define CPU_FTRS_GENERIC_32	(CPU_FTR_COMMON | CPU_FTR_NODSISRALIGN)
 
 /* 64-bit CPUs */