powerpc: Add real mode cache inhibited IO accessors

These accessors allow us to do cache inhibited accesses when in real
mode. They should only be used in real mode.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/include/asm/io.h

@@ -191,8 +191,24 @@ DEF_MMIO_OUT_D(out_le32, 32, stw);
 
 #endif /* __BIG_ENDIAN */
 
+/*
+ * Cache inhibitied accessors for use in real mode, you don't want to use these
+ * unless you know what you're doing.
+ *
+ * NB. These use the cpu byte ordering.
+ */
+DEF_MMIO_OUT_X(out_rm8,   8, stbcix);
+DEF_MMIO_OUT_X(out_rm16, 16, sthcix);
+DEF_MMIO_OUT_X(out_rm32, 32, stwcix);
+DEF_MMIO_IN_X(in_rm8,   8, lbzcix);
+DEF_MMIO_IN_X(in_rm16, 16, lhzcix);
+DEF_MMIO_IN_X(in_rm32, 32, lwzcix);
+
 #ifdef __powerpc64__
 
+DEF_MMIO_OUT_X(out_rm64, 64, stdcix);
+DEF_MMIO_IN_X(in_rm64, 64, ldcix);
+
 #ifdef __BIG_ENDIAN__
 DEF_MMIO_OUT_D(out_be64, 64, std);
 DEF_MMIO_IN_D(in_be64, 64, ld);