powerpc/boot: Define byteswapping routines for little endian
These are not the most efficient versions of swab but the wrapper does
not do much byte swapping. On a big endian cpu, these routines are
a no-op.
Signed-off-by: Cédric Le Goater <clg@fr.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/boot/of.h b/arch/powerpc/boot/of.h
index e1ef620..c8c1750 100644
--- a/arch/powerpc/boot/of.h
+++ b/arch/powerpc/boot/of.h
@@ -1,6 +1,8 @@
#ifndef _PPC_BOOT_OF_H_
#define _PPC_BOOT_OF_H_
+#include "swab.h"
+
typedef void *phandle;
typedef u32 ihandle;
@@ -21,8 +23,13 @@
typedef u32 __be32;
+#ifdef __LITTLE_ENDIAN__
+#define cpu_to_be32(x) swab32(x)
+#define be32_to_cpu(x) swab32(x)
+#else
#define cpu_to_be32(x) (x)
#define be32_to_cpu(x) (x)
+#endif
#define PROM_ERROR (-1u)
diff --git a/arch/powerpc/boot/swab.h b/arch/powerpc/boot/swab.h
new file mode 100644
index 0000000..d0e1431
--- /dev/null
+++ b/arch/powerpc/boot/swab.h
@@ -0,0 +1,29 @@
+#ifndef _PPC_BOOT_SWAB_H_
+#define _PPC_BOOT_SWAB_H_
+
+static inline u16 swab16(u16 x)
+{
+ return ((x & (u16)0x00ffU) << 8) |
+ ((x & (u16)0xff00U) >> 8);
+}
+
+static inline u32 swab32(u32 x)
+{
+ return ((x & (u32)0x000000ffUL) << 24) |
+ ((x & (u32)0x0000ff00UL) << 8) |
+ ((x & (u32)0x00ff0000UL) >> 8) |
+ ((x & (u32)0xff000000UL) >> 24);
+}
+
+static inline u64 swab64(u64 x)
+{
+ return (u64)((x & (u64)0x00000000000000ffULL) << 56) |
+ (u64)((x & (u64)0x000000000000ff00ULL) << 40) |
+ (u64)((x & (u64)0x0000000000ff0000ULL) << 24) |
+ (u64)((x & (u64)0x00000000ff000000ULL) << 8) |
+ (u64)((x & (u64)0x000000ff00000000ULL) >> 8) |
+ (u64)((x & (u64)0x0000ff0000000000ULL) >> 24) |
+ (u64)((x & (u64)0x00ff000000000000ULL) >> 40) |
+ (u64)((x & (u64)0xff00000000000000ULL) >> 56);
+}
+#endif /* _PPC_BOOT_SWAB_H_ */
