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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>
This commit is contained in:
Cédric Le Goater 2014-04-24 09:23:33 +02:00 committed by Benjamin Herrenschmidt
parent b636031a7b
commit 98fd433aa6
2 changed files with 36 additions and 0 deletions
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7
arch/powerpc/boot/of.h
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@ -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 @@ void of_console_init(void);
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)

29
arch/powerpc/boot/swab.h Normal file
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@ -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_ */