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author | Graf Yang <graf.yang@analog.com> | 2009-01-07 23:14:39 +0800 |
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committer | Bryan Wu <cooloney@kernel.org> | 2009-01-07 23:14:39 +0800 |
commit | 6b3087c64a92a36ae20d33479b4df6d7afc910d4 (patch) | |
tree | 95984fc623658ebf150d0d912a7f6c5a0301a5a9 /arch/blackfin/include/asm/mutex.h | |
parent | c51b4488cd5bff08ed5690a8f303ff7f0894da2a (diff) | |
download | kernel_samsung_smdk4412-6b3087c64a92a36ae20d33479b4df6d7afc910d4.zip kernel_samsung_smdk4412-6b3087c64a92a36ae20d33479b4df6d7afc910d4.tar.gz kernel_samsung_smdk4412-6b3087c64a92a36ae20d33479b4df6d7afc910d4.tar.bz2 |
Blackfin arch: SMP supporting patchset: Blackfin header files and machine common code
Blackfin dual core BF561 processor can support SMP like features.
https://docs.blackfin.uclinux.org/doku.php?id=linux-kernel:smp-like
In this patch, we provide SMP extend to Blackfin header files
and machine common code
Signed-off-by: Graf Yang <graf.yang@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Diffstat (limited to 'arch/blackfin/include/asm/mutex.h')
-rw-r--r-- | arch/blackfin/include/asm/mutex.h | 63 |
1 files changed, 63 insertions, 0 deletions
diff --git a/arch/blackfin/include/asm/mutex.h b/arch/blackfin/include/asm/mutex.h index 458c1f7..5d39925 100644 --- a/arch/blackfin/include/asm/mutex.h +++ b/arch/blackfin/include/asm/mutex.h @@ -6,4 +6,67 @@ * implementation. (see asm-generic/mutex-xchg.h for details) */ +#ifndef _ASM_MUTEX_H +#define _ASM_MUTEX_H + +#ifndef CONFIG_SMP #include <asm-generic/mutex-dec.h> +#else + +static inline void +__mutex_fastpath_lock(atomic_t *count, void (*fail_fn)(atomic_t *)) +{ + if (unlikely(atomic_dec_return(count) < 0)) + fail_fn(count); + else + smp_mb(); +} + +static inline int +__mutex_fastpath_lock_retval(atomic_t *count, int (*fail_fn)(atomic_t *)) +{ + if (unlikely(atomic_dec_return(count) < 0)) + return fail_fn(count); + else { + smp_mb(); + return 0; + } +} + +static inline void +__mutex_fastpath_unlock(atomic_t *count, void (*fail_fn)(atomic_t *)) +{ + smp_mb(); + if (unlikely(atomic_inc_return(count) <= 0)) + fail_fn(count); +} + +#define __mutex_slowpath_needs_to_unlock() 1 + +static inline int +__mutex_fastpath_trylock(atomic_t *count, int (*fail_fn)(atomic_t *)) +{ + /* + * We have two variants here. The cmpxchg based one is the best one + * because it never induce a false contention state. It is included + * here because architectures using the inc/dec algorithms over the + * xchg ones are much more likely to support cmpxchg natively. + * + * If not we fall back to the spinlock based variant - that is + * just as efficient (and simpler) as a 'destructive' probing of + * the mutex state would be. + */ +#ifdef __HAVE_ARCH_CMPXCHG + if (likely(atomic_cmpxchg(count, 1, 0) == 1)) { + smp_mb(); + return 1; + } + return 0; +#else + return fail_fn(count); +#endif +} + +#endif + +#endif |