From 6b3087c64a92a36ae20d33479b4df6d7afc910d4 Mon Sep 17 00:00:00 2001 From: Graf Yang Date: Wed, 7 Jan 2009 23:14:39 +0800 Subject: 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 Signed-off-by: Bryan Wu --- arch/blackfin/include/asm/mutex.h | 63 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 63 insertions(+) (limited to 'arch/blackfin/include/asm/mutex.h') diff --git a/arch/blackfin/include/asm/mutex.h b/arch/blackfin/include/asm/mutex.h index 458c1f7fbc1..5d399256bf0 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 +#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 -- cgit v1.2.3