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[/] [or1k_soc_on_altera_embedded_dev_kit/] [trunk/] [linux-2.6/] [linux-2.6.24/] [include/] [asm-xtensa/] [semaphore.h] - Rev 9
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/* * linux/include/asm-xtensa/semaphore.h * * This file is subject to the terms and conditions of the GNU General Public * License. See the file "COPYING" in the main directory of this archive * for more details. * * Copyright (C) 2001 - 2005 Tensilica Inc. */ #ifndef _XTENSA_SEMAPHORE_H #define _XTENSA_SEMAPHORE_H #include <asm/atomic.h> #include <asm/system.h> #include <linux/wait.h> #include <linux/rwsem.h> struct semaphore { atomic_t count; int sleepers; wait_queue_head_t wait; }; #define __SEMAPHORE_INITIALIZER(name,n) \ { \ .count = ATOMIC_INIT(n), \ .sleepers = 0, \ .wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \ } #define __DECLARE_SEMAPHORE_GENERIC(name,count) \ struct semaphore name = __SEMAPHORE_INITIALIZER(name,count) #define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1) static inline void sema_init (struct semaphore *sem, int val) { atomic_set(&sem->count, val); sem->sleepers = 0; init_waitqueue_head(&sem->wait); } static inline void init_MUTEX (struct semaphore *sem) { sema_init(sem, 1); } static inline void init_MUTEX_LOCKED (struct semaphore *sem) { sema_init(sem, 0); } asmlinkage void __down(struct semaphore * sem); asmlinkage int __down_interruptible(struct semaphore * sem); asmlinkage int __down_trylock(struct semaphore * sem); asmlinkage void __up(struct semaphore * sem); extern spinlock_t semaphore_wake_lock; static inline void down(struct semaphore * sem) { might_sleep(); if (atomic_sub_return(1, &sem->count) < 0) __down(sem); } static inline int down_interruptible(struct semaphore * sem) { int ret = 0; might_sleep(); if (atomic_sub_return(1, &sem->count) < 0) ret = __down_interruptible(sem); return ret; } static inline int down_trylock(struct semaphore * sem) { int ret = 0; if (atomic_sub_return(1, &sem->count) < 0) ret = __down_trylock(sem); return ret; } /* * Note! This is subtle. We jump to wake people up only if * the semaphore was negative (== somebody was waiting on it). */ static inline void up(struct semaphore * sem) { if (atomic_add_return(1, &sem->count) <= 0) __up(sem); } #endif /* _XTENSA_SEMAPHORE_H */
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