/* * 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 #include #include #include struct semaphore { atomic_t count; int sleepers; wait_queue_head_t wait; #if WAITQUEUE_DEBUG long __magic; #endif }; #if WAITQUEUE_DEBUG # define __SEM_DEBUG_INIT(name) \ , (int)&(name).__magic #else # define __SEM_DEBUG_INIT(name) #endif #define __SEMAPHORE_INITIALIZER(name,count) \ { ATOMIC_INIT(count), \ 0, \ __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \ __SEM_DEBUG_INIT(name) } #define __MUTEX_INITIALIZER(name) \ __SEMAPHORE_INITIALIZER(name, 1) #define __DECLARE_SEMAPHORE_GENERIC(name,count) \ struct semaphore name = __SEMAPHORE_INITIALIZER(name,count) #define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1) #define DECLARE_MUTEX_LOCKED(name) __DECLARE_SEMAPHORE_GENERIC(name,0) static inline void sema_init (struct semaphore *sem, int val) { /* * *sem = (struct semaphore)__SEMAPHORE_INITIALIZER((*sem),val); * * i'd rather use the more flexible initialization above, but sadly * GCC 2.7.2.3 emits a bogus warning. EGCS doesnt. Oh well. */ atomic_set(&sem->count, val); init_waitqueue_head(&sem->wait); #if WAITQUEUE_DEBUG sem->__magic = (int)&sem->__magic; #endif } 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) { #if WAITQUEUE_DEBUG CHECK_MAGIC(sem->__magic); #endif if (atomic_sub_return(1, &sem->count) < 0) __down(sem); } static inline int down_interruptible(struct semaphore * sem) { int ret = 0; #if WAITQUEUE_DEBUG CHECK_MAGIC(sem->__magic); #endif 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 WAITQUEUE_DEBUG CHECK_MAGIC(sem->__magic); #endif 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 WAITQUEUE_DEBUG CHECK_MAGIC(sem->__magic); #endif if (atomic_add_return(1, &sem->count) <= 0) __up(sem); } #endif /* _XTENSA_SEMAPHORE_H */