/* * linux/include/asm-arm/semaphore.h */ #ifndef __ASM_ARM_SEMAPHORE_H #define __ASM_ARM_SEMAPHORE_H #include <linux/linkage.h> #include <linux/spinlock.h> #include <linux/wait.h> #include <linux/rwsem.h> #include <asm/atomic.h> #include <asm/locks.h> struct semaphore { atomic_t count; int sleepers; wait_queue_head_t wait; }; #define __SEMAPHORE_INIT(name, cnt) \ { \ .count = ATOMIC_INIT(cnt), \ .wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait), \ } #define __MUTEX_INITIALIZER(name) __SEMAPHORE_INIT(name,1) #define __DECLARE_SEMAPHORE_GENERIC(name,count) \ struct semaphore name = __SEMAPHORE_INIT(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) { 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); } static inline int sema_count(struct semaphore *sem) { return atomic_read(&sem->count); } /* * special register calling convention */ asmlinkage void __down_failed(void); asmlinkage int __down_interruptible_failed(void); asmlinkage int __down_trylock_failed(void); asmlinkage void __up_wakeup(void); extern void __down(struct semaphore * sem); extern int __down_interruptible(struct semaphore * sem); extern int __down_trylock(struct semaphore * sem); extern void __up(struct semaphore * sem); /* * This is ugly, but we want the default case to fall through. * "__down" is the actual routine that waits... */ static inline void down(struct semaphore * sem) { might_sleep(); __down_op(sem, __down_failed); } /* * This is ugly, but we want the default case to fall through. * "__down_interruptible" is the actual routine that waits... */ static inline int down_interruptible (struct semaphore * sem) { might_sleep(); return __down_op_ret(sem, __down_interruptible_failed); } static inline int down_trylock(struct semaphore *sem) { return __down_op_ret(sem, __down_trylock_failed); } /* * Note! This is subtle. We jump to wake people up only if * the semaphore was negative (== somebody was waiting on it). * The default case (no contention) will result in NO * jumps for both down() and up(). */ static inline void up(struct semaphore * sem) { __up_op(sem, __up_wakeup); } #endif