1/* 2 * linux/include/asm-arm/semaphore.h 3 */ 4#ifndef __ASM_ARM_SEMAPHORE_H 5#define __ASM_ARM_SEMAPHORE_H 6 7#include <linux/linkage.h> 8#include <linux/spinlock.h> 9#include <linux/wait.h> 10#include <linux/rwsem.h> 11 12#include <asm/atomic.h> 13#include <asm/locks.h> 14 15struct semaphore { 16 atomic_t count; 17 int sleepers; 18 wait_queue_head_t wait; 19}; 20 21#define __SEMAPHORE_INIT(name, cnt) \ 22{ \ 23 .count = ATOMIC_INIT(cnt), \ 24 .wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait), \ 25} 26 27#define __DECLARE_SEMAPHORE_GENERIC(name,count) \ 28 struct semaphore name = __SEMAPHORE_INIT(name,count) 29 30#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1) 31#define DECLARE_MUTEX_LOCKED(name) __DECLARE_SEMAPHORE_GENERIC(name,0) 32 33static inline void sema_init(struct semaphore *sem, int val) 34{ 35 atomic_set(&sem->count, val); 36 sem->sleepers = 0; 37 init_waitqueue_head(&sem->wait); 38} 39 40static inline void init_MUTEX(struct semaphore *sem) 41{ 42 sema_init(sem, 1); 43} 44 45static inline void init_MUTEX_LOCKED(struct semaphore *sem) 46{ 47 sema_init(sem, 0); 48} 49 50/* 51 * special register calling convention 52 */ 53asmlinkage void __down_failed(void); 54asmlinkage int __down_interruptible_failed(void); 55asmlinkage int __down_trylock_failed(void); 56asmlinkage void __up_wakeup(void); 57 58extern void __down(struct semaphore * sem); 59extern int __down_interruptible(struct semaphore * sem); 60extern int __down_trylock(struct semaphore * sem); 61extern void __up(struct semaphore * sem); 62 63/* 64 * This is ugly, but we want the default case to fall through. 65 * "__down" is the actual routine that waits... 66 */ 67static inline void down(struct semaphore * sem) 68{ 69 might_sleep(); 70 __down_op(sem, __down_failed); 71} 72 73/* 74 * This is ugly, but we want the default case to fall through. 75 * "__down_interruptible" is the actual routine that waits... 76 */ 77static inline int down_interruptible (struct semaphore * sem) 78{ 79 might_sleep(); 80 return __down_op_ret(sem, __down_interruptible_failed); 81} 82 83static inline int down_trylock(struct semaphore *sem) 84{ 85 return __down_op_ret(sem, __down_trylock_failed); 86} 87 88/* 89 * Note! This is subtle. We jump to wake people up only if 90 * the semaphore was negative (== somebody was waiting on it). 91 * The default case (no contention) will result in NO 92 * jumps for both down() and up(). 93 */ 94static inline void up(struct semaphore * sem) 95{ 96 __up_op(sem, __up_wakeup); 97} 98 99#endif 100