1/* 2 * linux/include/asm-arm26/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, n) \ 22{ \ 23 .count = ATOMIC_INIT(n), \ 24 .sleepers = 0, \ 25 .wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait), \ 26} 27 28#define __DECLARE_SEMAPHORE_GENERIC(name,count) \ 29 struct semaphore name = __SEMAPHORE_INIT(name,count) 30 31#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1) 32#define DECLARE_MUTEX_LOCKED(name) __DECLARE_SEMAPHORE_GENERIC(name,0) 33 34static inline void sema_init(struct semaphore *sem, int val) 35{ 36 atomic_set(&sem->count, val); 37 sem->sleepers = 0; 38 init_waitqueue_head(&sem->wait); 39} 40 41static inline void init_MUTEX(struct semaphore *sem) 42{ 43 sema_init(sem, 1); 44} 45 46static inline void init_MUTEX_LOCKED(struct semaphore *sem) 47{ 48 sema_init(sem, 0); 49} 50 51/* 52 * special register calling convention 53 */ 54asmlinkage void __down_failed(void); 55asmlinkage int __down_interruptible_failed(void); 56asmlinkage int __down_trylock_failed(void); 57asmlinkage void __up_wakeup(void); 58 59extern void __down(struct semaphore * sem); 60extern int __down_interruptible(struct semaphore * sem); 61extern int __down_trylock(struct semaphore * sem); 62extern void __up(struct semaphore * sem); 63 64/* 65 * This is ugly, but we want the default case to fall through. 66 * "__down" is the actual routine that waits... 67 */ 68static inline void down(struct semaphore * sem) 69{ 70 might_sleep(); 71 __down_op(sem, __down_failed); 72} 73 74/* 75 * This is ugly, but we want the default case to fall through. 76 * "__down_interruptible" is the actual routine that waits... 77 */ 78static inline int down_interruptible (struct semaphore * sem) 79{ 80 might_sleep(); 81 return __down_op_ret(sem, __down_interruptible_failed); 82} 83 84static inline int down_trylock(struct semaphore *sem) 85{ 86 return __down_op_ret(sem, __down_trylock_failed); 87} 88 89/* 90 * Note! This is subtle. We jump to wake people up only if 91 * the semaphore was negative (== somebody was waiting on it). 92 * The default case (no contention) will result in NO 93 * jumps for both down() and up(). 94 */ 95static inline void up(struct semaphore * sem) 96{ 97 __up_op(sem, __up_wakeup); 98} 99 100#endif 101