blob: d5dc624f452a203142908c5cf96adf642dcdbd2b [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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
Linus Torvalds1da177e2005-04-16 15:20:36 -070027#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
Linus Torvalds1da177e2005-04-16 15:20:36 -070050/*
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