blob: ccf15e7041092d01f520c22772773678b41b4e73 [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, n) \
22{ \
23 .count = ATOMIC_INIT(n), \
24 .sleepers = 0, \
25 .wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait), \
26}
27
Linus Torvalds1da177e2005-04-16 15:20:36 -070028#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