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