1#ifndef _BFIN_SEMAPHORE_H
2#define _BFIN_SEMAPHORE_H
3
4#ifndef __ASSEMBLY__
5
6#include <linux/linkage.h>
7#include <linux/wait.h>
8#include <linux/spinlock.h>
9#include <linux/rwsem.h>
10#include <asm/atomic.h>
11
12/*
13 * Interrupt-safe semaphores..
14 *
15 * (C) Copyright 1996 Linus Torvalds
16 *
17 * BFIN version by akbar hussain Lineo Inc  April 2001
18 *
19 */
20
21struct semaphore {
22	atomic_t count;
23	int sleepers;
24	wait_queue_head_t wait;
25};
26
27#define __SEMAPHORE_INITIALIZER(name, n)				\
28{									\
29	.count		= ATOMIC_INIT(n),				\
30	.sleepers	= 0,						\
31	.wait		= __WAIT_QUEUE_HEAD_INITIALIZER((name).wait)	\
32}
33
34#define __DECLARE_SEMAPHORE_GENERIC(name,count) \
35	struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
36
37#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
38#define DECLARE_MUTEX_LOCKED(name) __DECLARE_SEMAPHORE_GENERIC(name,0)
39
40static inline void sema_init(struct semaphore *sem, int val)
41{
42	*sem = (struct semaphore)__SEMAPHORE_INITIALIZER(*sem, val);
43}
44
45static inline void init_MUTEX(struct semaphore *sem)
46{
47	sema_init(sem, 1);
48}
49
50static inline void init_MUTEX_LOCKED(struct semaphore *sem)
51{
52	sema_init(sem, 0);
53}
54
55asmlinkage void __down(struct semaphore *sem);
56asmlinkage int __down_interruptible(struct semaphore *sem);
57asmlinkage int __down_trylock(struct semaphore *sem);
58asmlinkage void __up(struct semaphore *sem);
59
60extern spinlock_t semaphore_wake_lock;
61
62/*
63 * This is ugly, but we want the default case to fall through.
64 * "down_failed" is a special asm handler that calls the C
65 * routine that actually waits.
66 */
67static inline void down(struct semaphore *sem)
68{
69	might_sleep();
70	if (atomic_dec_return(&sem->count) < 0)
71		__down(sem);
72}
73
74static inline int down_interruptible(struct semaphore *sem)
75{
76	int ret = 0;
77
78	might_sleep();
79	if (atomic_dec_return(&sem->count) < 0)
80		ret = __down_interruptible(sem);
81	return (ret);
82}
83
84static inline int down_trylock(struct semaphore *sem)
85{
86	int ret = 0;
87
88	if (atomic_dec_return(&sem->count) < 0)
89		ret = __down_trylock(sem);
90	return ret;
91}
92
93/*
94 * Note! This is subtle. We jump to wake people up only if
95 * the semaphore was negative (== somebody was waiting on it).
96 * The default case (no contention) will result in NO
97 * jumps for both down() and up().
98 */
99static inline void up(struct semaphore *sem)
100{
101	if (atomic_inc_return(&sem->count) <= 0)
102		__up(sem);
103}
104
105#endif				/* __ASSEMBLY__ */
106#endif				/* _BFIN_SEMAPHORE_H */
107