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