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1#ifndef __ASM_SH64_SEMAPHORE_H
2#define __ASM_SH64_SEMAPHORE_H
3
4/*
5 * This file is subject to the terms and conditions of the GNU General Public
6 * License. See the file "COPYING" in the main directory of this archive
7 * for more details.
8 *
9 * include/asm-sh64/semaphore.h
10 *
11 * Copyright (C) 2000, 2001 Paolo Alberelli
12 *
13 * SMP- and interrupt-safe semaphores.
14 *
15 * (C) Copyright 1996 Linus Torvalds
16 *
17 * SuperH verison by Niibe Yutaka
18 * (Currently no asm implementation but generic C code...)
19 *
20 */
21
22#include <linux/linkage.h>
23#include <linux/spinlock.h>
24#include <linux/wait.h>
25#include <linux/rwsem.h>
26
27#include <asm/system.h>
28#include <asm/atomic.h>
29
30struct semaphore {
31 atomic_t count;
32 int sleepers;
33 wait_queue_head_t wait;
34};
35
36#define __SEMAPHORE_INITIALIZER(name, n) \
37{ \
38 .count = ATOMIC_INIT(n), \
39 .sleepers = 0, \
40 .wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \
41}
42
43#define __DECLARE_SEMAPHORE_GENERIC(name,count) \
44 struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
45
46#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
47#define DECLARE_MUTEX_LOCKED(name) __DECLARE_SEMAPHORE_GENERIC(name,0)
48
49static inline void sema_init (struct semaphore *sem, int val)
50{
51/*
52 * *sem = (struct semaphore)__SEMAPHORE_INITIALIZER((*sem),val);
53 *
54 * i'd rather use the more flexible initialization above, but sadly
55 * GCC 2.7.2.3 emits a bogus warning. EGCS doesnt. Oh well.
56 */
57 atomic_set(&sem->count, val);
58 sem->sleepers = 0;
59 init_waitqueue_head(&sem->wait);
60}
61
62static inline void init_MUTEX (struct semaphore *sem)
63{
64 sema_init(sem, 1);
65}
66
67static inline void init_MUTEX_LOCKED (struct semaphore *sem)
68{
69 sema_init(sem, 0);
70}
71
72#if 0
73asmlinkage void __down_failed(void /* special register calling convention */);
74asmlinkage int __down_failed_interruptible(void /* params in registers */);
75asmlinkage int __down_failed_trylock(void /* params in registers */);
76asmlinkage void __up_wakeup(void /* special register calling convention */);
77#endif
78
79asmlinkage void __down(struct semaphore * sem);
80asmlinkage int __down_interruptible(struct semaphore * sem);
81asmlinkage int __down_trylock(struct semaphore * sem);
82asmlinkage void __up(struct semaphore * sem);
83
84extern spinlock_t semaphore_wake_lock;
85
86static inline void down(struct semaphore * sem)
87{
88 if (atomic_dec_return(&sem->count) < 0)
89 __down(sem);
90}
91
92static inline int down_interruptible(struct semaphore * sem)
93{
94 int ret = 0;
95
96 if (atomic_dec_return(&sem->count) < 0)
97 ret = __down_interruptible(sem);
98 return ret;
99}
100
101static inline int down_trylock(struct semaphore * sem)
102{
103 int ret = 0;
104
105 if (atomic_dec_return(&sem->count) < 0)
106 ret = __down_trylock(sem);
107 return ret;
108}
109
110/*
111 * Note! This is subtle. We jump to wake people up only if
112 * the semaphore was negative (== somebody was waiting on it).
113 */
114static inline void up(struct semaphore * sem)
115{
116 if (atomic_inc_return(&sem->count) <= 0)
117 __up(sem);
118}
119
120#endif /* __ASM_SH64_SEMAPHORE_H */