blob: 3e04167cd9dce22d2989f18e569255ecb059b11d [file] [log] [blame]
Chris Zankel9a8fd552005-06-23 22:01:26 -07001/*
2 * linux/include/asm-xtensa/semaphore.h
3 *
4 * This file is subject to the terms and conditions of the GNU General Public
5 * License. See the file "COPYING" in the main directory of this archive
6 * for more details.
7 *
8 * Copyright (C) 2001 - 2005 Tensilica Inc.
9 */
10
11#ifndef _XTENSA_SEMAPHORE_H
12#define _XTENSA_SEMAPHORE_H
13
14#include <asm/atomic.h>
15#include <asm/system.h>
16#include <linux/wait.h>
17#include <linux/rwsem.h>
18
19struct semaphore {
20 atomic_t count;
21 int sleepers;
22 wait_queue_head_t wait;
Chris Zankel9a8fd552005-06-23 22:01:26 -070023};
24
Chris Zankel288a60c2005-09-22 21:44:23 -070025#define __SEMAPHORE_INITIALIZER(name,n) \
26{ \
27 .count = ATOMIC_INIT(n), \
28 .sleepers = 0, \
29 .wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \
30}
Chris Zankel9a8fd552005-06-23 22:01:26 -070031
Chris Zankel288a60c2005-09-22 21:44:23 -070032#define __DECLARE_SEMAPHORE_GENERIC(name,count) \
Chris Zankel9a8fd552005-06-23 22:01:26 -070033 struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
34
35#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
Chris Zankel9a8fd552005-06-23 22:01:26 -070036
Adrian Bunkd99cf712005-09-03 15:57:53 -070037static inline void sema_init (struct semaphore *sem, int val)
Chris Zankel9a8fd552005-06-23 22:01:26 -070038{
Chris Zankel9a8fd552005-06-23 22:01:26 -070039 atomic_set(&sem->count, val);
Arthur Othienoaa3a6f42005-11-07 00:59:01 -080040 sem->sleepers = 0;
Chris Zankel9a8fd552005-06-23 22:01:26 -070041 init_waitqueue_head(&sem->wait);
Chris Zankel9a8fd552005-06-23 22:01:26 -070042}
43
44static inline void init_MUTEX (struct semaphore *sem)
45{
46 sema_init(sem, 1);
47}
48
49static inline void init_MUTEX_LOCKED (struct semaphore *sem)
50{
51 sema_init(sem, 0);
52}
53
54asmlinkage void __down(struct semaphore * sem);
55asmlinkage int __down_interruptible(struct semaphore * sem);
56asmlinkage int __down_trylock(struct semaphore * sem);
57asmlinkage void __up(struct semaphore * sem);
58
59extern spinlock_t semaphore_wake_lock;
60
Adrian Bunkd99cf712005-09-03 15:57:53 -070061static inline void down(struct semaphore * sem)
Chris Zankel9a8fd552005-06-23 22:01:26 -070062{
Chris Zankel288a60c2005-09-22 21:44:23 -070063 might_sleep();
Chris Zankel9a8fd552005-06-23 22:01:26 -070064
65 if (atomic_sub_return(1, &sem->count) < 0)
66 __down(sem);
67}
68
Adrian Bunkd99cf712005-09-03 15:57:53 -070069static inline int down_interruptible(struct semaphore * sem)
Chris Zankel9a8fd552005-06-23 22:01:26 -070070{
71 int ret = 0;
Chris Zankel288a60c2005-09-22 21:44:23 -070072
73 might_sleep();
Chris Zankel9a8fd552005-06-23 22:01:26 -070074
75 if (atomic_sub_return(1, &sem->count) < 0)
76 ret = __down_interruptible(sem);
77 return ret;
78}
79
Adrian Bunkd99cf712005-09-03 15:57:53 -070080static inline int down_trylock(struct semaphore * sem)
Chris Zankel9a8fd552005-06-23 22:01:26 -070081{
82 int ret = 0;
Chris Zankel9a8fd552005-06-23 22:01:26 -070083
84 if (atomic_sub_return(1, &sem->count) < 0)
85 ret = __down_trylock(sem);
86 return ret;
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 */
Adrian Bunkd99cf712005-09-03 15:57:53 -070093static inline void up(struct semaphore * sem)
Chris Zankel9a8fd552005-06-23 22:01:26 -070094{
Chris Zankel9a8fd552005-06-23 22:01:26 -070095 if (atomic_add_return(1, &sem->count) <= 0)
96 __up(sem);
97}
98
99#endif /* _XTENSA_SEMAPHORE_H */