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authorRussell King <rmk@dyn-67.arm.linux.org.uk>2008-04-19 12:17:34 -0400
committerRussell King <rmk+kernel@arm.linux.org.uk>2008-04-19 12:17:34 -0400
commitcf816ecb533ab96b883dfdc0db174598b5b5c4d2 (patch)
tree1b7705db288ae2917105e624b01fdf81e0882bf1 /include/asm-avr32/semaphore.h
parentadf6d34e460387ee3e8f1e1875d52bff51212c7d (diff)
parent15f7d677ccff6f0f5de8a1ee43a792567e9f9de9 (diff)
Merge branch 'merge-fixes' into devel
Diffstat (limited to 'include/asm-avr32/semaphore.h')
-rw-r--r--include/asm-avr32/semaphore.h109
1 files changed, 1 insertions, 108 deletions
diff --git a/include/asm-avr32/semaphore.h b/include/asm-avr32/semaphore.h
index feaf1d453386..d9b2034ed1d2 100644
--- a/include/asm-avr32/semaphore.h
+++ b/include/asm-avr32/semaphore.h
@@ -1,108 +1 @@
1/* #include <linux/semaphore.h>
2 * SMP- and interrupt-safe semaphores.
3 *
4 * Copyright (C) 2006 Atmel Corporation
5 *
6 * Based on include/asm-i386/semaphore.h
7 * Copyright (C) 1996 Linus Torvalds
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
12 */
13#ifndef __ASM_AVR32_SEMAPHORE_H
14#define __ASM_AVR32_SEMAPHORE_H
15
16#include <linux/linkage.h>
17
18#include <asm/system.h>
19#include <asm/atomic.h>
20#include <linux/wait.h>
21#include <linux/rwsem.h>
22
23struct semaphore {
24 atomic_t count;
25 int sleepers;
26 wait_queue_head_t wait;
27};
28
29#define __SEMAPHORE_INITIALIZER(name, n) \
30{ \
31 .count = ATOMIC_INIT(n), \
32 .wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \
33}
34
35#define __DECLARE_SEMAPHORE_GENERIC(name,count) \
36 struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
37
38#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
39
40static inline void sema_init (struct semaphore *sem, int val)
41{
42 atomic_set(&sem->count, val);
43 sem->sleepers = 0;
44 init_waitqueue_head(&sem->wait);
45}
46
47static inline void init_MUTEX (struct semaphore *sem)
48{
49 sema_init(sem, 1);
50}
51
52static inline void init_MUTEX_LOCKED (struct semaphore *sem)
53{
54 sema_init(sem, 0);
55}
56
57void __down(struct semaphore * sem);
58int __down_interruptible(struct semaphore * sem);
59void __up(struct semaphore * sem);
60
61/*
62 * This is ugly, but we want the default case to fall through.
63 * "__down_failed" is a special asm handler that calls the C
64 * routine that actually waits. See arch/i386/kernel/semaphore.c
65 */
66static inline void down(struct semaphore * sem)
67{
68 might_sleep();
69 if (unlikely(atomic_dec_return (&sem->count) < 0))
70 __down (sem);
71}
72
73/*
74 * Interruptible try to acquire a semaphore. If we obtained
75 * it, return zero. If we were interrupted, returns -EINTR
76 */
77static inline int down_interruptible(struct semaphore * sem)
78{
79 int ret = 0;
80
81 might_sleep();
82 if (unlikely(atomic_dec_return (&sem->count) < 0))
83 ret = __down_interruptible (sem);
84 return ret;
85}
86
87/*
88 * Non-blockingly attempt to down() a semaphore.
89 * Returns zero if we acquired it
90 */
91static inline int down_trylock(struct semaphore * sem)
92{
93 return atomic_dec_if_positive(&sem->count) < 0;
94}
95
96/*
97 * Note! This is subtle. We jump to wake people up only if
98 * the semaphore was negative (== somebody was waiting on it).
99 * The default case (no contention) will result in NO
100 * jumps for both down() and up().
101 */
102static inline void up(struct semaphore * sem)
103{
104 if (unlikely(atomic_inc_return (&sem->count) <= 0))
105 __up (sem);
106}
107
108#endif /*__ASM_AVR32_SEMAPHORE_H */