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1da177e4 LT |
1 | /* semaphore.h: semaphores for the FR-V |
2 | * | |
3 | * Copyright (C) 2003 Red Hat, Inc. All Rights Reserved. | |
4 | * Written by David Howells (dhowells@redhat.com) | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public License | |
8 | * as published by the Free Software Foundation; either version | |
9 | * 2 of the License, or (at your option) any later version. | |
10 | */ | |
11 | #ifndef _ASM_SEMAPHORE_H | |
12 | #define _ASM_SEMAPHORE_H | |
13 | ||
14 | #define RW_LOCK_BIAS 0x01000000 | |
15 | ||
16 | #ifndef __ASSEMBLY__ | |
17 | ||
18 | #include <linux/linkage.h> | |
19 | #include <linux/wait.h> | |
20 | #include <linux/spinlock.h> | |
21 | #include <linux/rwsem.h> | |
22 | ||
1da177e4 LT |
23 | /* |
24 | * the semaphore definition | |
25 | * - if counter is >0 then there are tokens available on the semaphore for down to collect | |
26 | * - if counter is <=0 then there are no spare tokens, and anyone that wants one must wait | |
27 | * - if wait_list is not empty, then there are processes waiting for the semaphore | |
28 | */ | |
29 | struct semaphore { | |
30 | unsigned counter; | |
31 | spinlock_t wait_lock; | |
32 | struct list_head wait_list; | |
c761c841 | 33 | #ifdef CONFIG_DEBUG_SEMAPHORE |
1da177e4 LT |
34 | unsigned __magic; |
35 | #endif | |
36 | }; | |
37 | ||
c761c841 | 38 | #ifdef CONFIG_DEBUG_SEMAPHORE |
1da177e4 LT |
39 | # define __SEM_DEBUG_INIT(name) , (long)&(name).__magic |
40 | #else | |
41 | # define __SEM_DEBUG_INIT(name) | |
42 | #endif | |
43 | ||
44 | ||
45 | #define __SEMAPHORE_INITIALIZER(name,count) \ | |
46 | { count, SPIN_LOCK_UNLOCKED, LIST_HEAD_INIT((name).wait_list) __SEM_DEBUG_INIT(name) } | |
47 | ||
1da177e4 LT |
48 | #define __DECLARE_SEMAPHORE_GENERIC(name,count) \ |
49 | struct semaphore name = __SEMAPHORE_INITIALIZER(name,count) | |
50 | ||
51 | #define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1) | |
1da177e4 LT |
52 | |
53 | static inline void sema_init (struct semaphore *sem, int val) | |
54 | { | |
55 | *sem = (struct semaphore) __SEMAPHORE_INITIALIZER(*sem, val); | |
56 | } | |
57 | ||
58 | static inline void init_MUTEX (struct semaphore *sem) | |
59 | { | |
60 | sema_init(sem, 1); | |
61 | } | |
62 | ||
63 | static inline void init_MUTEX_LOCKED (struct semaphore *sem) | |
64 | { | |
65 | sema_init(sem, 0); | |
66 | } | |
67 | ||
68 | extern void __down(struct semaphore *sem, unsigned long flags); | |
69 | extern int __down_interruptible(struct semaphore *sem, unsigned long flags); | |
70 | extern void __up(struct semaphore *sem); | |
71 | ||
72 | static inline void down(struct semaphore *sem) | |
73 | { | |
74 | unsigned long flags; | |
75 | ||
c761c841 | 76 | #ifdef CONFIG_DEBUG_SEMAPHORE |
1da177e4 LT |
77 | CHECK_MAGIC(sem->__magic); |
78 | #endif | |
79 | ||
80 | spin_lock_irqsave(&sem->wait_lock, flags); | |
81 | if (likely(sem->counter > 0)) { | |
82 | sem->counter--; | |
83 | spin_unlock_irqrestore(&sem->wait_lock, flags); | |
84 | } | |
85 | else { | |
86 | __down(sem, flags); | |
87 | } | |
88 | } | |
89 | ||
90 | static inline int down_interruptible(struct semaphore *sem) | |
91 | { | |
92 | unsigned long flags; | |
93 | int ret = 0; | |
94 | ||
c761c841 | 95 | #ifdef CONFIG_DEBUG_SEMAPHORE |
1da177e4 LT |
96 | CHECK_MAGIC(sem->__magic); |
97 | #endif | |
98 | ||
99 | spin_lock_irqsave(&sem->wait_lock, flags); | |
100 | if (likely(sem->counter > 0)) { | |
101 | sem->counter--; | |
102 | spin_unlock_irqrestore(&sem->wait_lock, flags); | |
103 | } | |
104 | else { | |
105 | ret = __down_interruptible(sem, flags); | |
106 | } | |
107 | return ret; | |
108 | } | |
109 | ||
110 | /* | |
111 | * non-blockingly attempt to down() a semaphore. | |
112 | * - returns zero if we acquired it | |
113 | */ | |
114 | static inline int down_trylock(struct semaphore *sem) | |
115 | { | |
116 | unsigned long flags; | |
117 | int success = 0; | |
118 | ||
c761c841 | 119 | #ifdef CONFIG_DEBUG_SEMAPHORE |
1da177e4 LT |
120 | CHECK_MAGIC(sem->__magic); |
121 | #endif | |
122 | ||
123 | spin_lock_irqsave(&sem->wait_lock, flags); | |
124 | if (sem->counter > 0) { | |
125 | sem->counter--; | |
126 | success = 1; | |
127 | } | |
128 | spin_unlock_irqrestore(&sem->wait_lock, flags); | |
129 | return !success; | |
130 | } | |
131 | ||
132 | static inline void up(struct semaphore *sem) | |
133 | { | |
134 | unsigned long flags; | |
135 | ||
c761c841 | 136 | #ifdef CONFIG_DEBUG_SEMAPHORE |
1da177e4 LT |
137 | CHECK_MAGIC(sem->__magic); |
138 | #endif | |
139 | ||
140 | spin_lock_irqsave(&sem->wait_lock, flags); | |
141 | if (!list_empty(&sem->wait_list)) | |
142 | __up(sem); | |
143 | else | |
144 | sem->counter++; | |
145 | spin_unlock_irqrestore(&sem->wait_lock, flags); | |
146 | } | |
147 | ||
148 | static inline int sem_getcount(struct semaphore *sem) | |
149 | { | |
150 | return sem->counter; | |
151 | } | |
152 | ||
153 | #endif /* __ASSEMBLY__ */ | |
154 | ||
155 | #endif |