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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) | |
52 | #define DECLARE_MUTEX_LOCKED(name) __DECLARE_SEMAPHORE_GENERIC(name,0) | |
53 | ||
54 | static inline void sema_init (struct semaphore *sem, int val) | |
55 | { | |
56 | *sem = (struct semaphore) __SEMAPHORE_INITIALIZER(*sem, val); | |
57 | } | |
58 | ||
59 | static inline void init_MUTEX (struct semaphore *sem) | |
60 | { | |
61 | sema_init(sem, 1); | |
62 | } | |
63 | ||
64 | static inline void init_MUTEX_LOCKED (struct semaphore *sem) | |
65 | { | |
66 | sema_init(sem, 0); | |
67 | } | |
68 | ||
69 | extern void __down(struct semaphore *sem, unsigned long flags); | |
70 | extern int __down_interruptible(struct semaphore *sem, unsigned long flags); | |
71 | extern void __up(struct semaphore *sem); | |
72 | ||
73 | static inline void down(struct semaphore *sem) | |
74 | { | |
75 | unsigned long flags; | |
76 | ||
c761c841 | 77 | #ifdef CONFIG_DEBUG_SEMAPHORE |
1da177e4 LT |
78 | CHECK_MAGIC(sem->__magic); |
79 | #endif | |
80 | ||
81 | spin_lock_irqsave(&sem->wait_lock, flags); | |
82 | if (likely(sem->counter > 0)) { | |
83 | sem->counter--; | |
84 | spin_unlock_irqrestore(&sem->wait_lock, flags); | |
85 | } | |
86 | else { | |
87 | __down(sem, flags); | |
88 | } | |
89 | } | |
90 | ||
91 | static inline int down_interruptible(struct semaphore *sem) | |
92 | { | |
93 | unsigned long flags; | |
94 | int ret = 0; | |
95 | ||
c761c841 | 96 | #ifdef CONFIG_DEBUG_SEMAPHORE |
1da177e4 LT |
97 | CHECK_MAGIC(sem->__magic); |
98 | #endif | |
99 | ||
100 | spin_lock_irqsave(&sem->wait_lock, flags); | |
101 | if (likely(sem->counter > 0)) { | |
102 | sem->counter--; | |
103 | spin_unlock_irqrestore(&sem->wait_lock, flags); | |
104 | } | |
105 | else { | |
106 | ret = __down_interruptible(sem, flags); | |
107 | } | |
108 | return ret; | |
109 | } | |
110 | ||
111 | /* | |
112 | * non-blockingly attempt to down() a semaphore. | |
113 | * - returns zero if we acquired it | |
114 | */ | |
115 | static inline int down_trylock(struct semaphore *sem) | |
116 | { | |
117 | unsigned long flags; | |
118 | int success = 0; | |
119 | ||
c761c841 | 120 | #ifdef CONFIG_DEBUG_SEMAPHORE |
1da177e4 LT |
121 | CHECK_MAGIC(sem->__magic); |
122 | #endif | |
123 | ||
124 | spin_lock_irqsave(&sem->wait_lock, flags); | |
125 | if (sem->counter > 0) { | |
126 | sem->counter--; | |
127 | success = 1; | |
128 | } | |
129 | spin_unlock_irqrestore(&sem->wait_lock, flags); | |
130 | return !success; | |
131 | } | |
132 | ||
133 | static inline void up(struct semaphore *sem) | |
134 | { | |
135 | unsigned long flags; | |
136 | ||
c761c841 | 137 | #ifdef CONFIG_DEBUG_SEMAPHORE |
1da177e4 LT |
138 | CHECK_MAGIC(sem->__magic); |
139 | #endif | |
140 | ||
141 | spin_lock_irqsave(&sem->wait_lock, flags); | |
142 | if (!list_empty(&sem->wait_list)) | |
143 | __up(sem); | |
144 | else | |
145 | sem->counter++; | |
146 | spin_unlock_irqrestore(&sem->wait_lock, flags); | |
147 | } | |
148 | ||
149 | static inline int sem_getcount(struct semaphore *sem) | |
150 | { | |
151 | return sem->counter; | |
152 | } | |
153 | ||
154 | #endif /* __ASSEMBLY__ */ | |
155 | ||
156 | #endif |