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9a8fd558 CZ |
1 | /* |
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 | ||
19 | struct semaphore { | |
20 | atomic_t count; | |
21 | int sleepers; | |
22 | wait_queue_head_t wait; | |
9a8fd558 CZ |
23 | }; |
24 | ||
288a60cf CZ |
25 | #define __SEMAPHORE_INITIALIZER(name,n) \ |
26 | { \ | |
27 | .count = ATOMIC_INIT(n), \ | |
28 | .sleepers = 0, \ | |
29 | .wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \ | |
30 | } | |
9a8fd558 | 31 | |
288a60cf | 32 | #define __DECLARE_SEMAPHORE_GENERIC(name,count) \ |
9a8fd558 CZ |
33 | struct semaphore name = __SEMAPHORE_INITIALIZER(name,count) |
34 | ||
35 | #define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1) | |
9a8fd558 | 36 | |
d99cf715 | 37 | static inline void sema_init (struct semaphore *sem, int val) |
9a8fd558 | 38 | { |
9a8fd558 | 39 | atomic_set(&sem->count, val); |
aa3a6f45 | 40 | sem->sleepers = 0; |
9a8fd558 | 41 | init_waitqueue_head(&sem->wait); |
9a8fd558 CZ |
42 | } |
43 | ||
44 | static inline void init_MUTEX (struct semaphore *sem) | |
45 | { | |
46 | sema_init(sem, 1); | |
47 | } | |
48 | ||
49 | static inline void init_MUTEX_LOCKED (struct semaphore *sem) | |
50 | { | |
51 | sema_init(sem, 0); | |
52 | } | |
53 | ||
54 | asmlinkage void __down(struct semaphore * sem); | |
55 | asmlinkage int __down_interruptible(struct semaphore * sem); | |
56 | asmlinkage int __down_trylock(struct semaphore * sem); | |
57 | asmlinkage void __up(struct semaphore * sem); | |
58 | ||
59 | extern spinlock_t semaphore_wake_lock; | |
60 | ||
d99cf715 | 61 | static inline void down(struct semaphore * sem) |
9a8fd558 | 62 | { |
288a60cf | 63 | might_sleep(); |
9a8fd558 CZ |
64 | |
65 | if (atomic_sub_return(1, &sem->count) < 0) | |
66 | __down(sem); | |
67 | } | |
68 | ||
d99cf715 | 69 | static inline int down_interruptible(struct semaphore * sem) |
9a8fd558 CZ |
70 | { |
71 | int ret = 0; | |
288a60cf CZ |
72 | |
73 | might_sleep(); | |
9a8fd558 CZ |
74 | |
75 | if (atomic_sub_return(1, &sem->count) < 0) | |
76 | ret = __down_interruptible(sem); | |
77 | return ret; | |
78 | } | |
79 | ||
d99cf715 | 80 | static inline int down_trylock(struct semaphore * sem) |
9a8fd558 CZ |
81 | { |
82 | int ret = 0; | |
9a8fd558 CZ |
83 | |
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 | */ | |
d99cf715 | 93 | static inline void up(struct semaphore * sem) |
9a8fd558 | 94 | { |
9a8fd558 CZ |
95 | if (atomic_add_return(1, &sem->count) <= 0) |
96 | __up(sem); | |
97 | } | |
98 | ||
99 | #endif /* _XTENSA_SEMAPHORE_H */ |