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1da177e4 LT |
1 | #ifndef __ASM_SH_SEMAPHORE_H |
2 | #define __ASM_SH_SEMAPHORE_H | |
3 | ||
4 | #include <linux/linkage.h> | |
5 | ||
6 | #ifdef __KERNEL__ | |
7 | /* | |
8 | * SMP- and interrupt-safe semaphores. | |
9 | * | |
10 | * (C) Copyright 1996 Linus Torvalds | |
11 | * | |
12 | * SuperH verison by Niibe Yutaka | |
13 | * (Currently no asm implementation but generic C code...) | |
14 | */ | |
15 | ||
16 | #include <linux/spinlock.h> | |
17 | #include <linux/rwsem.h> | |
18 | #include <linux/wait.h> | |
19 | ||
20 | #include <asm/system.h> | |
21 | #include <asm/atomic.h> | |
22 | ||
23 | struct 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 | .sleepers = 0, \ | |
33 | .wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \ | |
34 | } | |
35 | ||
1da177e4 LT |
36 | #define __DECLARE_SEMAPHORE_GENERIC(name,count) \ |
37 | struct semaphore name = __SEMAPHORE_INITIALIZER(name,count) | |
38 | ||
39 | #define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1) | |
1da177e4 LT |
40 | |
41 | static inline void sema_init (struct semaphore *sem, int val) | |
42 | { | |
43 | /* | |
44 | * *sem = (struct semaphore)__SEMAPHORE_INITIALIZER((*sem),val); | |
45 | * | |
46 | * i'd rather use the more flexible initialization above, but sadly | |
47 | * GCC 2.7.2.3 emits a bogus warning. EGCS doesn't. Oh well. | |
48 | */ | |
49 | atomic_set(&sem->count, val); | |
50 | sem->sleepers = 0; | |
51 | init_waitqueue_head(&sem->wait); | |
52 | } | |
53 | ||
54 | static inline void init_MUTEX (struct semaphore *sem) | |
55 | { | |
56 | sema_init(sem, 1); | |
57 | } | |
58 | ||
59 | static inline void init_MUTEX_LOCKED (struct semaphore *sem) | |
60 | { | |
61 | sema_init(sem, 0); | |
62 | } | |
63 | ||
64 | #if 0 | |
65 | asmlinkage void __down_failed(void /* special register calling convention */); | |
66 | asmlinkage int __down_failed_interruptible(void /* params in registers */); | |
67 | asmlinkage int __down_failed_trylock(void /* params in registers */); | |
68 | asmlinkage void __up_wakeup(void /* special register calling convention */); | |
69 | #endif | |
70 | ||
71 | asmlinkage void __down(struct semaphore * sem); | |
72 | asmlinkage int __down_interruptible(struct semaphore * sem); | |
73 | asmlinkage int __down_trylock(struct semaphore * sem); | |
74 | asmlinkage void __up(struct semaphore * sem); | |
75 | ||
76 | extern spinlock_t semaphore_wake_lock; | |
77 | ||
78 | static inline void down(struct semaphore * sem) | |
79 | { | |
80 | might_sleep(); | |
81 | if (atomic_dec_return(&sem->count) < 0) | |
82 | __down(sem); | |
83 | } | |
84 | ||
85 | static inline int down_interruptible(struct semaphore * sem) | |
86 | { | |
87 | int ret = 0; | |
88 | ||
89 | might_sleep(); | |
90 | if (atomic_dec_return(&sem->count) < 0) | |
91 | ret = __down_interruptible(sem); | |
92 | return ret; | |
93 | } | |
94 | ||
95 | static inline int down_trylock(struct semaphore * sem) | |
96 | { | |
97 | int ret = 0; | |
98 | ||
99 | if (atomic_dec_return(&sem->count) < 0) | |
100 | ret = __down_trylock(sem); | |
101 | return ret; | |
102 | } | |
103 | ||
104 | /* | |
105 | * Note! This is subtle. We jump to wake people up only if | |
106 | * the semaphore was negative (== somebody was waiting on it). | |
107 | */ | |
108 | static inline void up(struct semaphore * sem) | |
109 | { | |
110 | if (atomic_inc_return(&sem->count) <= 0) | |
111 | __up(sem); | |
112 | } | |
113 | ||
114 | #endif | |
115 | #endif /* __ASM_SH_SEMAPHORE_H */ |