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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) | |
40 | #define DECLARE_MUTEX_LOCKED(name) __DECLARE_SEMAPHORE_GENERIC(name,0) | |
41 | ||
42 | static inline void sema_init (struct semaphore *sem, int val) | |
43 | { | |
44 | /* | |
45 | * *sem = (struct semaphore)__SEMAPHORE_INITIALIZER((*sem),val); | |
46 | * | |
47 | * i'd rather use the more flexible initialization above, but sadly | |
48 | * GCC 2.7.2.3 emits a bogus warning. EGCS doesn't. Oh well. | |
49 | */ | |
50 | atomic_set(&sem->count, val); | |
51 | sem->sleepers = 0; | |
52 | init_waitqueue_head(&sem->wait); | |
53 | } | |
54 | ||
55 | static inline void init_MUTEX (struct semaphore *sem) | |
56 | { | |
57 | sema_init(sem, 1); | |
58 | } | |
59 | ||
60 | static inline void init_MUTEX_LOCKED (struct semaphore *sem) | |
61 | { | |
62 | sema_init(sem, 0); | |
63 | } | |
64 | ||
65 | #if 0 | |
66 | asmlinkage void __down_failed(void /* special register calling convention */); | |
67 | asmlinkage int __down_failed_interruptible(void /* params in registers */); | |
68 | asmlinkage int __down_failed_trylock(void /* params in registers */); | |
69 | asmlinkage void __up_wakeup(void /* special register calling convention */); | |
70 | #endif | |
71 | ||
72 | asmlinkage void __down(struct semaphore * sem); | |
73 | asmlinkage int __down_interruptible(struct semaphore * sem); | |
74 | asmlinkage int __down_trylock(struct semaphore * sem); | |
75 | asmlinkage void __up(struct semaphore * sem); | |
76 | ||
77 | extern spinlock_t semaphore_wake_lock; | |
78 | ||
79 | static inline void down(struct semaphore * sem) | |
80 | { | |
81 | might_sleep(); | |
82 | if (atomic_dec_return(&sem->count) < 0) | |
83 | __down(sem); | |
84 | } | |
85 | ||
86 | static inline int down_interruptible(struct semaphore * sem) | |
87 | { | |
88 | int ret = 0; | |
89 | ||
90 | might_sleep(); | |
91 | if (atomic_dec_return(&sem->count) < 0) | |
92 | ret = __down_interruptible(sem); | |
93 | return ret; | |
94 | } | |
95 | ||
96 | static inline int down_trylock(struct semaphore * sem) | |
97 | { | |
98 | int ret = 0; | |
99 | ||
100 | if (atomic_dec_return(&sem->count) < 0) | |
101 | ret = __down_trylock(sem); | |
102 | return ret; | |
103 | } | |
104 | ||
105 | /* | |
106 | * Note! This is subtle. We jump to wake people up only if | |
107 | * the semaphore was negative (== somebody was waiting on it). | |
108 | */ | |
109 | static inline void up(struct semaphore * sem) | |
110 | { | |
111 | if (atomic_inc_return(&sem->count) <= 0) | |
112 | __up(sem); | |
113 | } | |
114 | ||
115 | #endif | |
116 | #endif /* __ASM_SH_SEMAPHORE_H */ |