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1da177e4 LT |
1 | /* |
2 | * linux/include/asm-arm/semaphore.h | |
3 | */ | |
4 | #ifndef __ASM_ARM_SEMAPHORE_H | |
5 | #define __ASM_ARM_SEMAPHORE_H | |
6 | ||
7 | #include <linux/linkage.h> | |
8 | #include <linux/spinlock.h> | |
9 | #include <linux/wait.h> | |
10 | #include <linux/rwsem.h> | |
11 | ||
12 | #include <asm/atomic.h> | |
13 | #include <asm/locks.h> | |
14 | ||
15 | struct semaphore { | |
16 | atomic_t count; | |
17 | int sleepers; | |
18 | wait_queue_head_t wait; | |
19 | }; | |
20 | ||
21 | #define __SEMAPHORE_INIT(name, cnt) \ | |
22 | { \ | |
23 | .count = ATOMIC_INIT(cnt), \ | |
24 | .wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait), \ | |
25 | } | |
26 | ||
27 | #define __MUTEX_INITIALIZER(name) __SEMAPHORE_INIT(name,1) | |
28 | ||
29 | #define __DECLARE_SEMAPHORE_GENERIC(name,count) \ | |
30 | struct semaphore name = __SEMAPHORE_INIT(name,count) | |
31 | ||
32 | #define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1) | |
33 | #define DECLARE_MUTEX_LOCKED(name) __DECLARE_SEMAPHORE_GENERIC(name,0) | |
34 | ||
35 | static inline void sema_init(struct semaphore *sem, int val) | |
36 | { | |
37 | atomic_set(&sem->count, val); | |
38 | sem->sleepers = 0; | |
39 | init_waitqueue_head(&sem->wait); | |
40 | } | |
41 | ||
42 | static inline void init_MUTEX(struct semaphore *sem) | |
43 | { | |
44 | sema_init(sem, 1); | |
45 | } | |
46 | ||
47 | static inline void init_MUTEX_LOCKED(struct semaphore *sem) | |
48 | { | |
49 | sema_init(sem, 0); | |
50 | } | |
51 | ||
52 | static inline int sema_count(struct semaphore *sem) | |
53 | { | |
54 | return atomic_read(&sem->count); | |
55 | } | |
56 | ||
57 | /* | |
58 | * special register calling convention | |
59 | */ | |
60 | asmlinkage void __down_failed(void); | |
61 | asmlinkage int __down_interruptible_failed(void); | |
62 | asmlinkage int __down_trylock_failed(void); | |
63 | asmlinkage void __up_wakeup(void); | |
64 | ||
65 | extern void __down(struct semaphore * sem); | |
66 | extern int __down_interruptible(struct semaphore * sem); | |
67 | extern int __down_trylock(struct semaphore * sem); | |
68 | extern void __up(struct semaphore * sem); | |
69 | ||
70 | /* | |
71 | * This is ugly, but we want the default case to fall through. | |
72 | * "__down" is the actual routine that waits... | |
73 | */ | |
74 | static inline void down(struct semaphore * sem) | |
75 | { | |
76 | might_sleep(); | |
77 | __down_op(sem, __down_failed); | |
78 | } | |
79 | ||
80 | /* | |
81 | * This is ugly, but we want the default case to fall through. | |
82 | * "__down_interruptible" is the actual routine that waits... | |
83 | */ | |
84 | static inline int down_interruptible (struct semaphore * sem) | |
85 | { | |
86 | might_sleep(); | |
87 | return __down_op_ret(sem, __down_interruptible_failed); | |
88 | } | |
89 | ||
90 | static inline int down_trylock(struct semaphore *sem) | |
91 | { | |
92 | return __down_op_ret(sem, __down_trylock_failed); | |
93 | } | |
94 | ||
95 | /* | |
96 | * Note! This is subtle. We jump to wake people up only if | |
97 | * the semaphore was negative (== somebody was waiting on it). | |
98 | * The default case (no contention) will result in NO | |
99 | * jumps for both down() and up(). | |
100 | */ | |
101 | static inline void up(struct semaphore * sem) | |
102 | { | |
103 | __up_op(sem, __up_wakeup); | |
104 | } | |
105 | ||
106 | #endif |