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1 | #ifndef _ASM_M32R_SEMAPHORE_H |
2 | #define _ASM_M32R_SEMAPHORE_H | |
3 | ||
4 | #include <linux/linkage.h> | |
5 | ||
6 | #ifdef __KERNEL__ | |
7 | ||
8 | /* | |
9 | * SMP- and interrupt-safe semaphores.. | |
10 | * | |
11 | * Copyright (C) 1996 Linus Torvalds | |
fa372810 | 12 | * Copyright (C) 2004, 2006 Hirokazu Takata <takata at linux-m32r.org> |
1da177e4 LT |
13 | */ |
14 | ||
1da177e4 LT |
15 | #include <linux/wait.h> |
16 | #include <linux/rwsem.h> | |
17 | #include <asm/assembler.h> | |
18 | #include <asm/system.h> | |
19 | #include <asm/atomic.h> | |
20 | ||
21 | struct semaphore { | |
22 | atomic_t count; | |
23 | int sleepers; | |
24 | wait_queue_head_t wait; | |
25 | }; | |
26 | ||
27 | #define __SEMAPHORE_INITIALIZER(name, n) \ | |
28 | { \ | |
29 | .count = ATOMIC_INIT(n), \ | |
30 | .sleepers = 0, \ | |
31 | .wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \ | |
32 | } | |
33 | ||
1da177e4 LT |
34 | #define __DECLARE_SEMAPHORE_GENERIC(name,count) \ |
35 | struct semaphore name = __SEMAPHORE_INITIALIZER(name,count) | |
36 | ||
37 | #define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1) | |
1da177e4 LT |
38 | |
39 | static inline void sema_init (struct semaphore *sem, int val) | |
40 | { | |
41 | /* | |
42 | * *sem = (struct semaphore)__SEMAPHORE_INITIALIZER((*sem),val); | |
43 | * | |
44 | * i'd rather use the more flexible initialization above, but sadly | |
45 | * GCC 2.7.2.3 emits a bogus warning. EGCS doesnt. Oh well. | |
46 | */ | |
47 | atomic_set(&sem->count, val); | |
48 | sem->sleepers = 0; | |
49 | init_waitqueue_head(&sem->wait); | |
50 | } | |
51 | ||
52 | static inline void init_MUTEX (struct semaphore *sem) | |
53 | { | |
54 | sema_init(sem, 1); | |
55 | } | |
56 | ||
57 | static inline void init_MUTEX_LOCKED (struct semaphore *sem) | |
58 | { | |
59 | sema_init(sem, 0); | |
60 | } | |
61 | ||
62 | asmlinkage void __down_failed(void /* special register calling convention */); | |
63 | asmlinkage int __down_failed_interruptible(void /* params in registers */); | |
64 | asmlinkage int __down_failed_trylock(void /* params in registers */); | |
65 | asmlinkage void __up_wakeup(void /* special register calling convention */); | |
66 | ||
67 | asmlinkage void __down(struct semaphore * sem); | |
68 | asmlinkage int __down_interruptible(struct semaphore * sem); | |
69 | asmlinkage int __down_trylock(struct semaphore * sem); | |
70 | asmlinkage void __up(struct semaphore * sem); | |
71 | ||
72 | /* | |
73 | * Atomically decrement the semaphore's count. If it goes negative, | |
74 | * block the calling thread in the TASK_UNINTERRUPTIBLE state. | |
75 | */ | |
76 | static inline void down(struct semaphore * sem) | |
77 | { | |
1da177e4 | 78 | might_sleep(); |
fa372810 | 79 | if (unlikely(atomic_dec_return(&sem->count) < 0)) |
1da177e4 LT |
80 | __down(sem); |
81 | } | |
82 | ||
83 | /* | |
84 | * Interruptible try to acquire a semaphore. If we obtained | |
85 | * it, return zero. If we were interrupted, returns -EINTR | |
86 | */ | |
87 | static inline int down_interruptible(struct semaphore * sem) | |
88 | { | |
1da177e4 LT |
89 | int result = 0; |
90 | ||
91 | might_sleep(); | |
fa372810 | 92 | if (unlikely(atomic_dec_return(&sem->count) < 0)) |
1da177e4 LT |
93 | result = __down_interruptible(sem); |
94 | ||
95 | return result; | |
96 | } | |
97 | ||
98 | /* | |
99 | * Non-blockingly attempt to down() a semaphore. | |
100 | * Returns zero if we acquired it | |
101 | */ | |
102 | static inline int down_trylock(struct semaphore * sem) | |
103 | { | |
104 | unsigned long flags; | |
105 | long count; | |
106 | int result = 0; | |
107 | ||
108 | local_irq_save(flags); | |
109 | __asm__ __volatile__ ( | |
110 | "# down_trylock \n\t" | |
111 | DCACHE_CLEAR("%0", "r4", "%1") | |
112 | M32R_LOCK" %0, @%1; \n\t" | |
113 | "addi %0, #-1; \n\t" | |
114 | M32R_UNLOCK" %0, @%1; \n\t" | |
115 | : "=&r" (count) | |
116 | : "r" (&sem->count) | |
117 | : "memory" | |
118 | #ifdef CONFIG_CHIP_M32700_TS1 | |
119 | , "r4" | |
120 | #endif /* CONFIG_CHIP_M32700_TS1 */ | |
121 | ); | |
122 | local_irq_restore(flags); | |
123 | ||
124 | if (unlikely(count < 0)) | |
125 | result = __down_trylock(sem); | |
126 | ||
127 | return result; | |
128 | } | |
129 | ||
130 | /* | |
131 | * Note! This is subtle. We jump to wake people up only if | |
132 | * the semaphore was negative (== somebody was waiting on it). | |
133 | * The default case (no contention) will result in NO | |
134 | * jumps for both down() and up(). | |
135 | */ | |
136 | static inline void up(struct semaphore * sem) | |
137 | { | |
fa372810 | 138 | if (unlikely(atomic_inc_return(&sem->count) <= 0)) |
1da177e4 LT |
139 | __up(sem); |
140 | } | |
141 | ||
142 | #endif /* __KERNEL__ */ | |
143 | ||
144 | #endif /* _ASM_M32R_SEMAPHORE_H */ |