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
19 #include <asm/system.h>
20 #include <asm/atomic.h>
21
22 struct semaphore {
23 atomic_t count;
24 int sleepers;
25 wait_queue_head_t wait;
26 #if WAITQUEUE_DEBUG
27 long __magic;
28 #endif
29 };
30
31 #if WAITQUEUE_DEBUG
32 # define __SEM_DEBUG_INIT(name) \
33 , (int)&(name).__magic
34 #else
35 # define __SEM_DEBUG_INIT(name)
36 #endif
37
38 #define __SEMAPHORE_INITIALIZER(name,count) \
39 { ATOMIC_INIT(count), 0, __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \
40 __SEM_DEBUG_INIT(name) }
41
42 #define __MUTEX_INITIALIZER(name) \
43 __SEMAPHORE_INITIALIZER(name,1)
44
45 #define __DECLARE_SEMAPHORE_GENERIC(name,count) \
46 struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
47
48 #define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
49 #define DECLARE_MUTEX_LOCKED(name) __DECLARE_SEMAPHORE_GENERIC(name,0)
50
sema_init(struct semaphore * sem,int val)51 static inline void sema_init (struct semaphore *sem, int val)
52 {
53 /*
54 * *sem = (struct semaphore)__SEMAPHORE_INITIALIZER((*sem),val);
55 *
56 * i'd rather use the more flexible initialization above, but sadly
57 * GCC 2.7.2.3 emits a bogus warning. EGCS doesnt. Oh well.
58 */
59 atomic_set(&sem->count, val);
60 sem->sleepers = 0;
61 init_waitqueue_head(&sem->wait);
62 #if WAITQUEUE_DEBUG
63 sem->__magic = (int)&sem->__magic;
64 #endif
65 }
66
init_MUTEX(struct semaphore * sem)67 static inline void init_MUTEX (struct semaphore *sem)
68 {
69 sema_init(sem, 1);
70 }
71
init_MUTEX_LOCKED(struct semaphore * sem)72 static inline void init_MUTEX_LOCKED (struct semaphore *sem)
73 {
74 sema_init(sem, 0);
75 }
76
77 #if 0
78 asmlinkage void __down_failed(void /* special register calling convention */);
79 asmlinkage int __down_failed_interruptible(void /* params in registers */);
80 asmlinkage int __down_failed_trylock(void /* params in registers */);
81 asmlinkage void __up_wakeup(void /* special register calling convention */);
82 #endif
83
84 asmlinkage void __down(struct semaphore * sem);
85 asmlinkage int __down_interruptible(struct semaphore * sem);
86 asmlinkage int __down_trylock(struct semaphore * sem);
87 asmlinkage void __up(struct semaphore * sem);
88
89 extern spinlock_t semaphore_wake_lock;
90
down(struct semaphore * sem)91 static inline void down(struct semaphore * sem)
92 {
93 #if WAITQUEUE_DEBUG
94 CHECK_MAGIC(sem->__magic);
95 #endif
96
97 if (atomic_dec_return(&sem->count) < 0)
98 __down(sem);
99 }
100
down_interruptible(struct semaphore * sem)101 static inline int down_interruptible(struct semaphore * sem)
102 {
103 int ret = 0;
104 #if WAITQUEUE_DEBUG
105 CHECK_MAGIC(sem->__magic);
106 #endif
107
108 if (atomic_dec_return(&sem->count) < 0)
109 ret = __down_interruptible(sem);
110 return ret;
111 }
112
down_trylock(struct semaphore * sem)113 static inline int down_trylock(struct semaphore * sem)
114 {
115 int ret = 0;
116 #if WAITQUEUE_DEBUG
117 CHECK_MAGIC(sem->__magic);
118 #endif
119
120 if (atomic_dec_return(&sem->count) < 0)
121 ret = __down_trylock(sem);
122 return ret;
123 }
124
125 /*
126 * Note! This is subtle. We jump to wake people up only if
127 * the semaphore was negative (== somebody was waiting on it).
128 */
up(struct semaphore * sem)129 static inline void up(struct semaphore * sem)
130 {
131 #if WAITQUEUE_DEBUG
132 CHECK_MAGIC(sem->__magic);
133 #endif
134 if (atomic_inc_return(&sem->count) <= 0)
135 __up(sem);
136 }
137
138 #endif
139 #endif /* __ASM_SH_SEMAPHORE_H */
140