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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 | #ifndef __ASM_SH_SEMAPHORE_H
#define __ASM_SH_SEMAPHORE_H
#include <linux/linkage.h>
#ifdef __KERNEL__
/*
* SMP- and interrupt-safe semaphores.
*
* (C) Copyright 1996 Linus Torvalds
*
* SuperH verison by Niibe Yutaka
* (Currently no asm implementation but generic C code...)
*/
#include <linux/spinlock.h>
#include <linux/rwsem.h>
#include <linux/wait.h>
#include <asm/system.h>
#include <asm/atomic.h>
struct semaphore {
atomic_t count;
int sleepers;
wait_queue_head_t wait;
};
#define __SEMAPHORE_INITIALIZER(name, n) \
{ \
.count = ATOMIC_INIT(n), \
.sleepers = 0, \
.wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \
}
#define __DECLARE_SEMAPHORE_GENERIC(name,count) \
struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
#define DECLARE_MUTEX_LOCKED(name) __DECLARE_SEMAPHORE_GENERIC(name,0)
static inline void sema_init (struct semaphore *sem, int val)
{
/*
* *sem = (struct semaphore)__SEMAPHORE_INITIALIZER((*sem),val);
*
* i'd rather use the more flexible initialization above, but sadly
* GCC 2.7.2.3 emits a bogus warning. EGCS doesn't. Oh well.
*/
atomic_set(&sem->count, val);
sem->sleepers = 0;
init_waitqueue_head(&sem->wait);
}
static inline void init_MUTEX (struct semaphore *sem)
{
sema_init(sem, 1);
}
static inline void init_MUTEX_LOCKED (struct semaphore *sem)
{
sema_init(sem, 0);
}
#if 0
asmlinkage void __down_failed(void /* special register calling convention */);
asmlinkage int __down_failed_interruptible(void /* params in registers */);
asmlinkage int __down_failed_trylock(void /* params in registers */);
asmlinkage void __up_wakeup(void /* special register calling convention */);
#endif
asmlinkage void __down(struct semaphore * sem);
asmlinkage int __down_interruptible(struct semaphore * sem);
asmlinkage int __down_trylock(struct semaphore * sem);
asmlinkage void __up(struct semaphore * sem);
extern spinlock_t semaphore_wake_lock;
static inline void down(struct semaphore * sem)
{
might_sleep();
if (atomic_dec_return(&sem->count) < 0)
__down(sem);
}
static inline int down_interruptible(struct semaphore * sem)
{
int ret = 0;
might_sleep();
if (atomic_dec_return(&sem->count) < 0)
ret = __down_interruptible(sem);
return ret;
}
static inline int down_trylock(struct semaphore * sem)
{
int ret = 0;
if (atomic_dec_return(&sem->count) < 0)
ret = __down_trylock(sem);
return ret;
}
/*
* Note! This is subtle. We jump to wake people up only if
* the semaphore was negative (== somebody was waiting on it).
*/
static inline void up(struct semaphore * sem)
{
if (atomic_inc_return(&sem->count) <= 0)
__up(sem);
}
#endif
#endif /* __ASM_SH_SEMAPHORE_H */
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