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include/asm-sh64/semaphore.h
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1da177e4c
Linux-2.6.12-rc2
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#ifndef __ASM_SH64_SEMAPHORE_H
#define __ASM_SH64_SEMAPHORE_H
/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* include/asm-sh64/semaphore.h
*
* Copyright (C) 2000, 2001 Paolo Alberelli
*
* 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/linkage.h>
#include <linux/spinlock.h>
#include <linux/wait.h>
#include <linux/rwsem.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) \
}
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1da177e4c
Linux-2.6.12-rc2
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#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 doesnt. 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)
{
if (atomic_dec_return(&sem->count) < 0)
__down(sem);
}
static inline int down_interruptible(struct semaphore * sem)
{
int ret = 0;
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 /* __ASM_SH64_SEMAPHORE_H */
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