117 lines
2.7 KiB
C
117 lines
2.7 KiB
C
#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 */
|