mirror of https://gitee.com/openkylin/linux.git
103 lines
2.3 KiB
C
103 lines
2.3 KiB
C
/*
|
|
* linux/include/asm-xtensa/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.
|
|
*
|
|
* Copyright (C) 2001 - 2005 Tensilica Inc.
|
|
*/
|
|
|
|
#ifndef _XTENSA_SEMAPHORE_H
|
|
#define _XTENSA_SEMAPHORE_H
|
|
|
|
#include <asm/atomic.h>
|
|
#include <asm/system.h>
|
|
#include <linux/wait.h>
|
|
#include <linux/rwsem.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 __MUTEX_INITIALIZER(name) \
|
|
__SEMAPHORE_INITIALIZER(name, 1)
|
|
|
|
#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)
|
|
{
|
|
atomic_set(&sem->count, val);
|
|
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);
|
|
}
|
|
|
|
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_sub_return(1, &sem->count) < 0)
|
|
__down(sem);
|
|
}
|
|
|
|
static inline int down_interruptible(struct semaphore * sem)
|
|
{
|
|
int ret = 0;
|
|
|
|
might_sleep();
|
|
|
|
if (atomic_sub_return(1, &sem->count) < 0)
|
|
ret = __down_interruptible(sem);
|
|
return ret;
|
|
}
|
|
|
|
static inline int down_trylock(struct semaphore * sem)
|
|
{
|
|
int ret = 0;
|
|
|
|
if (atomic_sub_return(1, &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_add_return(1, &sem->count) <= 0)
|
|
__up(sem);
|
|
}
|
|
|
|
#endif /* _XTENSA_SEMAPHORE_H */
|