157 lines
3.5 KiB
C
157 lines
3.5 KiB
C
/* semaphore.h: semaphores for the FR-V
|
|
*
|
|
* Copyright (C) 2003 Red Hat, Inc. All Rights Reserved.
|
|
* Written by David Howells (dhowells@redhat.com)
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License
|
|
* as published by the Free Software Foundation; either version
|
|
* 2 of the License, or (at your option) any later version.
|
|
*/
|
|
#ifndef _ASM_SEMAPHORE_H
|
|
#define _ASM_SEMAPHORE_H
|
|
|
|
#define RW_LOCK_BIAS 0x01000000
|
|
|
|
#ifndef __ASSEMBLY__
|
|
|
|
#include <linux/linkage.h>
|
|
#include <linux/wait.h>
|
|
#include <linux/spinlock.h>
|
|
#include <linux/rwsem.h>
|
|
|
|
/*
|
|
* the semaphore definition
|
|
* - if counter is >0 then there are tokens available on the semaphore for down to collect
|
|
* - if counter is <=0 then there are no spare tokens, and anyone that wants one must wait
|
|
* - if wait_list is not empty, then there are processes waiting for the semaphore
|
|
*/
|
|
struct semaphore {
|
|
unsigned counter;
|
|
spinlock_t wait_lock;
|
|
struct list_head wait_list;
|
|
#ifdef CONFIG_DEBUG_SEMAPHORE
|
|
unsigned __magic;
|
|
#endif
|
|
};
|
|
|
|
#ifdef CONFIG_DEBUG_SEMAPHORE
|
|
# define __SEM_DEBUG_INIT(name) , (long)&(name).__magic
|
|
#else
|
|
# define __SEM_DEBUG_INIT(name)
|
|
#endif
|
|
|
|
|
|
#define __SEMAPHORE_INITIALIZER(name,count) \
|
|
{ count, SPIN_LOCK_UNLOCKED, LIST_HEAD_INIT((name).wait_list) __SEM_DEBUG_INIT(name) }
|
|
|
|
#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);
|
|
}
|
|
|
|
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);
|
|
}
|
|
|
|
extern void __down(struct semaphore *sem, unsigned long flags);
|
|
extern int __down_interruptible(struct semaphore *sem, unsigned long flags);
|
|
extern void __up(struct semaphore *sem);
|
|
|
|
static inline void down(struct semaphore *sem)
|
|
{
|
|
unsigned long flags;
|
|
|
|
#ifdef CONFIG_DEBUG_SEMAPHORE
|
|
CHECK_MAGIC(sem->__magic);
|
|
#endif
|
|
|
|
spin_lock_irqsave(&sem->wait_lock, flags);
|
|
if (likely(sem->counter > 0)) {
|
|
sem->counter--;
|
|
spin_unlock_irqrestore(&sem->wait_lock, flags);
|
|
}
|
|
else {
|
|
__down(sem, flags);
|
|
}
|
|
}
|
|
|
|
static inline int down_interruptible(struct semaphore *sem)
|
|
{
|
|
unsigned long flags;
|
|
int ret = 0;
|
|
|
|
#ifdef CONFIG_DEBUG_SEMAPHORE
|
|
CHECK_MAGIC(sem->__magic);
|
|
#endif
|
|
|
|
spin_lock_irqsave(&sem->wait_lock, flags);
|
|
if (likely(sem->counter > 0)) {
|
|
sem->counter--;
|
|
spin_unlock_irqrestore(&sem->wait_lock, flags);
|
|
}
|
|
else {
|
|
ret = __down_interruptible(sem, flags);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* non-blockingly attempt to down() a semaphore.
|
|
* - returns zero if we acquired it
|
|
*/
|
|
static inline int down_trylock(struct semaphore *sem)
|
|
{
|
|
unsigned long flags;
|
|
int success = 0;
|
|
|
|
#ifdef CONFIG_DEBUG_SEMAPHORE
|
|
CHECK_MAGIC(sem->__magic);
|
|
#endif
|
|
|
|
spin_lock_irqsave(&sem->wait_lock, flags);
|
|
if (sem->counter > 0) {
|
|
sem->counter--;
|
|
success = 1;
|
|
}
|
|
spin_unlock_irqrestore(&sem->wait_lock, flags);
|
|
return !success;
|
|
}
|
|
|
|
static inline void up(struct semaphore *sem)
|
|
{
|
|
unsigned long flags;
|
|
|
|
#ifdef CONFIG_DEBUG_SEMAPHORE
|
|
CHECK_MAGIC(sem->__magic);
|
|
#endif
|
|
|
|
spin_lock_irqsave(&sem->wait_lock, flags);
|
|
if (!list_empty(&sem->wait_list))
|
|
__up(sem);
|
|
else
|
|
sem->counter++;
|
|
spin_unlock_irqrestore(&sem->wait_lock, flags);
|
|
}
|
|
|
|
static inline int sem_getcount(struct semaphore *sem)
|
|
{
|
|
return sem->counter;
|
|
}
|
|
|
|
#endif /* __ASSEMBLY__ */
|
|
|
|
#endif
|