[linux-2.6-block.git] / include / asm-frv / semaphore.h

/* 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
Commit	Line	Data
1da177e4 LT	1	/* semaphore.h: semaphores for the FR-V
	2	*
	3	* Copyright (C) 2003 Red Hat, Inc. All Rights Reserved.
	4	* Written by David Howells (dhowells@redhat.com)
	5	*
	6	* This program is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU General Public License
	8	* as published by the Free Software Foundation; either version
	9	* 2 of the License, or (at your option) any later version.
	10	*/
	11	#ifndef _ASM_SEMAPHORE_H
	12	#define _ASM_SEMAPHORE_H
	13
	14	#define RW_LOCK_BIAS 0x01000000
	15
	16	#ifndef __ASSEMBLY__
	17
	18	#include <linux/linkage.h>
	19	#include <linux/wait.h>
	20	#include <linux/spinlock.h>
	21	#include <linux/rwsem.h>
	22
1da177e4 LT	23	/*
	24	* the semaphore definition
	25	* - if counter is >0 then there are tokens available on the semaphore for down to collect
	26	* - if counter is <=0 then there are no spare tokens, and anyone that wants one must wait
	27	* - if wait_list is not empty, then there are processes waiting for the semaphore
	28	*/
	29	struct semaphore {
	30	unsigned counter;
	31	spinlock_t wait_lock;
	32	struct list_head wait_list;
c761c841	33	#ifdef CONFIG_DEBUG_SEMAPHORE
1da177e4 LT	34	unsigned __magic;
	35	#endif
	36	};
	37
c761c841	38	#ifdef CONFIG_DEBUG_SEMAPHORE
1da177e4 LT	39	# define __SEM_DEBUG_INIT(name) , (long)&(name).__magic
	40	#else
	41	# define __SEM_DEBUG_INIT(name)
	42	#endif
	43
	44
	45	#define __SEMAPHORE_INITIALIZER(name,count) \
	46	{ count, SPIN_LOCK_UNLOCKED, LIST_HEAD_INIT((name).wait_list) __SEM_DEBUG_INIT(name) }
	47
1da177e4 LT	48	#define __DECLARE_SEMAPHORE_GENERIC(name,count) \
	49	struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
	50
	51	#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
	52	#define DECLARE_MUTEX_LOCKED(name) __DECLARE_SEMAPHORE_GENERIC(name,0)
	53
	54	static inline void sema_init (struct semaphore *sem, int val)
	55	{
	56	sem = (struct semaphore) __SEMAPHORE_INITIALIZER(sem, val);
	57	}
	58
	59	static inline void init_MUTEX (struct semaphore *sem)
	60	{
	61	sema_init(sem, 1);
	62	}
	63
	64	static inline void init_MUTEX_LOCKED (struct semaphore *sem)
	65	{
	66	sema_init(sem, 0);
	67	}
	68
	69	extern void __down(struct semaphore *sem, unsigned long flags);
	70	extern int __down_interruptible(struct semaphore *sem, unsigned long flags);
	71	extern void __up(struct semaphore *sem);
	72
	73	static inline void down(struct semaphore *sem)
	74	{
	75	unsigned long flags;
	76
c761c841	77	#ifdef CONFIG_DEBUG_SEMAPHORE
1da177e4 LT	78	CHECK_MAGIC(sem->__magic);
	79	#endif
	80
	81	spin_lock_irqsave(&sem->wait_lock, flags);
	82	if (likely(sem->counter > 0)) {
	83	sem->counter--;
	84	spin_unlock_irqrestore(&sem->wait_lock, flags);
	85	}
	86	else {
	87	__down(sem, flags);
	88	}
	89	}
	90
	91	static inline int down_interruptible(struct semaphore *sem)
	92	{
	93	unsigned long flags;
	94	int ret = 0;
	95
c761c841	96	#ifdef CONFIG_DEBUG_SEMAPHORE
1da177e4 LT	97	CHECK_MAGIC(sem->__magic);
	98	#endif
	99
	100	spin_lock_irqsave(&sem->wait_lock, flags);
	101	if (likely(sem->counter > 0)) {
	102	sem->counter--;
	103	spin_unlock_irqrestore(&sem->wait_lock, flags);
	104	}
	105	else {
	106	ret = __down_interruptible(sem, flags);
	107	}
	108	return ret;
	109	}
	110
	111	/*
	112	* non-blockingly attempt to down() a semaphore.
	113	* - returns zero if we acquired it
	114	*/
	115	static inline int down_trylock(struct semaphore *sem)
	116	{
	117	unsigned long flags;
	118	int success = 0;
	119
c761c841	120	#ifdef CONFIG_DEBUG_SEMAPHORE
1da177e4 LT	121	CHECK_MAGIC(sem->__magic);
	122	#endif
	123
	124	spin_lock_irqsave(&sem->wait_lock, flags);
	125	if (sem->counter > 0) {
	126	sem->counter--;
	127	success = 1;
	128	}
	129	spin_unlock_irqrestore(&sem->wait_lock, flags);
	130	return !success;
	131	}
	132
	133	static inline void up(struct semaphore *sem)
	134	{
	135	unsigned long flags;
	136
c761c841	137	#ifdef CONFIG_DEBUG_SEMAPHORE
1da177e4 LT	138	CHECK_MAGIC(sem->__magic);
	139	#endif
	140
	141	spin_lock_irqsave(&sem->wait_lock, flags);
	142	if (!list_empty(&sem->wait_list))
	143	__up(sem);
	144	else
	145	sem->counter++;
	146	spin_unlock_irqrestore(&sem->wait_lock, flags);
	147	}
	148
	149	static inline int sem_getcount(struct semaphore *sem)
	150	{
	151	return sem->counter;
	152	}
	153
	154	#endif /* __ASSEMBLY__ */
	155
	156	#endif