[mirror_ubuntu-zesty-kernel.git] / include / asm-parisc / semaphore.h

/*    SMP- and interrupt-safe semaphores.
 *    PA-RISC version by Matthew Wilcox
 *
 *    Linux/PA-RISC Project (http://www.parisc-linux.org/)
 *    Copyright (C) 1996 Linus Torvalds
 *    Copyright (C) 1999-2001 Matthew Wilcox < willy at debian d0T org >
 *    Copyright (C) 2000 Grant Grundler < grundler a debian org >
 *
 *    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.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with this program; if not, write to the Free Software
 *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#ifndef _ASM_PARISC_SEMAPHORE_H
#define _ASM_PARISC_SEMAPHORE_H

#include <linux/spinlock.h>
#include <linux/wait.h>
#include <linux/rwsem.h>

#include <asm/system.h>

/*
 * The `count' is initialised to the number of people who are allowed to
 * take the lock.  (Normally we want a mutex, so this is `1').  if
 * `count' is positive, the lock can be taken.  if it's 0, no-one is
 * waiting on it.  if it's -1, at least one task is waiting.
 */
struct semaphore {
	spinlock_t	sentry;
	int		count;
	wait_queue_head_t wait;
};

#define __SEMAPHORE_INITIALIZER(name, n)				\
{									\
	.sentry		= SPIN_LOCK_UNLOCKED,				\
	.count		= n,						\
	.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)

extern 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);
}

static inline int sem_getcount(struct semaphore *sem)
{
	return sem->count;
}

asmlinkage void __down(struct semaphore * sem);
asmlinkage int  __down_interruptible(struct semaphore * sem);
asmlinkage void __up(struct semaphore * sem);

/* Semaphores can be `tried' from irq context.  So we have to disable
 * interrupts while we're messing with the semaphore.  Sorry.
 */

extern __inline__ void down(struct semaphore * sem)
{
	might_sleep();
	spin_lock_irq(&sem->sentry);
	if (sem->count > 0) {
		sem->count--;
	} else {
		__down(sem);
	}
	spin_unlock_irq(&sem->sentry);
}

extern __inline__ int down_interruptible(struct semaphore * sem)
{
	int ret = 0;
	might_sleep();
	spin_lock_irq(&sem->sentry);
	if (sem->count > 0) {
		sem->count--;
	} else {
		ret = __down_interruptible(sem);
	}
	spin_unlock_irq(&sem->sentry);
	return ret;
}

/*
 * down_trylock returns 0 on success, 1 if we failed to get the lock.
 * May not sleep, but must preserve irq state
 */
extern __inline__ int down_trylock(struct semaphore * sem)
{
	unsigned long flags;
	int count;

	spin_lock_irqsave(&sem->sentry, flags);
	count = sem->count - 1;
	if (count >= 0)
		sem->count = count;
	spin_unlock_irqrestore(&sem->sentry, flags);
	return (count < 0);
}

/*
 * Note! This is subtle. We jump to wake people up only if
 * the semaphore was negative (== somebody was waiting on it).
 */
extern __inline__ void up(struct semaphore * sem)
{
	unsigned long flags;

	spin_lock_irqsave(&sem->sentry, flags);
	if (sem->count < 0) {
		__up(sem);
	} else {
		sem->count++;
	}
	spin_unlock_irqrestore(&sem->sentry, flags);
}

#endif /* _ASM_PARISC_SEMAPHORE_H */
Commit	Line	Data
1da177e4 LT	1	/* SMP- and interrupt-safe semaphores.
	2	* PA-RISC version by Matthew Wilcox
	3	*
	4	* Linux/PA-RISC Project (http://www.parisc-linux.org/)
	5	* Copyright (C) 1996 Linus Torvalds
	6	* Copyright (C) 1999-2001 Matthew Wilcox < willy at debian d0T org >
	7	* Copyright (C) 2000 Grant Grundler < grundler a debian org >
	8	*
	9	* This program is free software; you can redistribute it and/or modify
	10	* it under the terms of the GNU General Public License as published by
	11	* the Free Software Foundation; either version 2 of the License, or
	12	* (at your option) any later version.
	13	*
	14	* This program is distributed in the hope that it will be useful,
	15	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	16	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	17	* GNU General Public License for more details.
	18	*
	19	* You should have received a copy of the GNU General Public License
	20	* along with this program; if not, write to the Free Software
	21	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	22	*/
	23
	24	#ifndef _ASM_PARISC_SEMAPHORE_H
	25	#define _ASM_PARISC_SEMAPHORE_H
	26
	27	#include <linux/spinlock.h>
	28	#include <linux/wait.h>
	29	#include <linux/rwsem.h>
	30
	31	#include <asm/system.h>
	32
	33	/*
	34	* The `count' is initialised to the number of people who are allowed to
	35	* take the lock. (Normally we want a mutex, so this is `1'). if
	36	* `count' is positive, the lock can be taken. if it's 0, no-one is
	37	* waiting on it. if it's -1, at least one task is waiting.
	38	*/
	39	struct semaphore {
	40	spinlock_t sentry;
	41	int count;
	42	wait_queue_head_t wait;
	43	};
	44
	45	#define __SEMAPHORE_INITIALIZER(name, n) \
	46	{ \
	47	.sentry = SPIN_LOCK_UNLOCKED, \
	48	.count = n, \
	49	.wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \
	50	}
	51
1da177e4 LT	52	#define __DECLARE_SEMAPHORE_GENERIC(name,count) \
	53	struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
	54
	55	#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
	56	#define DECLARE_MUTEX_LOCKED(name) __DECLARE_SEMAPHORE_GENERIC(name,0)
	57
	58	extern inline void sema_init (struct semaphore *sem, int val)
	59	{
	60	sem = (struct semaphore)__SEMAPHORE_INITIALIZER((sem),val);
	61	}
	62
	63	static inline void init_MUTEX (struct semaphore *sem)
	64	{
	65	sema_init(sem, 1);
	66	}
	67
	68	static inline void init_MUTEX_LOCKED (struct semaphore *sem)
	69	{
	70	sema_init(sem, 0);
	71	}
	72
	73	static inline int sem_getcount(struct semaphore *sem)
	74	{
	75	return sem->count;
	76	}
	77
	78	asmlinkage void __down(struct semaphore * sem);
	79	asmlinkage int __down_interruptible(struct semaphore * sem);
	80	asmlinkage void __up(struct semaphore * sem);
	81
	82	/* Semaphores can be `tried' from irq context. So we have to disable
	83	* interrupts while we're messing with the semaphore. Sorry.
	84	*/
	85
	86	extern __inline__ void down(struct semaphore * sem)
	87	{
	88	might_sleep();
	89	spin_lock_irq(&sem->sentry);
	90	if (sem->count > 0) {
	91	sem->count--;
	92	} else {
	93	__down(sem);
	94	}
	95	spin_unlock_irq(&sem->sentry);
	96	}
	97
	98	extern __inline__ int down_interruptible(struct semaphore * sem)
	99	{
	100	int ret = 0;
	101	might_sleep();
	102	spin_lock_irq(&sem->sentry);
	103	if (sem->count > 0) {
	104	sem->count--;
	105	} else {
	106	ret = __down_interruptible(sem);
	107	}
	108	spin_unlock_irq(&sem->sentry);
	109	return ret;
	110	}
	111
	112	/*
	113	* down_trylock returns 0 on success, 1 if we failed to get the lock.
	114	* May not sleep, but must preserve irq state
	115	*/
116	extern __inline__ int down_trylock(struct semaphore * sem)
117	{
c9c3b86f KM	118	unsigned long flags;
c9c3b86f KM	119	int count;
1da177e4 LT	120
	121	spin_lock_irqsave(&sem->sentry, flags);
	122	count = sem->count - 1;
	123	if (count >= 0)
	124	sem->count = count;
	125	spin_unlock_irqrestore(&sem->sentry, flags);
	126	return (count < 0);
	127	}
	128
	129	/*
	130	* Note! This is subtle. We jump to wake people up only if
	131	* the semaphore was negative (== somebody was waiting on it).
	132	*/
	133	extern __inline__ void up(struct semaphore * sem)
	134	{
c9c3b86f KM	135	unsigned long flags;
c9c3b86f KM	136
1da177e4 LT	137	spin_lock_irqsave(&sem->sentry, flags);
	138	if (sem->count < 0) {
	139	__up(sem);
	140	} else {
	141	sem->count++;
	142	}
	143	spin_unlock_irqrestore(&sem->sentry, flags);
	144	}
	145
	146	#endif /* _ASM_PARISC_SEMAPHORE_H */