[deliverable/linux.git] / include / asm-sh / semaphore.h

#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)

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 */
Commit	Line	Data
1da177e4 LT	1	#ifndef __ASM_SH_SEMAPHORE_H
	2	#define __ASM_SH_SEMAPHORE_H
	3
	4	#include <linux/linkage.h>
	5
	6	#ifdef __KERNEL__
	7	/*
	8	* SMP- and interrupt-safe semaphores.
	9	*
	10	* (C) Copyright 1996 Linus Torvalds
	11	*
	12	* SuperH verison by Niibe Yutaka
	13	* (Currently no asm implementation but generic C code...)
	14	*/
	15
	16	#include <linux/spinlock.h>
	17	#include <linux/rwsem.h>
	18	#include <linux/wait.h>
	19
	20	#include <asm/system.h>
	21	#include <asm/atomic.h>
	22
	23	struct semaphore {
	24	atomic_t count;
	25	int sleepers;
	26	wait_queue_head_t wait;
	27	};
	28
	29	#define __SEMAPHORE_INITIALIZER(name, n) \
	30	{ \
	31	.count = ATOMIC_INIT(n), \
	32	.sleepers = 0, \
	33	.wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \
	34	}
	35
1da177e4 LT	36	#define __DECLARE_SEMAPHORE_GENERIC(name,count) \
	37	struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
	38
	39	#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
1da177e4 LT	40
	41	static inline void sema_init (struct semaphore *sem, int val)
	42	{
	43	/*
	44	* sem = (struct semaphore)__SEMAPHORE_INITIALIZER((sem),val);
	45	*
	46	* i'd rather use the more flexible initialization above, but sadly
	47	* GCC 2.7.2.3 emits a bogus warning. EGCS doesn't. Oh well.
	48	*/
	49	atomic_set(&sem->count, val);
	50	sem->sleepers = 0;
	51	init_waitqueue_head(&sem->wait);
	52	}
	53
	54	static inline void init_MUTEX (struct semaphore *sem)
	55	{
	56	sema_init(sem, 1);
	57	}
	58
	59	static inline void init_MUTEX_LOCKED (struct semaphore *sem)
	60	{
	61	sema_init(sem, 0);
	62	}
	63
	64	#if 0
	65	asmlinkage void __down_failed(void /* special register calling convention */);
	66	asmlinkage int __down_failed_interruptible(void /* params in registers */);
	67	asmlinkage int __down_failed_trylock(void /* params in registers */);
	68	asmlinkage void __up_wakeup(void /* special register calling convention */);
	69	#endif
	70
	71	asmlinkage void __down(struct semaphore * sem);
	72	asmlinkage int __down_interruptible(struct semaphore * sem);
	73	asmlinkage int __down_trylock(struct semaphore * sem);
	74	asmlinkage void __up(struct semaphore * sem);
	75
	76	extern spinlock_t semaphore_wake_lock;
	77
	78	static inline void down(struct semaphore * sem)
	79	{
	80	might_sleep();
	81	if (atomic_dec_return(&sem->count) < 0)
	82	__down(sem);
	83	}
	84
	85	static inline int down_interruptible(struct semaphore * sem)
	86	{
	87	int ret = 0;
	88
	89	might_sleep();
	90	if (atomic_dec_return(&sem->count) < 0)
	91	ret = __down_interruptible(sem);
	92	return ret;
	93	}
	94
	95	static inline int down_trylock(struct semaphore * sem)
	96	{
	97	int ret = 0;
	98
	99	if (atomic_dec_return(&sem->count) < 0)
	100	ret = __down_trylock(sem);
	101	return ret;
	102	}
	103
104	/*
105	* Note! This is subtle. We jump to wake people up only if
106	* the semaphore was negative (== somebody was waiting on it).
107	*/
108	static inline void up(struct semaphore * sem)
109	{
110	if (atomic_inc_return(&sem->count) <= 0)
111	__up(sem);
112	}
113
114	#endif
115	#endif /* __ASM_SH_SEMAPHORE_H */