[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 __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)
{
/*
 *	*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
	36	#define __MUTEX_INITIALIZER(name) \
	37	__SEMAPHORE_INITIALIZER(name,1)
	38
	39	#define __DECLARE_SEMAPHORE_GENERIC(name,count) \
	40	struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
	41
	42	#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
	43	#define DECLARE_MUTEX_LOCKED(name) __DECLARE_SEMAPHORE_GENERIC(name,0)
	44
	45	static inline void sema_init (struct semaphore *sem, int val)
	46	{
	47	/*
	48	* sem = (struct semaphore)__SEMAPHORE_INITIALIZER((sem),val);
	49	*
	50	* i'd rather use the more flexible initialization above, but sadly
	51	* GCC 2.7.2.3 emits a bogus warning. EGCS doesn't. Oh well.
	52	*/
	53	atomic_set(&sem->count, val);
	54	sem->sleepers = 0;
	55	init_waitqueue_head(&sem->wait);
	56	}
	57
	58	static inline void init_MUTEX (struct semaphore *sem)
	59	{
	60	sema_init(sem, 1);
	61	}
	62
	63	static inline void init_MUTEX_LOCKED (struct semaphore *sem)
	64	{
65	sema_init(sem, 0);
66	}
67
68	#if 0
69	asmlinkage void __down_failed(void /* special register calling convention */);
70	asmlinkage int __down_failed_interruptible(void /* params in registers */);
71	asmlinkage int __down_failed_trylock(void /* params in registers */);
72	asmlinkage void __up_wakeup(void /* special register calling convention */);
73	#endif
74
75	asmlinkage void __down(struct semaphore * sem);
76	asmlinkage int __down_interruptible(struct semaphore * sem);
77	asmlinkage int __down_trylock(struct semaphore * sem);
78	asmlinkage void __up(struct semaphore * sem);
79
80	extern spinlock_t semaphore_wake_lock;
81
82	static inline void down(struct semaphore * sem)
83	{
84	might_sleep();
85	if (atomic_dec_return(&sem->count) < 0)
86	__down(sem);
87	}
88
89	static inline int down_interruptible(struct semaphore * sem)
90	{
91	int ret = 0;
92
93	might_sleep();
94	if (atomic_dec_return(&sem->count) < 0)
95	ret = __down_interruptible(sem);
96	return ret;
97	}
98
99	static inline int down_trylock(struct semaphore * sem)
100	{
101	int ret = 0;
102
103	if (atomic_dec_return(&sem->count) < 0)
104	ret = __down_trylock(sem);
105	return ret;
106	}
107
108	/*
109	* Note! This is subtle. We jump to wake people up only if
110	* the semaphore was negative (== somebody was waiting on it).
111	*/
112	static inline void up(struct semaphore * sem)
113	{
114	if (atomic_inc_return(&sem->count) <= 0)
115	__up(sem);
116	}
117
118	#endif
119	#endif /* __ASM_SH_SEMAPHORE_H */