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

#ifndef _ALPHA_SEMAPHORE_H
#define _ALPHA_SEMAPHORE_H

/*
 * SMP- and interrupt-safe semaphores..
 *
 * (C) Copyright 1996 Linus Torvalds
 * (C) Copyright 1996, 2000 Richard Henderson
 */

#include <asm/current.h>
#include <asm/system.h>
#include <asm/atomic.h>
#include <linux/compiler.h>
#include <linux/wait.h>
#include <linux/rwsem.h>

struct semaphore {
	atomic_t count;
	wait_queue_head_t wait;
};

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

static inline void sema_init(struct semaphore *sem, int val)
{
	/*
	 * Logically, 
	 *   *sem = (struct semaphore)__SEMAPHORE_INITIALIZER((*sem),val);
	 * except that gcc produces better initializing by parts yet.
	 */

	atomic_set(&sem->count, val);
	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);
}

extern void down(struct semaphore *);
extern void __down_failed(struct semaphore *);
extern int  down_interruptible(struct semaphore *);
extern int  __down_failed_interruptible(struct semaphore *);
extern int  down_trylock(struct semaphore *);
extern void up(struct semaphore *);
extern void __up_wakeup(struct semaphore *);

/*
 * Hidden out of line code is fun, but extremely messy.  Rely on newer
 * compilers to do a respectable job with this.  The contention cases
 * are handled out of line in arch/alpha/kernel/semaphore.c.
 */

static inline void __down(struct semaphore *sem)
{
	long count;
	might_sleep();
	count = atomic_dec_return(&sem->count);
	if (unlikely(count < 0))
		__down_failed(sem);
}

static inline int __down_interruptible(struct semaphore *sem)
{
	long count;
	might_sleep();
	count = atomic_dec_return(&sem->count);
	if (unlikely(count < 0))
		return __down_failed_interruptible(sem);
	return 0;
}

/*
 * down_trylock returns 0 on success, 1 if we failed to get the lock.
 */

static inline int __down_trylock(struct semaphore *sem)
{
	long ret;

	/* "Equivalent" C:

	   do {
		ret = ldl_l;
		--ret;
		if (ret < 0)
			break;
		ret = stl_c = ret;
	   } while (ret == 0);
	*/
	__asm__ __volatile__(
		"1:	ldl_l	%0,%1\n"
		"	subl	%0,1,%0\n"
		"	blt	%0,2f\n"
		"	stl_c	%0,%1\n"
		"	beq	%0,3f\n"
		"	mb\n"
		"2:\n"
		".subsection 2\n"
		"3:	br	1b\n"
		".previous"
		: "=&r" (ret), "=m" (sem->count)
		: "m" (sem->count));

	return ret < 0;
}

static inline void __up(struct semaphore *sem)
{
	if (unlikely(atomic_inc_return(&sem->count) <= 0))
		__up_wakeup(sem);
}

#if !defined(CONFIG_DEBUG_SEMAPHORE)
extern inline void down(struct semaphore *sem)
{
	__down(sem);
}
extern inline int down_interruptible(struct semaphore *sem)
{
	return __down_interruptible(sem);
}
extern inline int down_trylock(struct semaphore *sem)
{
	return __down_trylock(sem);
}
extern inline void up(struct semaphore *sem)
{
	__up(sem);
}
#endif

#endif
Commit	Line	Data
1da177e4 LT	1	#ifndef _ALPHA_SEMAPHORE_H
	2	#define _ALPHA_SEMAPHORE_H
	3
	4	/*
	5	* SMP- and interrupt-safe semaphores..
	6	*
	7	* (C) Copyright 1996 Linus Torvalds
	8	* (C) Copyright 1996, 2000 Richard Henderson
	9	*/
	10
	11	#include <asm/current.h>
	12	#include <asm/system.h>
	13	#include <asm/atomic.h>
	14	#include <linux/compiler.h>
	15	#include <linux/wait.h>
	16	#include <linux/rwsem.h>
	17
	18	struct semaphore {
	19	atomic_t count;
	20	wait_queue_head_t wait;
	21	};
	22
	23	#define __SEMAPHORE_INITIALIZER(name, n) \
	24	{ \
	25	.count = ATOMIC_INIT(n), \
	26	.wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait), \
	27	}
	28
1da177e4 LT	29	#define __DECLARE_SEMAPHORE_GENERIC(name,count) \
	30	struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
	31
	32	#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
1da177e4 LT	33
	34	static inline void sema_init(struct semaphore *sem, int val)
	35	{
	36	/*
	37	* Logically,
	38	* sem = (struct semaphore)__SEMAPHORE_INITIALIZER((sem),val);
	39	* except that gcc produces better initializing by parts yet.
	40	*/
	41
	42	atomic_set(&sem->count, val);
	43	init_waitqueue_head(&sem->wait);
	44	}
	45
	46	static inline void init_MUTEX (struct semaphore *sem)
	47	{
	48	sema_init(sem, 1);
	49	}
	50
	51	static inline void init_MUTEX_LOCKED (struct semaphore *sem)
	52	{
	53	sema_init(sem, 0);
	54	}
	55
	56	extern void down(struct semaphore *);
	57	extern void __down_failed(struct semaphore *);
	58	extern int down_interruptible(struct semaphore *);
	59	extern int __down_failed_interruptible(struct semaphore *);
	60	extern int down_trylock(struct semaphore *);
	61	extern void up(struct semaphore *);
	62	extern void __up_wakeup(struct semaphore *);
	63
	64	/*
	65	* Hidden out of line code is fun, but extremely messy. Rely on newer
	66	* compilers to do a respectable job with this. The contention cases
	67	* are handled out of line in arch/alpha/kernel/semaphore.c.
	68	*/
	69
	70	static inline void __down(struct semaphore *sem)
	71	{
	72	long count;
	73	might_sleep();
	74	count = atomic_dec_return(&sem->count);
	75	if (unlikely(count < 0))
	76	__down_failed(sem);
	77	}
	78
	79	static inline int __down_interruptible(struct semaphore *sem)
	80	{
	81	long count;
	82	might_sleep();
	83	count = atomic_dec_return(&sem->count);
	84	if (unlikely(count < 0))
	85	return __down_failed_interruptible(sem);
	86	return 0;
	87	}
	88
	89	/*
	90	* down_trylock returns 0 on success, 1 if we failed to get the lock.
	91	*/
	92
	93	static inline int __down_trylock(struct semaphore *sem)
	94	{
	95	long ret;
	96
97	/* "Equivalent" C:
98
99	do {
100	ret = ldl_l;
101	--ret;
102	if (ret < 0)
103	break;
104	ret = stl_c = ret;
105	} while (ret == 0);
106	*/
107	__asm__ __volatile__(
108	"1: ldl_l %0,%1\n"
109	" subl %0,1,%0\n"
110	" blt %0,2f\n"
111	" stl_c %0,%1\n"
112	" beq %0,3f\n"
113	" mb\n"
114	"2:\n"
115	".subsection 2\n"
116	"3: br 1b\n"
117	".previous"
118	: "=&r" (ret), "=m" (sem->count)
119	: "m" (sem->count));
120
121	return ret < 0;
122	}
123
124	static inline void __up(struct semaphore *sem)
125	{
126	if (unlikely(atomic_inc_return(&sem->count) <= 0))
127	__up_wakeup(sem);
128	}
129
130	#if !defined(CONFIG_DEBUG_SEMAPHORE)
131	extern inline void down(struct semaphore *sem)
132	{
133	__down(sem);
134	}
135	extern inline int down_interruptible(struct semaphore *sem)
136	{
137	return __down_interruptible(sem);
138	}
139	extern inline int down_trylock(struct semaphore *sem)
140	{
141	return __down_trylock(sem);
142	}
143	extern inline void up(struct semaphore *sem)
144	{
145	__up(sem);
146	}
147	#endif
148
149	#endif