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

/* $Id: semaphore.h,v 1.3 2001/05/08 13:54:09 bjornw Exp $ */

/* On the i386 these are coded in asm, perhaps we should as well. Later.. */

#ifndef _CRIS_SEMAPHORE_H
#define _CRIS_SEMAPHORE_H

#define RW_LOCK_BIAS             0x01000000

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

#include <asm/system.h>
#include <asm/atomic.h>

/*
 * CRIS semaphores, implemented in C-only so far. 
 */

int printk(const char *fmt, ...);

struct semaphore {
	atomic_t count;
	atomic_t waking;
	wait_queue_head_t wait;
};

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

extern inline void sema_init(struct semaphore *sem, int val)
{
	*sem = (struct semaphore)__SEMAPHORE_INITIALIZER((*sem),val);
}

extern inline void init_MUTEX (struct semaphore *sem)
{
        sema_init(sem, 1);
}

extern inline void init_MUTEX_LOCKED (struct semaphore *sem)
{
        sema_init(sem, 0);
}

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

/* notice - we probably can do cli/sti here instead of saving */

extern inline void down(struct semaphore * sem)
{
	unsigned long flags;
	int failed;

	might_sleep();

	/* atomically decrement the semaphores count, and if its negative, we wait */
	cris_atomic_save(sem, flags);
	failed = --(sem->count.counter) < 0;
	cris_atomic_restore(sem, flags);
	if(failed) {
		__down(sem);
	}
}

/*
 * This version waits in interruptible state so that the waiting
 * process can be killed.  The down_interruptible routine
 * returns negative for signalled and zero for semaphore acquired.
 */

extern inline int down_interruptible(struct semaphore * sem)
{
	unsigned long flags;
	int failed;

	might_sleep();

	/* atomically decrement the semaphores count, and if its negative, we wait */
	cris_atomic_save(sem, flags);
	failed = --(sem->count.counter) < 0;
	cris_atomic_restore(sem, flags);
	if(failed)
		failed = __down_interruptible(sem);
	return(failed);
}

extern inline int down_trylock(struct semaphore * sem)
{
	unsigned long flags;
	int failed;

	cris_atomic_save(sem, flags);
	failed = --(sem->count.counter) < 0;
	cris_atomic_restore(sem, flags);
	if(failed)
		failed = __down_trylock(sem);
	return(failed);

}

/*
 * Note! This is subtle. We jump to wake people up only if
 * the semaphore was negative (== somebody was waiting on it).
 * The default case (no contention) will result in NO
 * jumps for both down() and up().
 */
extern inline void up(struct semaphore * sem)
{  
	unsigned long flags;
	int wakeup;

	/* atomically increment the semaphores count, and if it was negative, we wake people */
	cris_atomic_save(sem, flags);
	wakeup = ++(sem->count.counter) <= 0;
	cris_atomic_restore(sem, flags);
	if(wakeup) {
		__up(sem);
	}
}

#endif
Commit	Line	Data
1da177e4 LT	1	/* $Id: semaphore.h,v 1.3 2001/05/08 13:54:09 bjornw Exp $ */
	2
	3	/* On the i386 these are coded in asm, perhaps we should as well. Later.. */
	4
	5	#ifndef _CRIS_SEMAPHORE_H
	6	#define _CRIS_SEMAPHORE_H
	7
	8	#define RW_LOCK_BIAS 0x01000000
	9
	10	#include <linux/wait.h>
	11	#include <linux/spinlock.h>
	12	#include <linux/rwsem.h>
	13
	14	#include <asm/system.h>
	15	#include <asm/atomic.h>
	16
	17	/*
	18	* CRIS semaphores, implemented in C-only so far.
	19	*/
	20
	21	int printk(const char *fmt, ...);
	22
	23	struct semaphore {
	24	atomic_t count;
	25	atomic_t waking;
	26	wait_queue_head_t wait;
	27	};
	28
	29	#define __SEMAPHORE_INITIALIZER(name, n) \
	30	{ \
	31	.count = ATOMIC_INIT(n), \
	32	.waking = ATOMIC_INIT(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	extern inline void sema_init(struct semaphore *sem, int val)
	46	{
	47	sem = (struct semaphore)__SEMAPHORE_INITIALIZER((sem),val);
	48	}
	49
	50	extern inline void init_MUTEX (struct semaphore *sem)
	51	{
	52	sema_init(sem, 1);
	53	}
	54
	55	extern inline void init_MUTEX_LOCKED (struct semaphore *sem)
	56	{
	57	sema_init(sem, 0);
	58	}
	59
	60	extern void __down(struct semaphore * sem);
	61	extern int __down_interruptible(struct semaphore * sem);
	62	extern int __down_trylock(struct semaphore * sem);
	63	extern void __up(struct semaphore * sem);
	64
65	/* notice - we probably can do cli/sti here instead of saving */
66
67	extern inline void down(struct semaphore * sem)
68	{
69	unsigned long flags;
70	int failed;
71
72	might_sleep();
73
74	/* atomically decrement the semaphores count, and if its negative, we wait */
8d20a541	75	cris_atomic_save(sem, flags);
1da177e4	76	failed = --(sem->count.counter) < 0;
8d20a541	77	cris_atomic_restore(sem, flags);
1da177e4 LT	78	if(failed) {
	79	__down(sem);
	80	}
	81	}
	82
	83	/*
	84	* This version waits in interruptible state so that the waiting
	85	* process can be killed. The down_interruptible routine
	86	* returns negative for signalled and zero for semaphore acquired.
	87	*/
	88
	89	extern inline int down_interruptible(struct semaphore * sem)
	90	{
	91	unsigned long flags;
	92	int failed;
	93
	94	might_sleep();
	95
	96	/* atomically decrement the semaphores count, and if its negative, we wait */
8d20a541	97	cris_atomic_save(sem, flags);
1da177e4	98	failed = --(sem->count.counter) < 0;
8d20a541	99	cris_atomic_restore(sem, flags);
1da177e4 LT	100	if(failed)
	101	failed = __down_interruptible(sem);
	102	return(failed);
	103	}
	104
	105	extern inline int down_trylock(struct semaphore * sem)
	106	{
	107	unsigned long flags;
	108	int failed;
	109
8d20a541	110	cris_atomic_save(sem, flags);
1da177e4	111	failed = --(sem->count.counter) < 0;
8d20a541	112	cris_atomic_restore(sem, flags);
1da177e4 LT	113	if(failed)
	114	failed = __down_trylock(sem);
	115	return(failed);
8d20a541	116
1da177e4 LT	117	}
	118
	119	/*
	120	* Note! This is subtle. We jump to wake people up only if
	121	* the semaphore was negative (== somebody was waiting on it).
	122	* The default case (no contention) will result in NO
	123	* jumps for both down() and up().
	124	*/
	125	extern inline void up(struct semaphore * sem)
	126	{
	127	unsigned long flags;
	128	int wakeup;
	129
	130	/* atomically increment the semaphores count, and if it was negative, we wake people */
8d20a541	131	cris_atomic_save(sem, flags);
1da177e4	132	wakeup = ++(sem->count.counter) <= 0;
8d20a541	133	cris_atomic_restore(sem, flags);
1da177e4 LT	134	if(wakeup) {
	135	__up(sem);
	136	}
	137	}
	138
	139	#endif