Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

/*
 * Based on:
 * include/asm-cris/semaphore.h
 */
 
#ifndef _OR32_SEMAPHORE_H
#define _OR32_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>
 
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)    \
}
#if 0 /*RGD*/
#define __MUTEX_INITIALIZER(name) \
        __SEMAPHORE_INITIALIZER(name,1)
#endif /*RGD*/
#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 */
	local_irq_save(flags);
	failed = --(sem->count.counter) < 0;
	local_irq_restore(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 */
	local_irq_save(flags);
	failed = --(sem->count.counter) < 0;
	local_irq_restore(flags);
	if(failed)
		failed = __down_interruptible(sem);
	return(failed);
}
 
extern inline int down_trylock(struct semaphore * sem)
{
	unsigned long flags;
	int failed;
 
	local_irq_save(flags);
	failed = --(sem->count.counter) < 0;
	local_irq_restore(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 */
	local_irq_save(flags);
	wakeup = ++(sem->count.counter) <= 0;
	local_irq_restore(flags);
	if(wakeup) {
		__up(sem);
	}
}
 
 
#endif /* _OR32_SEMAPHORE_H */