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 */