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#ifndef _M68K_SEMAPHORE_H

#define _M68K_SEMAPHORE_H

#include <linux/linkage.h>

/*

 * SMP- and interrupt-safe semaphores..

 *

 * (C) Copyright 1996 Linus Torvalds

 *

 * m68k version by Andreas Schwab

 */

struct semaphore {

        int count;

        int waking;

        int lock;                       /* to make waking testing atomic */

        struct wait_queue * wait;

};

#define MUTEX ((struct semaphore) { 1, 0, 0, NULL })

#define MUTEX_LOCKED ((struct semaphore) { 0, 0, 0, NULL })

asmlinkage void __down_failed(void /* special register calling convention */);

asmlinkage int  __down_failed_interruptible(void);  /* params in registers */

asmlinkage void __up_wakeup(void /* special register calling convention */);

extern void __down(struct semaphore * sem);

extern void __up(struct semaphore * sem);

/*

 * This is ugly, but we want the default case to fall through.

 * "down_failed" is a special asm handler that calls the C

 * routine that actually waits. See arch/m68k/lib/semaphore.S

 */

extern inline void down(struct semaphore * sem)

{

        register struct semaphore *sem1 __asm__ ("%a1") = sem;

        __asm__ __volatile__(

                "| atomic down operation\n\t"

                "lea %%pc@(1f),%%a0\n\t"

                "subql #1,%0@\n\t"

                "jmi " SYMBOL_NAME_STR(__down_failed) "\n"

                "1:"

                : /* no outputs */

                : "a" (sem1)

                : "%a0", "memory");

}

/*

 * This version waits in interruptible state so that the waiting

 * process can be killed.  The down_failed_interruptible routine

 * returns negative for signalled and zero for semaphore acquired.

 */

extern inline int down_interruptible(struct semaphore * sem)

{

        register int ret __asm__ ("%d0");

        register struct semaphore *sem1 __asm__ ("%a1") = sem;

        __asm__ __volatile__(

                "| atomic down operation\n\t"

                "lea %%pc@(1f),%%a0\n\t"

                "subql #1,%1@\n\t"

                "jmi " SYMBOL_NAME_STR(__down_failed_interruptible) "\n"

                "clrl %0\n"

                "1:"

                : "=d" (ret)

                : "a" (sem1)

                : "%a0", "memory");

        return(ret);

}

/*

 * Primitives to spin on a lock.  Needed only for SMP version ... so

 * somebody should start playing with one of those Sony NeWS stations.

 */

extern inline void get_buzz_lock(int *lock_ptr)

{

#ifdef __SMP__

        while (xchg(lock_ptr,1) != 0) ;

#endif

}

extern inline void give_buzz_lock(int *lock_ptr)

{

#ifdef __SMP__

        *lock_ptr = 0 ;

#endif

}

/*

 * 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)

{

        register struct semaphore *sem1 __asm__ ("%a1") = sem;

        __asm__ __volatile__(

                "| atomic up operation\n\t"

                "lea %%pc@(1f),%%a0\n\t"

                "addql #1,%0@\n\t"

                "jle " SYMBOL_NAME_STR(__up_wakeup) "\n"

                "1:"

                : /* no outputs */

                : "a" (sem1)

                : "%a0", "memory");

}

#endif