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/*

 *  linux/include/asm-arm/atomic.h

 *

 *  Copyright (c) 1996 Russell King.

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation.

 *

 *  Changelog:

 *   27-06-1996 RMK     Created

 *   13-04-1997 RMK     Made functions atomic!

 *   07-12-1997 RMK     Upgraded for v2.1.

 *   26-08-1998 PJB     Added #ifdef __KERNEL__

 */

#ifndef __ASM_ARM_ATOMIC_H

#define __ASM_ARM_ATOMIC_H

#include <linux/config.h>

#ifdef CONFIG_SMP

#error SMP not supported

#endif

typedef struct { volatile int counter; } atomic_t;

#define ATOMIC_INIT(i)  { (i) }

#ifdef __KERNEL__

#include <asm/proc/system.h>

#define atomic_read(v)  ((v)->counter)

#define atomic_set(v,i) (((v)->counter) = (i))

static inline void atomic_add(int i, volatile atomic_t *v)

{

        unsigned long flags;

        local_irq_save(flags);

        v->counter += i;

        local_irq_restore(flags);

}

static inline void atomic_sub(int i, volatile atomic_t *v)

{

        unsigned long flags;

        local_irq_save(flags);

        v->counter -= i;

        local_irq_restore(flags);

}

static inline void atomic_inc(volatile atomic_t *v)

{

        unsigned long flags;

        local_irq_save(flags);

        v->counter += 1;

        local_irq_restore(flags);

}

static inline void atomic_dec(volatile atomic_t *v)

{

        unsigned long flags;

        local_irq_save(flags);

        v->counter -= 1;

        local_irq_restore(flags);

}

static inline int atomic_dec_and_test(volatile atomic_t *v)

{

        unsigned long flags;

        int val;

        local_irq_save(flags);

        val = v->counter;

        v->counter = val -= 1;

        local_irq_restore(flags);

        return val == 0;

}

static inline int atomic_add_negative(int i, volatile atomic_t *v)

{

        unsigned long flags;

        int val;

        local_irq_save(flags);

        val = v->counter;

        v->counter = val += i;

        local_irq_restore(flags);

        return val < 0;

}

static inline void atomic_clear_mask(unsigned long mask, unsigned long *addr)

{

        unsigned long flags;

        local_irq_save(flags);

        *addr &= ~mask;

        local_irq_restore(flags);

}

/* Atomic operations are already serializing on ARM */

#define smp_mb__before_atomic_dec()     barrier()

#define smp_mb__after_atomic_dec()      barrier()

#define smp_mb__before_atomic_inc()     barrier()

#define smp_mb__after_atomic_inc()      barrier()

#endif

#endif