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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
#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
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