/* * 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