2 * linux/include/asm-arm/atomic.h
4 * Copyright (c) 1996 Russell King.
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
11 * 27-06-1996 RMK Created
12 * 13-04-1997 RMK Made functions atomic!
13 * 07-12-1997 RMK Upgraded for v2.1.
14 * 26-08-1998 PJB Added #ifdef __KERNEL__
16 #ifndef __ASM_ARM_ATOMIC_H
17 #define __ASM_ARM_ATOMIC_H
20 #error SMP not supported
23 typedef struct { volatile int counter; } atomic_t;
25 #define ATOMIC_INIT(i) { (i) }
28 #include <asm/proc-armv/system.h>
30 #define atomic_read(v) ((v)->counter)
31 #define atomic_set(v,i) (((v)->counter) = (i))
33 static inline void atomic_add(int i, volatile atomic_t *v)
37 local_irq_save(flags);
39 local_irq_restore(flags);
42 static inline void atomic_sub(int i, volatile atomic_t *v)
46 local_irq_save(flags);
48 local_irq_restore(flags);
51 static inline void atomic_inc(volatile atomic_t *v)
55 local_irq_save(flags);
57 local_irq_restore(flags);
60 static inline void atomic_dec(volatile atomic_t *v)
64 local_irq_save(flags);
66 local_irq_restore(flags);
69 static inline int atomic_dec_and_test(volatile atomic_t *v)
74 local_irq_save(flags);
76 v->counter = val -= 1;
77 local_irq_restore(flags);
82 static inline int atomic_add_negative(int i, volatile atomic_t *v)
87 local_irq_save(flags);
89 v->counter = val += i;
90 local_irq_restore(flags);
95 static inline void atomic_clear_mask(unsigned long mask, unsigned long *addr)
99 local_irq_save(flags);
101 local_irq_restore(flags);
104 /* Atomic operations are already serializing on ARM */
105 #define smp_mb__before_atomic_dec() barrier()
106 #define smp_mb__after_atomic_dec() barrier()
107 #define smp_mb__before_atomic_inc() barrier()
108 #define smp_mb__after_atomic_inc() barrier()