1 /* 2 * linux/include/asm-arm/atomic.h 3 * 4 * Copyright (c) 1996 Russell King. 5 * 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. 9 * 10 * Changelog: 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__ 15 */ 16 #ifndef __ASM_ARM_ATOMIC_H 17 #define __ASM_ARM_ATOMIC_H 18 19 #include <linux/config.h> 20 21 #ifdef CONFIG_SMP 22 #error SMP not supported 23 #endif 24 25 typedef struct { volatile int counter; } atomic_t; 26 27 #define ATOMIC_INIT(i) { (i) } 28 29 #ifdef __KERNEL__ 30 #include <asm/proc/system.h> 31 32 #define atomic_read(v) ((v)->counter) 33 #define atomic_set(v,i) (((v)->counter) = (i)) 34 35 static inline void atomic_add(int i, volatile atomic_t *v) 36 { 37 unsigned long flags; 38 39 local_irq_save(flags); 40 v->counter += i; 41 local_irq_restore(flags); 42 } 43 44 static inline void atomic_sub(int i, volatile atomic_t *v) 45 { 46 unsigned long flags; 47 48 local_irq_save(flags); 49 v->counter -= i; 50 local_irq_restore(flags); 51 } 52 53 static inline void atomic_inc(volatile atomic_t *v) 54 { 55 unsigned long flags; 56 57 local_irq_save(flags); 58 v->counter += 1; 59 local_irq_restore(flags); 60 } 61 62 static inline void atomic_dec(volatile atomic_t *v) 63 { 64 unsigned long flags; 65 66 local_irq_save(flags); 67 v->counter -= 1; 68 local_irq_restore(flags); 69 } 70 71 static inline int atomic_dec_and_test(volatile atomic_t *v) 72 { 73 unsigned long flags; 74 int val; 75 76 local_irq_save(flags); 77 val = v->counter; 78 v->counter = val -= 1; 79 local_irq_restore(flags); 80 81 return val == 0; 82 } 83 84 static inline int atomic_add_negative(int i, volatile atomic_t *v) 85 { 86 unsigned long flags; 87 int val; 88 89 local_irq_save(flags); 90 val = v->counter; 91 v->counter = val += i; 92 local_irq_restore(flags); 93 94 return val < 0; 95 } 96 97 static inline void atomic_clear_mask(unsigned long mask, unsigned long *addr) 98 { 99 unsigned long flags; 100 101 local_irq_save(flags); 102 *addr &= ~mask; 103 local_irq_restore(flags); 104 } 105 106 /* Atomic operations are already serializing on ARM */ 107 #define smp_mb__before_atomic_dec() barrier() 108 #define smp_mb__after_atomic_dec() barrier() 109 #define smp_mb__before_atomic_inc() barrier() 110 #define smp_mb__after_atomic_inc() barrier() 111 112 #endif 113 #endif 114