Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame^] | 1 | /* |
| 2 | * linux/include/asm-arm26/atomic.h |
| 3 | * |
| 4 | * Copyright (c) 1996 Russell King. |
| 5 | * Modified for arm26 by Ian Molton |
| 6 | * |
| 7 | * This program is free software; you can redistribute it and/or modify |
| 8 | * it under the terms of the GNU General Public License version 2 as |
| 9 | * published by the Free Software Foundation. |
| 10 | * |
| 11 | * Changelog: |
| 12 | * 25-11-2004 IM Updated for 2.6.9 |
| 13 | * 27-06-1996 RMK Created |
| 14 | * 13-04-1997 RMK Made functions atomic! |
| 15 | * 07-12-1997 RMK Upgraded for v2.1. |
| 16 | * 26-08-1998 PJB Added #ifdef __KERNEL__ |
| 17 | * |
| 18 | * FIXME - its probably worth seeing what these compile into... |
| 19 | */ |
| 20 | #ifndef __ASM_ARM_ATOMIC_H |
| 21 | #define __ASM_ARM_ATOMIC_H |
| 22 | |
| 23 | #include <linux/config.h> |
| 24 | |
| 25 | #ifdef CONFIG_SMP |
| 26 | #error SMP is NOT supported |
| 27 | #endif |
| 28 | |
| 29 | typedef struct { volatile int counter; } atomic_t; |
| 30 | |
| 31 | #define ATOMIC_INIT(i) { (i) } |
| 32 | |
| 33 | #ifdef __KERNEL__ |
| 34 | #include <asm/system.h> |
| 35 | |
| 36 | #define atomic_read(v) ((v)->counter) |
| 37 | #define atomic_set(v,i) (((v)->counter) = (i)) |
| 38 | |
| 39 | static inline int atomic_add_return(int i, atomic_t *v) |
| 40 | { |
| 41 | unsigned long flags; |
| 42 | int val; |
| 43 | |
| 44 | local_irq_save(flags); |
| 45 | val = v->counter; |
| 46 | v->counter = val += i; |
| 47 | local_irq_restore(flags); |
| 48 | |
| 49 | return val; |
| 50 | } |
| 51 | |
| 52 | static inline int atomic_sub_return(int i, atomic_t *v) |
| 53 | { |
| 54 | unsigned long flags; |
| 55 | int val; |
| 56 | |
| 57 | local_irq_save(flags); |
| 58 | val = v->counter; |
| 59 | v->counter = val -= i; |
| 60 | local_irq_restore(flags); |
| 61 | |
| 62 | return val; |
| 63 | } |
| 64 | |
| 65 | static inline void atomic_clear_mask(unsigned long mask, unsigned long *addr) |
| 66 | { |
| 67 | unsigned long flags; |
| 68 | |
| 69 | local_irq_save(flags); |
| 70 | *addr &= ~mask; |
| 71 | local_irq_restore(flags); |
| 72 | } |
| 73 | |
| 74 | #define atomic_add(i, v) (void) atomic_add_return(i, v) |
| 75 | #define atomic_inc(v) (void) atomic_add_return(1, v) |
| 76 | #define atomic_sub(i, v) (void) atomic_sub_return(i, v) |
| 77 | #define atomic_dec(v) (void) atomic_sub_return(1, v) |
| 78 | |
| 79 | #define atomic_inc_and_test(v) (atomic_add_return(1, v) == 0) |
| 80 | #define atomic_dec_and_test(v) (atomic_sub_return(1, v) == 0) |
| 81 | #define atomic_inc_return(v) (atomic_add_return(1, v)) |
| 82 | #define atomic_dec_return(v) (atomic_sub_return(1, v)) |
| 83 | |
| 84 | #define atomic_add_negative(i,v) (atomic_add_return(i, v) < 0) |
| 85 | |
| 86 | /* Atomic operations are already serializing on ARM26 */ |
| 87 | #define smp_mb__before_atomic_dec() barrier() |
| 88 | #define smp_mb__after_atomic_dec() barrier() |
| 89 | #define smp_mb__before_atomic_inc() barrier() |
| 90 | #define smp_mb__after_atomic_inc() barrier() |
| 91 | |
| 92 | #endif |
| 93 | #endif |