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1da177e4 LT |
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 |