Commit | Line | Data |
---|---|---|
3f7e212d | 1 | /* |
acac43e2 AS |
2 | * Generic C implementation of atomic counter operations. Usable on |
3 | * UP systems only. Do not include in machine independent code. | |
4 | * | |
3f7e212d AB |
5 | * Originally implemented for MN10300. |
6 | * | |
7 | * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. | |
8 | * Written by David Howells (dhowells@redhat.com) | |
9 | * | |
10 | * This program is free software; you can redistribute it and/or | |
11 | * modify it under the terms of the GNU General Public Licence | |
12 | * as published by the Free Software Foundation; either version | |
13 | * 2 of the Licence, or (at your option) any later version. | |
14 | */ | |
15 | #ifndef __ASM_GENERIC_ATOMIC_H | |
16 | #define __ASM_GENERIC_ATOMIC_H | |
17 | ||
34484277 DH |
18 | #include <asm/cmpxchg.h> |
19 | ||
3f7e212d | 20 | #ifdef CONFIG_SMP |
7505cb60 MF |
21 | /* Force people to define core atomics */ |
22 | # if !defined(atomic_add_return) || !defined(atomic_sub_return) || \ | |
23 | !defined(atomic_clear_mask) || !defined(atomic_set_mask) | |
24 | # error "SMP requires a little arch-specific magic" | |
25 | # endif | |
3f7e212d AB |
26 | #endif |
27 | ||
28 | /* | |
29 | * Atomic operations that C can't guarantee us. Useful for | |
30 | * resource counting etc.. | |
31 | */ | |
32 | ||
33 | #define ATOMIC_INIT(i) { (i) } | |
34 | ||
35 | #ifdef __KERNEL__ | |
36 | ||
37 | /** | |
38 | * atomic_read - read atomic variable | |
39 | * @v: pointer of type atomic_t | |
40 | * | |
37682177 | 41 | * Atomically reads the value of @v. |
3f7e212d | 42 | */ |
7505cb60 | 43 | #ifndef atomic_read |
f3d46f9d | 44 | #define atomic_read(v) (*(volatile int *)&(v)->counter) |
7505cb60 | 45 | #endif |
3f7e212d AB |
46 | |
47 | /** | |
48 | * atomic_set - set atomic variable | |
49 | * @v: pointer of type atomic_t | |
50 | * @i: required value | |
51 | * | |
37682177 | 52 | * Atomically sets the value of @v to @i. |
3f7e212d AB |
53 | */ |
54 | #define atomic_set(v, i) (((v)->counter) = (i)) | |
55 | ||
df9ee292 | 56 | #include <linux/irqflags.h> |
3f7e212d AB |
57 | |
58 | /** | |
59 | * atomic_add_return - add integer to atomic variable | |
60 | * @i: integer value to add | |
61 | * @v: pointer of type atomic_t | |
62 | * | |
63 | * Atomically adds @i to @v and returns the result | |
3f7e212d | 64 | */ |
7505cb60 | 65 | #ifndef atomic_add_return |
3f7e212d AB |
66 | static inline int atomic_add_return(int i, atomic_t *v) |
67 | { | |
68 | unsigned long flags; | |
69 | int temp; | |
70 | ||
df9ee292 | 71 | raw_local_irq_save(flags); /* Don't trace it in an irqsoff handler */ |
3f7e212d AB |
72 | temp = v->counter; |
73 | temp += i; | |
74 | v->counter = temp; | |
9e58143d | 75 | raw_local_irq_restore(flags); |
3f7e212d AB |
76 | |
77 | return temp; | |
78 | } | |
7505cb60 | 79 | #endif |
3f7e212d AB |
80 | |
81 | /** | |
82 | * atomic_sub_return - subtract integer from atomic variable | |
83 | * @i: integer value to subtract | |
84 | * @v: pointer of type atomic_t | |
85 | * | |
86 | * Atomically subtracts @i from @v and returns the result | |
3f7e212d | 87 | */ |
7505cb60 | 88 | #ifndef atomic_sub_return |
3f7e212d AB |
89 | static inline int atomic_sub_return(int i, atomic_t *v) |
90 | { | |
91 | unsigned long flags; | |
92 | int temp; | |
93 | ||
df9ee292 | 94 | raw_local_irq_save(flags); /* Don't trace it in an irqsoff handler */ |
3f7e212d AB |
95 | temp = v->counter; |
96 | temp -= i; | |
97 | v->counter = temp; | |
9e58143d | 98 | raw_local_irq_restore(flags); |
3f7e212d AB |
99 | |
100 | return temp; | |
101 | } | |
7505cb60 | 102 | #endif |
3f7e212d AB |
103 | |
104 | static inline int atomic_add_negative(int i, atomic_t *v) | |
105 | { | |
106 | return atomic_add_return(i, v) < 0; | |
107 | } | |
108 | ||
109 | static inline void atomic_add(int i, atomic_t *v) | |
110 | { | |
111 | atomic_add_return(i, v); | |
112 | } | |
113 | ||
114 | static inline void atomic_sub(int i, atomic_t *v) | |
115 | { | |
116 | atomic_sub_return(i, v); | |
117 | } | |
118 | ||
119 | static inline void atomic_inc(atomic_t *v) | |
120 | { | |
121 | atomic_add_return(1, v); | |
122 | } | |
123 | ||
124 | static inline void atomic_dec(atomic_t *v) | |
125 | { | |
126 | atomic_sub_return(1, v); | |
127 | } | |
128 | ||
129 | #define atomic_dec_return(v) atomic_sub_return(1, (v)) | |
130 | #define atomic_inc_return(v) atomic_add_return(1, (v)) | |
131 | ||
132 | #define atomic_sub_and_test(i, v) (atomic_sub_return((i), (v)) == 0) | |
3eea44ea MF |
133 | #define atomic_dec_and_test(v) (atomic_dec_return(v) == 0) |
134 | #define atomic_inc_and_test(v) (atomic_inc_return(v) == 0) | |
3f7e212d | 135 | |
8b9d4069 ML |
136 | #define atomic_xchg(ptr, v) (xchg(&(ptr)->counter, (v))) |
137 | #define atomic_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), (old), (new))) | |
138 | ||
f24219b4 | 139 | static inline int __atomic_add_unless(atomic_t *v, int a, int u) |
8b9d4069 ML |
140 | { |
141 | int c, old; | |
142 | c = atomic_read(v); | |
143 | while (c != u && (old = atomic_cmpxchg(v, c, c + a)) != c) | |
144 | c = old; | |
f24219b4 | 145 | return c; |
8b9d4069 | 146 | } |
3f7e212d | 147 | |
f6081bd3 MF |
148 | /** |
149 | * atomic_clear_mask - Atomically clear bits in atomic variable | |
150 | * @mask: Mask of the bits to be cleared | |
151 | * @v: pointer of type atomic_t | |
152 | * | |
153 | * Atomically clears the bits set in @mask from @v | |
154 | */ | |
7505cb60 | 155 | #ifndef atomic_clear_mask |
f6081bd3 | 156 | static inline void atomic_clear_mask(unsigned long mask, atomic_t *v) |
3f7e212d AB |
157 | { |
158 | unsigned long flags; | |
159 | ||
160 | mask = ~mask; | |
9e58143d | 161 | raw_local_irq_save(flags); /* Don't trace it in a irqsoff handler */ |
f6081bd3 | 162 | v->counter &= mask; |
9e58143d | 163 | raw_local_irq_restore(flags); |
3f7e212d | 164 | } |
7505cb60 | 165 | #endif |
3f7e212d | 166 | |
00b3c28b MF |
167 | /** |
168 | * atomic_set_mask - Atomically set bits in atomic variable | |
169 | * @mask: Mask of the bits to be set | |
170 | * @v: pointer of type atomic_t | |
171 | * | |
172 | * Atomically sets the bits set in @mask in @v | |
173 | */ | |
7505cb60 | 174 | #ifndef atomic_set_mask |
00b3c28b MF |
175 | static inline void atomic_set_mask(unsigned int mask, atomic_t *v) |
176 | { | |
177 | unsigned long flags; | |
178 | ||
179 | raw_local_irq_save(flags); /* Don't trace it in a irqsoff handler */ | |
180 | v->counter |= mask; | |
181 | raw_local_irq_restore(flags); | |
182 | } | |
7505cb60 | 183 | #endif |
00b3c28b | 184 | |
3f7e212d AB |
185 | /* Assume that atomic operations are already serializing */ |
186 | #define smp_mb__before_atomic_dec() barrier() | |
187 | #define smp_mb__after_atomic_dec() barrier() | |
188 | #define smp_mb__before_atomic_inc() barrier() | |
189 | #define smp_mb__after_atomic_inc() barrier() | |
190 | ||
3f7e212d AB |
191 | #endif /* __KERNEL__ */ |
192 | #endif /* __ASM_GENERIC_ATOMIC_H */ |