Linux kernel mirror (for testing)
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1#ifndef __ASM_SH_ATOMIC_H
2#define __ASM_SH_ATOMIC_H
3
4/*
5 * Atomic operations that C can't guarantee us. Useful for
6 * resource counting etc..
7 *
8 */
9
10typedef struct { volatile int counter; } atomic_t;
11
12#define ATOMIC_INIT(i) ( (atomic_t) { (i) } )
13
14#define atomic_read(v) ((v)->counter)
15#define atomic_set(v,i) ((v)->counter = (i))
16
17#include <asm/system.h>
18
19/*
20 * To get proper branch prediction for the main line, we must branch
21 * forward to code at the end of this object's .text section, then
22 * branch back to restart the operation.
23 */
24
25static __inline__ void atomic_add(int i, atomic_t * v)
26{
27 unsigned long flags;
28
29 local_irq_save(flags);
30 *(long *)v += i;
31 local_irq_restore(flags);
32}
33
34static __inline__ void atomic_sub(int i, atomic_t *v)
35{
36 unsigned long flags;
37
38 local_irq_save(flags);
39 *(long *)v -= i;
40 local_irq_restore(flags);
41}
42
43static __inline__ int atomic_add_return(int i, atomic_t * v)
44{
45 unsigned long temp, flags;
46
47 local_irq_save(flags);
48 temp = *(long *)v;
49 temp += i;
50 *(long *)v = temp;
51 local_irq_restore(flags);
52
53 return temp;
54}
55
56#define atomic_add_negative(a, v) (atomic_add_return((a), (v)) < 0)
57
58static __inline__ int atomic_sub_return(int i, atomic_t * v)
59{
60 unsigned long temp, flags;
61
62 local_irq_save(flags);
63 temp = *(long *)v;
64 temp -= i;
65 *(long *)v = temp;
66 local_irq_restore(flags);
67
68 return temp;
69}
70
71#define atomic_dec_return(v) atomic_sub_return(1,(v))
72#define atomic_inc_return(v) atomic_add_return(1,(v))
73
74/*
75 * atomic_inc_and_test - increment and test
76 * @v: pointer of type atomic_t
77 *
78 * Atomically increments @v by 1
79 * and returns true if the result is zero, or false for all
80 * other cases.
81 */
82#define atomic_inc_and_test(v) (atomic_inc_return(v) == 0)
83
84#define atomic_sub_and_test(i,v) (atomic_sub_return((i), (v)) == 0)
85#define atomic_dec_and_test(v) (atomic_sub_return(1, (v)) == 0)
86
87#define atomic_inc(v) atomic_add(1,(v))
88#define atomic_dec(v) atomic_sub(1,(v))
89
90static inline int atomic_cmpxchg(atomic_t *v, int old, int new)
91{
92 int ret;
93 unsigned long flags;
94
95 local_irq_save(flags);
96 ret = v->counter;
97 if (likely(ret == old))
98 v->counter = new;
99 local_irq_restore(flags);
100
101 return ret;
102}
103
104#define atomic_xchg(v, new) (xchg(&((v)->counter), new))
105
106static inline int atomic_add_unless(atomic_t *v, int a, int u)
107{
108 int ret;
109 unsigned long flags;
110
111 local_irq_save(flags);
112 ret = v->counter;
113 if (ret != u)
114 v->counter += a;
115 local_irq_restore(flags);
116
117 return ret != u;
118}
119#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
120
121static __inline__ void atomic_clear_mask(unsigned int mask, atomic_t *v)
122{
123 unsigned long flags;
124
125 local_irq_save(flags);
126 *(long *)v &= ~mask;
127 local_irq_restore(flags);
128}
129
130static __inline__ void atomic_set_mask(unsigned int mask, atomic_t *v)
131{
132 unsigned long flags;
133
134 local_irq_save(flags);
135 *(long *)v |= mask;
136 local_irq_restore(flags);
137}
138
139/* Atomic operations are already serializing on SH */
140#define smp_mb__before_atomic_dec() barrier()
141#define smp_mb__after_atomic_dec() barrier()
142#define smp_mb__before_atomic_inc() barrier()
143#define smp_mb__after_atomic_inc() barrier()
144
145#include <asm-generic/atomic.h>
146#endif /* __ASM_SH_ATOMIC_H */