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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 <linux/compiler.h>
18#include <asm/system.h>
19
20#ifdef CONFIG_CPU_SH4A
21#include <asm/atomic-llsc.h>
22#else
23#include <asm/atomic-irq.h>
24#endif
25
26#define atomic_add_negative(a, v) (atomic_add_return((a), (v)) < 0)
27
28#define atomic_dec_return(v) atomic_sub_return(1,(v))
29#define atomic_inc_return(v) atomic_add_return(1,(v))
30
31/*
32 * atomic_inc_and_test - increment and test
33 * @v: pointer of type atomic_t
34 *
35 * Atomically increments @v by 1
36 * and returns true if the result is zero, or false for all
37 * other cases.
38 */
39#define atomic_inc_and_test(v) (atomic_inc_return(v) == 0)
40
41#define atomic_sub_and_test(i,v) (atomic_sub_return((i), (v)) == 0)
42#define atomic_dec_and_test(v) (atomic_sub_return(1, (v)) == 0)
43
44#define atomic_inc(v) atomic_add(1,(v))
45#define atomic_dec(v) atomic_sub(1,(v))
46
47static inline int atomic_cmpxchg(atomic_t *v, int old, int new)
48{
49 int ret;
50 unsigned long flags;
51
52 local_irq_save(flags);
53 ret = v->counter;
54 if (likely(ret == old))
55 v->counter = new;
56 local_irq_restore(flags);
57
58 return ret;
59}
60
61#define atomic_xchg(v, new) (xchg(&((v)->counter), new))
62
63static inline int atomic_add_unless(atomic_t *v, int a, int u)
64{
65 int ret;
66 unsigned long flags;
67
68 local_irq_save(flags);
69 ret = v->counter;
70 if (ret != u)
71 v->counter += a;
72 local_irq_restore(flags);
73
74 return ret != u;
75}
76#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
77
78/* Atomic operations are already serializing on SH */
79#define smp_mb__before_atomic_dec() barrier()
80#define smp_mb__after_atomic_dec() barrier()
81#define smp_mb__before_atomic_inc() barrier()
82#define smp_mb__after_atomic_inc() barrier()
83
84#include <asm-generic/atomic.h>
85#endif /* __ASM_SH_ATOMIC_H */