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1/* MN10300 Atomic counter operations
2 *
3 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public Licence
8 * as published by the Free Software Foundation; either version
9 * 2 of the Licence, or (at your option) any later version.
10 */
11#ifndef _ASM_ATOMIC_H
12#define _ASM_ATOMIC_H
13
14#ifdef CONFIG_SMP
15#error not SMP safe
16#endif
17
18/*
19 * Atomic operations that C can't guarantee us. Useful for
20 * resource counting etc..
21 */
22
23#define ATOMIC_INIT(i) { (i) }
24
25#ifdef __KERNEL__
26
27/**
28 * atomic_read - read atomic variable
29 * @v: pointer of type atomic_t
30 *
31 * Atomically reads the value of @v. Note that the guaranteed
32 * useful range of an atomic_t is only 24 bits.
33 */
34#define atomic_read(v) ((v)->counter)
35
36/**
37 * atomic_set - set atomic variable
38 * @v: pointer of type atomic_t
39 * @i: required value
40 *
41 * Atomically sets the value of @v to @i. Note that the guaranteed
42 * useful range of an atomic_t is only 24 bits.
43 */
44#define atomic_set(v, i) (((v)->counter) = (i))
45
46#include <asm/system.h>
47
48/**
49 * atomic_add_return - add integer to atomic variable
50 * @i: integer value to add
51 * @v: pointer of type atomic_t
52 *
53 * Atomically adds @i to @v and returns the result
54 * Note that the guaranteed useful range of an atomic_t is only 24 bits.
55 */
56static inline int atomic_add_return(int i, atomic_t *v)
57{
58 unsigned long flags;
59 int temp;
60
61 local_irq_save(flags);
62 temp = v->counter;
63 temp += i;
64 v->counter = temp;
65 local_irq_restore(flags);
66
67 return temp;
68}
69
70/**
71 * atomic_sub_return - subtract integer from atomic variable
72 * @i: integer value to subtract
73 * @v: pointer of type atomic_t
74 *
75 * Atomically subtracts @i from @v and returns the result
76 * Note that the guaranteed useful range of an atomic_t is only 24 bits.
77 */
78static inline int atomic_sub_return(int i, atomic_t *v)
79{
80 unsigned long flags;
81 int temp;
82
83 local_irq_save(flags);
84 temp = v->counter;
85 temp -= i;
86 v->counter = temp;
87 local_irq_restore(flags);
88
89 return temp;
90}
91
92static inline int atomic_add_negative(int i, atomic_t *v)
93{
94 return atomic_add_return(i, v) < 0;
95}
96
97static inline void atomic_add(int i, atomic_t *v)
98{
99 atomic_add_return(i, v);
100}
101
102static inline void atomic_sub(int i, atomic_t *v)
103{
104 atomic_sub_return(i, v);
105}
106
107static inline void atomic_inc(atomic_t *v)
108{
109 atomic_add_return(1, v);
110}
111
112static inline void atomic_dec(atomic_t *v)
113{
114 atomic_sub_return(1, v);
115}
116
117#define atomic_dec_return(v) atomic_sub_return(1, (v))
118#define atomic_inc_return(v) atomic_add_return(1, (v))
119
120#define atomic_sub_and_test(i, v) (atomic_sub_return((i), (v)) == 0)
121#define atomic_dec_and_test(v) (atomic_sub_return(1, (v)) == 0)
122#define atomic_inc_and_test(v) (atomic_add_return(1, (v)) == 0)
123
124#define atomic_add_unless(v, a, u) \
125({ \
126 int c, old; \
127 c = atomic_read(v); \
128 while (c != (u) && (old = atomic_cmpxchg((v), c, c + (a))) != c) \
129 c = old; \
130 c != (u); \
131})
132
133#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
134
135static inline void atomic_clear_mask(unsigned long mask, unsigned long *addr)
136{
137 unsigned long flags;
138
139 mask = ~mask;
140 local_irq_save(flags);
141 *addr &= mask;
142 local_irq_restore(flags);
143}
144
145#define atomic_xchg(ptr, v) (xchg(&(ptr)->counter, (v)))
146#define atomic_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), (old), (new)))
147
148/* Atomic operations are already serializing on MN10300??? */
149#define smp_mb__before_atomic_dec() barrier()
150#define smp_mb__after_atomic_dec() barrier()
151#define smp_mb__before_atomic_inc() barrier()
152#define smp_mb__after_atomic_inc() barrier()
153
154#include <asm-generic/atomic.h>
155
156#endif /* __KERNEL__ */
157#endif /* _ASM_ATOMIC_H */