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 */
atomic_add_return(int i,atomic_t * v)56 static 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 */
atomic_sub_return(int i,atomic_t * v)78 static 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
atomic_add_negative(int i,atomic_t * v)92 static inline int atomic_add_negative(int i, atomic_t *v)
93 {
94 return atomic_add_return(i, v) < 0;
95 }
96
atomic_add(int i,atomic_t * v)97 static inline void atomic_add(int i, atomic_t *v)
98 {
99 atomic_add_return(i, v);
100 }
101
atomic_sub(int i,atomic_t * v)102 static inline void atomic_sub(int i, atomic_t *v)
103 {
104 atomic_sub_return(i, v);
105 }
106
atomic_inc(atomic_t * v)107 static inline void atomic_inc(atomic_t *v)
108 {
109 atomic_add_return(1, v);
110 }
111
atomic_dec(atomic_t * v)112 static 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
atomic_clear_mask(unsigned long mask,unsigned long * addr)135 static 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 */
158