1 /*
2 * Copyright 2010 Tilera Corporation. All Rights Reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation, version 2.
7 *
8 * This program is distributed in the hope that it will be useful, but
9 * WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
11 * NON INFRINGEMENT. See the GNU General Public License for
12 * more details.
13 *
14 * Atomic primitives.
15 */
16
17 #ifndef _ASM_TILE_ATOMIC_H
18 #define _ASM_TILE_ATOMIC_H
19
20 #include <asm/cmpxchg.h>
21
22 #ifndef __ASSEMBLY__
23
24 #include <linux/compiler.h>
25 #include <linux/types.h>
26
27 #define ATOMIC_INIT(i) { (i) }
28
29 /**
30 * atomic_read - read atomic variable
31 * @v: pointer of type atomic_t
32 *
33 * Atomically reads the value of @v.
34 */
atomic_read(const atomic_t * v)35 static inline int atomic_read(const atomic_t *v)
36 {
37 return READ_ONCE(v->counter);
38 }
39
40 /**
41 * atomic_sub_return - subtract integer and return
42 * @v: pointer of type atomic_t
43 * @i: integer value to subtract
44 *
45 * Atomically subtracts @i from @v and returns @v - @i
46 */
47 #define atomic_sub_return(i, v) atomic_add_return((int)(-(i)), (v))
48
49 /**
50 * atomic_sub - subtract integer from atomic variable
51 * @i: integer value to subtract
52 * @v: pointer of type atomic_t
53 *
54 * Atomically subtracts @i from @v.
55 */
56 #define atomic_sub(i, v) atomic_add((int)(-(i)), (v))
57
58 /**
59 * atomic_sub_and_test - subtract value from variable and test result
60 * @i: integer value to subtract
61 * @v: pointer of type atomic_t
62 *
63 * Atomically subtracts @i from @v and returns true if the result is
64 * zero, or false for all other cases.
65 */
66 #define atomic_sub_and_test(i, v) (atomic_sub_return((i), (v)) == 0)
67
68 /**
69 * atomic_inc_return - increment memory and return
70 * @v: pointer of type atomic_t
71 *
72 * Atomically increments @v by 1 and returns the new value.
73 */
74 #define atomic_inc_return(v) atomic_add_return(1, (v))
75
76 /**
77 * atomic_dec_return - decrement memory and return
78 * @v: pointer of type atomic_t
79 *
80 * Atomically decrements @v by 1 and returns the new value.
81 */
82 #define atomic_dec_return(v) atomic_sub_return(1, (v))
83
84 /**
85 * atomic_inc - increment atomic variable
86 * @v: pointer of type atomic_t
87 *
88 * Atomically increments @v by 1.
89 */
90 #define atomic_inc(v) atomic_add(1, (v))
91
92 /**
93 * atomic_dec - decrement atomic variable
94 * @v: pointer of type atomic_t
95 *
96 * Atomically decrements @v by 1.
97 */
98 #define atomic_dec(v) atomic_sub(1, (v))
99
100 /**
101 * atomic_dec_and_test - decrement and test
102 * @v: pointer of type atomic_t
103 *
104 * Atomically decrements @v by 1 and returns true if the result is 0.
105 */
106 #define atomic_dec_and_test(v) (atomic_dec_return(v) == 0)
107
108 /**
109 * atomic_inc_and_test - increment and test
110 * @v: pointer of type atomic_t
111 *
112 * Atomically increments @v by 1 and returns true if the result is 0.
113 */
114 #define atomic_inc_and_test(v) (atomic_inc_return(v) == 0)
115
116 /**
117 * atomic_xchg - atomically exchange contents of memory with a new value
118 * @v: pointer of type atomic_t
119 * @i: integer value to store in memory
120 *
121 * Atomically sets @v to @i and returns old @v
122 */
atomic_xchg(atomic_t * v,int n)123 static inline int atomic_xchg(atomic_t *v, int n)
124 {
125 return xchg(&v->counter, n);
126 }
127
128 /**
129 * atomic_cmpxchg - atomically exchange contents of memory if it matches
130 * @v: pointer of type atomic_t
131 * @o: old value that memory should have
132 * @n: new value to write to memory if it matches
133 *
134 * Atomically checks if @v holds @o and replaces it with @n if so.
135 * Returns the old value at @v.
136 */
atomic_cmpxchg(atomic_t * v,int o,int n)137 static inline int atomic_cmpxchg(atomic_t *v, int o, int n)
138 {
139 return cmpxchg(&v->counter, o, n);
140 }
141
142 /**
143 * atomic_add_negative - add and test if negative
144 * @v: pointer of type atomic_t
145 * @i: integer value to add
146 *
147 * Atomically adds @i to @v and returns true if the result is
148 * negative, or false when result is greater than or equal to zero.
149 */
150 #define atomic_add_negative(i, v) (atomic_add_return((i), (v)) < 0)
151
152 #endif /* __ASSEMBLY__ */
153
154 #ifndef __tilegx__
155 #include <asm/atomic_32.h>
156 #else
157 #include <asm/atomic_64.h>
158 #endif
159
160 #ifndef __ASSEMBLY__
161
162 /**
163 * atomic64_xchg - atomically exchange contents of memory with a new value
164 * @v: pointer of type atomic64_t
165 * @i: integer value to store in memory
166 *
167 * Atomically sets @v to @i and returns old @v
168 */
atomic64_xchg(atomic64_t * v,long long n)169 static inline long long atomic64_xchg(atomic64_t *v, long long n)
170 {
171 return xchg64(&v->counter, n);
172 }
173
174 /**
175 * atomic64_cmpxchg - atomically exchange contents of memory if it matches
176 * @v: pointer of type atomic64_t
177 * @o: old value that memory should have
178 * @n: new value to write to memory if it matches
179 *
180 * Atomically checks if @v holds @o and replaces it with @n if so.
181 * Returns the old value at @v.
182 */
atomic64_cmpxchg(atomic64_t * v,long long o,long long n)183 static inline long long atomic64_cmpxchg(atomic64_t *v, long long o,
184 long long n)
185 {
186 return cmpxchg64(&v->counter, o, n);
187 }
188
atomic64_dec_if_positive(atomic64_t * v)189 static inline long long atomic64_dec_if_positive(atomic64_t *v)
190 {
191 long long c, old, dec;
192
193 c = atomic64_read(v);
194 for (;;) {
195 dec = c - 1;
196 if (unlikely(dec < 0))
197 break;
198 old = atomic64_cmpxchg((v), c, dec);
199 if (likely(old == c))
200 break;
201 c = old;
202 }
203 return dec;
204 }
205
206 #endif /* __ASSEMBLY__ */
207
208 #endif /* _ASM_TILE_ATOMIC_H */
209