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 #ifndef __ASSEMBLY__
21
22 #include <linux/compiler.h>
23 #include <asm/system.h>
24
25 #define ATOMIC_INIT(i) { (i) }
26
27 /**
28 * atomic_read - read atomic variable
29 * @v: pointer of type atomic_t
30 *
31 * Atomically reads the value of @v.
32 */
atomic_read(const atomic_t * v)33 static inline int atomic_read(const atomic_t *v)
34 {
35 return ACCESS_ONCE(v->counter);
36 }
37
38 /**
39 * atomic_sub_return - subtract integer and return
40 * @v: pointer of type atomic_t
41 * @i: integer value to subtract
42 *
43 * Atomically subtracts @i from @v and returns @v - @i
44 */
45 #define atomic_sub_return(i, v) atomic_add_return((int)(-(i)), (v))
46
47 /**
48 * atomic_sub - subtract integer from atomic variable
49 * @i: integer value to subtract
50 * @v: pointer of type atomic_t
51 *
52 * Atomically subtracts @i from @v.
53 */
54 #define atomic_sub(i, v) atomic_add((int)(-(i)), (v))
55
56 /**
57 * atomic_sub_and_test - subtract value from variable and test result
58 * @i: integer value to subtract
59 * @v: pointer of type atomic_t
60 *
61 * Atomically subtracts @i from @v and returns true if the result is
62 * zero, or false for all other cases.
63 */
64 #define atomic_sub_and_test(i, v) (atomic_sub_return((i), (v)) == 0)
65
66 /**
67 * atomic_inc_return - increment memory and return
68 * @v: pointer of type atomic_t
69 *
70 * Atomically increments @v by 1 and returns the new value.
71 */
72 #define atomic_inc_return(v) atomic_add_return(1, (v))
73
74 /**
75 * atomic_dec_return - decrement memory and return
76 * @v: pointer of type atomic_t
77 *
78 * Atomically decrements @v by 1 and returns the new value.
79 */
80 #define atomic_dec_return(v) atomic_sub_return(1, (v))
81
82 /**
83 * atomic_inc - increment atomic variable
84 * @v: pointer of type atomic_t
85 *
86 * Atomically increments @v by 1.
87 */
88 #define atomic_inc(v) atomic_add(1, (v))
89
90 /**
91 * atomic_dec - decrement atomic variable
92 * @v: pointer of type atomic_t
93 *
94 * Atomically decrements @v by 1.
95 */
96 #define atomic_dec(v) atomic_sub(1, (v))
97
98 /**
99 * atomic_dec_and_test - decrement and test
100 * @v: pointer of type atomic_t
101 *
102 * Atomically decrements @v by 1 and returns true if the result is 0.
103 */
104 #define atomic_dec_and_test(v) (atomic_dec_return(v) == 0)
105
106 /**
107 * atomic_inc_and_test - increment and test
108 * @v: pointer of type atomic_t
109 *
110 * Atomically increments @v by 1 and returns true if the result is 0.
111 */
112 #define atomic_inc_and_test(v) (atomic_inc_return(v) == 0)
113
114 /**
115 * atomic_add_negative - add and test if negative
116 * @v: pointer of type atomic_t
117 * @i: integer value to add
118 *
119 * Atomically adds @i to @v and returns true if the result is
120 * negative, or false when result is greater than or equal to zero.
121 */
122 #define atomic_add_negative(i, v) (atomic_add_return((i), (v)) < 0)
123
124 /* Nonexistent functions intended to cause link errors. */
125 extern unsigned long __xchg_called_with_bad_pointer(void);
126 extern unsigned long __cmpxchg_called_with_bad_pointer(void);
127
128 #define xchg(ptr, x) \
129 ({ \
130 typeof(*(ptr)) __x; \
131 switch (sizeof(*(ptr))) { \
132 case 4: \
133 __x = (typeof(__x))(typeof(__x-__x))atomic_xchg( \
134 (atomic_t *)(ptr), \
135 (u32)(typeof((x)-(x)))(x)); \
136 break; \
137 case 8: \
138 __x = (typeof(__x))(typeof(__x-__x))atomic64_xchg( \
139 (atomic64_t *)(ptr), \
140 (u64)(typeof((x)-(x)))(x)); \
141 break; \
142 default: \
143 __xchg_called_with_bad_pointer(); \
144 } \
145 __x; \
146 })
147
148 #define cmpxchg(ptr, o, n) \
149 ({ \
150 typeof(*(ptr)) __x; \
151 switch (sizeof(*(ptr))) { \
152 case 4: \
153 __x = (typeof(__x))(typeof(__x-__x))atomic_cmpxchg( \
154 (atomic_t *)(ptr), \
155 (u32)(typeof((o)-(o)))(o), \
156 (u32)(typeof((n)-(n)))(n)); \
157 break; \
158 case 8: \
159 __x = (typeof(__x))(typeof(__x-__x))atomic64_cmpxchg( \
160 (atomic64_t *)(ptr), \
161 (u64)(typeof((o)-(o)))(o), \
162 (u64)(typeof((n)-(n)))(n)); \
163 break; \
164 default: \
165 __cmpxchg_called_with_bad_pointer(); \
166 } \
167 __x; \
168 })
169
170 #define tas(ptr) (xchg((ptr), 1))
171
172 #endif /* __ASSEMBLY__ */
173
174 #ifndef __tilegx__
175 #include <asm/atomic_32.h>
176 #else
177 #include <asm/atomic_64.h>
178 #endif
179
180 #endif /* _ASM_TILE_ATOMIC_H */
181