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5f97f7f9 HS |
1 | /* |
2 | * Atomic operations that C can't guarantee us. Useful for | |
3 | * resource counting etc. | |
4 | * | |
5 | * But use these as seldom as possible since they are slower than | |
6 | * regular operations. | |
7 | * | |
8 | * Copyright (C) 2004-2006 Atmel Corporation | |
9 | * | |
10 | * This program is free software; you can redistribute it and/or modify | |
11 | * it under the terms of the GNU General Public License version 2 as | |
12 | * published by the Free Software Foundation. | |
13 | */ | |
14 | #ifndef __ASM_AVR32_ATOMIC_H | |
15 | #define __ASM_AVR32_ATOMIC_H | |
16 | ||
17 | #include <asm/system.h> | |
18 | ||
19 | typedef struct { volatile int counter; } atomic_t; | |
20 | #define ATOMIC_INIT(i) { (i) } | |
21 | ||
22 | #define atomic_read(v) ((v)->counter) | |
23 | #define atomic_set(v, i) (((v)->counter) = i) | |
24 | ||
25 | /* | |
26 | * atomic_sub_return - subtract the atomic variable | |
27 | * @i: integer value to subtract | |
28 | * @v: pointer of type atomic_t | |
29 | * | |
30 | * Atomically subtracts @i from @v. Returns the resulting value. | |
31 | */ | |
32 | static inline int atomic_sub_return(int i, atomic_t *v) | |
33 | { | |
34 | int result; | |
35 | ||
36 | asm volatile( | |
37 | "/* atomic_sub_return */\n" | |
38 | "1: ssrf 5\n" | |
39 | " ld.w %0, %2\n" | |
40 | " sub %0, %3\n" | |
41 | " stcond %1, %0\n" | |
42 | " brne 1b" | |
43 | : "=&r"(result), "=o"(v->counter) | |
fa352240 | 44 | : "m"(v->counter), "rKs21"(i) |
5f97f7f9 HS |
45 | : "cc"); |
46 | ||
47 | return result; | |
48 | } | |
49 | ||
50 | /* | |
51 | * atomic_add_return - add integer to atomic variable | |
52 | * @i: integer value to add | |
53 | * @v: pointer of type atomic_t | |
54 | * | |
55 | * Atomically adds @i to @v. Returns the resulting value. | |
56 | */ | |
57 | static inline int atomic_add_return(int i, atomic_t *v) | |
58 | { | |
59 | int result; | |
60 | ||
fa352240 | 61 | if (__builtin_constant_p(i) && (i >= -1048575) && (i <= 1048576)) |
5f97f7f9 HS |
62 | result = atomic_sub_return(-i, v); |
63 | else | |
64 | asm volatile( | |
65 | "/* atomic_add_return */\n" | |
66 | "1: ssrf 5\n" | |
67 | " ld.w %0, %1\n" | |
68 | " add %0, %3\n" | |
69 | " stcond %2, %0\n" | |
70 | " brne 1b" | |
71 | : "=&r"(result), "=o"(v->counter) | |
72 | : "m"(v->counter), "r"(i) | |
73 | : "cc", "memory"); | |
74 | ||
75 | return result; | |
76 | } | |
77 | ||
78 | /* | |
79 | * atomic_sub_unless - sub unless the number is a given value | |
80 | * @v: pointer of type atomic_t | |
81 | * @a: the amount to add to v... | |
82 | * @u: ...unless v is equal to u. | |
83 | * | |
84 | * If the atomic value v is not equal to u, this function subtracts a | |
85 | * from v, and returns non zero. If v is equal to u then it returns | |
86 | * zero. This is done as an atomic operation. | |
87 | */ | |
88 | static inline int atomic_sub_unless(atomic_t *v, int a, int u) | |
89 | { | |
90 | int tmp, result = 0; | |
91 | ||
92 | asm volatile( | |
93 | "/* atomic_sub_unless */\n" | |
94 | "1: ssrf 5\n" | |
95 | " ld.w %0, %3\n" | |
96 | " cp.w %0, %5\n" | |
97 | " breq 1f\n" | |
98 | " sub %0, %4\n" | |
99 | " stcond %2, %0\n" | |
100 | " brne 1b\n" | |
101 | " mov %1, 1\n" | |
102 | "1:" | |
103 | : "=&r"(tmp), "=&r"(result), "=o"(v->counter) | |
3da86ee4 | 104 | : "m"(v->counter), "rKs21"(a), "rKs21"(u), "1"(result) |
5f97f7f9 HS |
105 | : "cc", "memory"); |
106 | ||
107 | return result; | |
108 | } | |
109 | ||
110 | /* | |
111 | * atomic_add_unless - add unless the number is a given value | |
112 | * @v: pointer of type atomic_t | |
113 | * @a: the amount to add to v... | |
114 | * @u: ...unless v is equal to u. | |
115 | * | |
116 | * If the atomic value v is not equal to u, this function adds a to v, | |
117 | * and returns non zero. If v is equal to u then it returns zero. This | |
118 | * is done as an atomic operation. | |
119 | */ | |
120 | static inline int atomic_add_unless(atomic_t *v, int a, int u) | |
121 | { | |
122 | int tmp, result; | |
123 | ||
fa352240 | 124 | if (__builtin_constant_p(a) && (a >= -1048575) && (a <= 1048576)) |
5f97f7f9 HS |
125 | result = atomic_sub_unless(v, -a, u); |
126 | else { | |
127 | result = 0; | |
128 | asm volatile( | |
129 | "/* atomic_add_unless */\n" | |
130 | "1: ssrf 5\n" | |
131 | " ld.w %0, %3\n" | |
132 | " cp.w %0, %5\n" | |
133 | " breq 1f\n" | |
134 | " add %0, %4\n" | |
135 | " stcond %2, %0\n" | |
136 | " brne 1b\n" | |
137 | " mov %1, 1\n" | |
138 | "1:" | |
139 | : "=&r"(tmp), "=&r"(result), "=o"(v->counter) | |
3da86ee4 | 140 | : "m"(v->counter), "r"(a), "ir"(u), "1"(result) |
5f97f7f9 HS |
141 | : "cc", "memory"); |
142 | } | |
143 | ||
144 | return result; | |
145 | } | |
146 | ||
147 | /* | |
148 | * atomic_sub_if_positive - conditionally subtract integer from atomic variable | |
149 | * @i: integer value to subtract | |
150 | * @v: pointer of type atomic_t | |
151 | * | |
152 | * Atomically test @v and subtract @i if @v is greater or equal than @i. | |
153 | * The function returns the old value of @v minus @i. | |
154 | */ | |
155 | static inline int atomic_sub_if_positive(int i, atomic_t *v) | |
156 | { | |
157 | int result; | |
158 | ||
159 | asm volatile( | |
160 | "/* atomic_sub_if_positive */\n" | |
161 | "1: ssrf 5\n" | |
162 | " ld.w %0, %2\n" | |
163 | " sub %0, %3\n" | |
164 | " brlt 1f\n" | |
165 | " stcond %1, %0\n" | |
166 | " brne 1b\n" | |
167 | "1:" | |
168 | : "=&r"(result), "=o"(v->counter) | |
169 | : "m"(v->counter), "ir"(i) | |
170 | : "cc", "memory"); | |
171 | ||
172 | return result; | |
173 | } | |
174 | ||
175 | #define atomic_xchg(v, new) (xchg(&((v)->counter), new)) | |
a4022b0d | 176 | #define atomic_cmpxchg(v, o, n) (cmpxchg(&((v)->counter), (o), (n))) |
5f97f7f9 HS |
177 | |
178 | #define atomic_sub(i, v) (void)atomic_sub_return(i, v) | |
179 | #define atomic_add(i, v) (void)atomic_add_return(i, v) | |
180 | #define atomic_dec(v) atomic_sub(1, (v)) | |
181 | #define atomic_inc(v) atomic_add(1, (v)) | |
182 | ||
183 | #define atomic_dec_return(v) atomic_sub_return(1, v) | |
184 | #define atomic_inc_return(v) atomic_add_return(1, v) | |
185 | ||
186 | #define atomic_sub_and_test(i, v) (atomic_sub_return(i, v) == 0) | |
187 | #define atomic_inc_and_test(v) (atomic_add_return(1, v) == 0) | |
188 | #define atomic_dec_and_test(v) (atomic_sub_return(1, v) == 0) | |
189 | #define atomic_add_negative(i, v) (atomic_add_return(i, v) < 0) | |
190 | ||
191 | #define atomic_inc_not_zero(v) atomic_add_unless(v, 1, 0) | |
192 | #define atomic_dec_if_positive(v) atomic_sub_if_positive(1, v) | |
193 | ||
194 | #define smp_mb__before_atomic_dec() barrier() | |
195 | #define smp_mb__after_atomic_dec() barrier() | |
196 | #define smp_mb__before_atomic_inc() barrier() | |
197 | #define smp_mb__after_atomic_inc() barrier() | |
198 | ||
199 | #include <asm-generic/atomic.h> | |
200 | ||
201 | #endif /* __ASM_AVR32_ATOMIC_H */ |