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9a8fd558 CZ |
1 | /* |
2 | * include/asm-xtensa/atomic.h | |
3 | * | |
4 | * Atomic operations that C can't guarantee us. Useful for resource counting.. | |
5 | * | |
6 | * This file is subject to the terms and conditions of the GNU General Public | |
7 | * License. See the file "COPYING" in the main directory of this archive | |
8 | * for more details. | |
9 | * | |
2d1c645c | 10 | * Copyright (C) 2001 - 2008 Tensilica Inc. |
9a8fd558 CZ |
11 | */ |
12 | ||
13 | #ifndef _XTENSA_ATOMIC_H | |
14 | #define _XTENSA_ATOMIC_H | |
15 | ||
9a8fd558 | 16 | #include <linux/stringify.h> |
ea435467 | 17 | #include <linux/types.h> |
9a8fd558 CZ |
18 | |
19 | #ifdef __KERNEL__ | |
20 | #include <asm/processor.h> | |
f9aa7e18 | 21 | #include <asm/cmpxchg.h> |
09a01c0c | 22 | #include <asm/barrier.h> |
9a8fd558 | 23 | |
288a60cf | 24 | #define ATOMIC_INIT(i) { (i) } |
9a8fd558 CZ |
25 | |
26 | /* | |
27 | * This Xtensa implementation assumes that the right mechanism | |
2d1c645c | 28 | * for exclusion is for locking interrupts to level EXCM_LEVEL. |
9a8fd558 CZ |
29 | * |
30 | * Locking interrupts looks like this: | |
31 | * | |
38fef73c | 32 | * rsil a15, TOPLEVEL |
9a8fd558 CZ |
33 | * <code> |
34 | * wsr a15, PS | |
35 | * rsync | |
36 | * | |
37 | * Note that a15 is used here because the register allocation | |
38 | * done by the compiler is not guaranteed and a window overflow | |
39 | * may not occur between the rsil and wsr instructions. By using | |
40 | * a15 in the rsil, the machine is guaranteed to be in a state | |
41 | * where no register reference will cause an overflow. | |
42 | */ | |
43 | ||
44 | /** | |
45 | * atomic_read - read atomic variable | |
46 | * @v: pointer of type atomic_t | |
47 | * | |
48 | * Atomically reads the value of @v. | |
49 | */ | |
2291059c | 50 | #define atomic_read(v) ACCESS_ONCE((v)->counter) |
9a8fd558 CZ |
51 | |
52 | /** | |
53 | * atomic_set - set atomic variable | |
54 | * @v: pointer of type atomic_t | |
55 | * @i: required value | |
56 | * | |
57 | * Atomically sets the value of @v to @i. | |
58 | */ | |
59 | #define atomic_set(v,i) ((v)->counter = (i)) | |
60 | ||
219b1e4c | 61 | #if XCHAL_HAVE_S32C1I |
d4608dd5 PZ |
62 | #define ATOMIC_OP(op) \ |
63 | static inline void atomic_##op(int i, atomic_t * v) \ | |
64 | { \ | |
65 | unsigned long tmp; \ | |
66 | int result; \ | |
67 | \ | |
68 | __asm__ __volatile__( \ | |
69 | "1: l32i %1, %3, 0\n" \ | |
70 | " wsr %1, scompare1\n" \ | |
71 | " " #op " %0, %1, %2\n" \ | |
72 | " s32c1i %0, %3, 0\n" \ | |
73 | " bne %0, %1, 1b\n" \ | |
74 | : "=&a" (result), "=&a" (tmp) \ | |
75 | : "a" (i), "a" (v) \ | |
76 | : "memory" \ | |
77 | ); \ | |
78 | } \ | |
79 | ||
80 | #define ATOMIC_OP_RETURN(op) \ | |
81 | static inline int atomic_##op##_return(int i, atomic_t * v) \ | |
82 | { \ | |
83 | unsigned long tmp; \ | |
84 | int result; \ | |
85 | \ | |
86 | __asm__ __volatile__( \ | |
87 | "1: l32i %1, %3, 0\n" \ | |
88 | " wsr %1, scompare1\n" \ | |
89 | " " #op " %0, %1, %2\n" \ | |
90 | " s32c1i %0, %3, 0\n" \ | |
91 | " bne %0, %1, 1b\n" \ | |
92 | " " #op " %0, %0, %2\n" \ | |
93 | : "=&a" (result), "=&a" (tmp) \ | |
94 | : "a" (i), "a" (v) \ | |
95 | : "memory" \ | |
96 | ); \ | |
97 | \ | |
98 | return result; \ | |
9a8fd558 CZ |
99 | } |
100 | ||
d4608dd5 PZ |
101 | #else /* XCHAL_HAVE_S32C1I */ |
102 | ||
103 | #define ATOMIC_OP(op) \ | |
104 | static inline void atomic_##op(int i, atomic_t * v) \ | |
105 | { \ | |
106 | unsigned int vval; \ | |
107 | \ | |
108 | __asm__ __volatile__( \ | |
38fef73c | 109 | " rsil a15, "__stringify(TOPLEVEL)"\n"\ |
d4608dd5 PZ |
110 | " l32i %0, %2, 0\n" \ |
111 | " " #op " %0, %0, %1\n" \ | |
112 | " s32i %0, %2, 0\n" \ | |
113 | " wsr a15, ps\n" \ | |
114 | " rsync\n" \ | |
115 | : "=&a" (vval) \ | |
116 | : "a" (i), "a" (v) \ | |
117 | : "a15", "memory" \ | |
118 | ); \ | |
119 | } \ | |
120 | ||
121 | #define ATOMIC_OP_RETURN(op) \ | |
122 | static inline int atomic_##op##_return(int i, atomic_t * v) \ | |
123 | { \ | |
124 | unsigned int vval; \ | |
125 | \ | |
126 | __asm__ __volatile__( \ | |
38fef73c | 127 | " rsil a15,"__stringify(TOPLEVEL)"\n" \ |
d4608dd5 PZ |
128 | " l32i %0, %2, 0\n" \ |
129 | " " #op " %0, %0, %1\n" \ | |
130 | " s32i %0, %2, 0\n" \ | |
131 | " wsr a15, ps\n" \ | |
132 | " rsync\n" \ | |
133 | : "=&a" (vval) \ | |
134 | : "a" (i), "a" (v) \ | |
135 | : "a15", "memory" \ | |
136 | ); \ | |
137 | \ | |
138 | return vval; \ | |
9a8fd558 CZ |
139 | } |
140 | ||
d4608dd5 | 141 | #endif /* XCHAL_HAVE_S32C1I */ |
219b1e4c | 142 | |
d4608dd5 | 143 | #define ATOMIC_OPS(op) ATOMIC_OP(op) ATOMIC_OP_RETURN(op) |
219b1e4c | 144 | |
d4608dd5 PZ |
145 | ATOMIC_OPS(add) |
146 | ATOMIC_OPS(sub) | |
9a8fd558 | 147 | |
2a3ed90f PZ |
148 | ATOMIC_OP(and) |
149 | ATOMIC_OP(or) | |
150 | ATOMIC_OP(xor) | |
151 | ||
d4608dd5 PZ |
152 | #undef ATOMIC_OPS |
153 | #undef ATOMIC_OP_RETURN | |
154 | #undef ATOMIC_OP | |
9a8fd558 CZ |
155 | |
156 | /** | |
157 | * atomic_sub_and_test - subtract value from variable and test result | |
158 | * @i: integer value to subtract | |
159 | * @v: pointer of type atomic_t | |
160 | * | |
161 | * Atomically subtracts @i from @v and returns | |
162 | * true if the result is zero, or false for all | |
163 | * other cases. | |
164 | */ | |
165 | #define atomic_sub_and_test(i,v) (atomic_sub_return((i),(v)) == 0) | |
166 | ||
167 | /** | |
168 | * atomic_inc - increment atomic variable | |
169 | * @v: pointer of type atomic_t | |
170 | * | |
171 | * Atomically increments @v by 1. | |
172 | */ | |
173 | #define atomic_inc(v) atomic_add(1,(v)) | |
174 | ||
175 | /** | |
176 | * atomic_inc - increment atomic variable | |
177 | * @v: pointer of type atomic_t | |
178 | * | |
179 | * Atomically increments @v by 1. | |
180 | */ | |
181 | #define atomic_inc_return(v) atomic_add_return(1,(v)) | |
182 | ||
183 | /** | |
184 | * atomic_dec - decrement atomic variable | |
185 | * @v: pointer of type atomic_t | |
186 | * | |
187 | * Atomically decrements @v by 1. | |
188 | */ | |
189 | #define atomic_dec(v) atomic_sub(1,(v)) | |
190 | ||
191 | /** | |
192 | * atomic_dec_return - decrement atomic variable | |
193 | * @v: pointer of type atomic_t | |
194 | * | |
195 | * Atomically decrements @v by 1. | |
196 | */ | |
197 | #define atomic_dec_return(v) atomic_sub_return(1,(v)) | |
198 | ||
199 | /** | |
200 | * atomic_dec_and_test - decrement and test | |
201 | * @v: pointer of type atomic_t | |
202 | * | |
203 | * Atomically decrements @v by 1 and | |
204 | * returns true if the result is 0, or false for all other | |
205 | * cases. | |
206 | */ | |
207 | #define atomic_dec_and_test(v) (atomic_sub_return(1,(v)) == 0) | |
208 | ||
209 | /** | |
210 | * atomic_inc_and_test - increment and test | |
211 | * @v: pointer of type atomic_t | |
212 | * | |
213 | * Atomically increments @v by 1 | |
214 | * and returns true if the result is zero, or false for all | |
215 | * other cases. | |
216 | */ | |
217 | #define atomic_inc_and_test(v) (atomic_add_return(1,(v)) == 0) | |
218 | ||
219 | /** | |
220 | * atomic_add_negative - add and test if negative | |
221 | * @v: pointer of type atomic_t | |
222 | * @i: integer value to add | |
223 | * | |
224 | * Atomically adds @i to @v and returns true | |
225 | * if the result is negative, or false when | |
226 | * result is greater than or equal to zero. | |
227 | */ | |
228 | #define atomic_add_negative(i,v) (atomic_add_return((i),(v)) < 0) | |
229 | ||
4a6dae6d | 230 | #define atomic_cmpxchg(v, o, n) ((int)cmpxchg(&((v)->counter), (o), (n))) |
ffbf670f | 231 | #define atomic_xchg(v, new) (xchg(&((v)->counter), new)) |
9a8fd558 | 232 | |
8426e1f6 | 233 | /** |
f24219b4 | 234 | * __atomic_add_unless - add unless the number is a given value |
8426e1f6 NP |
235 | * @v: pointer of type atomic_t |
236 | * @a: the amount to add to v... | |
237 | * @u: ...unless v is equal to u. | |
238 | * | |
239 | * Atomically adds @a to @v, so long as it was not @u. | |
f24219b4 | 240 | * Returns the old value of @v. |
8426e1f6 | 241 | */ |
f24219b4 | 242 | static __inline__ int __atomic_add_unless(atomic_t *v, int a, int u) |
2856f5e3 MD |
243 | { |
244 | int c, old; | |
245 | c = atomic_read(v); | |
246 | for (;;) { | |
247 | if (unlikely(c == (u))) | |
248 | break; | |
249 | old = atomic_cmpxchg((v), c, c + (a)); | |
250 | if (likely(old == c)) | |
251 | break; | |
252 | c = old; | |
253 | } | |
f24219b4 | 254 | return c; |
2856f5e3 MD |
255 | } |
256 | ||
9a8fd558 CZ |
257 | #endif /* __KERNEL__ */ |
258 | ||
259 | #endif /* _XTENSA_ATOMIC_H */ |