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-rw-r--r--include/asm-xtensa/atomic.h299
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diff --git a/include/asm-xtensa/atomic.h b/include/asm-xtensa/atomic.h
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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 *
10 * Copyright (C) 2001 - 2005 Tensilica Inc.
11 */
12
13#ifndef _XTENSA_ATOMIC_H
14#define _XTENSA_ATOMIC_H
15
16#include <linux/stringify.h>
17#include <linux/types.h>
18
19#ifdef __KERNEL__
20#include <asm/processor.h>
21#include <asm/system.h>
22
23#define ATOMIC_INIT(i) { (i) }
24
25/*
26 * This Xtensa implementation assumes that the right mechanism
27 * for exclusion is for locking interrupts to level 1.
28 *
29 * Locking interrupts looks like this:
30 *
31 * rsil a15, 1
32 * <code>
33 * wsr a15, PS
34 * rsync
35 *
36 * Note that a15 is used here because the register allocation
37 * done by the compiler is not guaranteed and a window overflow
38 * may not occur between the rsil and wsr instructions. By using
39 * a15 in the rsil, the machine is guaranteed to be in a state
40 * where no register reference will cause an overflow.
41 */
42
43/**
44 * atomic_read - read atomic variable
45 * @v: pointer of type atomic_t
46 *
47 * Atomically reads the value of @v.
48 */
49#define atomic_read(v) ((v)->counter)
50
51/**
52 * atomic_set - set atomic variable
53 * @v: pointer of type atomic_t
54 * @i: required value
55 *
56 * Atomically sets the value of @v to @i.
57 */
58#define atomic_set(v,i) ((v)->counter = (i))
59
60/**
61 * atomic_add - add integer to atomic variable
62 * @i: integer value to add
63 * @v: pointer of type atomic_t
64 *
65 * Atomically adds @i to @v.
66 */
67static inline void atomic_add(int i, atomic_t * v)
68{
69 unsigned int vval;
70
71 __asm__ __volatile__(
72 "rsil a15, "__stringify(LOCKLEVEL)"\n\t"
73 "l32i %0, %2, 0 \n\t"
74 "add %0, %0, %1 \n\t"
75 "s32i %0, %2, 0 \n\t"
76 "wsr a15, "__stringify(PS)" \n\t"
77 "rsync \n"
78 : "=&a" (vval)
79 : "a" (i), "a" (v)
80 : "a15", "memory"
81 );
82}
83
84/**
85 * atomic_sub - subtract the atomic variable
86 * @i: integer value to subtract
87 * @v: pointer of type atomic_t
88 *
89 * Atomically subtracts @i from @v.
90 */
91static inline void atomic_sub(int i, atomic_t *v)
92{
93 unsigned int vval;
94
95 __asm__ __volatile__(
96 "rsil a15, "__stringify(LOCKLEVEL)"\n\t"
97 "l32i %0, %2, 0 \n\t"
98 "sub %0, %0, %1 \n\t"
99 "s32i %0, %2, 0 \n\t"
100 "wsr a15, "__stringify(PS)" \n\t"
101 "rsync \n"
102 : "=&a" (vval)
103 : "a" (i), "a" (v)
104 : "a15", "memory"
105 );
106}
107
108/*
109 * We use atomic_{add|sub}_return to define other functions.
110 */
111
112static inline int atomic_add_return(int i, atomic_t * v)
113{
114 unsigned int vval;
115
116 __asm__ __volatile__(
117 "rsil a15,"__stringify(LOCKLEVEL)"\n\t"
118 "l32i %0, %2, 0 \n\t"
119 "add %0, %0, %1 \n\t"
120 "s32i %0, %2, 0 \n\t"
121 "wsr a15, "__stringify(PS)" \n\t"
122 "rsync \n"
123 : "=&a" (vval)
124 : "a" (i), "a" (v)
125 : "a15", "memory"
126 );
127
128 return vval;
129}
130
131static inline int atomic_sub_return(int i, atomic_t * v)
132{
133 unsigned int vval;
134
135 __asm__ __volatile__(
136 "rsil a15,"__stringify(LOCKLEVEL)"\n\t"
137 "l32i %0, %2, 0 \n\t"
138 "sub %0, %0, %1 \n\t"
139 "s32i %0, %2, 0 \n\t"
140 "wsr a15, "__stringify(PS)" \n\t"
141 "rsync \n"
142 : "=&a" (vval)
143 : "a" (i), "a" (v)
144 : "a15", "memory"
145 );
146
147 return vval;
148}
149
150/**
151 * atomic_sub_and_test - subtract value from variable and test result
152 * @i: integer value to subtract
153 * @v: pointer of type atomic_t
154 *
155 * Atomically subtracts @i from @v and returns
156 * true if the result is zero, or false for all
157 * other cases.
158 */
159#define atomic_sub_and_test(i,v) (atomic_sub_return((i),(v)) == 0)
160
161/**
162 * atomic_inc - increment atomic variable
163 * @v: pointer of type atomic_t
164 *
165 * Atomically increments @v by 1.
166 */
167#define atomic_inc(v) atomic_add(1,(v))
168
169/**
170 * atomic_inc - increment atomic variable
171 * @v: pointer of type atomic_t
172 *
173 * Atomically increments @v by 1.
174 */
175#define atomic_inc_return(v) atomic_add_return(1,(v))
176
177/**
178 * atomic_dec - decrement atomic variable
179 * @v: pointer of type atomic_t
180 *
181 * Atomically decrements @v by 1.
182 */
183#define atomic_dec(v) atomic_sub(1,(v))
184
185/**
186 * atomic_dec_return - decrement atomic variable
187 * @v: pointer of type atomic_t
188 *
189 * Atomically decrements @v by 1.
190 */
191#define atomic_dec_return(v) atomic_sub_return(1,(v))
192
193/**
194 * atomic_dec_and_test - decrement and test
195 * @v: pointer of type atomic_t
196 *
197 * Atomically decrements @v by 1 and
198 * returns true if the result is 0, or false for all other
199 * cases.
200 */
201#define atomic_dec_and_test(v) (atomic_sub_return(1,(v)) == 0)
202
203/**
204 * atomic_inc_and_test - increment and test
205 * @v: pointer of type atomic_t
206 *
207 * Atomically increments @v by 1
208 * and returns true if the result is zero, or false for all
209 * other cases.
210 */
211#define atomic_inc_and_test(v) (atomic_add_return(1,(v)) == 0)
212
213/**
214 * atomic_add_negative - add and test if negative
215 * @v: pointer of type atomic_t
216 * @i: integer value to add
217 *
218 * Atomically adds @i to @v and returns true
219 * if the result is negative, or false when
220 * result is greater than or equal to zero.
221 */
222#define atomic_add_negative(i,v) (atomic_add_return((i),(v)) < 0)
223
224#define atomic_cmpxchg(v, o, n) ((int)cmpxchg(&((v)->counter), (o), (n)))
225#define atomic_xchg(v, new) (xchg(&((v)->counter), new))
226
227/**
228 * atomic_add_unless - add unless the number is a given value
229 * @v: pointer of type atomic_t
230 * @a: the amount to add to v...
231 * @u: ...unless v is equal to u.
232 *
233 * Atomically adds @a to @v, so long as it was not @u.
234 * Returns non-zero if @v was not @u, and zero otherwise.
235 */
236static __inline__ int atomic_add_unless(atomic_t *v, int a, int u)
237{
238 int c, old;
239 c = atomic_read(v);
240 for (;;) {
241 if (unlikely(c == (u)))
242 break;
243 old = atomic_cmpxchg((v), c, c + (a));
244 if (likely(old == c))
245 break;
246 c = old;
247 }
248 return c != (u);
249}
250
251#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
252
253static inline void atomic_clear_mask(unsigned int mask, atomic_t *v)
254{
255 unsigned int all_f = -1;
256 unsigned int vval;
257
258 __asm__ __volatile__(
259 "rsil a15,"__stringify(LOCKLEVEL)"\n\t"
260 "l32i %0, %2, 0 \n\t"
261 "xor %1, %4, %3 \n\t"
262 "and %0, %0, %4 \n\t"
263 "s32i %0, %2, 0 \n\t"
264 "wsr a15, "__stringify(PS)" \n\t"
265 "rsync \n"
266 : "=&a" (vval), "=a" (mask)
267 : "a" (v), "a" (all_f), "1" (mask)
268 : "a15", "memory"
269 );
270}
271
272static inline void atomic_set_mask(unsigned int mask, atomic_t *v)
273{
274 unsigned int vval;
275
276 __asm__ __volatile__(
277 "rsil a15,"__stringify(LOCKLEVEL)"\n\t"
278 "l32i %0, %2, 0 \n\t"
279 "or %0, %0, %1 \n\t"
280 "s32i %0, %2, 0 \n\t"
281 "wsr a15, "__stringify(PS)" \n\t"
282 "rsync \n"
283 : "=&a" (vval)
284 : "a" (mask), "a" (v)
285 : "a15", "memory"
286 );
287}
288
289/* Atomic operations are already serializing */
290#define smp_mb__before_atomic_dec() barrier()
291#define smp_mb__after_atomic_dec() barrier()
292#define smp_mb__before_atomic_inc() barrier()
293#define smp_mb__after_atomic_inc() barrier()
294
295#include <asm-generic/atomic.h>
296#endif /* __KERNEL__ */
297
298#endif /* _XTENSA_ATOMIC_H */
299
generated by cgit v1.2.2 (git 2.25.0) at 2025-01-27 17:50:26 -0500