1 /* Copyright (C) 2000 Philipp Rumpf <prumpf@tux.org>
2 * Copyright (C) 2006 Kyle McMartin <kyle@parisc-linux.org>
3 */
4
5 #ifndef _ASM_PARISC_ATOMIC_H_
6 #define _ASM_PARISC_ATOMIC_H_
7
8 #include <linux/types.h>
9 #include <asm/cmpxchg.h>
10 #include <asm/barrier.h>
11
12 /*
13 * Atomic operations that C can't guarantee us. Useful for
14 * resource counting etc..
15 *
16 * And probably incredibly slow on parisc. OTOH, we don't
17 * have to write any serious assembly. prumpf
18 */
19
20 #ifdef CONFIG_SMP
21 #include <asm/spinlock.h>
22 #include <asm/cache.h> /* we use L1_CACHE_BYTES */
23
24 /* Use an array of spinlocks for our atomic_ts.
25 * Hash function to index into a different SPINLOCK.
26 * Since "a" is usually an address, use one spinlock per cacheline.
27 */
28 # define ATOMIC_HASH_SIZE 4
29 # define ATOMIC_HASH(a) (&(__atomic_hash[ (((unsigned long) (a))/L1_CACHE_BYTES) & (ATOMIC_HASH_SIZE-1) ]))
30
31 extern arch_spinlock_t __atomic_hash[ATOMIC_HASH_SIZE] __lock_aligned;
32
33 /* Can't use raw_spin_lock_irq because of #include problems, so
34 * this is the substitute */
35 #define _atomic_spin_lock_irqsave(l,f) do { \
36 arch_spinlock_t *s = ATOMIC_HASH(l); \
37 local_irq_save(f); \
38 arch_spin_lock(s); \
39 } while(0)
40
41 #define _atomic_spin_unlock_irqrestore(l,f) do { \
42 arch_spinlock_t *s = ATOMIC_HASH(l); \
43 arch_spin_unlock(s); \
44 local_irq_restore(f); \
45 } while(0)
46
47
48 #else
49 # define _atomic_spin_lock_irqsave(l,f) do { local_irq_save(f); } while (0)
50 # define _atomic_spin_unlock_irqrestore(l,f) do { local_irq_restore(f); } while (0)
51 #endif
52
53 /*
54 * Note that we need not lock read accesses - aligned word writes/reads
55 * are atomic, so a reader never sees inconsistent values.
56 */
57
atomic_set(atomic_t * v,int i)58 static __inline__ void atomic_set(atomic_t *v, int i)
59 {
60 unsigned long flags;
61 _atomic_spin_lock_irqsave(v, flags);
62
63 v->counter = i;
64
65 _atomic_spin_unlock_irqrestore(v, flags);
66 }
67
atomic_read(const atomic_t * v)68 static __inline__ int atomic_read(const atomic_t *v)
69 {
70 return READ_ONCE((v)->counter);
71 }
72
73 /* exported interface */
74 #define atomic_cmpxchg(v, o, n) (cmpxchg(&((v)->counter), (o), (n)))
75 #define atomic_xchg(v, new) (xchg(&((v)->counter), new))
76
77 /**
78 * __atomic_add_unless - add unless the number is a given value
79 * @v: pointer of type atomic_t
80 * @a: the amount to add to v...
81 * @u: ...unless v is equal to u.
82 *
83 * Atomically adds @a to @v, so long as it was not @u.
84 * Returns the old value of @v.
85 */
__atomic_add_unless(atomic_t * v,int a,int u)86 static __inline__ int __atomic_add_unless(atomic_t *v, int a, int u)
87 {
88 int c, old;
89 c = atomic_read(v);
90 for (;;) {
91 if (unlikely(c == (u)))
92 break;
93 old = atomic_cmpxchg((v), c, c + (a));
94 if (likely(old == c))
95 break;
96 c = old;
97 }
98 return c;
99 }
100
101 #define ATOMIC_OP(op, c_op) \
102 static __inline__ void atomic_##op(int i, atomic_t *v) \
103 { \
104 unsigned long flags; \
105 \
106 _atomic_spin_lock_irqsave(v, flags); \
107 v->counter c_op i; \
108 _atomic_spin_unlock_irqrestore(v, flags); \
109 } \
110
111 #define ATOMIC_OP_RETURN(op, c_op) \
112 static __inline__ int atomic_##op##_return(int i, atomic_t *v) \
113 { \
114 unsigned long flags; \
115 int ret; \
116 \
117 _atomic_spin_lock_irqsave(v, flags); \
118 ret = (v->counter c_op i); \
119 _atomic_spin_unlock_irqrestore(v, flags); \
120 \
121 return ret; \
122 }
123
124 #define ATOMIC_OPS(op, c_op) ATOMIC_OP(op, c_op) ATOMIC_OP_RETURN(op, c_op)
125
126 ATOMIC_OPS(add, +=)
127 ATOMIC_OPS(sub, -=)
128
129 ATOMIC_OP(and, &=)
130 ATOMIC_OP(or, |=)
131 ATOMIC_OP(xor, ^=)
132
133 #undef ATOMIC_OPS
134 #undef ATOMIC_OP_RETURN
135 #undef ATOMIC_OP
136
137 #define atomic_inc(v) (atomic_add( 1,(v)))
138 #define atomic_dec(v) (atomic_add( -1,(v)))
139
140 #define atomic_inc_return(v) (atomic_add_return( 1,(v)))
141 #define atomic_dec_return(v) (atomic_add_return( -1,(v)))
142
143 #define atomic_add_negative(a, v) (atomic_add_return((a), (v)) < 0)
144
145 /*
146 * atomic_inc_and_test - increment and test
147 * @v: pointer of type atomic_t
148 *
149 * Atomically increments @v by 1
150 * and returns true if the result is zero, or false for all
151 * other cases.
152 */
153 #define atomic_inc_and_test(v) (atomic_inc_return(v) == 0)
154
155 #define atomic_dec_and_test(v) (atomic_dec_return(v) == 0)
156
157 #define atomic_sub_and_test(i,v) (atomic_sub_return((i),(v)) == 0)
158
159 #define ATOMIC_INIT(i) { (i) }
160
161 #ifdef CONFIG_64BIT
162
163 #define ATOMIC64_INIT(i) { (i) }
164
165 #define ATOMIC64_OP(op, c_op) \
166 static __inline__ void atomic64_##op(s64 i, atomic64_t *v) \
167 { \
168 unsigned long flags; \
169 \
170 _atomic_spin_lock_irqsave(v, flags); \
171 v->counter c_op i; \
172 _atomic_spin_unlock_irqrestore(v, flags); \
173 } \
174
175 #define ATOMIC64_OP_RETURN(op, c_op) \
176 static __inline__ s64 atomic64_##op##_return(s64 i, atomic64_t *v) \
177 { \
178 unsigned long flags; \
179 s64 ret; \
180 \
181 _atomic_spin_lock_irqsave(v, flags); \
182 ret = (v->counter c_op i); \
183 _atomic_spin_unlock_irqrestore(v, flags); \
184 \
185 return ret; \
186 }
187
188 #define ATOMIC64_OPS(op, c_op) ATOMIC64_OP(op, c_op) ATOMIC64_OP_RETURN(op, c_op)
189
190 ATOMIC64_OPS(add, +=)
191 ATOMIC64_OPS(sub, -=)
192 ATOMIC64_OP(and, &=)
193 ATOMIC64_OP(or, |=)
194 ATOMIC64_OP(xor, ^=)
195
196 #undef ATOMIC64_OPS
197 #undef ATOMIC64_OP_RETURN
198 #undef ATOMIC64_OP
199
200 static __inline__ void
atomic64_set(atomic64_t * v,s64 i)201 atomic64_set(atomic64_t *v, s64 i)
202 {
203 unsigned long flags;
204 _atomic_spin_lock_irqsave(v, flags);
205
206 v->counter = i;
207
208 _atomic_spin_unlock_irqrestore(v, flags);
209 }
210
211 static __inline__ s64
atomic64_read(const atomic64_t * v)212 atomic64_read(const atomic64_t *v)
213 {
214 return ACCESS_ONCE((v)->counter);
215 }
216
217 #define atomic64_inc(v) (atomic64_add( 1,(v)))
218 #define atomic64_dec(v) (atomic64_add( -1,(v)))
219
220 #define atomic64_inc_return(v) (atomic64_add_return( 1,(v)))
221 #define atomic64_dec_return(v) (atomic64_add_return( -1,(v)))
222
223 #define atomic64_add_negative(a, v) (atomic64_add_return((a), (v)) < 0)
224
225 #define atomic64_inc_and_test(v) (atomic64_inc_return(v) == 0)
226 #define atomic64_dec_and_test(v) (atomic64_dec_return(v) == 0)
227 #define atomic64_sub_and_test(i,v) (atomic64_sub_return((i),(v)) == 0)
228
229 /* exported interface */
230 #define atomic64_cmpxchg(v, o, n) \
231 ((__typeof__((v)->counter))cmpxchg(&((v)->counter), (o), (n)))
232 #define atomic64_xchg(v, new) (xchg(&((v)->counter), new))
233
234 /**
235 * atomic64_add_unless - add unless the number is a given value
236 * @v: pointer of type atomic64_t
237 * @a: the amount to add to v...
238 * @u: ...unless v is equal to u.
239 *
240 * Atomically adds @a to @v, so long as it was not @u.
241 * Returns the old value of @v.
242 */
atomic64_add_unless(atomic64_t * v,long a,long u)243 static __inline__ int atomic64_add_unless(atomic64_t *v, long a, long u)
244 {
245 long c, old;
246 c = atomic64_read(v);
247 for (;;) {
248 if (unlikely(c == (u)))
249 break;
250 old = atomic64_cmpxchg((v), c, c + (a));
251 if (likely(old == c))
252 break;
253 c = old;
254 }
255 return c != (u);
256 }
257
258 #define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0)
259
260 /*
261 * atomic64_dec_if_positive - decrement by 1 if old value positive
262 * @v: pointer of type atomic_t
263 *
264 * The function returns the old value of *v minus 1, even if
265 * the atomic variable, v, was not decremented.
266 */
atomic64_dec_if_positive(atomic64_t * v)267 static inline long atomic64_dec_if_positive(atomic64_t *v)
268 {
269 long c, old, dec;
270 c = atomic64_read(v);
271 for (;;) {
272 dec = c - 1;
273 if (unlikely(dec < 0))
274 break;
275 old = atomic64_cmpxchg((v), c, dec);
276 if (likely(old == c))
277 break;
278 c = old;
279 }
280 return dec;
281 }
282
283 #endif /* !CONFIG_64BIT */
284
285
286 #endif /* _ASM_PARISC_ATOMIC_H_ */
287