arch/frv/include/asm/atomic.h

   1 /* atomic.h: atomic operation emulation for FR-V
   2  *
   3  * For an explanation of how atomic ops work in this arch, see:
   4  *   Documentation/frv/atomic-ops.txt
   5  *
   6  * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
   7  * Written by David Howells (dhowells@redhat.com)
   8  *
   9  * This program is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU General Public License
  11  * as published by the Free Software Foundation; either version
  12  * 2 of the License, or (at your option) any later version.
  13  */
  14 #ifndef _ASM_ATOMIC_H
  15 #define _ASM_ATOMIC_H
  16
  17 #include <linux/types.h>
  18 #include <asm/cmpxchg.h>
  19 #include <asm/barrier.h>
  20
  21 #ifdef CONFIG_SMP
  22 #error not SMP safe
  23 #endif
  24
  25 #include <asm/atomic_defs.h>
  26
  27 /*
  28  * Atomic operations that C can't guarantee us.  Useful for
  29  * resource counting etc..
  30  *
  31  * We do not have SMP systems, so we don't have to deal with that.
  32  */
  33
  34 #define ATOMIC_INIT(i)          { (i) }
  35 #define atomic_read(v)          READ_ONCE((v)->counter)
  36 #define atomic_set(v, i)        WRITE_ONCE(((v)->counter), (i))
  37
  38 static inline int atomic_inc_return(atomic_t *v)
  39 {
  40         return __atomic_add_return(1, &v->counter);
  41 }
  42
  43 static inline int atomic_dec_return(atomic_t *v)
  44 {
  45         return __atomic_sub_return(1, &v->counter);
  46 }
  47
  48 static inline int atomic_add_return(int i, atomic_t *v)
  49 {
  50         return __atomic_add_return(i, &v->counter);
  51 }
  52
  53 static inline int atomic_sub_return(int i, atomic_t *v)
  54 {
  55         return __atomic_sub_return(i, &v->counter);
  56 }
  57
  58 static inline int atomic_add_negative(int i, atomic_t *v)
  59 {
  60         return atomic_add_return(i, v) < 0;
  61 }
  62
  63 static inline void atomic_inc(atomic_t *v)
  64 {
  65         atomic_inc_return(v);
  66 }
  67
  68 static inline void atomic_dec(atomic_t *v)
  69 {
  70         atomic_dec_return(v);
  71 }
  72
  73 #define atomic_sub_and_test(i,v)        (atomic_sub_return((i), (v)) == 0)
  74 #define atomic_dec_and_test(v)          (atomic_sub_return(1, (v)) == 0)
  75 #define atomic_inc_and_test(v)          (atomic_add_return(1, (v)) == 0)
  76
  77 /*
  78  * 64-bit atomic ops
  79  */
  80 typedef struct {
  81         long long counter;
  82 } atomic64_t;
  83
  84 #define ATOMIC64_INIT(i)        { (i) }
  85
  86 static inline long long atomic64_read(const atomic64_t *v)
  87 {
  88         long long counter;
  89
  90         asm("ldd%I1 %M1,%0"
  91             : "=e"(counter)
  92             : "m"(v->counter));
  93
  94         return counter;
  95 }
  96
  97 static inline void atomic64_set(atomic64_t *v, long long i)
  98 {
  99         asm volatile("std%I0 %1,%M0"
 100                      : "=m"(v->counter)
 101                      : "e"(i));
 102 }
 103
 104 static inline long long atomic64_inc_return(atomic64_t *v)
 105 {
 106         return __atomic64_add_return(1, &v->counter);
 107 }
 108
 109 static inline long long atomic64_dec_return(atomic64_t *v)
 110 {
 111         return __atomic64_sub_return(1, &v->counter);
 112 }
 113
 114 static inline long long atomic64_add_return(long long i, atomic64_t *v)
 115 {
 116         return __atomic64_add_return(i, &v->counter);
 117 }
 118
 119 static inline long long atomic64_sub_return(long long i, atomic64_t *v)
 120 {
 121         return __atomic64_sub_return(i, &v->counter);
 122 }
 123
 124 static inline long long atomic64_add_negative(long long i, atomic64_t *v)
 125 {
 126         return atomic64_add_return(i, v) < 0;
 127 }
 128
 129 static inline void atomic64_inc(atomic64_t *v)
 130 {
 131         atomic64_inc_return(v);
 132 }
 133
 134 static inline void atomic64_dec(atomic64_t *v)
 135 {
 136         atomic64_dec_return(v);
 137 }
 138
 139 #define atomic64_sub_and_test(i,v)      (atomic64_sub_return((i), (v)) == 0)
 140 #define atomic64_dec_and_test(v)        (atomic64_dec_return((v)) == 0)
 141 #define atomic64_inc_and_test(v)        (atomic64_inc_return((v)) == 0)
 142 #define atomic64_inc_not_zero(v)        atomic64_add_unless((v), 1, 0)
 143
 144 #define atomic_cmpxchg(v, old, new)     (cmpxchg(&(v)->counter, old, new))
 145 #define atomic_xchg(v, new)             (xchg(&(v)->counter, new))
 146 #define atomic64_cmpxchg(v, old, new)   (__cmpxchg_64(old, new, &(v)->counter))
 147 #define atomic64_xchg(v, new)           (__xchg_64(new, &(v)->counter))
 148
 149 static __inline__ int __atomic_add_unless(atomic_t *v, int a, int u)
 150 {
 151         int c, old;
 152         c = atomic_read(v);
 153         for (;;) {
 154                 if (unlikely(c == (u)))
 155                         break;
 156                 old = atomic_cmpxchg((v), c, c + (a));
 157                 if (likely(old == c))
 158                         break;
 159                 c = old;
 160         }
 161         return c;
 162 }
 163
 164 static inline int atomic64_add_unless(atomic64_t *v, long long i, long long u)
 165 {
 166         long long c, old;
 167
 168         c = atomic64_read(v);
 169         for (;;) {
 170                 if (unlikely(c == u))
 171                         break;
 172                 old = atomic64_cmpxchg(v, c, c + i);
 173                 if (likely(old == c))
 174                         break;
 175                 c = old;
 176         }
 177         return c != u;
 178 }
 179
 180 static inline long long atomic64_dec_if_positive(atomic64_t *v)
 181 {
 182         long long c, old, dec;
 183
 184         c = atomic64_read(v);
 185         for (;;) {
 186                 dec = c - 1;
 187                 if (unlikely(dec < 0))
 188                         break;
 189                 old = atomic64_cmpxchg((v), c, dec);
 190                 if (likely(old == c))
 191                         break;
 192                 c = old;
 193         }
 194                 return dec;
 195 }
 196
 197 #define ATOMIC_OP(op)                                                   \
 198 static inline int atomic_fetch_##op(int i, atomic_t *v)                 \
 199 {                                                                       \
 200         return __atomic32_fetch_##op(i, &v->counter);                   \
 201 }                                                                       \
 202 static inline void atomic_##op(int i, atomic_t *v)                      \
 203 {                                                                       \
 204         (void)__atomic32_fetch_##op(i, &v->counter);                    \
 205 }                                                                       \
 206                                                                         \
 207 static inline long long atomic64_fetch_##op(long long i, atomic64_t *v) \
 208 {                                                                       \
 209         return __atomic64_fetch_##op(i, &v->counter);                   \
 210 }                                                                       \
 211 static inline void atomic64_##op(long long i, atomic64_t *v)            \
 212 {                                                                       \
 213         (void)__atomic64_fetch_##op(i, &v->counter);                    \
 214 }
 215
 216 ATOMIC_OP(or)
 217 ATOMIC_OP(and)
 218 ATOMIC_OP(xor)
 219 ATOMIC_OP(add)
 220 ATOMIC_OP(sub)
 221
 222 #undef ATOMIC_OP
 223
 224 #endif /* _ASM_ATOMIC_H */