arch/tile/include/asm/atomic.h

   1 /*
   2  * Copyright 2010 Tilera Corporation. All Rights Reserved.
   3  *
   4  *   This program is free software; you can redistribute it and/or
   5  *   modify it under the terms of the GNU General Public License
   6  *   as published by the Free Software Foundation, version 2.
   7  *
   8  *   This program is distributed in the hope that it will be useful, but
   9  *   WITHOUT ANY WARRANTY; without even the implied warranty of
  10  *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
  11  *   NON INFRINGEMENT.  See the GNU General Public License for
  12  *   more details.
  13  *
  14  * Atomic primitives.
  15  */
  16
  17 #ifndef _ASM_TILE_ATOMIC_H
  18 #define _ASM_TILE_ATOMIC_H
  19
  20 #include <asm/cmpxchg.h>
  21
  22 #ifndef __ASSEMBLY__
  23
  24 #include <linux/compiler.h>
  25 #include <linux/types.h>
  26
  27 #define ATOMIC_INIT(i)  { (i) }
  28
  29 /**
  30  * atomic_read - read atomic variable
  31  * @v: pointer of type atomic_t
  32  *
  33  * Atomically reads the value of @v.
  34  */
  35 static inline int atomic_read(const atomic_t *v)
  36 {
  37         return ACCESS_ONCE(v->counter);
  38 }
  39
  40 /**
  41  * atomic_sub_return - subtract integer and return
  42  * @v: pointer of type atomic_t
  43  * @i: integer value to subtract
  44  *
  45  * Atomically subtracts @i from @v and returns @v - @i
  46  */
  47 #define atomic_sub_return(i, v)         atomic_add_return((int)(-(i)), (v))
  48
  49 /**
  50  * atomic_sub - subtract integer from atomic variable
  51  * @i: integer value to subtract
  52  * @v: pointer of type atomic_t
  53  *
  54  * Atomically subtracts @i from @v.
  55  */
  56 #define atomic_sub(i, v)                atomic_add((int)(-(i)), (v))
  57
  58 /**
  59  * atomic_sub_and_test - subtract value from variable and test result
  60  * @i: integer value to subtract
  61  * @v: pointer of type atomic_t
  62  *
  63  * Atomically subtracts @i from @v and returns true if the result is
  64  * zero, or false for all other cases.
  65  */
  66 #define atomic_sub_and_test(i, v)       (atomic_sub_return((i), (v)) == 0)
  67
  68 /**
  69  * atomic_inc_return - increment memory and return
  70  * @v: pointer of type atomic_t
  71  *
  72  * Atomically increments @v by 1 and returns the new value.
  73  */
  74 #define atomic_inc_return(v)            atomic_add_return(1, (v))
  75
  76 /**
  77  * atomic_dec_return - decrement memory and return
  78  * @v: pointer of type atomic_t
  79  *
  80  * Atomically decrements @v by 1 and returns the new value.
  81  */
  82 #define atomic_dec_return(v)            atomic_sub_return(1, (v))
  83
  84 /**
  85  * atomic_inc - increment atomic variable
  86  * @v: pointer of type atomic_t
  87  *
  88  * Atomically increments @v by 1.
  89  */
  90 #define atomic_inc(v)                   atomic_add(1, (v))
  91
  92 /**
  93  * atomic_dec - decrement atomic variable
  94  * @v: pointer of type atomic_t
  95  *
  96  * Atomically decrements @v by 1.
  97  */
  98 #define atomic_dec(v)                   atomic_sub(1, (v))
  99
 100 /**
 101  * atomic_dec_and_test - decrement and test
 102  * @v: pointer of type atomic_t
 103  *
 104  * Atomically decrements @v by 1 and returns true if the result is 0.
 105  */
 106 #define atomic_dec_and_test(v)          (atomic_dec_return(v) == 0)
 107
 108 /**
 109  * atomic_inc_and_test - increment and test
 110  * @v: pointer of type atomic_t
 111  *
 112  * Atomically increments @v by 1 and returns true if the result is 0.
 113  */
 114 #define atomic_inc_and_test(v)          (atomic_inc_return(v) == 0)
 115
 116 /**
 117  * atomic_xchg - atomically exchange contents of memory with a new value
 118  * @v: pointer of type atomic_t
 119  * @i: integer value to store in memory
 120  *
 121  * Atomically sets @v to @i and returns old @v
 122  */
 123 static inline int atomic_xchg(atomic_t *v, int n)
 124 {
 125         return xchg(&v->counter, n);
 126 }
 127
 128 /**
 129  * atomic_cmpxchg - atomically exchange contents of memory if it matches
 130  * @v: pointer of type atomic_t
 131  * @o: old value that memory should have
 132  * @n: new value to write to memory if it matches
 133  *
 134  * Atomically checks if @v holds @o and replaces it with @n if so.
 135  * Returns the old value at @v.
 136  */
 137 static inline int atomic_cmpxchg(atomic_t *v, int o, int n)
 138 {
 139         return cmpxchg(&v->counter, o, n);
 140 }
 141
 142 /**
 143  * atomic_add_negative - add and test if negative
 144  * @v: pointer of type atomic_t
 145  * @i: integer value to add
 146  *
 147  * Atomically adds @i to @v and returns true if the result is
 148  * negative, or false when result is greater than or equal to zero.
 149  */
 150 #define atomic_add_negative(i, v)       (atomic_add_return((i), (v)) < 0)
 151
 152 #endif /* __ASSEMBLY__ */
 153
 154 #ifndef __tilegx__
 155 #include <asm/atomic_32.h>
 156 #else
 157 #include <asm/atomic_64.h>
 158 #endif
 159
 160 #ifndef __ASSEMBLY__
 161
 162 /**
 163  * atomic64_xchg - atomically exchange contents of memory with a new value
 164  * @v: pointer of type atomic64_t
 165  * @i: integer value to store in memory
 166  *
 167  * Atomically sets @v to @i and returns old @v
 168  */
 169 static inline long long atomic64_xchg(atomic64_t *v, long long n)
 170 {
 171         return xchg64(&v->counter, n);
 172 }
 173
 174 /**
 175  * atomic64_cmpxchg - atomically exchange contents of memory if it matches
 176  * @v: pointer of type atomic64_t
 177  * @o: old value that memory should have
 178  * @n: new value to write to memory if it matches
 179  *
 180  * Atomically checks if @v holds @o and replaces it with @n if so.
 181  * Returns the old value at @v.
 182  */
 183 static inline long long atomic64_cmpxchg(atomic64_t *v, long long o,
 184                                         long long n)
 185 {
 186         return cmpxchg64(&v->counter, o, n);
 187 }
 188
 189 static inline long long atomic64_dec_if_positive(atomic64_t *v)
 190 {
 191         long long c, old, dec;
 192
 193         c = atomic64_read(v);
 194         for (;;) {
 195                 dec = c - 1;
 196                 if (unlikely(dec < 0))
 197                         break;
 198                 old = atomic64_cmpxchg((v), c, dec);
 199                 if (likely(old == c))
 200                         break;
 201                 c = old;
 202         }
 203         return dec;
 204 }
 205
 206 #endif /* __ASSEMBLY__ */
 207
 208 #endif /* _ASM_TILE_ATOMIC_H */