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 READ_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 #define atomic_fetch_sub(i, v)          atomic_fetch_add(-(int)(i), (v))
  50
  51 /**
  52  * atomic_sub - subtract integer from atomic variable
  53  * @i: integer value to subtract
  54  * @v: pointer of type atomic_t
  55  *
  56  * Atomically subtracts @i from @v.
  57  */
  58 #define atomic_sub(i, v)                atomic_add((int)(-(i)), (v))
  59
  60 /**
  61  * atomic_sub_and_test - subtract value from variable and test result
  62  * @i: integer value to subtract
  63  * @v: pointer of type atomic_t
  64  *
  65  * Atomically subtracts @i from @v and returns true if the result is
  66  * zero, or false for all other cases.
  67  */
  68 #define atomic_sub_and_test(i, v)       (atomic_sub_return((i), (v)) == 0)
  69
  70 /**
  71  * atomic_inc_return - increment memory and return
  72  * @v: pointer of type atomic_t
  73  *
  74  * Atomically increments @v by 1 and returns the new value.
  75  */
  76 #define atomic_inc_return(v)            atomic_add_return(1, (v))
  77
  78 /**
  79  * atomic_dec_return - decrement memory and return
  80  * @v: pointer of type atomic_t
  81  *
  82  * Atomically decrements @v by 1 and returns the new value.
  83  */
  84 #define atomic_dec_return(v)            atomic_sub_return(1, (v))
  85
  86 /**
  87  * atomic_inc - increment atomic variable
  88  * @v: pointer of type atomic_t
  89  *
  90  * Atomically increments @v by 1.
  91  */
  92 #define atomic_inc(v)                   atomic_add(1, (v))
  93
  94 /**
  95  * atomic_dec - decrement atomic variable
  96  * @v: pointer of type atomic_t
  97  *
  98  * Atomically decrements @v by 1.
  99  */
 100 #define atomic_dec(v)                   atomic_sub(1, (v))
 101
 102 /**
 103  * atomic_dec_and_test - decrement and test
 104  * @v: pointer of type atomic_t
 105  *
 106  * Atomically decrements @v by 1 and returns true if the result is 0.
 107  */
 108 #define atomic_dec_and_test(v)          (atomic_dec_return(v) == 0)
 109
 110 /**
 111  * atomic_inc_and_test - increment and test
 112  * @v: pointer of type atomic_t
 113  *
 114  * Atomically increments @v by 1 and returns true if the result is 0.
 115  */
 116 #define atomic_inc_and_test(v)          (atomic_inc_return(v) == 0)
 117
 118 /**
 119  * atomic_xchg - atomically exchange contents of memory with a new value
 120  * @v: pointer of type atomic_t
 121  * @i: integer value to store in memory
 122  *
 123  * Atomically sets @v to @i and returns old @v
 124  */
 125 static inline int atomic_xchg(atomic_t *v, int n)
 126 {
 127         return xchg(&v->counter, n);
 128 }
 129
 130 /**
 131  * atomic_cmpxchg - atomically exchange contents of memory if it matches
 132  * @v: pointer of type atomic_t
 133  * @o: old value that memory should have
 134  * @n: new value to write to memory if it matches
 135  *
 136  * Atomically checks if @v holds @o and replaces it with @n if so.
 137  * Returns the old value at @v.
 138  */
 139 static inline int atomic_cmpxchg(atomic_t *v, int o, int n)
 140 {
 141         return cmpxchg(&v->counter, o, n);
 142 }
 143
 144 /**
 145  * atomic_add_negative - add and test if negative
 146  * @v: pointer of type atomic_t
 147  * @i: integer value to add
 148  *
 149  * Atomically adds @i to @v and returns true if the result is
 150  * negative, or false when result is greater than or equal to zero.
 151  */
 152 #define atomic_add_negative(i, v)       (atomic_add_return((i), (v)) < 0)
 153
 154 #endif /* __ASSEMBLY__ */
 155
 156 #ifndef __tilegx__
 157 #include <asm/atomic_32.h>
 158 #else
 159 #include <asm/atomic_64.h>
 160 #endif
 161
 162 #ifndef __ASSEMBLY__
 163
 164 /**
 165  * atomic64_xchg - atomically exchange contents of memory with a new value
 166  * @v: pointer of type atomic64_t
 167  * @i: integer value to store in memory
 168  *
 169  * Atomically sets @v to @i and returns old @v
 170  */
 171 static inline long long atomic64_xchg(atomic64_t *v, long long n)
 172 {
 173         return xchg64(&v->counter, n);
 174 }
 175
 176 /**
 177  * atomic64_cmpxchg - atomically exchange contents of memory if it matches
 178  * @v: pointer of type atomic64_t
 179  * @o: old value that memory should have
 180  * @n: new value to write to memory if it matches
 181  *
 182  * Atomically checks if @v holds @o and replaces it with @n if so.
 183  * Returns the old value at @v.
 184  */
 185 static inline long long atomic64_cmpxchg(atomic64_t *v, long long o,
 186                                         long long n)
 187 {
 188         return cmpxchg64(&v->counter, o, n);
 189 }
 190
 191 static inline long long atomic64_dec_if_positive(atomic64_t *v)
 192 {
 193         long long c, old, dec;
 194
 195         c = atomic64_read(v);
 196         for (;;) {
 197                 dec = c - 1;
 198                 if (unlikely(dec < 0))
 199                         break;
 200                 old = atomic64_cmpxchg((v), c, dec);
 201                 if (likely(old == c))
 202                         break;
 203                 c = old;
 204         }
 205         return dec;
 206 }
 207
 208 #endif /* __ASSEMBLY__ */
 209
 210 #endif /* _ASM_TILE_ATOMIC_H */