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 #ifndef __ASSEMBLY__
  21
  22 #include <linux/compiler.h>
  23 #include <asm/system.h>
  24
  25 #define ATOMIC_INIT(i)  { (i) }
  26
  27 /**
  28  * atomic_read - read atomic variable
  29  * @v: pointer of type atomic_t
  30  *
  31  * Atomically reads the value of @v.
  32  */
  33 static inline int atomic_read(const atomic_t *v)
  34 {
  35        return v->counter;
  36 }
  37
  38 /**
  39  * atomic_sub_return - subtract integer and return
  40  * @v: pointer of type atomic_t
  41  * @i: integer value to subtract
  42  *
  43  * Atomically subtracts @i from @v and returns @v - @i
  44  */
  45 #define atomic_sub_return(i, v)         atomic_add_return((int)(-(i)), (v))
  46
  47 /**
  48  * atomic_sub - subtract integer from atomic variable
  49  * @i: integer value to subtract
  50  * @v: pointer of type atomic_t
  51  *
  52  * Atomically subtracts @i from @v.
  53  */
  54 #define atomic_sub(i, v)                atomic_add((int)(-(i)), (v))
  55
  56 /**
  57  * atomic_sub_and_test - subtract value from variable and test result
  58  * @i: integer value to subtract
  59  * @v: pointer of type atomic_t
  60  *
  61  * Atomically subtracts @i from @v and returns true if the result is
  62  * zero, or false for all other cases.
  63  */
  64 #define atomic_sub_and_test(i, v)       (atomic_sub_return((i), (v)) == 0)
  65
  66 /**
  67  * atomic_inc_return - increment memory and return
  68  * @v: pointer of type atomic_t
  69  *
  70  * Atomically increments @v by 1 and returns the new value.
  71  */
  72 #define atomic_inc_return(v)            atomic_add_return(1, (v))
  73
  74 /**
  75  * atomic_dec_return - decrement memory and return
  76  * @v: pointer of type atomic_t
  77  *
  78  * Atomically decrements @v by 1 and returns the new value.
  79  */
  80 #define atomic_dec_return(v)            atomic_sub_return(1, (v))
  81
  82 /**
  83  * atomic_inc - increment atomic variable
  84  * @v: pointer of type atomic_t
  85  *
  86  * Atomically increments @v by 1.
  87  */
  88 #define atomic_inc(v)                   atomic_add(1, (v))
  89
  90 /**
  91  * atomic_dec - decrement atomic variable
  92  * @v: pointer of type atomic_t
  93  *
  94  * Atomically decrements @v by 1.
  95  */
  96 #define atomic_dec(v)                   atomic_sub(1, (v))
  97
  98 /**
  99  * atomic_dec_and_test - decrement and test
 100  * @v: pointer of type atomic_t
 101  *
 102  * Atomically decrements @v by 1 and returns true if the result is 0.
 103  */
 104 #define atomic_dec_and_test(v)          (atomic_dec_return(v) == 0)
 105
 106 /**
 107  * atomic_inc_and_test - increment and test
 108  * @v: pointer of type atomic_t
 109  *
 110  * Atomically increments @v by 1 and returns true if the result is 0.
 111  */
 112 #define atomic_inc_and_test(v)          (atomic_inc_return(v) == 0)
 113
 114 /**
 115  * atomic_add_negative - add and test if negative
 116  * @v: pointer of type atomic_t
 117  * @i: integer value to add
 118  *
 119  * Atomically adds @i to @v and returns true if the result is
 120  * negative, or false when result is greater than or equal to zero.
 121  */
 122 #define atomic_add_negative(i, v)       (atomic_add_return((i), (v)) < 0)
 123
 124 /**
 125  * atomic_inc_not_zero - increment unless the number is zero
 126  * @v: pointer of type atomic_t
 127  *
 128  * Atomically increments @v by 1, so long as @v is non-zero.
 129  * Returns non-zero if @v was non-zero, and zero otherwise.
 130  */
 131 #define atomic_inc_not_zero(v)          atomic_add_unless((v), 1, 0)
 132
 133
 134 /*
 135  * We define xchg() and cmpxchg() in the included headers.
 136  * Note that we do not define __HAVE_ARCH_CMPXCHG, since that would imply
 137  * that cmpxchg() is an efficient operation, which is not particularly true.
 138  */
 139
 140 /* Nonexistent functions intended to cause link errors. */
 141 extern unsigned long __xchg_called_with_bad_pointer(void);
 142 extern unsigned long __cmpxchg_called_with_bad_pointer(void);
 143
 144 #define tas(ptr) (xchg((ptr), 1))
 145
 146 #endif /* __ASSEMBLY__ */
 147
 148 #ifndef __tilegx__
 149 #include <asm/atomic_32.h>
 150 #else
 151 #include <asm/atomic_64.h>
 152 #endif
 153
 154 /* Provide the appropriate atomic_long_t definitions. */
 155 #ifndef __ASSEMBLY__
 156 #include <asm-generic/atomic-long.h>
 157 #endif
 158
 159 #endif /* _ASM_TILE_ATOMIC_H */