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 <linux/types.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 ACCESS_ONCE(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 /* Nonexistent functions intended to cause link errors. */
 125 extern unsigned long __xchg_called_with_bad_pointer(void);
 126 extern unsigned long __cmpxchg_called_with_bad_pointer(void);
 127
 128 #define xchg(ptr, x)                                                    \
 129         ({                                                              \
 130                 typeof(*(ptr)) __x;                                     \
 131                 switch (sizeof(*(ptr))) {                               \
 132                 case 4:                                                 \
 133                         __x = (typeof(__x))(typeof(__x-__x))atomic_xchg( \
 134                                 (atomic_t *)(ptr),                      \
 135                                 (u32)(typeof((x)-(x)))(x));             \
 136                         break;                                          \
 137                 case 8:                                                 \
 138                         __x = (typeof(__x))(typeof(__x-__x))atomic64_xchg( \
 139                                 (atomic64_t *)(ptr),                    \
 140                                 (u64)(typeof((x)-(x)))(x));             \
 141                         break;                                          \
 142                 default:                                                \
 143                         __xchg_called_with_bad_pointer();               \
 144                 }                                                       \
 145                 __x;                                                    \
 146         })
 147
 148 #define cmpxchg(ptr, o, n)                                              \
 149         ({                                                              \
 150                 typeof(*(ptr)) __x;                                     \
 151                 switch (sizeof(*(ptr))) {                               \
 152                 case 4:                                                 \
 153                         __x = (typeof(__x))(typeof(__x-__x))atomic_cmpxchg( \
 154                                 (atomic_t *)(ptr),                      \
 155                                 (u32)(typeof((o)-(o)))(o),              \
 156                                 (u32)(typeof((n)-(n)))(n));             \
 157                         break;                                          \
 158                 case 8:                                                 \
 159                         __x = (typeof(__x))(typeof(__x-__x))atomic64_cmpxchg( \
 160                                 (atomic64_t *)(ptr),                    \
 161                                 (u64)(typeof((o)-(o)))(o),              \
 162                                 (u64)(typeof((n)-(n)))(n));             \
 163                         break;                                          \
 164                 default:                                                \
 165                         __cmpxchg_called_with_bad_pointer();            \
 166                 }                                                       \
 167                 __x;                                                    \
 168         })
 169
 170 #define tas(ptr) (xchg((ptr), 1))
 171
 172 #endif /* __ASSEMBLY__ */
 173
 174 #ifndef __tilegx__
 175 #include <asm/atomic_32.h>
 176 #else
 177 #include <asm/atomic_64.h>
 178 #endif
 179
 180 #endif /* _ASM_TILE_ATOMIC_H */