LXR linux/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 */
  33static 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. */
 141extern unsigned long __xchg_called_with_bad_pointer(void);
 142extern 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 */
 160