LXR linux/arch/tile/include/asm/bitops

   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
  15#ifndef _ASM_TILE_BITOPS_32_H
  16#define _ASM_TILE_BITOPS_32_H
  17
  18#include <linux/compiler.h>
  19#include <linux/atomic.h>
  20#include <asm/system.h>
  21
  22/* Tile-specific routines to support <asm/bitops.h>. */
  23unsigned long _atomic_or(volatile unsigned long *p, unsigned long mask);
  24unsigned long _atomic_andn(volatile unsigned long *p, unsigned long mask);
  25unsigned long _atomic_xor(volatile unsigned long *p, unsigned long mask);
  26
  27/**
  28 * set_bit - Atomically set a bit in memory
  29 * @nr: the bit to set
  30 * @addr: the address to start counting from
  31 *
  32 * This function is atomic and may not be reordered.
  33 * See __set_bit() if you do not require the atomic guarantees.
  34 * Note that @nr may be almost arbitrarily large; this function is not
  35 * restricted to acting on a single-word quantity.
  36 */
  37static inline void set_bit(unsigned nr, volatile unsigned long *addr)
  38{
  39        _atomic_or(addr + BIT_WORD(nr), BIT_MASK(nr));
  40}
  41
  42/**
  43 * clear_bit - Clears a bit in memory
  44 * @nr: Bit to clear
  45 * @addr: Address to start counting from
  46 *
  47 * clear_bit() is atomic and may not be reordered.
  48 * See __clear_bit() if you do not require the atomic guarantees.
  49 * Note that @nr may be almost arbitrarily large; this function is not
  50 * restricted to acting on a single-word quantity.
  51 *
  52 * clear_bit() may not contain a memory barrier, so if it is used for
  53 * locking purposes, you should call smp_mb__before_clear_bit() and/or
  54 * smp_mb__after_clear_bit() to ensure changes are visible on other cpus.
  55 */
  56static inline void clear_bit(unsigned nr, volatile unsigned long *addr)
  57{
  58        _atomic_andn(addr + BIT_WORD(nr), BIT_MASK(nr));
  59}
  60
  61/**
  62 * change_bit - Toggle a bit in memory
  63 * @nr: Bit to change
  64 * @addr: Address to start counting from
  65 *
  66 * change_bit() is atomic and may not be reordered.
  67 * See __change_bit() if you do not require the atomic guarantees.
  68 * Note that @nr may be almost arbitrarily large; this function is not
  69 * restricted to acting on a single-word quantity.
  70 */
  71static inline void change_bit(unsigned nr, volatile unsigned long *addr)
  72{
  73        _atomic_xor(addr + BIT_WORD(nr), BIT_MASK(nr));
  74}
  75
  76/**
  77 * test_and_set_bit - Set a bit and return its old value
  78 * @nr: Bit to set
  79 * @addr: Address to count from
  80 *
  81 * This operation is atomic and cannot be reordered.
  82 * It also implies a memory barrier.
  83 */
  84static inline int test_and_set_bit(unsigned nr, volatile unsigned long *addr)
  85{
  86        unsigned long mask = BIT_MASK(nr);
  87        addr += BIT_WORD(nr);
  88        smp_mb();  /* barrier for proper semantics */
  89        return (_atomic_or(addr, mask) & mask) != 0;
  90}
  91
  92/**
  93 * test_and_clear_bit - Clear a bit and return its old value
  94 * @nr: Bit to clear
  95 * @addr: Address to count from
  96 *
  97 * This operation is atomic and cannot be reordered.
  98 * It also implies a memory barrier.
  99 */
 100static inline int test_and_clear_bit(unsigned nr, volatile unsigned long *addr)
 101{
 102        unsigned long mask = BIT_MASK(nr);
 103        addr += BIT_WORD(nr);
 104        smp_mb();  /* barrier for proper semantics */
 105        return (_atomic_andn(addr, mask) & mask) != 0;
 106}
 107
 108/**
 109 * test_and_change_bit - Change a bit and return its old value
 110 * @nr: Bit to change
 111 * @addr: Address to count from
 112 *
 113 * This operation is atomic and cannot be reordered.
 114 * It also implies a memory barrier.
 115 */
 116static inline int test_and_change_bit(unsigned nr,
 117                                      volatile unsigned long *addr)
 118{
 119        unsigned long mask = BIT_MASK(nr);
 120        addr += BIT_WORD(nr);
 121        smp_mb();  /* barrier for proper semantics */
 122        return (_atomic_xor(addr, mask) & mask) != 0;
 123}
 124
 125/* See discussion at smp_mb__before_atomic_dec() in <asm/atomic_32.h>. */
 126#define smp_mb__before_clear_bit()      smp_mb()
 127#define smp_mb__after_clear_bit()       do {} while (0)
 128
 129#include <asm-generic/bitops/ext2-atomic.h>
 130
 131#endif /* _ASM_TILE_BITOPS_32_H */
 132