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