arch/tile/include/asm/bitops_32.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
  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>. */
  23 unsigned long _atomic_or(volatile unsigned long *p, unsigned long mask);
  24 unsigned long _atomic_andn(volatile unsigned long *p, unsigned long mask);
  25 unsigned 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  */
  37 static 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  */
  56 static 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  */
  71 static 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  */
  84 static 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  */
 100 static 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  */
 116 static 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 */