LXR uboot/arch/nios2/include/asm/bitops/non-atomic.h

   1#ifndef _ASM_GENERIC_BITOPS_NON_ATOMIC_H_
   2#define _ASM_GENERIC_BITOPS_NON_ATOMIC_H_
   3
   4#include <asm/types.h>
   5
   6/**
   7 * __set_bit - Set a bit in memory
   8 * @nr: the bit to set
   9 * @addr: the address to start counting from
  10 *
  11 * Unlike set_bit(), this function is non-atomic and may be reordered.
  12 * If it's called on the same region of memory simultaneously, the effect
  13 * may be that only one operation succeeds.
  14 */
  15static inline void __set_bit(int nr, volatile unsigned long *addr)
  16{
  17        unsigned long mask = BIT_MASK(nr);
  18        unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
  19
  20        *p  |= mask;
  21}
  22
  23#define PLATFORM__SET_BIT
  24
  25static inline void __clear_bit(int nr, volatile unsigned long *addr)
  26{
  27        unsigned long mask = BIT_MASK(nr);
  28        unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
  29
  30        *p &= ~mask;
  31}
  32
  33#define PLATFORM__CLEAR_BIT
  34
  35/**
  36 * __change_bit - Toggle a bit in memory
  37 * @nr: the bit to change
  38 * @addr: the address to start counting from
  39 *
  40 * Unlike change_bit(), this function is non-atomic and may be reordered.
  41 * If it's called on the same region of memory simultaneously, the effect
  42 * may be that only one operation succeeds.
  43 */
  44static inline void __change_bit(int nr, volatile unsigned long *addr)
  45{
  46        unsigned long mask = BIT_MASK(nr);
  47        unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
  48
  49        *p ^= mask;
  50}
  51
  52/**
  53 * __test_and_set_bit - Set a bit and return its old value
  54 * @nr: Bit to set
  55 * @addr: Address to count from
  56 *
  57 * This operation is non-atomic and can be reordered.
  58 * If two examples of this operation race, one can appear to succeed
  59 * but actually fail.  You must protect multiple accesses with a lock.
  60 */
  61static inline int __test_and_set_bit(int nr, volatile unsigned long *addr)
  62{
  63        unsigned long mask = BIT_MASK(nr);
  64        unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
  65        unsigned long old = *p;
  66
  67        *p = old | mask;
  68        return (old & mask) != 0;
  69}
  70
  71/**
  72 * __test_and_clear_bit - Clear a bit and return its old value
  73 * @nr: Bit to clear
  74 * @addr: Address to count from
  75 *
  76 * This operation is non-atomic and can be reordered.
  77 * If two examples of this operation race, one can appear to succeed
  78 * but actually fail.  You must protect multiple accesses with a lock.
  79 */
  80static inline int __test_and_clear_bit(int nr, volatile unsigned long *addr)
  81{
  82        unsigned long mask = BIT_MASK(nr);
  83        unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
  84        unsigned long old = *p;
  85
  86        *p = old & ~mask;
  87        return (old & mask) != 0;
  88}
  89
  90/* WARNING: non atomic and it can be reordered! */
  91static inline int __test_and_change_bit(int nr,
  92                                            volatile unsigned long *addr)
  93{
  94        unsigned long mask = BIT_MASK(nr);
  95        unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
  96        unsigned long old = *p;
  97
  98        *p = old ^ mask;
  99        return (old & mask) != 0;
 100}
 101
 102/**
 103 * test_bit - Determine whether a bit is set
 104 * @nr: bit number to test
 105 * @addr: Address to start counting from
 106 */
 107static inline int test_bit(int nr, const volatile unsigned long *addr)
 108{
 109        return 1UL & (addr[BIT_WORD(nr)] >> (nr & (BITS_PER_LONG-1)));
 110}
 111
 112#endif /* _ASM_GENERIC_BITOPS_NON_ATOMIC_H_ */
 113