1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _ASM_GENERIC_BITOPS_NON_ATOMIC_H_
3#define _ASM_GENERIC_BITOPS_NON_ATOMIC_H_
4
5#include <asm/types.h>
6
7/**
8 * __set_bit - Set a bit in memory
9 * @nr: the bit to set
10 * @addr: the address to start counting from
11 *
12 * Unlike set_bit(), this function is non-atomic and may be reordered.
13 * If it's called on the same region of memory simultaneously, the effect
14 * may be that only one operation succeeds.
15 */
16static inline void __set_bit(int nr, volatile unsigned long *addr)
17{
18	unsigned long mask = BIT_MASK(nr);
19	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
20
21	*p  |= mask;
22}
23
24static inline void __clear_bit(int nr, volatile unsigned long *addr)
25{
26	unsigned long mask = BIT_MASK(nr);
27	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
28
29	*p &= ~mask;
30}
31
32/**
33 * __change_bit - Toggle a bit in memory
34 * @nr: the bit to change
35 * @addr: the address to start counting from
36 *
37 * Unlike change_bit(), this function is non-atomic and may be reordered.
38 * If it's called on the same region of memory simultaneously, the effect
39 * may be that only one operation succeeds.
40 */
41static inline void __change_bit(int nr, volatile unsigned long *addr)
42{
43	unsigned long mask = BIT_MASK(nr);
44	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
45
46	*p ^= mask;
47}
48
49/**
50 * __test_and_set_bit - Set a bit and return its old value
51 * @nr: Bit to set
52 * @addr: Address to count from
53 *
54 * This operation is non-atomic and can be reordered.
55 * If two examples of this operation race, one can appear to succeed
56 * but actually fail.  You must protect multiple accesses with a lock.
57 */
58static inline int __test_and_set_bit(int nr, volatile unsigned long *addr)
59{
60	unsigned long mask = BIT_MASK(nr);
61	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
62	unsigned long old = *p;
63
64	*p = old | mask;
65	return (old & mask) != 0;
66}
67
68/**
69 * __test_and_clear_bit - Clear a bit and return its old value
70 * @nr: Bit to clear
71 * @addr: Address to count from
72 *
73 * This operation is non-atomic and can be reordered.
74 * If two examples of this operation race, one can appear to succeed
75 * but actually fail.  You must protect multiple accesses with a lock.
76 */
77static inline int __test_and_clear_bit(int nr, volatile unsigned long *addr)
78{
79	unsigned long mask = BIT_MASK(nr);
80	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
81	unsigned long old = *p;
82
83	*p = old & ~mask;
84	return (old & mask) != 0;
85}
86
87/* WARNING: non atomic and it can be reordered! */
88static inline int __test_and_change_bit(int nr,
89					    volatile unsigned long *addr)
90{
91	unsigned long mask = BIT_MASK(nr);
92	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
93	unsigned long old = *p;
94
95	*p = old ^ mask;
96	return (old & mask) != 0;
97}
98
99/**
100 * test_bit - Determine whether a bit is set
101 * @nr: bit number to test
102 * @addr: Address to start counting from
103 */
104static inline int test_bit(int nr, const volatile unsigned long *addr)
105{
106	return 1UL & (addr[BIT_WORD(nr)] >> (nr & (BITS_PER_LONG-1)));
107}
108
109#endif /* _ASM_GENERIC_BITOPS_NON_ATOMIC_H_ */
110