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
21 /* Tile-specific routines to support <asm/bitops.h>. */
22 unsigned long _atomic_or(volatile unsigned long *p, unsigned long mask);
23 unsigned long _atomic_andn(volatile unsigned long *p, unsigned long mask);
24 unsigned 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 */
set_bit(unsigned nr,volatile unsigned long * addr)36 static 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 */
clear_bit(unsigned nr,volatile unsigned long * addr)55 static 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 */
change_bit(unsigned nr,volatile unsigned long * addr)70 static 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 */
test_and_set_bit(unsigned nr,volatile unsigned long * addr)83 static 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 */
test_and_clear_bit(unsigned nr,volatile unsigned long * addr)99 static 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 */
test_and_change_bit(unsigned nr,volatile unsigned long * addr)115 static 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