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1 | /* |
2 | * Queued spinlock | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License as published by | |
6 | * the Free Software Foundation; either version 2 of the License, or | |
7 | * (at your option) any later version. | |
8 | * | |
9 | * This program is distributed in the hope that it will be useful, | |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 | * GNU General Public License for more details. | |
13 | * | |
14 | * (C) Copyright 2013-2015 Hewlett-Packard Development Company, L.P. | |
15 | * | |
16 | * Authors: Waiman Long <waiman.long@hp.com> | |
17 | */ | |
18 | #ifndef __ASM_GENERIC_QSPINLOCK_TYPES_H | |
19 | #define __ASM_GENERIC_QSPINLOCK_TYPES_H | |
20 | ||
21 | /* | |
22 | * Including atomic.h with PARAVIRT on will cause compilation errors because | |
23 | * of recursive header file incluson via paravirt_types.h. So don't include | |
24 | * it if PARAVIRT is on. | |
25 | */ | |
26 | #ifndef CONFIG_PARAVIRT | |
27 | #include <linux/types.h> | |
28 | #include <linux/atomic.h> | |
29 | #endif | |
30 | ||
31 | typedef struct qspinlock { | |
32 | atomic_t val; | |
33 | } arch_spinlock_t; | |
34 | ||
35 | /* | |
36 | * Bitfields in the atomic value: | |
37 | * | |
38 | * 0- 7: locked byte | |
39 | * 8- 9: tail index | |
40 | * 10-31: tail cpu (+1) | |
41 | */ | |
42 | #define _Q_SET_MASK(type) (((1U << _Q_ ## type ## _BITS) - 1)\ | |
43 | << _Q_ ## type ## _OFFSET) | |
44 | #define _Q_LOCKED_OFFSET 0 | |
45 | #define _Q_LOCKED_BITS 8 | |
46 | #define _Q_LOCKED_MASK _Q_SET_MASK(LOCKED) | |
47 | ||
48 | #define _Q_TAIL_IDX_OFFSET (_Q_LOCKED_OFFSET + _Q_LOCKED_BITS) | |
49 | #define _Q_TAIL_IDX_BITS 2 | |
50 | #define _Q_TAIL_IDX_MASK _Q_SET_MASK(TAIL_IDX) | |
51 | ||
52 | #define _Q_TAIL_CPU_OFFSET (_Q_TAIL_IDX_OFFSET + _Q_TAIL_IDX_BITS) | |
53 | #define _Q_TAIL_CPU_BITS (32 - _Q_TAIL_CPU_OFFSET) | |
54 | #define _Q_TAIL_CPU_MASK _Q_SET_MASK(TAIL_CPU) | |
55 | ||
56 | #define _Q_LOCKED_VAL (1U << _Q_LOCKED_OFFSET) | |
57 | ||
58 | #endif /* __ASM_GENERIC_QSPINLOCK_TYPES_H */ |