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Ard Biesheuvel67bad2f2014-02-08 13:34:09 +01001/*
2 * Copyright (C) 2014 Linaro Ltd. <ard.biesheuvel@linaro.org>
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 version 2 as
6 * published by the Free Software Foundation.
7 */
8
9#ifndef __LINUX_CPUFEATURE_H
10#define __LINUX_CPUFEATURE_H
11
12#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
13
14#include <linux/mod_devicetable.h>
15#include <asm/cpufeature.h>
16
17/*
18 * Macros imported from <asm/cpufeature.h>:
19 * - cpu_feature(x) ordinal value of feature called 'x'
20 * - cpu_have_feature(u32 n) whether feature #n is available
21 * - MAX_CPU_FEATURES upper bound for feature ordinal values
22 * Optional:
23 * - CPU_FEATURE_TYPEFMT format string fragment for printing the cpu type
24 * - CPU_FEATURE_TYPEVAL set of values matching the format string above
25 */
26
27#ifndef CPU_FEATURE_TYPEFMT
28#define CPU_FEATURE_TYPEFMT "%s"
29#endif
30
31#ifndef CPU_FEATURE_TYPEVAL
32#define CPU_FEATURE_TYPEVAL ELF_PLATFORM
33#endif
34
35/*
36 * Use module_cpu_feature_match(feature, module_init_function) to
37 * declare that
38 * a) the module shall be probed upon discovery of CPU feature 'feature'
39 * (typically at boot time using udev)
40 * b) the module must not be loaded if CPU feature 'feature' is not present
41 * (not even by manual insmod).
42 *
43 * For a list of legal values for 'feature', please consult the file
44 * 'asm/cpufeature.h' of your favorite architecture.
45 */
46#define module_cpu_feature_match(x, __init) \
47static struct cpu_feature const cpu_feature_match_ ## x[] = \
48 { { .feature = cpu_feature(x) }, { } }; \
49MODULE_DEVICE_TABLE(cpu, cpu_feature_match_ ## x); \
50 \
51static int cpu_feature_match_ ## x ## _init(void) \
52{ \
53 if (!cpu_have_feature(cpu_feature(x))) \
54 return -ENODEV; \
55 return __init(); \
56} \
57module_init(cpu_feature_match_ ## x ## _init)
58
59#endif
60#endif