1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * Abstract code for CPUFreq governor tunable sysfs attributes. |
4 | * |
5 | * Copyright (C) 2016, Intel Corporation |
6 | * Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com> |
7 | */ |
8 | |
9 | #include "cpufreq_governor.h" |
10 | |
11 | static inline struct governor_attr *to_gov_attr(struct attribute *attr) |
12 | { |
13 | return container_of(attr, struct governor_attr, attr); |
14 | } |
15 | |
16 | static ssize_t governor_show(struct kobject *kobj, struct attribute *attr, |
17 | char *buf) |
18 | { |
19 | struct governor_attr *gattr = to_gov_attr(attr); |
20 | |
21 | return gattr->show(to_gov_attr_set(kobj), buf); |
22 | } |
23 | |
24 | static ssize_t governor_store(struct kobject *kobj, struct attribute *attr, |
25 | const char *buf, size_t count) |
26 | { |
27 | struct gov_attr_set *attr_set = to_gov_attr_set(kobj); |
28 | struct governor_attr *gattr = to_gov_attr(attr); |
29 | int ret; |
30 | |
31 | mutex_lock(&attr_set->update_lock); |
32 | ret = attr_set->usage_count ? gattr->store(attr_set, buf, count) : -EBUSY; |
33 | mutex_unlock(lock: &attr_set->update_lock); |
34 | return ret; |
35 | } |
36 | |
37 | const struct sysfs_ops governor_sysfs_ops = { |
38 | .show = governor_show, |
39 | .store = governor_store, |
40 | }; |
41 | EXPORT_SYMBOL_GPL(governor_sysfs_ops); |
42 | |
43 | void gov_attr_set_init(struct gov_attr_set *attr_set, struct list_head *list_node) |
44 | { |
45 | INIT_LIST_HEAD(list: &attr_set->policy_list); |
46 | mutex_init(&attr_set->update_lock); |
47 | attr_set->usage_count = 1; |
48 | list_add(new: list_node, head: &attr_set->policy_list); |
49 | } |
50 | EXPORT_SYMBOL_GPL(gov_attr_set_init); |
51 | |
52 | void gov_attr_set_get(struct gov_attr_set *attr_set, struct list_head *list_node) |
53 | { |
54 | mutex_lock(&attr_set->update_lock); |
55 | attr_set->usage_count++; |
56 | list_add(new: list_node, head: &attr_set->policy_list); |
57 | mutex_unlock(lock: &attr_set->update_lock); |
58 | } |
59 | EXPORT_SYMBOL_GPL(gov_attr_set_get); |
60 | |
61 | unsigned int gov_attr_set_put(struct gov_attr_set *attr_set, struct list_head *list_node) |
62 | { |
63 | unsigned int count; |
64 | |
65 | mutex_lock(&attr_set->update_lock); |
66 | list_del(entry: list_node); |
67 | count = --attr_set->usage_count; |
68 | mutex_unlock(lock: &attr_set->update_lock); |
69 | if (count) |
70 | return count; |
71 | |
72 | mutex_destroy(lock: &attr_set->update_lock); |
73 | kobject_put(kobj: &attr_set->kobj); |
74 | return 0; |
75 | } |
76 | EXPORT_SYMBOL_GPL(gov_attr_set_put); |
77 | |