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
11static inline struct governor_attr *to_gov_attr(struct attribute *attr)
12{
13	return container_of(attr, struct governor_attr, attr);
14}
15
16static 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
24static 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(&attr_set->update_lock);
34	return ret;
35}
36
37const struct sysfs_ops governor_sysfs_ops = {
38	.show	= governor_show,
39	.store	= governor_store,
40};
41EXPORT_SYMBOL_GPL(governor_sysfs_ops);
42
43void gov_attr_set_init(struct gov_attr_set *attr_set, struct list_head *list_node)
44{
45	INIT_LIST_HEAD(&attr_set->policy_list);
46	mutex_init(&attr_set->update_lock);
47	attr_set->usage_count = 1;
48	list_add(list_node, &attr_set->policy_list);
49}
50EXPORT_SYMBOL_GPL(gov_attr_set_init);
51
52void 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(list_node, &attr_set->policy_list);
57	mutex_unlock(&attr_set->update_lock);
58}
59EXPORT_SYMBOL_GPL(gov_attr_set_get);
60
61unsigned 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(list_node);
67	count = --attr_set->usage_count;
68	mutex_unlock(&attr_set->update_lock);
69	if (count)
70		return count;
71
72	mutex_destroy(&attr_set->update_lock);
73	kobject_put(&attr_set->kobj);
74	return 0;
75}
76EXPORT_SYMBOL_GPL(gov_attr_set_put);
77