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 gov_attr_set *to_gov_attr_set(struct kobject *kobj)
12{
13	return container_of(kobj, struct gov_attr_set, kobj);
14}
15
16static inline struct governor_attr *to_gov_attr(struct attribute *attr)
17{
18	return container_of(attr, struct governor_attr, attr);
19}
20
21static ssize_t governor_show(struct kobject *kobj, struct attribute *attr,
22			     char *buf)
23{
24	struct governor_attr *gattr = to_gov_attr(attr);
25
26	return gattr->show(to_gov_attr_set(kobj), buf);
27}
28
29static ssize_t governor_store(struct kobject *kobj, struct attribute *attr,
30			      const char *buf, size_t count)
31{
32	struct gov_attr_set *attr_set = to_gov_attr_set(kobj);
33	struct governor_attr *gattr = to_gov_attr(attr);
34	int ret;
35
36	mutex_lock(&attr_set->update_lock);
37	ret = attr_set->usage_count ? gattr->store(attr_set, buf, count) : -EBUSY;
38	mutex_unlock(&attr_set->update_lock);
39	return ret;
40}
41
42const struct sysfs_ops governor_sysfs_ops = {
43	.show	= governor_show,
44	.store	= governor_store,
45};
46EXPORT_SYMBOL_GPL(governor_sysfs_ops);
47
48void gov_attr_set_init(struct gov_attr_set *attr_set, struct list_head *list_node)
49{
50	INIT_LIST_HEAD(&attr_set->policy_list);
51	mutex_init(&attr_set->update_lock);
52	attr_set->usage_count = 1;
53	list_add(list_node, &attr_set->policy_list);
54}
55EXPORT_SYMBOL_GPL(gov_attr_set_init);
56
57void gov_attr_set_get(struct gov_attr_set *attr_set, struct list_head *list_node)
58{
59	mutex_lock(&attr_set->update_lock);
60	attr_set->usage_count++;
61	list_add(list_node, &attr_set->policy_list);
62	mutex_unlock(&attr_set->update_lock);
63}
64EXPORT_SYMBOL_GPL(gov_attr_set_get);
65
66unsigned int gov_attr_set_put(struct gov_attr_set *attr_set, struct list_head *list_node)
67{
68	unsigned int count;
69
70	mutex_lock(&attr_set->update_lock);
71	list_del(list_node);
72	count = --attr_set->usage_count;
73	mutex_unlock(&attr_set->update_lock);
74	if (count)
75		return count;
76
77	mutex_destroy(&attr_set->update_lock);
78	kobject_put(&attr_set->kobj);
79	return 0;
80}
81EXPORT_SYMBOL_GPL(gov_attr_set_put);