1/*
 2 * Abstract code for CPUFreq governor tunable sysfs attributes.
 3 *
 4 * Copyright (C) 2016, Intel Corporation
 5 * Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
 6 *
 7 * This program is free software; you can redistribute it and/or modify
 8 * it under the terms of the GNU General Public License version 2 as
 9 * published by the Free Software Foundation.
10 */
11
12#include "cpufreq_governor.h"
13
14static inline struct gov_attr_set *to_gov_attr_set(struct kobject *kobj)
15{
16	return container_of(kobj, struct gov_attr_set, kobj);
17}
18
19static inline struct governor_attr *to_gov_attr(struct attribute *attr)
20{
21	return container_of(attr, struct governor_attr, attr);
22}
23
24static ssize_t governor_show(struct kobject *kobj, struct attribute *attr,
25			     char *buf)
26{
27	struct governor_attr *gattr = to_gov_attr(attr);
28
29	return gattr->show(to_gov_attr_set(kobj), buf);
30}
31
32static ssize_t governor_store(struct kobject *kobj, struct attribute *attr,
33			      const char *buf, size_t count)
34{
35	struct gov_attr_set *attr_set = to_gov_attr_set(kobj);
36	struct governor_attr *gattr = to_gov_attr(attr);
37	int ret;
38
39	mutex_lock(&attr_set->update_lock);
40	ret = attr_set->usage_count ? gattr->store(attr_set, buf, count) : -EBUSY;
41	mutex_unlock(&attr_set->update_lock);
42	return ret;
43}
44
45const struct sysfs_ops governor_sysfs_ops = {
46	.show	= governor_show,
47	.store	= governor_store,
48};
49EXPORT_SYMBOL_GPL(governor_sysfs_ops);
50
51void gov_attr_set_init(struct gov_attr_set *attr_set, struct list_head *list_node)
52{
53	INIT_LIST_HEAD(&attr_set->policy_list);
54	mutex_init(&attr_set->update_lock);
55	attr_set->usage_count = 1;
56	list_add(list_node, &attr_set->policy_list);
57}
58EXPORT_SYMBOL_GPL(gov_attr_set_init);
59
60void gov_attr_set_get(struct gov_attr_set *attr_set, struct list_head *list_node)
61{
62	mutex_lock(&attr_set->update_lock);
63	attr_set->usage_count++;
64	list_add(list_node, &attr_set->policy_list);
65	mutex_unlock(&attr_set->update_lock);
66}
67EXPORT_SYMBOL_GPL(gov_attr_set_get);
68
69unsigned int gov_attr_set_put(struct gov_attr_set *attr_set, struct list_head *list_node)
70{
71	unsigned int count;
72
73	mutex_lock(&attr_set->update_lock);
74	list_del(list_node);
75	count = --attr_set->usage_count;
76	mutex_unlock(&attr_set->update_lock);
77	if (count)
78		return count;
79
80	kobject_put(&attr_set->kobj);
81	mutex_destroy(&attr_set->update_lock);
82	return 0;
83}
84EXPORT_SYMBOL_GPL(gov_attr_set_put);