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
to_gov_attr_set(struct kobject * kobj)11 static 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
to_gov_attr(struct attribute * attr)16 static inline struct governor_attr *to_gov_attr(struct attribute *attr)
17 {
18 return container_of(attr, struct governor_attr, attr);
19 }
20
governor_show(struct kobject * kobj,struct attribute * attr,char * buf)21 static 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
governor_store(struct kobject * kobj,struct attribute * attr,const char * buf,size_t count)29 static 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
42 const struct sysfs_ops governor_sysfs_ops = {
43 .show = governor_show,
44 .store = governor_store,
45 };
46 EXPORT_SYMBOL_GPL(governor_sysfs_ops);
47
gov_attr_set_init(struct gov_attr_set * attr_set,struct list_head * list_node)48 void 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 }
55 EXPORT_SYMBOL_GPL(gov_attr_set_init);
56
gov_attr_set_get(struct gov_attr_set * attr_set,struct list_head * list_node)57 void 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 }
64 EXPORT_SYMBOL_GPL(gov_attr_set_get);
65
gov_attr_set_put(struct gov_attr_set * attr_set,struct list_head * list_node)66 unsigned 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 }
81 EXPORT_SYMBOL_GPL(gov_attr_set_put);
82