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
to_gov_attr_set(struct kobject * kobj)14 static 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
to_gov_attr(struct attribute * attr)19 static inline struct governor_attr *to_gov_attr(struct attribute *attr)
20 {
21 return container_of(attr, struct governor_attr, attr);
22 }
23
governor_show(struct kobject * kobj,struct attribute * attr,char * buf)24 static 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
governor_store(struct kobject * kobj,struct attribute * attr,const char * buf,size_t count)32 static 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
45 const struct sysfs_ops governor_sysfs_ops = {
46 .show = governor_show,
47 .store = governor_store,
48 };
49 EXPORT_SYMBOL_GPL(governor_sysfs_ops);
50
gov_attr_set_init(struct gov_attr_set * attr_set,struct list_head * list_node)51 void 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 }
58 EXPORT_SYMBOL_GPL(gov_attr_set_init);
59
gov_attr_set_get(struct gov_attr_set * attr_set,struct list_head * list_node)60 void 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 }
67 EXPORT_SYMBOL_GPL(gov_attr_set_get);
68
gov_attr_set_put(struct gov_attr_set * attr_set,struct list_head * list_node)69 unsigned 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 mutex_destroy(&attr_set->update_lock);
81 kobject_put(&attr_set->kobj);
82 return 0;
83 }
84 EXPORT_SYMBOL_GPL(gov_attr_set_put);
85