77 lines · c
1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Abstract code for CPUFreq governor tunable sysfs attributes.4 *5 * Copyright (C) 2016, Intel Corporation6 * 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