LXR linux/drivers/cpufreq/cpufreq_governor_attr

   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);
  82