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![Guenter Roeck](/assets/img/avatar_default.png)
In preparation to protecting access to thermal operations against thermal zone device removal, protect hwmon accesses to thermal zone operations with the thermal zone mutex. After acquiring the mutex, ensure that the thermal zone device is registered before proceeding. Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
289 lines
7.1 KiB
C
289 lines
7.1 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* thermal_hwmon.c - Generic Thermal Management hwmon support.
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*
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* Code based on Intel thermal_core.c. Copyrights of the original code:
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* Copyright (C) 2008 Intel Corp
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* Copyright (C) 2008 Zhang Rui <rui.zhang@intel.com>
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* Copyright (C) 2008 Sujith Thomas <sujith.thomas@intel.com>
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*
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* Copyright (C) 2013 Texas Instruments
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* Copyright (C) 2013 Eduardo Valentin <eduardo.valentin@ti.com>
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*/
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#include <linux/err.h>
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#include <linux/export.h>
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#include <linux/hwmon.h>
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#include <linux/slab.h>
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#include <linux/thermal.h>
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#include "thermal_hwmon.h"
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/* hwmon sys I/F */
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/* thermal zone devices with the same type share one hwmon device */
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struct thermal_hwmon_device {
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char type[THERMAL_NAME_LENGTH];
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struct device *device;
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int count;
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struct list_head tz_list;
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struct list_head node;
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};
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struct thermal_hwmon_attr {
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struct device_attribute attr;
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char name[16];
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};
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/* one temperature input for each thermal zone */
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struct thermal_hwmon_temp {
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struct list_head hwmon_node;
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struct thermal_zone_device *tz;
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struct thermal_hwmon_attr temp_input; /* hwmon sys attr */
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struct thermal_hwmon_attr temp_crit; /* hwmon sys attr */
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};
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static LIST_HEAD(thermal_hwmon_list);
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static DEFINE_MUTEX(thermal_hwmon_list_lock);
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static ssize_t
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temp_input_show(struct device *dev, struct device_attribute *attr, char *buf)
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{
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int temperature;
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int ret;
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struct thermal_hwmon_attr *hwmon_attr
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= container_of(attr, struct thermal_hwmon_attr, attr);
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struct thermal_hwmon_temp *temp
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= container_of(hwmon_attr, struct thermal_hwmon_temp,
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temp_input);
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struct thermal_zone_device *tz = temp->tz;
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ret = thermal_zone_get_temp(tz, &temperature);
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if (ret)
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return ret;
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return sprintf(buf, "%d\n", temperature);
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}
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static ssize_t
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temp_crit_show(struct device *dev, struct device_attribute *attr, char *buf)
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{
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struct thermal_hwmon_attr *hwmon_attr
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= container_of(attr, struct thermal_hwmon_attr, attr);
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struct thermal_hwmon_temp *temp
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= container_of(hwmon_attr, struct thermal_hwmon_temp,
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temp_crit);
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struct thermal_zone_device *tz = temp->tz;
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int temperature;
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int ret;
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mutex_lock(&tz->lock);
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if (device_is_registered(&tz->device))
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ret = tz->ops->get_crit_temp(tz, &temperature);
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else
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ret = -ENODEV;
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mutex_unlock(&tz->lock);
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if (ret)
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return ret;
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return sprintf(buf, "%d\n", temperature);
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}
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static struct thermal_hwmon_device *
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thermal_hwmon_lookup_by_type(const struct thermal_zone_device *tz)
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{
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struct thermal_hwmon_device *hwmon;
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char type[THERMAL_NAME_LENGTH];
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mutex_lock(&thermal_hwmon_list_lock);
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list_for_each_entry(hwmon, &thermal_hwmon_list, node) {
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strcpy(type, tz->type);
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strreplace(type, '-', '_');
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if (!strcmp(hwmon->type, type)) {
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mutex_unlock(&thermal_hwmon_list_lock);
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return hwmon;
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}
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}
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mutex_unlock(&thermal_hwmon_list_lock);
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return NULL;
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}
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/* Find the temperature input matching a given thermal zone */
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static struct thermal_hwmon_temp *
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thermal_hwmon_lookup_temp(const struct thermal_hwmon_device *hwmon,
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const struct thermal_zone_device *tz)
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{
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struct thermal_hwmon_temp *temp;
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mutex_lock(&thermal_hwmon_list_lock);
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list_for_each_entry(temp, &hwmon->tz_list, hwmon_node)
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if (temp->tz == tz) {
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mutex_unlock(&thermal_hwmon_list_lock);
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return temp;
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}
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mutex_unlock(&thermal_hwmon_list_lock);
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return NULL;
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}
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static bool thermal_zone_crit_temp_valid(struct thermal_zone_device *tz)
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{
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int temp;
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return tz->ops->get_crit_temp && !tz->ops->get_crit_temp(tz, &temp);
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}
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int thermal_add_hwmon_sysfs(struct thermal_zone_device *tz)
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{
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struct thermal_hwmon_device *hwmon;
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struct thermal_hwmon_temp *temp;
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int new_hwmon_device = 1;
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int result;
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hwmon = thermal_hwmon_lookup_by_type(tz);
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if (hwmon) {
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new_hwmon_device = 0;
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goto register_sys_interface;
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}
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hwmon = kzalloc(sizeof(*hwmon), GFP_KERNEL);
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if (!hwmon)
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return -ENOMEM;
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INIT_LIST_HEAD(&hwmon->tz_list);
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strscpy(hwmon->type, tz->type, THERMAL_NAME_LENGTH);
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strreplace(hwmon->type, '-', '_');
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hwmon->device = hwmon_device_register_for_thermal(&tz->device,
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hwmon->type, hwmon);
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if (IS_ERR(hwmon->device)) {
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result = PTR_ERR(hwmon->device);
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goto free_mem;
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}
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register_sys_interface:
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temp = kzalloc(sizeof(*temp), GFP_KERNEL);
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if (!temp) {
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result = -ENOMEM;
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goto unregister_name;
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}
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temp->tz = tz;
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hwmon->count++;
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snprintf(temp->temp_input.name, sizeof(temp->temp_input.name),
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"temp%d_input", hwmon->count);
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temp->temp_input.attr.attr.name = temp->temp_input.name;
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temp->temp_input.attr.attr.mode = 0444;
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temp->temp_input.attr.show = temp_input_show;
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sysfs_attr_init(&temp->temp_input.attr.attr);
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result = device_create_file(hwmon->device, &temp->temp_input.attr);
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if (result)
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goto free_temp_mem;
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if (thermal_zone_crit_temp_valid(tz)) {
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snprintf(temp->temp_crit.name,
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sizeof(temp->temp_crit.name),
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"temp%d_crit", hwmon->count);
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temp->temp_crit.attr.attr.name = temp->temp_crit.name;
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temp->temp_crit.attr.attr.mode = 0444;
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temp->temp_crit.attr.show = temp_crit_show;
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sysfs_attr_init(&temp->temp_crit.attr.attr);
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result = device_create_file(hwmon->device,
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&temp->temp_crit.attr);
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if (result)
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goto unregister_input;
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}
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mutex_lock(&thermal_hwmon_list_lock);
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if (new_hwmon_device)
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list_add_tail(&hwmon->node, &thermal_hwmon_list);
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list_add_tail(&temp->hwmon_node, &hwmon->tz_list);
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mutex_unlock(&thermal_hwmon_list_lock);
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return 0;
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unregister_input:
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device_remove_file(hwmon->device, &temp->temp_input.attr);
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free_temp_mem:
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kfree(temp);
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unregister_name:
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if (new_hwmon_device)
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hwmon_device_unregister(hwmon->device);
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free_mem:
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kfree(hwmon);
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return result;
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}
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EXPORT_SYMBOL_GPL(thermal_add_hwmon_sysfs);
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void thermal_remove_hwmon_sysfs(struct thermal_zone_device *tz)
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{
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struct thermal_hwmon_device *hwmon;
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struct thermal_hwmon_temp *temp;
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hwmon = thermal_hwmon_lookup_by_type(tz);
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if (unlikely(!hwmon)) {
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/* Should never happen... */
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dev_dbg(&tz->device, "hwmon device lookup failed!\n");
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return;
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}
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temp = thermal_hwmon_lookup_temp(hwmon, tz);
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if (unlikely(!temp)) {
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/* Should never happen... */
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dev_dbg(&tz->device, "temperature input lookup failed!\n");
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return;
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}
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device_remove_file(hwmon->device, &temp->temp_input.attr);
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if (thermal_zone_crit_temp_valid(tz))
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device_remove_file(hwmon->device, &temp->temp_crit.attr);
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mutex_lock(&thermal_hwmon_list_lock);
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list_del(&temp->hwmon_node);
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kfree(temp);
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if (!list_empty(&hwmon->tz_list)) {
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mutex_unlock(&thermal_hwmon_list_lock);
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return;
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}
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list_del(&hwmon->node);
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mutex_unlock(&thermal_hwmon_list_lock);
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hwmon_device_unregister(hwmon->device);
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kfree(hwmon);
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}
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EXPORT_SYMBOL_GPL(thermal_remove_hwmon_sysfs);
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static void devm_thermal_hwmon_release(struct device *dev, void *res)
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{
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thermal_remove_hwmon_sysfs(*(struct thermal_zone_device **)res);
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}
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int devm_thermal_add_hwmon_sysfs(struct thermal_zone_device *tz)
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{
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struct thermal_zone_device **ptr;
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int ret;
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ptr = devres_alloc(devm_thermal_hwmon_release, sizeof(*ptr),
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GFP_KERNEL);
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if (!ptr)
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return -ENOMEM;
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ret = thermal_add_hwmon_sysfs(tz);
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if (ret) {
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devres_free(ptr);
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return ret;
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}
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*ptr = tz;
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devres_add(&tz->device, ptr);
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return ret;
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}
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EXPORT_SYMBOL_GPL(devm_thermal_add_hwmon_sysfs);
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MODULE_IMPORT_NS(HWMON_THERMAL);
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