thermal_sys.c

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/*
 *  thermal.c - Generic Thermal Management Sysfs support.
 *
 *  Copyright (C) 2008 Intel Corp
 *  Copyright (C) 2008 Zhang Rui <[email protected]>
 *  Copyright (C) 2008 Sujith Thomas <[email protected]>
 *
 *  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; version 2 of the License.
 *
 *  This program is distributed in the hope that it will be useful, but
 *  WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/kdev_t.h>
#include <linux/idr.h>
#include <linux/thermal.h>
#include <linux/spinlock.h>
#include <linux/reboot.h>
#include <net/netlink.h>
#include <net/genetlink.h>

MODULE_AUTHOR("Zhang Rui");
MODULE_DESCRIPTION("Generic thermal management sysfs support");
MODULE_LICENSE("GPL");

#define THERMAL_NO_TARGET -1UL
/*
 * This structure is used to describe the behavior of
 * a certain cooling device on a certain trip point
 * in a certain thermal zone
 */
struct thermal_instance {
    int id;
    char name[THERMAL_NAME_LENGTH];
    struct thermal_zone_device *tz;
    struct thermal_cooling_device *cdev;
    int trip;
    unsigned long upper;    /* Highest cooling state for this trip point */
    unsigned long lower;    /* Lowest cooling state for this trip point */
    unsigned long target;   /* expected cooling state */
    char attr_name[THERMAL_NAME_LENGTH];
    struct device_attribute attr;
    struct list_head tz_node; /* node in tz->thermal_instances */
    struct list_head cdev_node; /* node in cdev->thermal_instances */
};

static DEFINE_IDR(thermal_tz_idr);
static DEFINE_IDR(thermal_cdev_idr);
static DEFINE_MUTEX(thermal_idr_lock);

static LIST_HEAD(thermal_tz_list);
static LIST_HEAD(thermal_cdev_list);
static DEFINE_MUTEX(thermal_list_lock);

static int get_idr(struct idr *idr, struct mutex *lock, int *id)
{
    int err;

again:
    if (unlikely(idr_pre_get(idr, GFP_KERNEL) == 0))
        return -ENOMEM;

    if (lock)
        mutex_lock(lock);
    err = idr_get_new(idr, NULL, id);
    if (lock)
        mutex_unlock(lock);
    if (unlikely(err == -EAGAIN))
        goto again;
    else if (unlikely(err))
        return err;

    *id = *id & MAX_IDR_MASK;
    return 0;
}

static void release_idr(struct idr *idr, struct mutex *lock, int id)
{
    if (lock)
        mutex_lock(lock);
    idr_remove(idr, id);
    if (lock)
        mutex_unlock(lock);
}

/* sys I/F for thermal zone */

#define to_thermal_zone(_dev) \
    container_of(_dev, struct thermal_zone_device, device)

static ssize_t
type_show(struct device *dev, struct device_attribute *attr, char *buf)
{
    struct thermal_zone_device *tz = to_thermal_zone(dev);

    return sprintf(buf, "%s\n", tz->type);
}

static ssize_t
temp_show(struct device *dev, struct device_attribute *attr, char *buf)
{
    struct thermal_zone_device *tz = to_thermal_zone(dev);
    long temperature;
    int ret;

    if (!tz->ops->get_temp)
        return -EPERM;

    ret = tz->ops->get_temp(tz, &temperature);

    if (ret)
        return ret;

    return sprintf(buf, "%ld\n", temperature);
}

static ssize_t
mode_show(struct device *dev, struct device_attribute *attr, char *buf)
{
    struct thermal_zone_device *tz = to_thermal_zone(dev);
    enum thermal_device_mode mode;
    int result;

    if (!tz->ops->get_mode)
        return -EPERM;

    result = tz->ops->get_mode(tz, &mode);
    if (result)
        return result;

    return sprintf(buf, "%s\n", mode == THERMAL_DEVICE_ENABLED ? "enabled"
               : "disabled");
}

static ssize_t
mode_store(struct device *dev, struct device_attribute *attr,
       const char *buf, size_t count)
{
    struct thermal_zone_device *tz = to_thermal_zone(dev);
    int result;

    if (!tz->ops->set_mode)
        return -EPERM;

    if (!strncmp(buf, "enabled", sizeof("enabled") - 1))
        result = tz->ops->set_mode(tz, THERMAL_DEVICE_ENABLED);
    else if (!strncmp(buf, "disabled", sizeof("disabled") - 1))
        result = tz->ops->set_mode(tz, THERMAL_DEVICE_DISABLED);
    else
        result = -EINVAL;

    if (result)
        return result;

    return count;
}

static ssize_t
trip_point_type_show(struct device *dev, struct device_attribute *attr,
             char *buf)
{
    struct thermal_zone_device *tz = to_thermal_zone(dev);
    enum thermal_trip_type type;
    int trip, result;

    if (!tz->ops->get_trip_type)
        return -EPERM;

    if (!sscanf(attr->attr.name, "trip_point_%d_type", &trip))
        return -EINVAL;

    result = tz->ops->get_trip_type(tz, trip, &type);
    if (result)
        return result;

    switch (type) {
    case THERMAL_TRIP_CRITICAL:
        return sprintf(buf, "critical\n");
    case THERMAL_TRIP_HOT:
        return sprintf(buf, "hot\n");
    case THERMAL_TRIP_PASSIVE:
        return sprintf(buf, "passive\n");
    case THERMAL_TRIP_ACTIVE:
        return sprintf(buf, "active\n");
    default:
        return sprintf(buf, "unknown\n");
    }
}

static ssize_t
trip_point_temp_store(struct device *dev, struct device_attribute *attr,
             const char *buf, size_t count)
{
    struct thermal_zone_device *tz = to_thermal_zone(dev);
    int trip, ret;
    unsigned long temperature;

    if (!tz->ops->set_trip_temp)
        return -EPERM;

    if (!sscanf(attr->attr.name, "trip_point_%d_temp", &trip))
        return -EINVAL;

    if (kstrtoul(buf, 10, &temperature))
        return -EINVAL;

    ret = tz->ops->set_trip_temp(tz, trip, temperature);

    return ret ? ret : count;
}

static ssize_t
trip_point_temp_show(struct device *dev, struct device_attribute *attr,
             char *buf)
{
    struct thermal_zone_device *tz = to_thermal_zone(dev);
    int trip, ret;
    long temperature;

    if (!tz->ops->get_trip_temp)
        return -EPERM;

    if (!sscanf(attr->attr.name, "trip_point_%d_temp", &trip))
        return -EINVAL;

    ret = tz->ops->get_trip_temp(tz, trip, &temperature);

    if (ret)
        return ret;

    return sprintf(buf, "%ld\n", temperature);
}

static ssize_t
trip_point_hyst_store(struct device *dev, struct device_attribute *attr,
            const char *buf, size_t count)
{
    struct thermal_zone_device *tz = to_thermal_zone(dev);
    int trip, ret;
    unsigned long temperature;

    if (!tz->ops->set_trip_hyst)
        return -EPERM;

    if (!sscanf(attr->attr.name, "trip_point_%d_hyst", &trip))
        return -EINVAL;

    if (kstrtoul(buf, 10, &temperature))
        return -EINVAL;

    /*
     * We are not doing any check on the 'temperature' value
     * here. The driver implementing 'set_trip_hyst' has to
     * take care of this.
     */
    ret = tz->ops->set_trip_hyst(tz, trip, temperature);

    return ret ? ret : count;
}

static ssize_t
trip_point_hyst_show(struct device *dev, struct device_attribute *attr,
            char *buf)
{
    struct thermal_zone_device *tz = to_thermal_zone(dev);
    int trip, ret;
    unsigned long temperature;

    if (!tz->ops->get_trip_hyst)
        return -EPERM;

    if (!sscanf(attr->attr.name, "trip_point_%d_hyst", &trip))
        return -EINVAL;

    ret = tz->ops->get_trip_hyst(tz, trip, &temperature);

    return ret ? ret : sprintf(buf, "%ld\n", temperature);
}

static ssize_t
passive_store(struct device *dev, struct device_attribute *attr,
            const char *buf, size_t count)
{
    struct thermal_zone_device *tz = to_thermal_zone(dev);
    struct thermal_cooling_device *cdev = NULL;
    int state;

    if (!sscanf(buf, "%d\n", &state))
        return -EINVAL;

    /* sanity check: values below 1000 millicelcius don't make sense
     * and can cause the system to go into a thermal heart attack
     */
    if (state && state < 1000)
        return -EINVAL;

    if (state && !tz->forced_passive) {
        mutex_lock(&thermal_list_lock);
        list_for_each_entry(cdev, &thermal_cdev_list, node) {
            if (!strncmp("Processor", cdev->type,
                     sizeof("Processor")))
                thermal_zone_bind_cooling_device(tz,
                        THERMAL_TRIPS_NONE, cdev,
                        THERMAL_NO_LIMIT,
                        THERMAL_NO_LIMIT);
        }
        mutex_unlock(&thermal_list_lock);
        if (!tz->passive_delay)
            tz->passive_delay = 1000;
    } else if (!state && tz->forced_passive) {
        mutex_lock(&thermal_list_lock);
        list_for_each_entry(cdev, &thermal_cdev_list, node) {
            if (!strncmp("Processor", cdev->type,
                     sizeof("Processor")))
                thermal_zone_unbind_cooling_device(tz,
                                   THERMAL_TRIPS_NONE,
                                   cdev);
        }
        mutex_unlock(&thermal_list_lock);
        tz->passive_delay = 0;
    }

    tz->forced_passive = state;

    thermal_zone_device_update(tz);

    return count;
}

static ssize_t
passive_show(struct device *dev, struct device_attribute *attr,
           char *buf)
{
    struct thermal_zone_device *tz = to_thermal_zone(dev);

    return sprintf(buf, "%d\n", tz->forced_passive);
}

static DEVICE_ATTR(type, 0444, type_show, NULL);
static DEVICE_ATTR(temp, 0444, temp_show, NULL);
static DEVICE_ATTR(mode, 0644, mode_show, mode_store);
static DEVICE_ATTR(passive, S_IRUGO | S_IWUSR, passive_show, passive_store);

/* sys I/F for cooling device */
#define to_cooling_device(_dev) \
    container_of(_dev, struct thermal_cooling_device, device)

static ssize_t
thermal_cooling_device_type_show(struct device *dev,
                 struct device_attribute *attr, char *buf)
{
    struct thermal_cooling_device *cdev = to_cooling_device(dev);

    return sprintf(buf, "%s\n", cdev->type);
}

static ssize_t
thermal_cooling_device_max_state_show(struct device *dev,
                      struct device_attribute *attr, char *buf)
{
    struct thermal_cooling_device *cdev = to_cooling_device(dev);
    unsigned long state;
    int ret;

    ret = cdev->ops->get_max_state(cdev, &state);
    if (ret)
        return ret;
    return sprintf(buf, "%ld\n", state);
}

static ssize_t
thermal_cooling_device_cur_state_show(struct device *dev,
                      struct device_attribute *attr, char *buf)
{
    struct thermal_cooling_device *cdev = to_cooling_device(dev);
    unsigned long state;
    int ret;

    ret = cdev->ops->get_cur_state(cdev, &state);
    if (ret)
        return ret;
    return sprintf(buf, "%ld\n", state);
}

static ssize_t
thermal_cooling_device_cur_state_store(struct device *dev,
                       struct device_attribute *attr,
                       const char *buf, size_t count)
{
    struct thermal_cooling_device *cdev = to_cooling_device(dev);
    unsigned long state;
    int result;

    if (!sscanf(buf, "%ld\n", &state))
        return -EINVAL;

    if ((long)state < 0)
        return -EINVAL;

    result = cdev->ops->set_cur_state(cdev, state);
    if (result)
        return result;
    return count;
}

static struct device_attribute dev_attr_cdev_type =
__ATTR(type, 0444, thermal_cooling_device_type_show, NULL);
static DEVICE_ATTR(max_state, 0444,
           thermal_cooling_device_max_state_show, NULL);
static DEVICE_ATTR(cur_state, 0644,
           thermal_cooling_device_cur_state_show,
           thermal_cooling_device_cur_state_store);

static ssize_t
thermal_cooling_device_trip_point_show(struct device *dev,
                       struct device_attribute *attr, char *buf)
{
    struct thermal_instance *instance;

    instance =
        container_of(attr, struct thermal_instance, attr);

    if (instance->trip == THERMAL_TRIPS_NONE)
        return sprintf(buf, "-1\n");
    else
        return sprintf(buf, "%d\n", instance->trip);
}

/* Device management */

#if defined(CONFIG_THERMAL_HWMON)

/* hwmon sys I/F */
#include <linux/hwmon.h>

/* thermal zone devices with the same type share one hwmon device */
struct thermal_hwmon_device {
    char type[THERMAL_NAME_LENGTH];
    struct device *device;
    int count;
    struct list_head tz_list;
    struct list_head node;
};

struct thermal_hwmon_attr {
    struct device_attribute attr;
    char name[16];
};

/* one temperature input for each thermal zone */
struct thermal_hwmon_temp {
    struct list_head hwmon_node;
    struct thermal_zone_device *tz;
    struct thermal_hwmon_attr temp_input;   /* hwmon sys attr */
    struct thermal_hwmon_attr temp_crit;    /* hwmon sys attr */
};

static LIST_HEAD(thermal_hwmon_list);

static ssize_t
name_show(struct device *dev, struct device_attribute *attr, char *buf)
{
    struct thermal_hwmon_device *hwmon = dev_get_drvdata(dev);
    return sprintf(buf, "%s\n", hwmon->type);
}
static DEVICE_ATTR(name, 0444, name_show, NULL);

static ssize_t
temp_input_show(struct device *dev, struct device_attribute *attr, char *buf)
{
    long temperature;
    int ret;
    struct thermal_hwmon_attr *hwmon_attr
            = container_of(attr, struct thermal_hwmon_attr, attr);
    struct thermal_hwmon_temp *temp
            = container_of(hwmon_attr, struct thermal_hwmon_temp,
                       temp_input);
    struct thermal_zone_device *tz = temp->tz;

    ret = tz->ops->get_temp(tz, &temperature);

    if (ret)
        return ret;

    return sprintf(buf, "%ld\n", temperature);
}

static ssize_t
temp_crit_show(struct device *dev, struct device_attribute *attr,
        char *buf)
{
    struct thermal_hwmon_attr *hwmon_attr
            = container_of(attr, struct thermal_hwmon_attr, attr);
    struct thermal_hwmon_temp *temp
            = container_of(hwmon_attr, struct thermal_hwmon_temp,
                       temp_crit);
    struct thermal_zone_device *tz = temp->tz;
    long temperature;
    int ret;

    ret = tz->ops->get_trip_temp(tz, 0, &temperature);
    if (ret)
        return ret;

    return sprintf(buf, "%ld\n", temperature);
}


static struct thermal_hwmon_device *
thermal_hwmon_lookup_by_type(const struct thermal_zone_device *tz)
{
    struct thermal_hwmon_device *hwmon;

    mutex_lock(&thermal_list_lock);
    list_for_each_entry(hwmon, &thermal_hwmon_list, node)
        if (!strcmp(hwmon->type, tz->type)) {
            mutex_unlock(&thermal_list_lock);
            return hwmon;
        }
    mutex_unlock(&thermal_list_lock);

    return NULL;
}

/* Find the temperature input matching a given thermal zone */
static struct thermal_hwmon_temp *
thermal_hwmon_lookup_temp(const struct thermal_hwmon_device *hwmon,
              const struct thermal_zone_device *tz)
{
    struct thermal_hwmon_temp *temp;

    mutex_lock(&thermal_list_lock);
    list_for_each_entry(temp, &hwmon->tz_list, hwmon_node)
        if (temp->tz == tz) {
            mutex_unlock(&thermal_list_lock);
            return temp;
        }
    mutex_unlock(&thermal_list_lock);

    return NULL;
}

static int
thermal_add_hwmon_sysfs(struct thermal_zone_device *tz)
{
    struct thermal_hwmon_device *hwmon;
    struct thermal_hwmon_temp *temp;
    int new_hwmon_device = 1;
    int result;

    hwmon = thermal_hwmon_lookup_by_type(tz);
    if (hwmon) {
        new_hwmon_device = 0;
        goto register_sys_interface;
    }

    hwmon = kzalloc(sizeof(struct thermal_hwmon_device), GFP_KERNEL);
    if (!hwmon)
        return -ENOMEM;

    INIT_LIST_HEAD(&hwmon->tz_list);
    strlcpy(hwmon->type, tz->type, THERMAL_NAME_LENGTH);
    hwmon->device = hwmon_device_register(NULL);
    if (IS_ERR(hwmon->device)) {
        result = PTR_ERR(hwmon->device);
        goto free_mem;
    }
    dev_set_drvdata(hwmon->device, hwmon);
    result = device_create_file(hwmon->device, &dev_attr_name);
    if (result)
        goto free_mem;

 register_sys_interface:
    temp = kzalloc(sizeof(struct thermal_hwmon_temp), GFP_KERNEL);
    if (!temp) {
        result = -ENOMEM;
        goto unregister_name;
    }

    temp->tz = tz;
    hwmon->count++;

    snprintf(temp->temp_input.name, sizeof(temp->temp_input.name),
         "temp%d_input", hwmon->count);
    temp->temp_input.attr.attr.name = temp->temp_input.name;
    temp->temp_input.attr.attr.mode = 0444;
    temp->temp_input.attr.show = temp_input_show;
    sysfs_attr_init(&temp->temp_input.attr.attr);
    result = device_create_file(hwmon->device, &temp->temp_input.attr);
    if (result)
        goto free_temp_mem;

    if (tz->ops->get_crit_temp) {
        unsigned long temperature;
        if (!tz->ops->get_crit_temp(tz, &temperature)) {
            snprintf(temp->temp_crit.name,
                 sizeof(temp->temp_crit.name),
                "temp%d_crit", hwmon->count);
            temp->temp_crit.attr.attr.name = temp->temp_crit.name;
            temp->temp_crit.attr.attr.mode = 0444;
            temp->temp_crit.attr.show = temp_crit_show;
            sysfs_attr_init(&temp->temp_crit.attr.attr);
            result = device_create_file(hwmon->device,
                            &temp->temp_crit.attr);
            if (result)
                goto unregister_input;
        }
    }

    mutex_lock(&thermal_list_lock);
    if (new_hwmon_device)
        list_add_tail(&hwmon->node, &thermal_hwmon_list);
    list_add_tail(&temp->hwmon_node, &hwmon->tz_list);
    mutex_unlock(&thermal_list_lock);

    return 0;

 unregister_input:
    device_remove_file(hwmon->device, &temp->temp_input.attr);
 free_temp_mem:
    kfree(temp);
 unregister_name:
    if (new_hwmon_device) {
        device_remove_file(hwmon->device, &dev_attr_name);
        hwmon_device_unregister(hwmon->device);
    }
 free_mem:
    if (new_hwmon_device)
        kfree(hwmon);

    return result;
}

static void
thermal_remove_hwmon_sysfs(struct thermal_zone_device *tz)
{
    struct thermal_hwmon_device *hwmon;
    struct thermal_hwmon_temp *temp;

    hwmon = thermal_hwmon_lookup_by_type(tz);
    if (unlikely(!hwmon)) {
        /* Should never happen... */
        dev_dbg(&tz->device, "hwmon device lookup failed!\n");
        return;
    }

    temp = thermal_hwmon_lookup_temp(hwmon, tz);
    if (unlikely(!temp)) {
        /* Should never happen... */
        dev_dbg(&tz->device, "temperature input lookup failed!\n");
        return;
    }

    device_remove_file(hwmon->device, &temp->temp_input.attr);
    if (tz->ops->get_crit_temp)
        device_remove_file(hwmon->device, &temp->temp_crit.attr);

    mutex_lock(&thermal_list_lock);
    list_del(&temp->hwmon_node);
    kfree(temp);
    if (!list_empty(&hwmon->tz_list)) {
        mutex_unlock(&thermal_list_lock);
        return;
    }
    list_del(&hwmon->node);
    mutex_unlock(&thermal_list_lock);

    device_remove_file(hwmon->device, &dev_attr_name);
    hwmon_device_unregister(hwmon->device);
    kfree(hwmon);
}
#else
static int
thermal_add_hwmon_sysfs(struct thermal_zone_device *tz)
{
    return 0;
}

static void
thermal_remove_hwmon_sysfs(struct thermal_zone_device *tz)
{
}
#endif

static void thermal_zone_device_set_polling(struct thermal_zone_device *tz,
                        int delay)
{
    if (delay > 1000)
        mod_delayed_work(system_freezable_wq, &tz->poll_queue,
                 round_jiffies(msecs_to_jiffies(delay)));
    else if (delay)
        mod_delayed_work(system_freezable_wq, &tz->poll_queue,
                 msecs_to_jiffies(delay));
    else
        cancel_delayed_work(&tz->poll_queue);
}

static void thermal_zone_device_check(struct work_struct *work)
{
    struct thermal_zone_device *tz = container_of(work, struct
                              thermal_zone_device,
                              poll_queue.work);
    thermal_zone_device_update(tz);
}

int thermal_zone_bind_cooling_device(struct thermal_zone_device *tz,
                     int trip,
                     struct thermal_cooling_device *cdev,
                     unsigned long upper, unsigned long lower)
{
    struct thermal_instance *dev;
    struct thermal_instance *pos;
    struct thermal_zone_device *pos1;
    struct thermal_cooling_device *pos2;
    unsigned long max_state;
    int result;

    if (trip >= tz->trips || (trip < 0 && trip != THERMAL_TRIPS_NONE))
        return -EINVAL;

    list_for_each_entry(pos1, &thermal_tz_list, node) {
        if (pos1 == tz)
            break;
    }
    list_for_each_entry(pos2, &thermal_cdev_list, node) {
        if (pos2 == cdev)
            break;
    }

    if (tz != pos1 || cdev != pos2)
        return -EINVAL;

    cdev->ops->get_max_state(cdev, &max_state);

    /* lower default 0, upper default max_state */
    lower = lower == THERMAL_NO_LIMIT ? 0 : lower;
    upper = upper == THERMAL_NO_LIMIT ? max_state : upper;

    if (lower > upper || upper > max_state)
        return -EINVAL;

    dev =
        kzalloc(sizeof(struct thermal_instance), GFP_KERNEL);
    if (!dev)
        return -ENOMEM;
    dev->tz = tz;
    dev->cdev = cdev;
    dev->trip = trip;
    dev->upper = upper;
    dev->lower = lower;
    dev->target = THERMAL_NO_TARGET;

    result = get_idr(&tz->idr, &tz->lock, &dev->id);
    if (result)
        goto free_mem;

    sprintf(dev->name, "cdev%d", dev->id);
    result =
        sysfs_create_link(&tz->device.kobj, &cdev->device.kobj, dev->name);
    if (result)
        goto release_idr;

    sprintf(dev->attr_name, "cdev%d_trip_point", dev->id);
    sysfs_attr_init(&dev->attr.attr);
    dev->attr.attr.name = dev->attr_name;
    dev->attr.attr.mode = 0444;
    dev->attr.show = thermal_cooling_device_trip_point_show;
    result = device_create_file(&tz->device, &dev->attr);
    if (result)
        goto remove_symbol_link;

    mutex_lock(&tz->lock);
    mutex_lock(&cdev->lock);
    list_for_each_entry(pos, &tz->thermal_instances, tz_node)
        if (pos->tz == tz && pos->trip == trip && pos->cdev == cdev) {
        result = -EEXIST;
        break;
    }
    if (!result) {
        list_add_tail(&dev->tz_node, &tz->thermal_instances);
        list_add_tail(&dev->cdev_node, &cdev->thermal_instances);
    }
    mutex_unlock(&cdev->lock);
    mutex_unlock(&tz->lock);

    if (!result)
        return 0;

    device_remove_file(&tz->device, &dev->attr);
remove_symbol_link:
    sysfs_remove_link(&tz->device.kobj, dev->name);
release_idr:
    release_idr(&tz->idr, &tz->lock, dev->id);
free_mem:
    kfree(dev);
    return result;
}
EXPORT_SYMBOL(thermal_zone_bind_cooling_device);

int thermal_zone_unbind_cooling_device(struct thermal_zone_device *tz,
                       int trip,
                       struct thermal_cooling_device *cdev)
{
    struct thermal_instance *pos, *next;

    mutex_lock(&tz->lock);
    mutex_lock(&cdev->lock);
    list_for_each_entry_safe(pos, next, &tz->thermal_instances, tz_node) {
        if (pos->tz == tz && pos->trip == trip && pos->cdev == cdev) {
            list_del(&pos->tz_node);
            list_del(&pos->cdev_node);
            mutex_unlock(&cdev->lock);
            mutex_unlock(&tz->lock);
            goto unbind;
        }
    }
    mutex_unlock(&cdev->lock);
    mutex_unlock(&tz->lock);

    return -ENODEV;

unbind:
    device_remove_file(&tz->device, &pos->attr);
    sysfs_remove_link(&tz->device.kobj, pos->name);
    release_idr(&tz->idr, &tz->lock, pos->id);
    kfree(pos);
    return 0;
}
EXPORT_SYMBOL(thermal_zone_unbind_cooling_device);

static void thermal_release(struct device *dev)
{
    struct thermal_zone_device *tz;
    struct thermal_cooling_device *cdev;

    if (!strncmp(dev_name(dev), "thermal_zone",
             sizeof("thermal_zone") - 1)) {
        tz = to_thermal_zone(dev);
        kfree(tz);
    } else {
        cdev = to_cooling_device(dev);
        kfree(cdev);
    }
}

static struct class thermal_class = {
    .name = "thermal",
    .dev_release = thermal_release,
};

struct thermal_cooling_device *
thermal_cooling_device_register(char *type, void *devdata,
                const struct thermal_cooling_device_ops *ops)
{
    struct thermal_cooling_device *cdev;
    struct thermal_zone_device *pos;
    int result;

    if (type && strlen(type) >= THERMAL_NAME_LENGTH)
        return ERR_PTR(-EINVAL);

    if (!ops || !ops->get_max_state || !ops->get_cur_state ||
        !ops->set_cur_state)
        return ERR_PTR(-EINVAL);

    cdev = kzalloc(sizeof(struct thermal_cooling_device), GFP_KERNEL);
    if (!cdev)
        return ERR_PTR(-ENOMEM);

    result = get_idr(&thermal_cdev_idr, &thermal_idr_lock, &cdev->id);
    if (result) {
        kfree(cdev);
        return ERR_PTR(result);
    }

    strcpy(cdev->type, type ? : "");
    mutex_init(&cdev->lock);
    INIT_LIST_HEAD(&cdev->thermal_instances);
    cdev->ops = ops;
    cdev->updated = true;
    cdev->device.class = &thermal_class;
    cdev->devdata = devdata;
    dev_set_name(&cdev->device, "cooling_device%d", cdev->id);
    result = device_register(&cdev->device);
    if (result) {
        release_idr(&thermal_cdev_idr, &thermal_idr_lock, cdev->id);
        kfree(cdev);
        return ERR_PTR(result);
    }

    /* sys I/F */
    if (type) {
        result = device_create_file(&cdev->device, &dev_attr_cdev_type);
        if (result)
            goto unregister;
    }

    result = device_create_file(&cdev->device, &dev_attr_max_state);
    if (result)
        goto unregister;

    result = device_create_file(&cdev->device, &dev_attr_cur_state);
    if (result)
        goto unregister;

    mutex_lock(&thermal_list_lock);
    list_add(&cdev->node, &thermal_cdev_list);
    list_for_each_entry(pos, &thermal_tz_list, node) {
        if (!pos->ops->bind)
            continue;
        result = pos->ops->bind(pos, cdev);
        if (result)
            break;

    }
    mutex_unlock(&thermal_list_lock);

    if (!result)
        return cdev;

unregister:
    release_idr(&thermal_cdev_idr, &thermal_idr_lock, cdev->id);
    device_unregister(&cdev->device);
    return ERR_PTR(result);
}
EXPORT_SYMBOL(thermal_cooling_device_register);

void thermal_cooling_device_unregister(struct
                       thermal_cooling_device
                       *cdev)
{
    struct thermal_zone_device *tz;
    struct thermal_cooling_device *pos = NULL;

    if (!cdev)
        return;

    mutex_lock(&thermal_list_lock);
    list_for_each_entry(pos, &thermal_cdev_list, node)
        if (pos == cdev)
        break;
    if (pos != cdev) {
        /* thermal cooling device not found */
        mutex_unlock(&thermal_list_lock);
        return;
    }
    list_del(&cdev->node);
    list_for_each_entry(tz, &thermal_tz_list, node) {
        if (!tz->ops->unbind)
            continue;
        tz->ops->unbind(tz, cdev);
    }
    mutex_unlock(&thermal_list_lock);
    if (cdev->type[0])
        device_remove_file(&cdev->device, &dev_attr_cdev_type);
    device_remove_file(&cdev->device, &dev_attr_max_state);
    device_remove_file(&cdev->device, &dev_attr_cur_state);

    release_idr(&thermal_cdev_idr, &thermal_idr_lock, cdev->id);
    device_unregister(&cdev->device);
    return;
}
EXPORT_SYMBOL(thermal_cooling_device_unregister);

static void thermal_cdev_do_update(struct thermal_cooling_device *cdev)
{
    struct thermal_instance *instance;
    unsigned long target = 0;

    /* cooling device is updated*/
    if (cdev->updated)
        return;

    mutex_lock(&cdev->lock);
    /* Make sure cdev enters the deepest cooling state */
    list_for_each_entry(instance, &cdev->thermal_instances, cdev_node) {
        if (instance->target == THERMAL_NO_TARGET)
            continue;
        if (instance->target > target)
            target = instance->target;
    }
    mutex_unlock(&cdev->lock);
    cdev->ops->set_cur_state(cdev, target);
    cdev->updated = true;
}

static void thermal_zone_do_update(struct thermal_zone_device *tz)
{
    struct thermal_instance *instance;

    list_for_each_entry(instance, &tz->thermal_instances, tz_node)
        thermal_cdev_do_update(instance->cdev);
}

/*
 * Cooling algorithm for both active and passive cooling
 *
 * 1. if the temperature is higher than a trip point,
 *    a. if the trend is THERMAL_TREND_RAISING, use higher cooling
 *       state for this trip point
 *    b. if the trend is THERMAL_TREND_DROPPING, use lower cooling
 *       state for this trip point
 *
 * 2. if the temperature is lower than a trip point, use lower
 *    cooling state for this trip point
 *
 * Note that this behaves the same as the previous passive cooling
 * algorithm.
 */

static void thermal_zone_trip_update(struct thermal_zone_device *tz,
                     int trip, long temp)
{
    struct thermal_instance *instance;
    struct thermal_cooling_device *cdev = NULL;
    unsigned long cur_state, max_state;
    long trip_temp;
    enum thermal_trip_type trip_type;
    enum thermal_trend trend;

    if (trip == THERMAL_TRIPS_NONE) {
        trip_temp = tz->forced_passive;
        trip_type = THERMAL_TRIPS_NONE;
    } else {
        tz->ops->get_trip_temp(tz, trip, &trip_temp);
        tz->ops->get_trip_type(tz, trip, &trip_type);
    }

    if (!tz->ops->get_trend || tz->ops->get_trend(tz, trip, &trend)) {
        /*
         * compare the current temperature and previous temperature
         * to get the thermal trend, if no special requirement
         */
        if (tz->temperature > tz->last_temperature)
            trend = THERMAL_TREND_RAISING;
        else if (tz->temperature < tz->last_temperature)
            trend = THERMAL_TREND_DROPPING;
        else
            trend = THERMAL_TREND_STABLE;
    }

    if (temp >= trip_temp) {
        list_for_each_entry(instance, &tz->thermal_instances, tz_node) {
            if (instance->trip != trip)
                continue;

            cdev = instance->cdev;

            cdev->ops->get_cur_state(cdev, &cur_state);
            cdev->ops->get_max_state(cdev, &max_state);

            if (trend == THERMAL_TREND_RAISING) {
                cur_state = cur_state < instance->upper ?
                        (cur_state + 1) : instance->upper;
            } else if (trend == THERMAL_TREND_DROPPING) {
                cur_state = cur_state > instance->lower ?
                    (cur_state - 1) : instance->lower;
            }

            /* activate a passive thermal instance */
            if ((trip_type == THERMAL_TRIP_PASSIVE ||
                 trip_type == THERMAL_TRIPS_NONE) &&
                 instance->target == THERMAL_NO_TARGET)
                tz->passive++;

            instance->target = cur_state;
            cdev->updated = false; /* cooling device needs update */
        }
    } else {    /* below trip */
        list_for_each_entry(instance, &tz->thermal_instances, tz_node) {
            if (instance->trip != trip)
                continue;

            /* Do not use the inactive thermal instance */
            if (instance->target == THERMAL_NO_TARGET)
                continue;
            cdev = instance->cdev;
            cdev->ops->get_cur_state(cdev, &cur_state);

            cur_state = cur_state > instance->lower ?
                    (cur_state - 1) : THERMAL_NO_TARGET;

            /* deactivate a passive thermal instance */
            if ((trip_type == THERMAL_TRIP_PASSIVE ||
                 trip_type == THERMAL_TRIPS_NONE) &&
                 cur_state == THERMAL_NO_TARGET)
                tz->passive--;
            instance->target = cur_state;
            cdev->updated = false; /* cooling device needs update */
        }
    }

    return;
}
void thermal_zone_device_update(struct thermal_zone_device *tz)
{
    int count, ret = 0;
    long temp, trip_temp;
    enum thermal_trip_type trip_type;

    mutex_lock(&tz->lock);

    if (tz->ops->get_temp(tz, &temp)) {
        /* get_temp failed - retry it later */
        pr_warn("failed to read out thermal zone %d\n", tz->id);
        goto leave;
    }

    tz->last_temperature = tz->temperature;
    tz->temperature = temp;

    for (count = 0; count < tz->trips; count++) {
        tz->ops->get_trip_type(tz, count, &trip_type);
        tz->ops->get_trip_temp(tz, count, &trip_temp);

        switch (trip_type) {
        case THERMAL_TRIP_CRITICAL:
            if (temp >= trip_temp) {
                if (tz->ops->notify)
                    ret = tz->ops->notify(tz, count,
                                  trip_type);
                if (!ret) {
                    pr_emerg("Critical temperature reached (%ld C), shutting down\n",
                         temp/1000);
                    orderly_poweroff(true);
                }
            }
            break;
        case THERMAL_TRIP_HOT:
            if (temp >= trip_temp)
                if (tz->ops->notify)
                    tz->ops->notify(tz, count, trip_type);
            break;
        case THERMAL_TRIP_ACTIVE:
            thermal_zone_trip_update(tz, count, temp);
            break;
        case THERMAL_TRIP_PASSIVE:
            if (temp >= trip_temp || tz->passive)
                thermal_zone_trip_update(tz, count, temp);
            break;
        }
    }

    if (tz->forced_passive)
        thermal_zone_trip_update(tz, THERMAL_TRIPS_NONE, temp);
    thermal_zone_do_update(tz);

leave:
    if (tz->passive)
        thermal_zone_device_set_polling(tz, tz->passive_delay);
    else if (tz->polling_delay)
        thermal_zone_device_set_polling(tz, tz->polling_delay);
    else
        thermal_zone_device_set_polling(tz, 0);
    mutex_unlock(&tz->lock);
}
EXPORT_SYMBOL(thermal_zone_device_update);

static int create_trip_attrs(struct thermal_zone_device *tz, int mask)
{
    int indx;
    int size = sizeof(struct thermal_attr) * tz->trips;

    tz->trip_type_attrs = kzalloc(size, GFP_KERNEL);
    if (!tz->trip_type_attrs)
        return -ENOMEM;

    tz->trip_temp_attrs = kzalloc(size, GFP_KERNEL);
    if (!tz->trip_temp_attrs) {
        kfree(tz->trip_type_attrs);
        return -ENOMEM;
    }

    if (tz->ops->get_trip_hyst) {
        tz->trip_hyst_attrs = kzalloc(size, GFP_KERNEL);
        if (!tz->trip_hyst_attrs) {
            kfree(tz->trip_type_attrs);
            kfree(tz->trip_temp_attrs);
            return -ENOMEM;
        }
    }


    for (indx = 0; indx < tz->trips; indx++) {
        /* create trip type attribute */
        snprintf(tz->trip_type_attrs[indx].name, THERMAL_NAME_LENGTH,
             "trip_point_%d_type", indx);

        sysfs_attr_init(&tz->trip_type_attrs[indx].attr.attr);
        tz->trip_type_attrs[indx].attr.attr.name =
                        tz->trip_type_attrs[indx].name;
        tz->trip_type_attrs[indx].attr.attr.mode = S_IRUGO;
        tz->trip_type_attrs[indx].attr.show = trip_point_type_show;

        device_create_file(&tz->device,
                   &tz->trip_type_attrs[indx].attr);

        /* create trip temp attribute */
        snprintf(tz->trip_temp_attrs[indx].name, THERMAL_NAME_LENGTH,
             "trip_point_%d_temp", indx);

        sysfs_attr_init(&tz->trip_temp_attrs[indx].attr.attr);
        tz->trip_temp_attrs[indx].attr.attr.name =
                        tz->trip_temp_attrs[indx].name;
        tz->trip_temp_attrs[indx].attr.attr.mode = S_IRUGO;
        tz->trip_temp_attrs[indx].attr.show = trip_point_temp_show;
        if (mask & (1 << indx)) {
            tz->trip_temp_attrs[indx].attr.attr.mode |= S_IWUSR;
            tz->trip_temp_attrs[indx].attr.store =
                            trip_point_temp_store;
        }

        device_create_file(&tz->device,
                   &tz->trip_temp_attrs[indx].attr);

        /* create Optional trip hyst attribute */
        if (!tz->ops->get_trip_hyst)
            continue;
        snprintf(tz->trip_hyst_attrs[indx].name, THERMAL_NAME_LENGTH,
             "trip_point_%d_hyst", indx);

        sysfs_attr_init(&tz->trip_hyst_attrs[indx].attr.attr);
        tz->trip_hyst_attrs[indx].attr.attr.name =
                    tz->trip_hyst_attrs[indx].name;
        tz->trip_hyst_attrs[indx].attr.attr.mode = S_IRUGO;
        tz->trip_hyst_attrs[indx].attr.show = trip_point_hyst_show;
        if (tz->ops->set_trip_hyst) {
            tz->trip_hyst_attrs[indx].attr.attr.mode |= S_IWUSR;
            tz->trip_hyst_attrs[indx].attr.store =
                    trip_point_hyst_store;
        }

        device_create_file(&tz->device,
                   &tz->trip_hyst_attrs[indx].attr);
    }
    return 0;
}

static void remove_trip_attrs(struct thermal_zone_device *tz)
{
    int indx;

    for (indx = 0; indx < tz->trips; indx++) {
        device_remove_file(&tz->device,
                   &tz->trip_type_attrs[indx].attr);
        device_remove_file(&tz->device,
                   &tz->trip_temp_attrs[indx].attr);
        if (tz->ops->get_trip_hyst)
            device_remove_file(&tz->device,
                  &tz->trip_hyst_attrs[indx].attr);
    }
    kfree(tz->trip_type_attrs);
    kfree(tz->trip_temp_attrs);
    kfree(tz->trip_hyst_attrs);
}

struct thermal_zone_device *thermal_zone_device_register(const char *type,
    int trips, int mask, void *devdata,
    const struct thermal_zone_device_ops *ops,
    int passive_delay, int polling_delay)
{
    struct thermal_zone_device *tz;
    struct thermal_cooling_device *pos;
    enum thermal_trip_type trip_type;
    int result;
    int count;
    int passive = 0;

    if (type && strlen(type) >= THERMAL_NAME_LENGTH)
        return ERR_PTR(-EINVAL);

    if (trips > THERMAL_MAX_TRIPS || trips < 0 || mask >> trips)
        return ERR_PTR(-EINVAL);

    if (!ops || !ops->get_temp)
        return ERR_PTR(-EINVAL);

    tz = kzalloc(sizeof(struct thermal_zone_device), GFP_KERNEL);
    if (!tz)
        return ERR_PTR(-ENOMEM);

    INIT_LIST_HEAD(&tz->thermal_instances);
    idr_init(&tz->idr);
    mutex_init(&tz->lock);
    result = get_idr(&thermal_tz_idr, &thermal_idr_lock, &tz->id);
    if (result) {
        kfree(tz);
        return ERR_PTR(result);
    }

    strcpy(tz->type, type ? : "");
    tz->ops = ops;
    tz->device.class = &thermal_class;
    tz->devdata = devdata;
    tz->trips = trips;
    tz->passive_delay = passive_delay;
    tz->polling_delay = polling_delay;

    dev_set_name(&tz->device, "thermal_zone%d", tz->id);
    result = device_register(&tz->device);
    if (result) {
        release_idr(&thermal_tz_idr, &thermal_idr_lock, tz->id);
        kfree(tz);
        return ERR_PTR(result);
    }

    /* sys I/F */
    if (type) {
        result = device_create_file(&tz->device, &dev_attr_type);
        if (result)
            goto unregister;
    }

    result = device_create_file(&tz->device, &dev_attr_temp);
    if (result)
        goto unregister;

    if (ops->get_mode) {
        result = device_create_file(&tz->device, &dev_attr_mode);
        if (result)
            goto unregister;
    }

    result = create_trip_attrs(tz, mask);
    if (result)
        goto unregister;

    for (count = 0; count < trips; count++) {
        tz->ops->get_trip_type(tz, count, &trip_type);
        if (trip_type == THERMAL_TRIP_PASSIVE)
            passive = 1;
    }

    if (!passive)
        result = device_create_file(&tz->device,
                        &dev_attr_passive);

    if (result)
        goto unregister;

    result = thermal_add_hwmon_sysfs(tz);
    if (result)
        goto unregister;

    mutex_lock(&thermal_list_lock);
    list_add_tail(&tz->node, &thermal_tz_list);
    if (ops->bind)
        list_for_each_entry(pos, &thermal_cdev_list, node) {
        result = ops->bind(tz, pos);
        if (result)
            break;
        }
    mutex_unlock(&thermal_list_lock);

    INIT_DELAYED_WORK(&(tz->poll_queue), thermal_zone_device_check);

    thermal_zone_device_update(tz);

    if (!result)
        return tz;

unregister:
    release_idr(&thermal_tz_idr, &thermal_idr_lock, tz->id);
    device_unregister(&tz->device);
    return ERR_PTR(result);
}
EXPORT_SYMBOL(thermal_zone_device_register);

void thermal_zone_device_unregister(struct thermal_zone_device *tz)
{
    struct thermal_cooling_device *cdev;
    struct thermal_zone_device *pos = NULL;

    if (!tz)
        return;

    mutex_lock(&thermal_list_lock);
    list_for_each_entry(pos, &thermal_tz_list, node)
        if (pos == tz)
        break;
    if (pos != tz) {
        /* thermal zone device not found */
        mutex_unlock(&thermal_list_lock);
        return;
    }
    list_del(&tz->node);
    if (tz->ops->unbind)
        list_for_each_entry(cdev, &thermal_cdev_list, node)
            tz->ops->unbind(tz, cdev);
    mutex_unlock(&thermal_list_lock);

    thermal_zone_device_set_polling(tz, 0);

    if (tz->type[0])
        device_remove_file(&tz->device, &dev_attr_type);
    device_remove_file(&tz->device, &dev_attr_temp);
    if (tz->ops->get_mode)
        device_remove_file(&tz->device, &dev_attr_mode);
    remove_trip_attrs(tz);

    thermal_remove_hwmon_sysfs(tz);
    release_idr(&thermal_tz_idr, &thermal_idr_lock, tz->id);
    idr_destroy(&tz->idr);
    mutex_destroy(&tz->lock);
    device_unregister(&tz->device);
    return;
}
EXPORT_SYMBOL(thermal_zone_device_unregister);

#ifdef CONFIG_NET
static struct genl_family thermal_event_genl_family = {
    .id = GENL_ID_GENERATE,
    .name = THERMAL_GENL_FAMILY_NAME,
    .version = THERMAL_GENL_VERSION,
    .maxattr = THERMAL_GENL_ATTR_MAX,
};

static struct genl_multicast_group thermal_event_mcgrp = {
    .name = THERMAL_GENL_MCAST_GROUP_NAME,
};

int thermal_generate_netlink_event(u32 orig, enum events event)
{
    struct sk_buff *skb;
    struct nlattr *attr;
    struct thermal_genl_event *thermal_event;
    void *msg_header;
    int size;
    int result;
    static unsigned int thermal_event_seqnum;

    /* allocate memory */
    size = nla_total_size(sizeof(struct thermal_genl_event)) +
           nla_total_size(0);

    skb = genlmsg_new(size, GFP_ATOMIC);
    if (!skb)
        return -ENOMEM;

    /* add the genetlink message header */
    msg_header = genlmsg_put(skb, 0, thermal_event_seqnum++,
                 &thermal_event_genl_family, 0,
                 THERMAL_GENL_CMD_EVENT);
    if (!msg_header) {
        nlmsg_free(skb);
        return -ENOMEM;
    }

    /* fill the data */
    attr = nla_reserve(skb, THERMAL_GENL_ATTR_EVENT,
               sizeof(struct thermal_genl_event));

    if (!attr) {
        nlmsg_free(skb);
        return -EINVAL;
    }

    thermal_event = nla_data(attr);
    if (!thermal_event) {
        nlmsg_free(skb);
        return -EINVAL;
    }

    memset(thermal_event, 0, sizeof(struct thermal_genl_event));

    thermal_event->orig = orig;
    thermal_event->event = event;

    /* send multicast genetlink message */
    result = genlmsg_end(skb, msg_header);
    if (result < 0) {
        nlmsg_free(skb);
        return result;
    }

    result = genlmsg_multicast(skb, 0, thermal_event_mcgrp.id, GFP_ATOMIC);
    if (result)
        pr_info("failed to send netlink event:%d\n", result);

    return result;
}
EXPORT_SYMBOL(thermal_generate_netlink_event);

static int genetlink_init(void)
{
    int result;

    result = genl_register_family(&thermal_event_genl_family);
    if (result)
        return result;

    result = genl_register_mc_group(&thermal_event_genl_family,
                    &thermal_event_mcgrp);
    if (result)
        genl_unregister_family(&thermal_event_genl_family);
    return result;
}

static void genetlink_exit(void)
{
    genl_unregister_family(&thermal_event_genl_family);
}
#else /* !CONFIG_NET */
static inline int genetlink_init(void) { return 0; }
static inline void genetlink_exit(void) {}
#endif /* !CONFIG_NET */

static int __init thermal_init(void)
{
    int result = 0;

    result = class_register(&thermal_class);
    if (result) {
        idr_destroy(&thermal_tz_idr);
        idr_destroy(&thermal_cdev_idr);
        mutex_destroy(&thermal_idr_lock);
        mutex_destroy(&thermal_list_lock);
    }
    result = genetlink_init();
    return result;
}

static void __exit thermal_exit(void)
{
    class_unregister(&thermal_class);
    idr_destroy(&thermal_tz_idr);
    idr_destroy(&thermal_cdev_idr);
    mutex_destroy(&thermal_idr_lock);
    mutex_destroy(&thermal_list_lock);
    genetlink_exit();
}

fs_initcall(thermal_init);
module_exit(thermal_exit);