// SPDX-License-Identifier: GPL-2.0
/*
 *  thermal_helpers.c - helper functions to handle thermal devices
 *
 *  Copyright (C) 2016 Eduardo Valentin <edubezval@gmail.com>
 *
 *  Highly based on original thermal_core.c
 *  Copyright (C) 2008 Intel Corp
 *  Copyright (C) 2008 Zhang Rui <rui.zhang@intel.com>
 *  Copyright (C) 2008 Sujith Thomas <sujith.thomas@intel.com>
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/sysfs.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/string.h>

#include <trace/events/thermal.h>

#include "thermal_core.h"

int get_tz_trend(struct thermal_zone_device *tz, int trip)
{
        enum thermal_trend trend;

        if (tz->emul_temperature || !tz->ops->get_trend ||
            tz->ops->get_trend(tz, trip, &trend)) {
                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;
        }

        return trend;
}
EXPORT_SYMBOL(get_tz_trend);

struct thermal_instance *
get_thermal_instance(struct thermal_zone_device *tz,
                     struct thermal_cooling_device *cdev, int trip)
{
        struct thermal_instance *pos = NULL;
        struct thermal_instance *target_instance = NULL;

        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) {
                        target_instance = pos;
                        break;
                }
        }

        mutex_unlock(&cdev->lock);
        mutex_unlock(&tz->lock);

        return target_instance;
}
EXPORT_SYMBOL(get_thermal_instance);

/**
 * thermal_zone_get_temp() - returns the temperature of a thermal zone
 * @tz: a valid pointer to a struct thermal_zone_device
 * @temp: a valid pointer to where to store the resulting temperature.
 *
 * When a valid thermal zone reference is passed, it will fetch its
 * temperature and fill @temp.
 *
 * Return: On success returns 0, an error code otherwise
 */
int thermal_zone_get_temp(struct thermal_zone_device *tz, int *temp)
{
        int ret = -EINVAL;
        int count;
        int crit_temp = INT_MAX;
        enum thermal_trip_type type;

        if (!tz || IS_ERR(tz) || !tz->ops->get_temp)
                goto exit;

        mutex_lock(&tz->lock);

        ret = tz->ops->get_temp(tz, temp);

        if (IS_ENABLED(CONFIG_THERMAL_EMULATION) && tz->emul_temperature) {
                for (count = 0; count < tz->trips; count++) {
                        ret = tz->ops->get_trip_type(tz, count, &type);
                        if (!ret && type == THERMAL_TRIP_CRITICAL) {
                                ret = tz->ops->get_trip_temp(tz, count,
                                                &crit_temp);
                                break;
                        }
                }

                /*
                 * Only allow emulating a temperature when the real temperature
                 * is below the critical temperature so that the emulation code
                 * cannot hide critical conditions.
                 */
                if (!ret && *temp < crit_temp)
                        *temp = tz->emul_temperature;
        }

        mutex_unlock(&tz->lock);
exit:
        return ret;
}
EXPORT_SYMBOL_GPL(thermal_zone_get_temp);

void thermal_zone_set_trips(struct thermal_zone_device *tz)
{
        int low = -INT_MAX;
        int high = INT_MAX;
        int trip_temp, hysteresis;
        int i, ret;

        mutex_lock(&tz->lock);

        if (!tz->ops->set_trips || !tz->ops->get_trip_hyst)
                goto exit;

        for (i = 0; i < tz->trips; i++) {
                int trip_low;

                tz->ops->get_trip_temp(tz, i, &trip_temp);
                tz->ops->get_trip_hyst(tz, i, &hysteresis);

                trip_low = trip_temp - hysteresis;

                if (trip_low < tz->temperature && trip_low > low)
                        low = trip_low;

                if (trip_temp > tz->temperature && trip_temp < high)
                        high = trip_temp;
        }

        /* No need to change trip points */
        if (tz->prev_low_trip == low && tz->prev_high_trip == high)
                goto exit;

        tz->prev_low_trip = low;
        tz->prev_high_trip = high;

        dev_dbg(&tz->device,
                "new temperature boundaries: %d < x < %d\n", low, high);

        /*
         * Set a temperature window. When this window is left the driver
         * must inform the thermal core via thermal_zone_device_update.
         */
        ret = tz->ops->set_trips(tz, low, high);
        if (ret)
                dev_err(&tz->device, "Failed to set trips: %d\n", ret);

exit:
        mutex_unlock(&tz->lock);
}
EXPORT_SYMBOL_GPL(thermal_zone_set_trips);

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

        mutex_lock(&cdev->lock);
        /* cooling device is updated*/
        if (cdev->updated) {
                mutex_unlock(&cdev->lock);
                return;
        }

        /* Make sure cdev enters the deepest cooling state */
        list_for_each_entry(instance, &cdev->thermal_instances, cdev_node) {
                dev_dbg(&cdev->device, "zone%d->target=%lu\n",
                        instance->tz->id, instance->target);
                if (instance->target == THERMAL_NO_TARGET)
                        continue;
                if (instance->target > target)
                        target = instance->target;
        }

        if (!cdev->ops->set_cur_state(cdev, target))
                thermal_cooling_device_stats_update(cdev, target);

        cdev->updated = true;
        mutex_unlock(&cdev->lock);
        trace_cdev_update(cdev, target);
        dev_dbg(&cdev->device, "set to state %lu\n", target);
}
EXPORT_SYMBOL(thermal_cdev_update);

/**
 * thermal_zone_get_slope - return the slope attribute of the thermal zone
 * @tz: thermal zone device with the slope attribute
 *
 * Return: If the thermal zone device has a slope attribute, return it, else
 * return 1.
 */
int thermal_zone_get_slope(struct thermal_zone_device *tz)
{
        if (tz && tz->tzp)
                return tz->tzp->slope;
        return 1;
}
EXPORT_SYMBOL_GPL(thermal_zone_get_slope);

/**
 * thermal_zone_get_offset - return the offset attribute of the thermal zone
 * @tz: thermal zone device with the offset attribute
 *
 * Return: If the thermal zone device has a offset attribute, return it, else
 * return 0.
 */
int thermal_zone_get_offset(struct thermal_zone_device *tz)
{
        if (tz && tz->tzp)
                return tz->tzp->offset;
        return 0;
}
EXPORT_SYMBOL_GPL(thermal_zone_get_offset);