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

#include "thermal_core.h"
#include "thermal_trace.h"

int get_tz_trend(struct thermal_zone_device *tz, const struct thermal_trip *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;
}

static bool thermal_instance_present(struct thermal_zone_device *tz,
                                     struct thermal_cooling_device *cdev,
                                     const struct thermal_trip *trip)
{
        const struct thermal_trip_desc *td = trip_to_trip_desc(trip);
        struct thermal_instance *ti;

        list_for_each_entry(ti, &td->thermal_instances, trip_node) {
                if (ti->cdev == cdev)
                        return true;
        }

        return false;
}

bool thermal_trip_is_bound_to_cdev(struct thermal_zone_device *tz,
                                   const struct thermal_trip *trip,
                                   struct thermal_cooling_device *cdev)
{
        guard(thermal_zone)(tz);
        guard(cooling_dev)(cdev);

        return thermal_instance_present(tz, cdev, trip);
}
EXPORT_SYMBOL_GPL(thermal_trip_is_bound_to_cdev);

/**
 * __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.
 *
 * Both tz and tz->ops must be valid pointers when calling this function,
 * and the tz->ops.get_temp callback must be provided.
 * The function must be called under tz->lock.
 *
 * Return: On success returns 0, an error code otherwise
 */
int __thermal_zone_get_temp(struct thermal_zone_device *tz, int *temp)
{
        const struct thermal_trip_desc *td;
        int crit_temp = INT_MAX;
        int ret = -EINVAL;

        lockdep_assert_held(&tz->lock);

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

        if (IS_ENABLED(CONFIG_THERMAL_EMULATION) && tz->emul_temperature) {
                for_each_trip_desc(tz, td) {
                        const struct thermal_trip *trip = &td->trip;

                        if (trip->type == THERMAL_TRIP_CRITICAL) {
                                crit_temp = trip->temperature;
                                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;
        }

        if (ret)
                dev_dbg(&tz->device, "Failed to get temperature: %d\n", ret);

        return ret;
}

/**
 * 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;

        if (IS_ERR_OR_NULL(tz))
                return -EINVAL;

        guard(thermal_zone)(tz);

        if (!tz->ops.get_temp)
                return -EINVAL;

        ret = __thermal_zone_get_temp(tz, temp);
        if (!ret && *temp <= THERMAL_TEMP_INVALID)
                return -ENODATA;

        return ret;
}
EXPORT_SYMBOL_GPL(thermal_zone_get_temp);

static int thermal_cdev_set_cur_state(struct thermal_cooling_device *cdev, int state)
{
        int ret;

        /*
         * No check is needed for the ops->set_cur_state as the
         * registering function checked the ops are correctly set
         */
        ret = cdev->ops->set_cur_state(cdev, state);
        if (ret)
                return ret;

        thermal_notify_cdev_state_update(cdev, state);
        thermal_cooling_device_stats_update(cdev, state);
        thermal_debug_cdev_state_update(cdev, state);

        return 0;
}

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

        /* 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;
        }

        thermal_cdev_set_cur_state(cdev, target);

        trace_cdev_update(cdev, target);
        dev_dbg(&cdev->device, "set to state %lu\n", target);
}

/**
 * thermal_cdev_update - update cooling device state if needed
 * @cdev:       pointer to struct thermal_cooling_device
 *
 * Update the cooling device state if there is a need.
 */
void thermal_cdev_update(struct thermal_cooling_device *cdev)
{
        guard(cooling_dev)(cdev);

        if (!cdev->updated) {
                __thermal_cdev_update(cdev);
                cdev->updated = true;
        }
}

/**
 * thermal_cdev_update_nocheck() - Unconditionally update cooling device state
 * @cdev: Target cooling device.
 */
void thermal_cdev_update_nocheck(struct thermal_cooling_device *cdev)
{
        guard(cooling_dev)(cdev);

        __thermal_cdev_update(cdev);
}

/**
 * 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);