drivers/thermal/devfreq_cooling.c - third_party/kernel - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * devfreq_cooling: Thermal cooling device implementation for devices using
  *                  devfreq
  *
  * Copyright (C) 2014-2015 ARM Limited
  *
  * TODO:
  *    - If OPPs are added or removed after devfreq cooling has
  *      registered, the devfreq cooling won't react to it.
  */

 #include <linux/devfreq.h>
 #include <linux/devfreq_cooling.h>
 #include <linux/energy_model.h>
 #include <linux/export.h>
 #include <linux/slab.h>
 #include <linux/pm_opp.h>
 #include <linux/pm_qos.h>
 #include <linux/thermal.h>
 #include <linux/units.h>

 #include <trace/events/thermal.h>

 #define SCALE_ERROR_MITIGATION	100

 /**
  * struct devfreq_cooling_device - Devfreq cooling device
  *		devfreq_cooling_device registered.
  * @cdev:	Pointer to associated thermal cooling device.
  * @cooling_ops: devfreq callbacks to thermal cooling device ops
  * @devfreq:	Pointer to associated devfreq device.
  * @cooling_state:	Current cooling state.
  * @freq_table:	Pointer to a table with the frequencies sorted in descending
  *		order.  You can index the table by cooling device state
  * @max_state:	It is the last index, that is, one less than the number of the
  *		OPPs
  * @power_ops:	Pointer to devfreq_cooling_power, a more precised model.
  * @res_util:	Resource utilization scaling factor for the power.
  *		It is multiplied by 100 to minimize the error. It is used
  *		for estimation of the power budget instead of using
  *		'utilization' (which is	'busy_time' / 'total_time').
  *		The 'res_util' range is from 100 to power * 100	for the
  *		corresponding 'state'.
  * @capped_state:	index to cooling state with in dynamic power budget
  * @req_max_freq:	PM QoS request for limiting the maximum frequency
  *			of the devfreq device.
  * @em_pd:		Energy Model for the associated Devfreq device
  */
 struct devfreq_cooling_device {
 	struct thermal_cooling_device *cdev;
 	struct thermal_cooling_device_ops cooling_ops;
 	struct devfreq *devfreq;
 	unsigned long cooling_state;
 	u32 *freq_table;
 	size_t max_state;
 	struct devfreq_cooling_power *power_ops;
 	u32 res_util;
 	int capped_state;
 	struct dev_pm_qos_request req_max_freq;
 	struct em_perf_domain *em_pd;
 };

 static int devfreq_cooling_get_max_state(struct thermal_cooling_device *cdev,
 					 unsigned long *state)
 {
 	struct devfreq_cooling_device *dfc = cdev->devdata;

 	*state = dfc->max_state;

 	return 0;
 }

 static int devfreq_cooling_get_cur_state(struct thermal_cooling_device *cdev,
 					 unsigned long *state)
 {
 	struct devfreq_cooling_device *dfc = cdev->devdata;

 	*state = dfc->cooling_state;

 	return 0;
 }

 static int devfreq_cooling_set_cur_state(struct thermal_cooling_device *cdev,
 					 unsigned long state)
 {
 	struct devfreq_cooling_device *dfc = cdev->devdata;
 	struct devfreq *df = dfc->devfreq;
 	struct device *dev = df->dev.parent;
 	unsigned long freq;
 	int perf_idx;

 	if (state == dfc->cooling_state)
 		return 0;

 	dev_dbg(dev, "Setting cooling state %lu\n", state);

 	if (state > dfc->max_state)
 		return -EINVAL;

 	if (dfc->em_pd) {
 		perf_idx = dfc->max_state - state;
 		freq = dfc->em_pd->table[perf_idx].frequency * 1000;
 	} else {
 		freq = dfc->freq_table[state];
 	}

 	dev_pm_qos_update_request(&dfc->req_max_freq,
 				  DIV_ROUND_UP(freq, HZ_PER_KHZ));

 	dfc->cooling_state = state;

 	return 0;
 }

 /**
  * get_perf_idx() - get the performance index corresponding to a frequency
  * @em_pd:	Pointer to device's Energy Model
  * @freq:	frequency in kHz
  *
  * Return: the performance index associated with the @freq, or
  * -EINVAL if it wasn't found.
  */
 static int get_perf_idx(struct em_perf_domain *em_pd, unsigned long freq)
 {
 	int i;

 	for (i = 0; i < em_pd->nr_perf_states; i++) {
 		if (em_pd->table[i].frequency == freq)
 			return i;
 	}

 	return -EINVAL;
 }

 static unsigned long get_voltage(struct devfreq *df, unsigned long freq)
 {
 	struct device *dev = df->dev.parent;
 	unsigned long voltage;
 	struct dev_pm_opp *opp;

 	opp = dev_pm_opp_find_freq_exact(dev, freq, true);
 	if (PTR_ERR(opp) == -ERANGE)
 		opp = dev_pm_opp_find_freq_exact(dev, freq, false);

 	if (IS_ERR(opp)) {
 		dev_err_ratelimited(dev, "Failed to find OPP for frequency %lu: %ld\n",
 				    freq, PTR_ERR(opp));
 		return 0;
 	}

 	voltage = dev_pm_opp_get_voltage(opp) / 1000; /* mV */
 	dev_pm_opp_put(opp);

 	if (voltage == 0) {
 		dev_err_ratelimited(dev,
 				    "Failed to get voltage for frequency %lu\n",
 				    freq);
 	}

 	return voltage;
 }

 static void _normalize_load(struct devfreq_dev_status *status)
 {
 	if (status->total_time > 0xfffff) {
 		status->total_time >>= 10;
 		status->busy_time >>= 10;
 	}

 	status->busy_time <<= 10;
 	status->busy_time /= status->total_time ? : 1;

 	status->busy_time = status->busy_time ? : 1;
 	status->total_time = 1024;
 }

 static int devfreq_cooling_get_requested_power(struct thermal_cooling_device *cdev,
 					       u32 *power)
 {
 	struct devfreq_cooling_device *dfc = cdev->devdata;
 	struct devfreq *df = dfc->devfreq;
 	struct devfreq_dev_status status;
 	unsigned long state;
 	unsigned long freq;
 	unsigned long voltage;
 	int res, perf_idx;

 	mutex_lock(&df->lock);
 	status = df->last_status;
 	mutex_unlock(&df->lock);

 	freq = status.current_frequency;

 	if (dfc->power_ops && dfc->power_ops->get_real_power) {
 		voltage = get_voltage(df, freq);
 		if (voltage == 0) {
 			res = -EINVAL;
 			goto fail;
 		}

 		res = dfc->power_ops->get_real_power(df, power, freq, voltage);
 		if (!res) {
 			state = dfc->capped_state;

 			/* Convert EM power into milli-Watts first */
 			dfc->res_util = dfc->em_pd->table[state].power;
 			dfc->res_util /= MICROWATT_PER_MILLIWATT;

 			dfc->res_util *= SCALE_ERROR_MITIGATION;

 			if (*power > 1)
 				dfc->res_util /= *power;
 		} else {
 			goto fail;
 		}
 	} else {
 		/* Energy Model frequencies are in kHz */
 		perf_idx = get_perf_idx(dfc->em_pd, freq / 1000);
 		if (perf_idx < 0) {
 			res = -EAGAIN;
 			goto fail;
 		}

 		_normalize_load(&status);

 		/* Convert EM power into milli-Watts first */
 		*power = dfc->em_pd->table[perf_idx].power;
 		*power /= MICROWATT_PER_MILLIWATT;
 		/* Scale power for utilization */
 		*power *= status.busy_time;
 		*power >>= 10;
 	}

 	trace_thermal_power_devfreq_get_power(cdev, &status, freq, *power);

 	return 0;
 fail:
 	/* It is safe to set max in this case */
 	dfc->res_util = SCALE_ERROR_MITIGATION;
 	return res;
 }

 static int devfreq_cooling_state2power(struct thermal_cooling_device *cdev,
 				       unsigned long state, u32 *power)
 {
 	struct devfreq_cooling_device *dfc = cdev->devdata;
 	int perf_idx;

 	if (state > dfc->max_state)
 		return -EINVAL;

 	perf_idx = dfc->max_state - state;
 	*power = dfc->em_pd->table[perf_idx].power;
 	*power /= MICROWATT_PER_MILLIWATT;

 	return 0;
 }

 static int devfreq_cooling_power2state(struct thermal_cooling_device *cdev,
 				       u32 power, unsigned long *state)
 {
 	struct devfreq_cooling_device *dfc = cdev->devdata;
 	struct devfreq *df = dfc->devfreq;
 	struct devfreq_dev_status status;
 	unsigned long freq, em_power_mw;
 	s32 est_power;
 	int i;

 	mutex_lock(&df->lock);
 	status = df->last_status;
 	mutex_unlock(&df->lock);

 	freq = status.current_frequency;

 	if (dfc->power_ops && dfc->power_ops->get_real_power) {
 		/* Scale for resource utilization */
 		est_power = power * dfc->res_util;
 		est_power /= SCALE_ERROR_MITIGATION;
 	} else {
 		/* Scale dynamic power for utilization */
 		_normalize_load(&status);
 		est_power = power << 10;
 		est_power /= status.busy_time;
 	}

 	/*
 	 * Find the first cooling state that is within the power
 	 * budget. The EM power table is sorted ascending.
 	 */
 	for (i = dfc->max_state; i > 0; i--) {
 		/* Convert EM power to milli-Watts to make safe comparison */
 		em_power_mw = dfc->em_pd->table[i].power;
 		em_power_mw /= MICROWATT_PER_MILLIWATT;
 		if (est_power >= em_power_mw)
 			break;
 	}

 	*state = dfc->max_state - i;
 	dfc->capped_state = *state;

 	trace_thermal_power_devfreq_limit(cdev, freq, *state, power);
 	return 0;
 }

 /**
  * devfreq_cooling_gen_tables() - Generate frequency table.
  * @dfc:	Pointer to devfreq cooling device.
  * @num_opps:	Number of OPPs
  *
  * Generate frequency table which holds the frequencies in descending
  * order. That way its indexed by cooling device state. This is for
  * compatibility with drivers which do not register Energy Model.
  *
  * Return: 0 on success, negative error code on failure.
  */
 static int devfreq_cooling_gen_tables(struct devfreq_cooling_device *dfc,
 				      int num_opps)
 {
 	struct devfreq *df = dfc->devfreq;
 	struct device *dev = df->dev.parent;
 	unsigned long freq;
 	int i;

 	dfc->freq_table = kcalloc(num_opps, sizeof(*dfc->freq_table),
 			     GFP_KERNEL);
 	if (!dfc->freq_table)
 		return -ENOMEM;

 	for (i = 0, freq = ULONG_MAX; i < num_opps; i++, freq--) {
 		struct dev_pm_opp *opp;

 		opp = dev_pm_opp_find_freq_floor(dev, &freq);
 		if (IS_ERR(opp)) {
 			kfree(dfc->freq_table);
 			return PTR_ERR(opp);
 		}

 		dev_pm_opp_put(opp);
 		dfc->freq_table[i] = freq;
 	}

 	return 0;
 }

 /**
  * of_devfreq_cooling_register_power() - Register devfreq cooling device,
  *                                      with OF and power information.
  * @np:	Pointer to OF device_node.
  * @df:	Pointer to devfreq device.
  * @dfc_power:	Pointer to devfreq_cooling_power.
  *
  * Register a devfreq cooling device.  The available OPPs must be
  * registered on the device.
  *
  * If @dfc_power is provided, the cooling device is registered with the
  * power extensions.  For the power extensions to work correctly,
  * devfreq should use the simple_ondemand governor, other governors
  * are not currently supported.
  */
 struct thermal_cooling_device *
 of_devfreq_cooling_register_power(struct device_node *np, struct devfreq *df,
 				  struct devfreq_cooling_power *dfc_power)
 {
 	struct thermal_cooling_device *cdev;
 	struct device *dev = df->dev.parent;
 	struct devfreq_cooling_device *dfc;
 	struct em_perf_domain *em;
 	struct thermal_cooling_device_ops *ops;
 	char *name;
 	int err, num_opps;


 	dfc = kzalloc(sizeof(*dfc), GFP_KERNEL);
 	if (!dfc)
 		return ERR_PTR(-ENOMEM);

 	dfc->devfreq = df;

 	ops = &dfc->cooling_ops;
 	ops->get_max_state = devfreq_cooling_get_max_state;
 	ops->get_cur_state = devfreq_cooling_get_cur_state;
 	ops->set_cur_state = devfreq_cooling_set_cur_state;

 	em = em_pd_get(dev);
 	if (em && !em_is_artificial(em)) {
 		dfc->em_pd = em;
 		ops->get_requested_power =
 			devfreq_cooling_get_requested_power;
 		ops->state2power = devfreq_cooling_state2power;
 		ops->power2state = devfreq_cooling_power2state;

 		dfc->power_ops = dfc_power;

 		num_opps = em_pd_nr_perf_states(dfc->em_pd);
 	} else {
 		/* Backward compatibility for drivers which do not use IPA */
 		dev_dbg(dev, "missing proper EM for cooling device\n");

 		num_opps = dev_pm_opp_get_opp_count(dev);

 		err = devfreq_cooling_gen_tables(dfc, num_opps);
 		if (err)
 			goto free_dfc;
 	}

 	if (num_opps <= 0) {
 		err = -EINVAL;
 		goto free_dfc;
 	}

 	/* max_state is an index, not a counter */
 	dfc->max_state = num_opps - 1;

 	err = dev_pm_qos_add_request(dev, &dfc->req_max_freq,
 				     DEV_PM_QOS_MAX_FREQUENCY,
 				     PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE);
 	if (err < 0)
 		goto free_table;

 	err = -ENOMEM;
 	name = kasprintf(GFP_KERNEL, "devfreq-%s", dev_name(dev));
 	if (!name)
 		goto remove_qos_req;

 	cdev = thermal_of_cooling_device_register(np, name, dfc, ops);
 	kfree(name);

 	if (IS_ERR(cdev)) {
 		err = PTR_ERR(cdev);
 		dev_err(dev,
 			"Failed to register devfreq cooling device (%d)\n",
 			err);
 		goto remove_qos_req;
 	}

 	dfc->cdev = cdev;

 	return cdev;

 remove_qos_req:
 	dev_pm_qos_remove_request(&dfc->req_max_freq);
 free_table:
 	kfree(dfc->freq_table);
 free_dfc:
 	kfree(dfc);

 	return ERR_PTR(err);
 }
 EXPORT_SYMBOL_GPL(of_devfreq_cooling_register_power);

 /**
  * of_devfreq_cooling_register() - Register devfreq cooling device,
  *                                with OF information.
  * @np: Pointer to OF device_node.
  * @df: Pointer to devfreq device.
  */
 struct thermal_cooling_device *
 of_devfreq_cooling_register(struct device_node *np, struct devfreq *df)
 {
 	return of_devfreq_cooling_register_power(np, df, NULL);
 }
 EXPORT_SYMBOL_GPL(of_devfreq_cooling_register);

 /**
  * devfreq_cooling_register() - Register devfreq cooling device.
  * @df: Pointer to devfreq device.
  */
 struct thermal_cooling_device *devfreq_cooling_register(struct devfreq *df)
 {
 	return of_devfreq_cooling_register(NULL, df);
 }
 EXPORT_SYMBOL_GPL(devfreq_cooling_register);

 /**
  * devfreq_cooling_em_register() - Register devfreq cooling device with
  *		power information and automatically register Energy Model (EM)
  * @df:		Pointer to devfreq device.
  * @dfc_power:	Pointer to devfreq_cooling_power.
  *
  * Register a devfreq cooling device and automatically register EM. The
  * available OPPs must be registered for the device.
  *
  * If @dfc_power is provided, the cooling device is registered with the
  * power extensions. It is using the simple Energy Model which requires
  * "dynamic-power-coefficient" a devicetree property. To not break drivers
  * which miss that DT property, the function won't bail out when the EM
  * registration failed. The cooling device will be registered if everything
  * else is OK.
  */
 struct thermal_cooling_device *
 devfreq_cooling_em_register(struct devfreq *df,
 			    struct devfreq_cooling_power *dfc_power)
 {
 	struct thermal_cooling_device *cdev;
 	struct device *dev;
 	int ret;

 	if (IS_ERR_OR_NULL(df))
 		return ERR_PTR(-EINVAL);

 	dev = df->dev.parent;

 	ret = dev_pm_opp_of_register_em(dev, NULL);
 	if (ret)
 		dev_dbg(dev, "Unable to register EM for devfreq cooling device (%d)\n",
 			ret);

 	cdev = of_devfreq_cooling_register_power(dev->of_node, df, dfc_power);

 	if (IS_ERR_OR_NULL(cdev))
 		em_dev_unregister_perf_domain(dev);

 	return cdev;
 }
 EXPORT_SYMBOL_GPL(devfreq_cooling_em_register);

 /**
  * devfreq_cooling_unregister() - Unregister devfreq cooling device.
  * @cdev: Pointer to devfreq cooling device to unregister.
  *
  * Unregisters devfreq cooling device and related Energy Model if it was
  * present.
  */
 void devfreq_cooling_unregister(struct thermal_cooling_device *cdev)
 {
 	struct devfreq_cooling_device *dfc;
 	struct device *dev;

 	if (IS_ERR_OR_NULL(cdev))
 		return;

 	dfc = cdev->devdata;
 	dev = dfc->devfreq->dev.parent;

 	thermal_cooling_device_unregister(dfc->cdev);
 	dev_pm_qos_remove_request(&dfc->req_max_freq);

 	em_dev_unregister_perf_domain(dev);

 	kfree(dfc->freq_table);
 	kfree(dfc);
 }
 EXPORT_SYMBOL_GPL(devfreq_cooling_unregister);
	// SPDX-License-Identifier: GPL-2.0
	/*
	* devfreq_cooling: Thermal cooling device implementation for devices using
	* devfreq
	*
	* Copyright (C) 2014-2015 ARM Limited
	*
	* TODO:
	* - If OPPs are added or removed after devfreq cooling has
	* registered, the devfreq cooling won't react to it.
	*/

	#include <linux/devfreq.h>
	#include <linux/devfreq_cooling.h>
	#include <linux/energy_model.h>
	#include <linux/export.h>
	#include <linux/slab.h>
	#include <linux/pm_opp.h>
	#include <linux/pm_qos.h>
	#include <linux/thermal.h>
	#include <linux/units.h>

	#include <trace/events/thermal.h>

	#define SCALE_ERROR_MITIGATION 100

	/**
	* struct devfreq_cooling_device - Devfreq cooling device
	* devfreq_cooling_device registered.
	* @cdev: Pointer to associated thermal cooling device.
	* @cooling_ops: devfreq callbacks to thermal cooling device ops
	* @devfreq: Pointer to associated devfreq device.
	* @cooling_state: Current cooling state.
	* @freq_table: Pointer to a table with the frequencies sorted in descending
	* order. You can index the table by cooling device state
	* @max_state: It is the last index, that is, one less than the number of the
	* OPPs
	* @power_ops: Pointer to devfreq_cooling_power, a more precised model.
	* @res_util: Resource utilization scaling factor for the power.
	* It is multiplied by 100 to minimize the error. It is used
	* for estimation of the power budget instead of using
	* 'utilization' (which is 'busy_time' / 'total_time').
	* The 'res_util' range is from 100 to power * 100 for the
	* corresponding 'state'.
	* @capped_state: index to cooling state with in dynamic power budget
	* @req_max_freq: PM QoS request for limiting the maximum frequency
	* of the devfreq device.
	* @em_pd: Energy Model for the associated Devfreq device
	*/
	struct devfreq_cooling_device {
	struct thermal_cooling_device *cdev;
	struct thermal_cooling_device_ops cooling_ops;
	struct devfreq *devfreq;
	unsigned long cooling_state;
	u32 *freq_table;
	size_t max_state;
	struct devfreq_cooling_power *power_ops;
	u32 res_util;
	int capped_state;
	struct dev_pm_qos_request req_max_freq;
	struct em_perf_domain *em_pd;
	};

	static int devfreq_cooling_get_max_state(struct thermal_cooling_device *cdev,
	unsigned long *state)
	{
	struct devfreq_cooling_device *dfc = cdev->devdata;

	*state = dfc->max_state;

	return 0;
	}

	static int devfreq_cooling_get_cur_state(struct thermal_cooling_device *cdev,
	unsigned long *state)
	{
	struct devfreq_cooling_device *dfc = cdev->devdata;

	*state = dfc->cooling_state;

	return 0;
	}

	static int devfreq_cooling_set_cur_state(struct thermal_cooling_device *cdev,
	unsigned long state)
	{
	struct devfreq_cooling_device *dfc = cdev->devdata;
	struct devfreq *df = dfc->devfreq;
	struct device *dev = df->dev.parent;
	unsigned long freq;
	int perf_idx;

	if (state == dfc->cooling_state)
	return 0;

	dev_dbg(dev, "Setting cooling state %lu\n", state);

	if (state > dfc->max_state)
	return -EINVAL;

	if (dfc->em_pd) {
	perf_idx = dfc->max_state - state;
	freq = dfc->em_pd->table[perf_idx].frequency * 1000;
	} else {
	freq = dfc->freq_table[state];
	}

	dev_pm_qos_update_request(&dfc->req_max_freq,
	DIV_ROUND_UP(freq, HZ_PER_KHZ));

	dfc->cooling_state = state;

	return 0;
	}

	/**
	* get_perf_idx() - get the performance index corresponding to a frequency
	* @em_pd: Pointer to device's Energy Model
	* @freq: frequency in kHz
	*
	* Return: the performance index associated with the @freq, or
	* -EINVAL if it wasn't found.
	*/
	static int get_perf_idx(struct em_perf_domain *em_pd, unsigned long freq)
	{
	int i;

	for (i = 0; i < em_pd->nr_perf_states; i++) {
	if (em_pd->table[i].frequency == freq)
	return i;
	}

	return -EINVAL;
	}

	static unsigned long get_voltage(struct devfreq *df, unsigned long freq)
	{
	struct device *dev = df->dev.parent;
	unsigned long voltage;
	struct dev_pm_opp *opp;

	opp = dev_pm_opp_find_freq_exact(dev, freq, true);
	if (PTR_ERR(opp) == -ERANGE)
	opp = dev_pm_opp_find_freq_exact(dev, freq, false);

	if (IS_ERR(opp)) {
	dev_err_ratelimited(dev, "Failed to find OPP for frequency %lu: %ld\n",
	freq, PTR_ERR(opp));
	return 0;
	}

	voltage = dev_pm_opp_get_voltage(opp) / 1000; /* mV */
	dev_pm_opp_put(opp);

	if (voltage == 0) {
	dev_err_ratelimited(dev,
	"Failed to get voltage for frequency %lu\n",
	freq);
	}

	return voltage;
	}

	static void _normalize_load(struct devfreq_dev_status *status)
	{
	if (status->total_time > 0xfffff) {
	status->total_time >>= 10;
	status->busy_time >>= 10;
	}

	status->busy_time <<= 10;
	status->busy_time /= status->total_time ? : 1;

	status->busy_time = status->busy_time ? : 1;
	status->total_time = 1024;
	}

	static int devfreq_cooling_get_requested_power(struct thermal_cooling_device *cdev,
	u32 *power)
	{
	struct devfreq_cooling_device *dfc = cdev->devdata;
	struct devfreq *df = dfc->devfreq;
	struct devfreq_dev_status status;
	unsigned long state;
	unsigned long freq;
	unsigned long voltage;
	int res, perf_idx;

	mutex_lock(&df->lock);
	status = df->last_status;
	mutex_unlock(&df->lock);

	freq = status.current_frequency;

	if (dfc->power_ops && dfc->power_ops->get_real_power) {
	voltage = get_voltage(df, freq);
	if (voltage == 0) {
	res = -EINVAL;
	goto fail;
	}

	res = dfc->power_ops->get_real_power(df, power, freq, voltage);
	if (!res) {
	state = dfc->capped_state;

	/* Convert EM power into milli-Watts first */
	dfc->res_util = dfc->em_pd->table[state].power;
	dfc->res_util /= MICROWATT_PER_MILLIWATT;

	dfc->res_util *= SCALE_ERROR_MITIGATION;

	if (*power > 1)
	dfc->res_util /= *power;
	} else {
	goto fail;
	}
	} else {
	/* Energy Model frequencies are in kHz */
	perf_idx = get_perf_idx(dfc->em_pd, freq / 1000);
	if (perf_idx < 0) {
	res = -EAGAIN;
	goto fail;
	}

	_normalize_load(&status);

	/* Convert EM power into milli-Watts first */
	*power = dfc->em_pd->table[perf_idx].power;
	*power /= MICROWATT_PER_MILLIWATT;
	/* Scale power for utilization */
	power = status.busy_time;
	*power >>= 10;
	}

	trace_thermal_power_devfreq_get_power(cdev, &status, freq, *power);

	return 0;
	fail:
	/* It is safe to set max in this case */
	dfc->res_util = SCALE_ERROR_MITIGATION;
	return res;
	}

	static int devfreq_cooling_state2power(struct thermal_cooling_device *cdev,
	unsigned long state, u32 *power)
	{
	struct devfreq_cooling_device *dfc = cdev->devdata;
	int perf_idx;

	if (state > dfc->max_state)
	return -EINVAL;

	perf_idx = dfc->max_state - state;
	*power = dfc->em_pd->table[perf_idx].power;
	*power /= MICROWATT_PER_MILLIWATT;

	return 0;
	}

	static int devfreq_cooling_power2state(struct thermal_cooling_device *cdev,
	u32 power, unsigned long *state)
	{
	struct devfreq_cooling_device *dfc = cdev->devdata;
	struct devfreq *df = dfc->devfreq;
	struct devfreq_dev_status status;
	unsigned long freq, em_power_mw;
	s32 est_power;
	int i;

	mutex_lock(&df->lock);
	status = df->last_status;
	mutex_unlock(&df->lock);

	freq = status.current_frequency;

	if (dfc->power_ops && dfc->power_ops->get_real_power) {
	/* Scale for resource utilization */
	est_power = power * dfc->res_util;
	est_power /= SCALE_ERROR_MITIGATION;
	} else {
	/* Scale dynamic power for utilization */
	_normalize_load(&status);
	est_power = power << 10;
	est_power /= status.busy_time;
	}

	/*
	* Find the first cooling state that is within the power
	* budget. The EM power table is sorted ascending.
	*/
	for (i = dfc->max_state; i > 0; i--) {
	/* Convert EM power to milli-Watts to make safe comparison */
	em_power_mw = dfc->em_pd->table[i].power;
	em_power_mw /= MICROWATT_PER_MILLIWATT;
	if (est_power >= em_power_mw)
	break;
	}

	*state = dfc->max_state - i;
	dfc->capped_state = *state;

	trace_thermal_power_devfreq_limit(cdev, freq, *state, power);
	return 0;
	}

	/**
	* devfreq_cooling_gen_tables() - Generate frequency table.
	* @dfc: Pointer to devfreq cooling device.
	* @num_opps: Number of OPPs
	*
	* Generate frequency table which holds the frequencies in descending
	* order. That way its indexed by cooling device state. This is for
	* compatibility with drivers which do not register Energy Model.
	*
	* Return: 0 on success, negative error code on failure.
	*/
	static int devfreq_cooling_gen_tables(struct devfreq_cooling_device *dfc,
	int num_opps)
	{
	struct devfreq *df = dfc->devfreq;
	struct device *dev = df->dev.parent;
	unsigned long freq;
	int i;

	dfc->freq_table = kcalloc(num_opps, sizeof(*dfc->freq_table),
	GFP_KERNEL);
	if (!dfc->freq_table)
	return -ENOMEM;

	for (i = 0, freq = ULONG_MAX; i < num_opps; i++, freq--) {
	struct dev_pm_opp *opp;

	opp = dev_pm_opp_find_freq_floor(dev, &freq);
	if (IS_ERR(opp)) {
	kfree(dfc->freq_table);
	return PTR_ERR(opp);
	}

	dev_pm_opp_put(opp);
	dfc->freq_table[i] = freq;
	}

	return 0;
	}

	/**
	* of_devfreq_cooling_register_power() - Register devfreq cooling device,
	* with OF and power information.
	* @np: Pointer to OF device_node.
	* @df: Pointer to devfreq device.
	* @dfc_power: Pointer to devfreq_cooling_power.
	*
	* Register a devfreq cooling device. The available OPPs must be
	* registered on the device.
	*
	* If @dfc_power is provided, the cooling device is registered with the
	* power extensions. For the power extensions to work correctly,
	* devfreq should use the simple_ondemand governor, other governors
	* are not currently supported.
	*/
	struct thermal_cooling_device *
	of_devfreq_cooling_register_power(struct device_node np, struct devfreq df,
	struct devfreq_cooling_power *dfc_power)
	{
	struct thermal_cooling_device *cdev;
	struct device *dev = df->dev.parent;
	struct devfreq_cooling_device *dfc;
	struct em_perf_domain *em;
	struct thermal_cooling_device_ops *ops;
	char *name;
	int err, num_opps;


	dfc = kzalloc(sizeof(*dfc), GFP_KERNEL);
	if (!dfc)
	return ERR_PTR(-ENOMEM);

	dfc->devfreq = df;

	ops = &dfc->cooling_ops;
	ops->get_max_state = devfreq_cooling_get_max_state;
	ops->get_cur_state = devfreq_cooling_get_cur_state;
	ops->set_cur_state = devfreq_cooling_set_cur_state;

	em = em_pd_get(dev);
	if (em && !em_is_artificial(em)) {
	dfc->em_pd = em;
	ops->get_requested_power =
	devfreq_cooling_get_requested_power;
	ops->state2power = devfreq_cooling_state2power;
	ops->power2state = devfreq_cooling_power2state;

	dfc->power_ops = dfc_power;

	num_opps = em_pd_nr_perf_states(dfc->em_pd);
	} else {
	/* Backward compatibility for drivers which do not use IPA */
	dev_dbg(dev, "missing proper EM for cooling device\n");

	num_opps = dev_pm_opp_get_opp_count(dev);

	err = devfreq_cooling_gen_tables(dfc, num_opps);
	if (err)
	goto free_dfc;
	}

	if (num_opps <= 0) {
	err = -EINVAL;
	goto free_dfc;
	}

	/* max_state is an index, not a counter */
	dfc->max_state = num_opps - 1;

	err = dev_pm_qos_add_request(dev, &dfc->req_max_freq,
	DEV_PM_QOS_MAX_FREQUENCY,
	PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE);
	if (err < 0)
	goto free_table;

	err = -ENOMEM;
	name = kasprintf(GFP_KERNEL, "devfreq-%s", dev_name(dev));
	if (!name)
	goto remove_qos_req;

	cdev = thermal_of_cooling_device_register(np, name, dfc, ops);
	kfree(name);

	if (IS_ERR(cdev)) {
	err = PTR_ERR(cdev);
	dev_err(dev,
	"Failed to register devfreq cooling device (%d)\n",
	err);
	goto remove_qos_req;
	}

	dfc->cdev = cdev;

	return cdev;

	remove_qos_req:
	dev_pm_qos_remove_request(&dfc->req_max_freq);
	free_table:
	kfree(dfc->freq_table);
	free_dfc:
	kfree(dfc);

	return ERR_PTR(err);
	}
	EXPORT_SYMBOL_GPL(of_devfreq_cooling_register_power);

	/**
	* of_devfreq_cooling_register() - Register devfreq cooling device,
	* with OF information.
	* @np: Pointer to OF device_node.
	* @df: Pointer to devfreq device.
	*/
	struct thermal_cooling_device *
	of_devfreq_cooling_register(struct device_node np, struct devfreq df)
	{
	return of_devfreq_cooling_register_power(np, df, NULL);
	}
	EXPORT_SYMBOL_GPL(of_devfreq_cooling_register);

	/**
	* devfreq_cooling_register() - Register devfreq cooling device.
	* @df: Pointer to devfreq device.
	*/
	struct thermal_cooling_device devfreq_cooling_register(struct devfreq df)
	{
	return of_devfreq_cooling_register(NULL, df);
	}
	EXPORT_SYMBOL_GPL(devfreq_cooling_register);

	/**
	* devfreq_cooling_em_register() - Register devfreq cooling device with
	* power information and automatically register Energy Model (EM)
	* @df: Pointer to devfreq device.
	* @dfc_power: Pointer to devfreq_cooling_power.
	*
	* Register a devfreq cooling device and automatically register EM. The
	* available OPPs must be registered for the device.
	*
	* If @dfc_power is provided, the cooling device is registered with the
	* power extensions. It is using the simple Energy Model which requires
	* "dynamic-power-coefficient" a devicetree property. To not break drivers
	* which miss that DT property, the function won't bail out when the EM
	* registration failed. The cooling device will be registered if everything
	* else is OK.
	*/
	struct thermal_cooling_device *
	devfreq_cooling_em_register(struct devfreq *df,
	struct devfreq_cooling_power *dfc_power)
	{
	struct thermal_cooling_device *cdev;
	struct device *dev;
	int ret;

	if (IS_ERR_OR_NULL(df))
	return ERR_PTR(-EINVAL);

	dev = df->dev.parent;

	ret = dev_pm_opp_of_register_em(dev, NULL);
	if (ret)
	dev_dbg(dev, "Unable to register EM for devfreq cooling device (%d)\n",
	ret);

	cdev = of_devfreq_cooling_register_power(dev->of_node, df, dfc_power);

	if (IS_ERR_OR_NULL(cdev))
	em_dev_unregister_perf_domain(dev);

	return cdev;
	}
	EXPORT_SYMBOL_GPL(devfreq_cooling_em_register);

	/**
	* devfreq_cooling_unregister() - Unregister devfreq cooling device.
	* @cdev: Pointer to devfreq cooling device to unregister.
	*
	* Unregisters devfreq cooling device and related Energy Model if it was
	* present.
	*/
	void devfreq_cooling_unregister(struct thermal_cooling_device *cdev)
	{
	struct devfreq_cooling_device *dfc;
	struct device *dev;

	if (IS_ERR_OR_NULL(cdev))
	return;

	dfc = cdev->devdata;
	dev = dfc->devfreq->dev.parent;

	thermal_cooling_device_unregister(dfc->cdev);
	dev_pm_qos_remove_request(&dfc->req_max_freq);

	em_dev_unregister_perf_domain(dev);

	kfree(dfc->freq_table);
	kfree(dfc);
	}
	EXPORT_SYMBOL_GPL(devfreq_cooling_unregister);