Commit a76caf55 authored by Ørjan Eide's avatar Ørjan Eide Committed by Eduardo Valentin
Browse files

thermal: Add devfreq cooling 



Add a generic thermal cooling device for devfreq, that is similar to
cpu_cooling.

The device must use devfreq.  In order to use the power extension of the
cooling device, it must have registered its OPPs using the OPP library.

Cc: Zhang Rui <rui.zhang@intel.com>
Cc: Eduardo Valentin <edubezval@gmail.com>
Signed-off-by: default avatarJavi Merino <javi.merino@arm.com>
Signed-off-by: default avatarØrjan Eide <orjan.eide@arm.com>
Signed-off-by: default avatarEduardo Valentin <edubezval@gmail.com>
parent d6d00742

drivers/thermal/Kconfig

+14 −0
Original line number Diff line number Diff line
@@ -147,6 +147,20 @@ config CLOCK_THERMAL 
	  device that is configured to use this cooling mechanism will be

	  controlled to reduce clock frequency whenever temperature is high.



config DEVFREQ_THERMAL

	bool "Generic device cooling support"

	depends on PM_DEVFREQ

	depends on PM_OPP

	help

	  This implements the generic devfreq cooling mechanism through

	  frequency reduction for devices using devfreq.



	  This will throttle the device by limiting the maximum allowed DVFS

	  frequency corresponding to the cooling level.



	  In order to use the power extensions of the cooling device,

	  devfreq should use the simple_ondemand governor.



	  If you want this support, you should say Y here.



config THERMAL_EMULATION

drivers/thermal/Makefile

+3 −0
Original line number Diff line number Diff line
@@ -22,6 +22,9 @@ thermal_sys-$(CONFIG_CPU_THERMAL) += cpu_cooling.o 
# clock cooling

thermal_sys-$(CONFIG_CLOCK_THERMAL)	+= clock_cooling.o



# devfreq cooling

thermal_sys-$(CONFIG_DEVFREQ_THERMAL) += devfreq_cooling.o



# platform thermal drivers

obj-$(CONFIG_QCOM_SPMI_TEMP_ALARM)	+= qcom-spmi-temp-alarm.o

obj-$(CONFIG_SPEAR_THERMAL)	+= spear_thermal.o

drivers/thermal/devfreq_cooling.c

0 → 100644
+563 −0
Original line number Diff line number Diff line 
/*

 * devfreq_cooling: Thermal cooling device implementation for devices using

 *                  devfreq

 *

 * Copyright (C) 2014-2015 ARM Limited

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation.

 *

 * This program is distributed "as is" WITHOUT ANY WARRANTY of any

 * kind, whether express or implied; without even the implied warranty

 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * 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/export.h>

#include <linux/slab.h>

#include <linux/pm_opp.h>

#include <linux/thermal.h>



static DEFINE_MUTEX(devfreq_lock);

static DEFINE_IDR(devfreq_idr);



/**

 * struct devfreq_cooling_device - Devfreq cooling device

 * @id:		unique integer value corresponding to each

 *		devfreq_cooling_device registered.

 * @cdev:	Pointer to associated thermal cooling device.

 * @devfreq:	Pointer to associated devfreq device.

 * @cooling_state:	Current cooling state.

 * @power_table:	Pointer to table with maximum power draw for each

 *			cooling state. State is the index into the table, and

 *			the power is in mW.

 * @freq_table:	Pointer to a table with the frequencies sorted in descending

 *		order.  You can index the table by cooling device state

 * @freq_table_size:	Size of the @freq_table and @power_table

 * @power_ops:	Pointer to devfreq_cooling_power, used to generate the

 *		@power_table.

 */

struct devfreq_cooling_device {

	int id;

	struct thermal_cooling_device *cdev;

	struct devfreq *devfreq;

	unsigned long cooling_state;

	u32 *power_table;

	u32 *freq_table;

	size_t freq_table_size;

	struct devfreq_cooling_power *power_ops;

};



/**

 * get_idr - function to get a unique id.

 * @idr: struct idr * handle used to create a id.

 * @id: int * value generated by this function.

 *

 * This function will populate @id with an unique

 * id, using the idr API.

 *

 * Return: 0 on success, an error code on failure.

 */

static int get_idr(struct idr *idr, int *id)

{

	int ret;



	mutex_lock(&devfreq_lock);

	ret = idr_alloc(idr, NULL, 0, 0, GFP_KERNEL);

	mutex_unlock(&devfreq_lock);

	if (unlikely(ret < 0))

		return ret;

	*id = ret;



	return 0;

}



/**

 * release_idr - function to free the unique id.

 * @idr: struct idr * handle used for creating the id.

 * @id: int value representing the unique id.

 */

static void release_idr(struct idr *idr, int id)

{

	mutex_lock(&devfreq_lock);

	idr_remove(idr, id);

	mutex_unlock(&devfreq_lock);

}



/**

 * partition_enable_opps() - disable all opps above a given state

 * @dfc:	Pointer to devfreq we are operating on

 * @cdev_state:	cooling device state we're setting

 *

 * Go through the OPPs of the device, enabling all OPPs until

 * @cdev_state and disabling those frequencies above it.

 */

static int partition_enable_opps(struct devfreq_cooling_device *dfc,

				 unsigned long cdev_state)

{

	int i;

	struct device *dev = dfc->devfreq->dev.parent;



	for (i = 0; i < dfc->freq_table_size; i++) {

		struct dev_pm_opp *opp;

		int ret = 0;

		unsigned int freq = dfc->freq_table[i];

		bool want_enable = i >= cdev_state ? true : false;



		rcu_read_lock();

		opp = dev_pm_opp_find_freq_exact(dev, freq, !want_enable);

		rcu_read_unlock();



		if (PTR_ERR(opp) == -ERANGE)

			continue;

		else if (IS_ERR(opp))

			return PTR_ERR(opp);



		if (want_enable)

			ret = dev_pm_opp_enable(dev, freq);

		else

			ret = dev_pm_opp_disable(dev, freq);



		if (ret)

			return ret;

	}



	return 0;

}



static int devfreq_cooling_get_max_state(struct thermal_cooling_device *cdev,

					 unsigned long *state)

{

	struct devfreq_cooling_device *dfc = cdev->devdata;



	*state = dfc->freq_table_size - 1;



	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;

	int ret;



	if (state == dfc->cooling_state)

		return 0;



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



	if (state >= dfc->freq_table_size)

		return -EINVAL;



	ret = partition_enable_opps(dfc, state);

	if (ret)

		return ret;



	dfc->cooling_state = state;



	return 0;

}



/**

 * freq_get_state() - get the cooling state corresponding to a frequency

 * @dfc:	Pointer to devfreq cooling device

 * @freq:	frequency in Hz

 *

 * Return: the cooling state associated with the @freq, or

 * THERMAL_CSTATE_INVALID if it wasn't found.

 */

static unsigned long

freq_get_state(struct devfreq_cooling_device *dfc, unsigned long freq)

{

	int i;



	for (i = 0; i < dfc->freq_table_size; i++) {

		if (dfc->freq_table[i] == freq)

			return i;

	}



	return THERMAL_CSTATE_INVALID;

}



/**

 * get_static_power() - calculate the static power

 * @dfc:	Pointer to devfreq cooling device

 * @freq:	Frequency in Hz

 *

 * Calculate the static power in milliwatts using the supplied

 * get_static_power().  The current voltage is calculated using the

 * OPP library.  If no get_static_power() was supplied, assume the

 * static power is negligible.

 */

static unsigned long

get_static_power(struct devfreq_cooling_device *dfc, unsigned long freq)

{

	struct devfreq *df = dfc->devfreq;

	struct device *dev = df->dev.parent;

	unsigned long voltage;

	struct dev_pm_opp *opp;



	if (!dfc->power_ops->get_static_power)

		return 0;



	rcu_read_lock();



	opp = dev_pm_opp_find_freq_exact(dev, freq, true);

	if (IS_ERR(opp) && (PTR_ERR(opp) == -ERANGE))

		opp = dev_pm_opp_find_freq_exact(dev, freq, false);



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



	rcu_read_unlock();



	if (voltage == 0) {

		dev_warn_ratelimited(dev,

				     "Failed to get voltage for frequency %lu: %ld\n",

				     freq, IS_ERR(opp) ? PTR_ERR(opp) : 0);

		return 0;

	}



	return dfc->power_ops->get_static_power(voltage);

}



/**

 * get_dynamic_power - calculate the dynamic power

 * @dfc:	Pointer to devfreq cooling device

 * @freq:	Frequency in Hz

 * @voltage:	Voltage in millivolts

 *

 * Calculate the dynamic power in milliwatts consumed by the device at

 * frequency @freq and voltage @voltage.  If the get_dynamic_power()

 * was supplied as part of the devfreq_cooling_power struct, then that

 * function is used.  Otherwise, a simple power model (Pdyn = Coeff *

 * Voltage^2 * Frequency) is used.

 */

static unsigned long

get_dynamic_power(struct devfreq_cooling_device *dfc, unsigned long freq,

		  unsigned long voltage)

{

	unsigned long power;

	u32 freq_mhz;

	struct devfreq_cooling_power *dfc_power = dfc->power_ops;



	if (dfc_power->get_dynamic_power)

		return dfc_power->get_dynamic_power(freq, voltage);



	freq_mhz = freq / 1000000;

	power = (u64)dfc_power->dyn_power_coeff * freq_mhz * voltage * voltage;

	do_div(power, 1000000000);



	return power;

}



static int devfreq_cooling_get_requested_power(struct thermal_cooling_device *cdev,

					       struct thermal_zone_device *tz,

					       u32 *power)

{

	struct devfreq_cooling_device *dfc = cdev->devdata;

	struct devfreq *df = dfc->devfreq;

	struct devfreq_dev_status *status = &df->last_status;

	unsigned long state;

	unsigned long freq = status->current_frequency;

	u32 dyn_power, static_power;



	/* Get dynamic power for state */

	state = freq_get_state(dfc, freq);

	if (state == THERMAL_CSTATE_INVALID)

		return -EAGAIN;



	dyn_power = dfc->power_table[state];



	/* Scale dynamic power for utilization */

	dyn_power = (dyn_power * status->busy_time) / status->total_time;



	/* Get static power */

	static_power = get_static_power(dfc, freq);



	*power = dyn_power + static_power;



	return 0;

}



static int devfreq_cooling_state2power(struct thermal_cooling_device *cdev,

				       struct thermal_zone_device *tz,

				       unsigned long state,

				       u32 *power)

{

	struct devfreq_cooling_device *dfc = cdev->devdata;

	unsigned long freq;

	u32 static_power;



	if (state < 0 || state >= dfc->freq_table_size)

		return -EINVAL;



	freq = dfc->freq_table[state];

	static_power = get_static_power(dfc, freq);



	*power = dfc->power_table[state] + static_power;

	return 0;

}



static int devfreq_cooling_power2state(struct thermal_cooling_device *cdev,

				       struct thermal_zone_device *tz,

				       u32 power, unsigned long *state)

{

	struct devfreq_cooling_device *dfc = cdev->devdata;

	struct devfreq *df = dfc->devfreq;

	struct devfreq_dev_status *status = &df->last_status;

	unsigned long freq = status->current_frequency;

	unsigned long busy_time;

	s32 dyn_power;

	u32 static_power;

	int i;



	static_power = get_static_power(dfc, freq);



	dyn_power = power - static_power;

	dyn_power = dyn_power > 0 ? dyn_power : 0;



	/* Scale dynamic power for utilization */

	busy_time = status->busy_time ?: 1;

	dyn_power = (dyn_power * status->total_time) / busy_time;



	/*

	 * Find the first cooling state that is within the power

	 * budget for dynamic power.

	 */

	for (i = 0; i < dfc->freq_table_size - 1; i++)

		if (dyn_power >= dfc->power_table[i])

			break;



	*state = i;

	return 0;

}



static struct thermal_cooling_device_ops devfreq_cooling_ops = {

	.get_max_state = devfreq_cooling_get_max_state,

	.get_cur_state = devfreq_cooling_get_cur_state,

	.set_cur_state = devfreq_cooling_set_cur_state,

};



/**

 * devfreq_cooling_gen_tables() - Generate power and freq tables.

 * @dfc: Pointer to devfreq cooling device.

 *

 * Generate power and frequency tables: the power table hold the

 * device's maximum power usage at each cooling state (OPP).  The

 * static and dynamic power using the appropriate voltage and

 * frequency for the state, is acquired from the struct

 * devfreq_cooling_power, and summed to make the maximum power draw.

 *

 * The frequency table holds the frequencies in descending order.

 * That way its indexed by cooling device state.

 *

 * The tables are malloced, and pointers put in dfc.  They must be

 * freed when unregistering the devfreq cooling device.

 *

 * Return: 0 on success, negative error code on failure.

 */

static int devfreq_cooling_gen_tables(struct devfreq_cooling_device *dfc)

{

	struct devfreq *df = dfc->devfreq;

	struct device *dev = df->dev.parent;

	int ret, num_opps;

	unsigned long freq;

	u32 *power_table = NULL;

	u32 *freq_table;

	int i;



	num_opps = dev_pm_opp_get_opp_count(dev);



	if (dfc->power_ops) {

		power_table = kcalloc(num_opps, sizeof(*power_table),

				      GFP_KERNEL);

		if (!power_table)

			ret = -ENOMEM;

	}



	freq_table = kcalloc(num_opps, sizeof(*freq_table),

			     GFP_KERNEL);

	if (!freq_table) {

		ret = -ENOMEM;

		goto free_power_table;

	}



	for (i = 0, freq = ULONG_MAX; i < num_opps; i++, freq--) {

		unsigned long power_dyn, voltage;

		struct dev_pm_opp *opp;



		rcu_read_lock();



		opp = dev_pm_opp_find_freq_floor(dev, &freq);

		if (IS_ERR(opp)) {

			rcu_read_unlock();

			ret = PTR_ERR(opp);

			goto free_tables;

		}



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



		rcu_read_unlock();



		if (dfc->power_ops) {

			power_dyn = get_dynamic_power(dfc, freq, voltage);



			dev_dbg(dev, "Dynamic power table: %lu MHz @ %lu mV: %lu = %lu mW\n",

				freq / 1000000, voltage, power_dyn, power_dyn);



			power_table[i] = power_dyn;

		}



		freq_table[i] = freq;

	}



	if (dfc->power_ops)

		dfc->power_table = power_table;



	dfc->freq_table = freq_table;

	dfc->freq_table_size = num_opps;



	return 0;



free_tables:

	kfree(freq_table);

free_power_table:

	kfree(power_table);



	return ret;

}



/**

 * 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 devfreq_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 devfreq_cooling_device *dfc;

	char dev_name[THERMAL_NAME_LENGTH];

	int err;



	dfc = kzalloc(sizeof(*dfc), GFP_KERNEL);

	if (!dfc)

		return ERR_PTR(-ENOMEM);



	dfc->devfreq = df;



	if (dfc_power) {

		dfc->power_ops = dfc_power;



		devfreq_cooling_ops.get_requested_power =

			devfreq_cooling_get_requested_power;

		devfreq_cooling_ops.state2power = devfreq_cooling_state2power;

		devfreq_cooling_ops.power2state = devfreq_cooling_power2state;

	}



	err = devfreq_cooling_gen_tables(dfc);

	if (err)

		goto free_dfc;



	err = get_idr(&devfreq_idr, &dfc->id);

	if (err)

		goto free_tables;



	snprintf(dev_name, sizeof(dev_name), "thermal-devfreq-%d", dfc->id);



	cdev = thermal_of_cooling_device_register(np, dev_name, dfc,

						  &devfreq_cooling_ops);

	if (IS_ERR(cdev)) {

		err = PTR_ERR(cdev);

		dev_err(df->dev.parent,

			"Failed to register devfreq cooling device (%d)\n",

			err);

		goto release_idr;

	}



	dfc->cdev = cdev;



	return dfc;



release_idr:

	release_idr(&devfreq_idr, dfc->id);

free_tables:

	kfree(dfc->power_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 devfreq_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 devfreq_cooling_device *devfreq_cooling_register(struct devfreq *df)

{

	return of_devfreq_cooling_register(NULL, df);

}

EXPORT_SYMBOL_GPL(devfreq_cooling_register);



/**

 * devfreq_cooling_unregister() - Unregister devfreq cooling device.

 * @dfc: Pointer to devfreq cooling device to unregister.

 */

void devfreq_cooling_unregister(struct devfreq_cooling_device *dfc)

{

	if (!dfc)

		return;



	thermal_cooling_device_unregister(dfc->cdev);

	release_idr(&devfreq_idr, dfc->id);

	kfree(dfc->power_table);

	kfree(dfc->freq_table);



	kfree(dfc);

}

EXPORT_SYMBOL_GPL(devfreq_cooling_unregister);

include/linux/devfreq_cooling.h

0 → 100644
+81 −0
Original line number Diff line number Diff line 
/*

 * devfreq_cooling: Thermal cooling device implementation for devices using

 *                  devfreq

 *

 * Copyright (C) 2014-2015 ARM Limited

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation.

 *

 * This program is distributed "as is" WITHOUT ANY WARRANTY of any

 * kind, whether express or implied; without even the implied warranty

 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 */



#ifndef __DEVFREQ_COOLING_H__

#define __DEVFREQ_COOLING_H__



#include <linux/devfreq.h>

#include <linux/thermal.h>



#ifdef CONFIG_DEVFREQ_THERMAL



/**

 * struct devfreq_cooling_power - Devfreq cooling power ops

 * @get_static_power:	Take voltage, in mV, and return the static power

 *			in mW.  If NULL, the static power is assumed

 *			to be 0.

 * @get_dynamic_power:	Take voltage, in mV, and frequency, in HZ, and

 *			return the dynamic power draw in mW.  If NULL,

 *			a simple power model is used.

 * @dyn_power_coeff:	Coefficient for the simple dynamic power model in

 *			mW/(MHz mV mV).

 *			If get_dynamic_power() is NULL, then the

 *			dynamic power is calculated as

 *			@dyn_power_coeff * frequency * voltage^2

 */

struct devfreq_cooling_power {

	unsigned long (*get_static_power)(unsigned long voltage);

	unsigned long (*get_dynamic_power)(unsigned long freq,

					   unsigned long voltage);

	unsigned long dyn_power_coeff;

};



struct devfreq_cooling_device *

of_devfreq_cooling_register_power(struct device_node *np, struct devfreq *df,

				  struct devfreq_cooling_power *dfc_power);

struct devfreq_cooling_device *

of_devfreq_cooling_register(struct device_node *np, struct devfreq *df);

struct devfreq_cooling_device *devfreq_cooling_register(struct devfreq *df);

void devfreq_cooling_unregister(struct devfreq_cooling_device *dfc);



#else /* !CONFIG_DEVFREQ_THERMAL */



struct devfreq_cooling_device *

of_devfreq_cooling_register_power(struct device_node *np, struct devfreq *df,

				  struct devfreq_cooling_power *dfc_power)

{

	return ERR_PTR(-EINVAL);

}



static inline struct devfreq_cooling_device *

of_devfreq_cooling_register(struct device_node *np, struct devfreq *df)

{

	return ERR_PTR(-EINVAL);

}



static inline struct devfreq_cooling_device *

devfreq_cooling_register(struct devfreq *df)

{

	return ERR_PTR(-EINVAL);

}



static inline void

devfreq_cooling_unregister(struct devfreq_cooling_device *dfc)

{

}



#endif /* CONFIG_DEVFREQ_THERMAL */

#endif /* __DEVFREQ_COOLING_H__ */

CRA Git | Maintained and supported by SUSTech CRA and CCSE