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Commit 75d2364e authored by Srinivas Pandruvada's avatar Srinivas Pandruvada Committed by Rafael J. Wysocki
Browse files

PowerCap: Add class driver 



The power capping framework providing a consistent interface between the
kernel and user space that allows power capping drivers to expose their
settings to user space in a uniform way.
The overall design of the framework is described in the documentation
added by the previous patch in this series.

Signed-off-by: default avatarSrinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: default avatarJacob Pan <jacob.jun.pan@linux.intel.com>
Reviewed-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent e23feb16

drivers/powercap/Kconfig

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#

# Generic power capping sysfs interface configuration

#



menuconfig POWERCAP

	bool "Generic powercap sysfs driver"

	help

	  The power capping sysfs interface allows kernel subsystems to expose power

	  capping settings to user space in a consistent way.  Usually, it consists

	  of multiple control types that determine which settings may be exposed and

	  power zones representing parts of the system that can be subject to power

	  capping.



	  If you want this code to be compiled in, say Y here.



if POWERCAP

# Client driver configurations go here.



endif

drivers/powercap/Makefile

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Original line number Diff line number Diff line 
obj-$(CONFIG_POWERCAP)	+= powercap_sys.o

drivers/powercap/powercap_sys.c

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Original line number Diff line number Diff line 
/*

 * Power capping class

 * Copyright (c) 2013, Intel Corporation.

 *

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

 * under the terms and conditions of the GNU General Public License,

 * version 2, as published by the Free Software Foundation.

 *

 * This program is distributed in the hope 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.

 *

 */



#include <linux/module.h>

#include <linux/device.h>

#include <linux/err.h>

#include <linux/slab.h>

#include <linux/powercap.h>



#define to_powercap_zone(n) container_of(n, struct powercap_zone, dev)

#define to_powercap_control_type(n) \

			container_of(n, struct powercap_control_type, dev)



/* Power zone show function */

#define define_power_zone_show(_attr)		\

static ssize_t _attr##_show(struct device *dev, \

					struct device_attribute *dev_attr,\

					char *buf) \

{ \

	u64 value; \

	ssize_t len = -EINVAL; \

	struct powercap_zone *power_zone = to_powercap_zone(dev); \

	\

	if (power_zone->ops->get_##_attr) { \

		if (!power_zone->ops->get_##_attr(power_zone, &value)) \

			len = sprintf(buf, "%lld\n", value); \

	} \

	\

	return len; \

}



/* The only meaningful input is 0 (reset), others are silently ignored */

#define define_power_zone_store(_attr)		\

static ssize_t _attr##_store(struct device *dev,\

				struct device_attribute *dev_attr, \

				const char *buf, size_t count) \

{ \

	int err; \

	struct powercap_zone *power_zone = to_powercap_zone(dev); \

	u64 value; \

	\

	err = kstrtoull(buf, 10, &value); \

	if (err) \

		return -EINVAL; \

	if (value) \

		return count; \

	if (power_zone->ops->reset_##_attr) { \

		if (!power_zone->ops->reset_##_attr(power_zone)) \

			return count; \

	} \

	\

	return -EINVAL; \

}



/* Power zone constraint show function */

#define define_power_zone_constraint_show(_attr) \

static ssize_t show_constraint_##_attr(struct device *dev, \

				struct device_attribute *dev_attr,\

				char *buf) \

{ \

	u64 value; \

	ssize_t len = -ENODATA; \

	struct powercap_zone *power_zone = to_powercap_zone(dev); \

	int id; \

	struct powercap_zone_constraint *pconst;\

	\

	if (!sscanf(dev_attr->attr.name, "constraint_%d_", &id)) \

		return -EINVAL; \

	if (id >= power_zone->const_id_cnt)	\

		return -EINVAL; \

	pconst = &power_zone->constraints[id]; \

	if (pconst && pconst->ops && pconst->ops->get_##_attr) { \

		if (!pconst->ops->get_##_attr(power_zone, id, &value)) \

			len = sprintf(buf, "%lld\n", value); \

	} \

	\

	return len; \

}



/* Power zone constraint store function */

#define define_power_zone_constraint_store(_attr) \

static ssize_t store_constraint_##_attr(struct device *dev,\

				struct device_attribute *dev_attr, \

				const char *buf, size_t count) \

{ \

	int err; \

	u64 value; \

	struct powercap_zone *power_zone = to_powercap_zone(dev); \

	int id; \

	struct powercap_zone_constraint *pconst;\

	\

	if (!sscanf(dev_attr->attr.name, "constraint_%d_", &id)) \

		return -EINVAL; \

	if (id >= power_zone->const_id_cnt)	\

		return -EINVAL; \

	pconst = &power_zone->constraints[id]; \

	err = kstrtoull(buf, 10, &value); \

	if (err) \

		return -EINVAL; \

	if (pconst && pconst->ops && pconst->ops->set_##_attr) { \

		if (!pconst->ops->set_##_attr(power_zone, id, value)) \

			return count; \

	} \

	\

	return -ENODATA; \

}



/* Power zone information callbacks */

define_power_zone_show(power_uw);

define_power_zone_show(max_power_range_uw);

define_power_zone_show(energy_uj);

define_power_zone_store(energy_uj);

define_power_zone_show(max_energy_range_uj);



/* Power zone attributes */

static DEVICE_ATTR_RO(max_power_range_uw);

static DEVICE_ATTR_RO(power_uw);

static DEVICE_ATTR_RO(max_energy_range_uj);

static DEVICE_ATTR_RW(energy_uj);



/* Power zone constraint attributes callbacks */

define_power_zone_constraint_show(power_limit_uw);

define_power_zone_constraint_store(power_limit_uw);

define_power_zone_constraint_show(time_window_us);

define_power_zone_constraint_store(time_window_us);

define_power_zone_constraint_show(max_power_uw);

define_power_zone_constraint_show(min_power_uw);

define_power_zone_constraint_show(max_time_window_us);

define_power_zone_constraint_show(min_time_window_us);



/* For one time seeding of constraint device attributes */

struct powercap_constraint_attr {

	struct device_attribute power_limit_attr;

	struct device_attribute time_window_attr;

	struct device_attribute max_power_attr;

	struct device_attribute min_power_attr;

	struct device_attribute max_time_window_attr;

	struct device_attribute min_time_window_attr;

	struct device_attribute name_attr;

};



static struct powercap_constraint_attr

				constraint_attrs[MAX_CONSTRAINTS_PER_ZONE];



/* A list of powercap control_types */

static LIST_HEAD(powercap_cntrl_list);

/* Mutex to protect list of powercap control_types */

static DEFINE_MUTEX(powercap_cntrl_list_lock);



#define POWERCAP_CONSTRAINT_NAME_LEN	30 /* Some limit to avoid overflow */

static ssize_t show_constraint_name(struct device *dev,

				struct device_attribute *dev_attr,

				char *buf)

{

	const char *name;

	struct powercap_zone *power_zone = to_powercap_zone(dev);

	int id;

	ssize_t len = -ENODATA;

	struct powercap_zone_constraint *pconst;



	if (!sscanf(dev_attr->attr.name, "constraint_%d_", &id))

		return -EINVAL;

	if (id >= power_zone->const_id_cnt)

		return -EINVAL;

	pconst = &power_zone->constraints[id];



	if (pconst && pconst->ops && pconst->ops->get_name) {

		name = pconst->ops->get_name(power_zone, id);

		if (name) {

			snprintf(buf, POWERCAP_CONSTRAINT_NAME_LEN,

								"%s\n", name);

			buf[POWERCAP_CONSTRAINT_NAME_LEN] = '\0';

			len = strlen(buf);

		}

	}



	return len;

}



static int create_constraint_attribute(int id, const char *name,

				int mode,

				struct device_attribute *dev_attr,

				ssize_t (*show)(struct device *,

					struct device_attribute *, char *),

				ssize_t (*store)(struct device *,

					struct device_attribute *,

				const char *, size_t)

				)

{



	dev_attr->attr.name = kasprintf(GFP_KERNEL, "constraint_%d_%s",

								id, name);

	if (!dev_attr->attr.name)

		return -ENOMEM;

	dev_attr->attr.mode = mode;

	dev_attr->show = show;

	dev_attr->store = store;



	return 0;

}



static void free_constraint_attributes(void)

{

	int i;



	for (i = 0; i < MAX_CONSTRAINTS_PER_ZONE; ++i) {

		kfree(constraint_attrs[i].power_limit_attr.attr.name);

		kfree(constraint_attrs[i].time_window_attr.attr.name);

		kfree(constraint_attrs[i].name_attr.attr.name);

		kfree(constraint_attrs[i].max_power_attr.attr.name);

		kfree(constraint_attrs[i].min_power_attr.attr.name);

		kfree(constraint_attrs[i].max_time_window_attr.attr.name);

		kfree(constraint_attrs[i].min_time_window_attr.attr.name);

	}

}



static int seed_constraint_attributes(void)

{

	int i;

	int ret;



	for (i = 0; i < MAX_CONSTRAINTS_PER_ZONE; ++i) {

		ret = create_constraint_attribute(i, "power_limit_uw",

					S_IWUSR | S_IRUGO,

					&constraint_attrs[i].power_limit_attr,

					show_constraint_power_limit_uw,

					store_constraint_power_limit_uw);

		if (ret)

			goto err_alloc;

		ret = create_constraint_attribute(i, "time_window_us",

					S_IWUSR | S_IRUGO,

					&constraint_attrs[i].time_window_attr,

					show_constraint_time_window_us,

					store_constraint_time_window_us);

		if (ret)

			goto err_alloc;

		ret = create_constraint_attribute(i, "name", S_IRUGO,

				&constraint_attrs[i].name_attr,

				show_constraint_name,

				NULL);

		if (ret)

			goto err_alloc;

		ret = create_constraint_attribute(i, "max_power_uw", S_IRUGO,

				&constraint_attrs[i].max_power_attr,

				show_constraint_max_power_uw,

				NULL);

		if (ret)

			goto err_alloc;

		ret = create_constraint_attribute(i, "min_power_uw", S_IRUGO,

				&constraint_attrs[i].min_power_attr,

				show_constraint_min_power_uw,

				NULL);

		if (ret)

			goto err_alloc;

		ret = create_constraint_attribute(i, "max_time_window_us",

				S_IRUGO,

				&constraint_attrs[i].max_time_window_attr,

				show_constraint_max_time_window_us,

				NULL);

		if (ret)

			goto err_alloc;

		ret = create_constraint_attribute(i, "min_time_window_us",

				S_IRUGO,

				&constraint_attrs[i].min_time_window_attr,

				show_constraint_min_time_window_us,

				NULL);

		if (ret)

			goto err_alloc;



	}



	return 0;



err_alloc:

	free_constraint_attributes();



	return ret;

}



static int create_constraints(struct powercap_zone *power_zone,

				int nr_constraints,

				struct powercap_zone_constraint_ops *const_ops)

{

	int i;

	int ret = 0;

	int count;

	struct powercap_zone_constraint *pconst;



	if (!power_zone || !const_ops || !const_ops->get_power_limit_uw ||

					!const_ops->set_power_limit_uw ||

					!const_ops->get_time_window_us ||

					!const_ops->set_time_window_us)

		return -EINVAL;



	count = power_zone->zone_attr_count;

	for (i = 0; i < nr_constraints; ++i) {

		pconst = &power_zone->constraints[i];

		pconst->ops = const_ops;

		pconst->id = power_zone->const_id_cnt;

		power_zone->const_id_cnt++;

		power_zone->zone_dev_attrs[count++] =

				&constraint_attrs[i].power_limit_attr.attr;

		power_zone->zone_dev_attrs[count++] =

				&constraint_attrs[i].time_window_attr.attr;

		if (pconst->ops->get_name)

			power_zone->zone_dev_attrs[count++] =

				&constraint_attrs[i].name_attr.attr;

		if (pconst->ops->get_max_power_uw)

			power_zone->zone_dev_attrs[count++] =

				&constraint_attrs[i].max_power_attr.attr;

		if (pconst->ops->get_min_power_uw)

			power_zone->zone_dev_attrs[count++] =

				&constraint_attrs[i].min_power_attr.attr;

		if (pconst->ops->get_max_time_window_us)

			power_zone->zone_dev_attrs[count++] =

				&constraint_attrs[i].max_time_window_attr.attr;

		if (pconst->ops->get_min_time_window_us)

			power_zone->zone_dev_attrs[count++] =

				&constraint_attrs[i].min_time_window_attr.attr;

	}

	power_zone->zone_attr_count = count;



	return ret;

}



static bool control_type_valid(void *control_type)

{

	struct powercap_control_type *pos = NULL;

	bool found = false;



	mutex_lock(&powercap_cntrl_list_lock);



	list_for_each_entry(pos, &powercap_cntrl_list, node) {

		if (pos == control_type) {

			found = true;

			break;

		}

	}

	mutex_unlock(&powercap_cntrl_list_lock);



	return found;

}



static ssize_t name_show(struct device *dev,

				struct device_attribute *attr,

				char *buf)

{

	struct powercap_zone *power_zone = to_powercap_zone(dev);



	return sprintf(buf, "%s\n", power_zone->name);

}



static DEVICE_ATTR_RO(name);



/* Create zone and attributes in sysfs */

static void create_power_zone_common_attributes(

					struct powercap_zone *power_zone)

{

	int count = 0;



	power_zone->zone_dev_attrs[count++] = &dev_attr_name.attr;

	if (power_zone->ops->get_max_energy_range_uj)

		power_zone->zone_dev_attrs[count++] =

					&dev_attr_max_energy_range_uj.attr;

	if (power_zone->ops->get_energy_uj)

		power_zone->zone_dev_attrs[count++] =

					&dev_attr_energy_uj.attr;

	if (power_zone->ops->get_power_uw)

		power_zone->zone_dev_attrs[count++] =

					&dev_attr_power_uw.attr;

	if (power_zone->ops->get_max_power_range_uw)

		power_zone->zone_dev_attrs[count++] =

					&dev_attr_max_power_range_uw.attr;

	power_zone->zone_dev_attrs[count] = NULL;

	power_zone->zone_attr_count = count;

}



static void powercap_release(struct device *dev)

{

	bool allocated;



	if (dev->parent) {

		struct powercap_zone *power_zone = to_powercap_zone(dev);



		/* Store flag as the release() may free memory */

		allocated = power_zone->allocated;

		/* Remove id from parent idr struct */

		idr_remove(power_zone->parent_idr, power_zone->id);

		/* Destroy idrs allocated for this zone */

		idr_destroy(&power_zone->idr);

		kfree(power_zone->name);

		kfree(power_zone->zone_dev_attrs);

		kfree(power_zone->constraints);

		if (power_zone->ops->release)

			power_zone->ops->release(power_zone);

		if (allocated)

			kfree(power_zone);

	} else {

		struct powercap_control_type *control_type =

						to_powercap_control_type(dev);



		/* Store flag as the release() may free memory */

		allocated = control_type->allocated;

		idr_destroy(&control_type->idr);

		mutex_destroy(&control_type->lock);

		if (control_type->ops && control_type->ops->release)

			control_type->ops->release(control_type);

		if (allocated)

			kfree(control_type);

	}

}



static ssize_t enabled_show(struct device *dev,

				struct device_attribute *attr,

				char *buf)

{

	bool mode = true;



	/* Default is enabled */

	if (dev->parent) {

		struct powercap_zone *power_zone = to_powercap_zone(dev);

		if (power_zone->ops->get_enable)

			if (power_zone->ops->get_enable(power_zone, &mode))

				mode = false;

	} else {

		struct powercap_control_type *control_type =

						to_powercap_control_type(dev);

		if (control_type->ops && control_type->ops->get_enable)

			if (control_type->ops->get_enable(control_type, &mode))

				mode = false;

	}



	return sprintf(buf, "%d\n", mode);

}



static ssize_t enabled_store(struct device *dev,

				struct device_attribute *attr,

				const char *buf,  size_t len)

{

	bool mode;



	if (strtobool(buf, &mode))

		return -EINVAL;

	if (dev->parent) {

		struct powercap_zone *power_zone = to_powercap_zone(dev);

		if (power_zone->ops->set_enable)

			if (!power_zone->ops->set_enable(power_zone, mode))

				return len;

	} else {

		struct powercap_control_type *control_type =

						to_powercap_control_type(dev);

		if (control_type->ops && control_type->ops->set_enable)

			if (!control_type->ops->set_enable(control_type, mode))

				return len;

	}



	return -ENOSYS;

}



static struct device_attribute powercap_def_attrs[] = {

		__ATTR(enabled, S_IWUSR | S_IRUGO, enabled_show,

							enabled_store),

		__ATTR_NULL

};



static struct class powercap_class = {

	.name = "powercap",

	.dev_release = powercap_release,

	.dev_attrs = powercap_def_attrs,

};



struct powercap_zone *powercap_register_zone(

				struct powercap_zone *power_zone,

				struct powercap_control_type *control_type,

				const char *name,

				struct powercap_zone *parent,

				const struct powercap_zone_ops *ops,

				int nr_constraints,

				struct powercap_zone_constraint_ops *const_ops)

{

	int result;

	int nr_attrs;



	if (!name || !control_type || !ops ||

			nr_constraints > MAX_CONSTRAINTS_PER_ZONE ||

			(!ops->get_energy_uj && !ops->get_power_uw) ||

			!control_type_valid(control_type))

		return ERR_PTR(-EINVAL);



	if (power_zone) {

		if (!ops->release)

			return ERR_PTR(-EINVAL);

		memset(power_zone, 0, sizeof(*power_zone));

	} else {

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

		if (!power_zone)

			return ERR_PTR(-ENOMEM);

		power_zone->allocated = true;

	}

	power_zone->ops = ops;

	power_zone->control_type_inst = control_type;

	if (!parent) {

		power_zone->dev.parent = &control_type->dev;

		power_zone->parent_idr = &control_type->idr;

	} else {

		power_zone->dev.parent = &parent->dev;

		power_zone->parent_idr = &parent->idr;

	}

	power_zone->dev.class = &powercap_class;



	mutex_lock(&control_type->lock);

	/* Using idr to get the unique id */

	result = idr_alloc(power_zone->parent_idr, NULL, 0, 0, GFP_KERNEL);

	if (result < 0)

		goto err_idr_alloc;



	power_zone->id = result;

	idr_init(&power_zone->idr);

	power_zone->name = kstrdup(name, GFP_KERNEL);

	if (!power_zone->name)

		goto err_name_alloc;

	dev_set_name(&power_zone->dev, "%s:%x",

					dev_name(power_zone->dev.parent),

					power_zone->id);

	power_zone->constraints = kzalloc(sizeof(*power_zone->constraints) *

					 nr_constraints, GFP_KERNEL);

	if (!power_zone->constraints)

		goto err_const_alloc;



	nr_attrs = nr_constraints * POWERCAP_CONSTRAINTS_ATTRS +

						POWERCAP_ZONE_MAX_ATTRS + 1;

	power_zone->zone_dev_attrs = kzalloc(sizeof(void *) *

						nr_attrs, GFP_KERNEL);

	if (!power_zone->zone_dev_attrs)

		goto err_attr_alloc;

	create_power_zone_common_attributes(power_zone);

	result = create_constraints(power_zone, nr_constraints, const_ops);

	if (result)

		goto err_dev_ret;



	power_zone->zone_dev_attrs[power_zone->zone_attr_count] = NULL;

	power_zone->dev_zone_attr_group.attrs = power_zone->zone_dev_attrs;

	power_zone->dev_attr_groups[0] = &power_zone->dev_zone_attr_group;

	power_zone->dev_attr_groups[1] = NULL;

	power_zone->dev.groups = power_zone->dev_attr_groups;

	result = device_register(&power_zone->dev);

	if (result)

		goto err_dev_ret;



	control_type->nr_zones++;

	mutex_unlock(&control_type->lock);



	return power_zone;



err_dev_ret:

	kfree(power_zone->zone_dev_attrs);

err_attr_alloc:

	kfree(power_zone->constraints);

err_const_alloc:

	kfree(power_zone->name);

err_name_alloc:

	idr_remove(power_zone->parent_idr, power_zone->id);

err_idr_alloc:

	if (power_zone->allocated)

		kfree(power_zone);

	mutex_unlock(&control_type->lock);



	return ERR_PTR(result);

}

EXPORT_SYMBOL_GPL(powercap_register_zone);



int powercap_unregister_zone(struct powercap_control_type *control_type,

				struct powercap_zone *power_zone)

{

	if (!power_zone || !control_type)

		return -EINVAL;



	mutex_lock(&control_type->lock);

	control_type->nr_zones--;

	mutex_unlock(&control_type->lock);



	device_unregister(&power_zone->dev);



	return 0;

}

EXPORT_SYMBOL_GPL(powercap_unregister_zone);



struct powercap_control_type *powercap_register_control_type(

				struct powercap_control_type *control_type,

				const char *name,

				const struct powercap_control_type_ops *ops)

{

	int result;



	if (!name)

		return ERR_PTR(-EINVAL);

	if (control_type) {

		if (!ops || !ops->release)

			return ERR_PTR(-EINVAL);

		memset(control_type, 0, sizeof(*control_type));

	} else {

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

		if (!control_type)

			return ERR_PTR(-ENOMEM);

		control_type->allocated = true;

	}

	mutex_init(&control_type->lock);

	control_type->ops = ops;

	INIT_LIST_HEAD(&control_type->node);

	control_type->dev.class = &powercap_class;

	dev_set_name(&control_type->dev, name);

	result = device_register(&control_type->dev);

	if (result) {

		if (control_type->allocated)

			kfree(control_type);

		return ERR_PTR(result);

	}

	idr_init(&control_type->idr);



	mutex_lock(&powercap_cntrl_list_lock);

	list_add_tail(&control_type->node, &powercap_cntrl_list);

	mutex_unlock(&powercap_cntrl_list_lock);



	return control_type;

}

EXPORT_SYMBOL_GPL(powercap_register_control_type);



int powercap_unregister_control_type(struct powercap_control_type *control_type)

{

	struct powercap_control_type *pos = NULL;



	if (control_type->nr_zones) {

		dev_err(&control_type->dev, "Zones of this type still not freed\n");

		return -EINVAL;

	}

	mutex_lock(&powercap_cntrl_list_lock);

	list_for_each_entry(pos, &powercap_cntrl_list, node) {

		if (pos == control_type) {

			list_del(&control_type->node);

			mutex_unlock(&powercap_cntrl_list_lock);

			device_unregister(&control_type->dev);

			return 0;

		}

	}

	mutex_unlock(&powercap_cntrl_list_lock);



	return -ENODEV;

}

EXPORT_SYMBOL_GPL(powercap_unregister_control_type);



static int __init powercap_init(void)

{

	int result = 0;



	result = seed_constraint_attributes();

	if (result)

		return result;



	result = class_register(&powercap_class);



	return result;

}



device_initcall(powercap_init);



MODULE_DESCRIPTION("PowerCap sysfs Driver");

MODULE_AUTHOR("Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>");

MODULE_LICENSE("GPL v2");

include/linux/powercap.h

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