drivers/devfreq/governor_memlat.c - kernel/msm.git - Git at Google

 /*
  * Copyright (c) 2015, The Linux Foundation. All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 and
  * only version 2 as published by the Free Software Foundation.
  *
  * This program is distributed in the hope that 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.
  */

 #define pr_fmt(fmt) "mem_lat: " fmt

 #include <linux/kernel.h>
 #include <linux/sizes.h>
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/io.h>
 #include <linux/delay.h>
 #include <linux/ktime.h>
 #include <linux/time.h>
 #include <linux/err.h>
 #include <linux/errno.h>
 #include <linux/mutex.h>
 #include <linux/interrupt.h>
 #include <linux/platform_device.h>
 #include <linux/of.h>
 #include <linux/devfreq.h>
 #include "governor.h"
 #include "governor_memlat.h"

 #include <trace/events/power.h>

 struct memlat_node {
 	unsigned int ratio_ceil;
 	unsigned int freq_thresh_mhz;
 	unsigned int mult_factor;
 	bool mon_started;
 	struct list_head list;
 	void *orig_data;
 	struct memlat_hwmon *hw;
 	struct devfreq_governor *gov;
 	struct attribute_group *attr_grp;
 };

 static LIST_HEAD(memlat_list);
 static DEFINE_MUTEX(list_lock);

 static int use_cnt;
 static DEFINE_MUTEX(state_lock);

 #define show_attr(name) \
 static ssize_t show_##name(struct device *dev,				\
 			struct device_attribute *attr, char *buf)	\
 {									\
 	struct devfreq *df = to_devfreq(dev);				\
 	struct memlat_node *hw = df->data;				\
 	return snprintf(buf, PAGE_SIZE, "%u\n", hw->name);		\
 }

 #define store_attr(name, _min, _max) \
 static ssize_t store_##name(struct device *dev,				\
 			struct device_attribute *attr, const char *buf,	\
 			size_t count)					\
 {									\
 	struct devfreq *df = to_devfreq(dev);				\
 	struct memlat_node *hw = df->data;				\
 	int ret;							\
 	unsigned int val;						\
 	ret = kstrtouint(buf, 10, &val);				\
 	if (ret)							\
 		return ret;						\
 	val = max(val, _min);						\
 	val = min(val, _max);						\
 	hw->name = val;							\
 	return count;							\
 }

 #define gov_attr(__attr, min, max)	\
 show_attr(__attr)			\
 store_attr(__attr, min, max)		\
 static DEVICE_ATTR(__attr, 0644, show_##__attr, store_##__attr)

 static unsigned long compute_dev_vote(struct devfreq *df)
 {
 	int i, lat_dev;
 	struct memlat_node *node = df->data;
 	struct memlat_hwmon *hw = node->hw;
 	unsigned long max_freq = 0;
 	unsigned int ratio;

 	hw->get_cnt(hw);

 	for (i = 0; i < hw->num_cores; i++) {
 		ratio = hw->core_stats[i].inst_count;

 		if (hw->core_stats[i].mem_count)
 			ratio /= hw->core_stats[i].mem_count;

 		trace_memlat_dev_meas(dev_name(df->dev.parent),
 					hw->core_stats[i].id,
 					hw->core_stats[i].inst_count,
 					hw->core_stats[i].mem_count,
 					hw->core_stats[i].freq, ratio);

 		if (ratio && ratio <= node->ratio_ceil
 		    && hw->core_stats[i].freq >= node->freq_thresh_mhz
 		    && hw->core_stats[i].freq > max_freq) {
 			lat_dev = i;
 			max_freq = hw->core_stats[i].freq;
 		}
 	}

 	if (max_freq)
 		trace_memlat_dev_update(dev_name(df->dev.parent),
 					hw->core_stats[lat_dev].id,
 					hw->core_stats[lat_dev].inst_count,
 					hw->core_stats[lat_dev].mem_count,
 					hw->core_stats[lat_dev].freq,
 					max_freq * node->mult_factor);

 	return max_freq;
 }

 static struct memlat_node *find_memlat_node(struct devfreq *df)
 {
 	struct memlat_node *node, *found = NULL;

 	mutex_lock(&list_lock);
 	list_for_each_entry(node, &memlat_list, list)
 		if (node->hw->dev == df->dev.parent ||
 		    node->hw->of_node == df->dev.parent->of_node) {
 			found = node;
 			break;
 		}
 	mutex_unlock(&list_lock);

 	return found;
 }

 static int start_monitor(struct devfreq *df)
 {
 	struct memlat_node *node = df->data;
 	struct memlat_hwmon *hw = node->hw;
 	struct device *dev = df->dev.parent;
 	int ret;

 	ret = hw->start_hwmon(hw);

 	if (ret) {
 		dev_err(dev, "Unable to start HW monitor! (%d)\n", ret);
 		return ret;
 	}

 	devfreq_monitor_start(df);

 	node->mon_started = true;

 	return 0;
 }

 static void stop_monitor(struct devfreq *df)
 {
 	struct memlat_node *node = df->data;
 	struct memlat_hwmon *hw = node->hw;

 	node->mon_started = false;

 	devfreq_monitor_stop(df);
 	hw->stop_hwmon(hw);
 }

 static int gov_start(struct devfreq *df)
 {
 	int ret = 0;
 	struct device *dev = df->dev.parent;
 	struct memlat_node *node;
 	struct memlat_hwmon *hw;

 	node = find_memlat_node(df);
 	if (!node) {
 		dev_err(dev, "Unable to find HW monitor!\n");
 		return -ENODEV;
 	}
 	hw = node->hw;

 	hw->df = df;
 	node->orig_data = df->data;
 	df->data = node;

 	if (start_monitor(df))
 		goto err_start;

 	ret = sysfs_create_group(&df->dev.kobj, node->attr_grp);
 	if (ret)
 		goto err_sysfs;

 	return 0;

 err_sysfs:
 	stop_monitor(df);
 err_start:
 	df->data = node->orig_data;
 	node->orig_data = NULL;
 	hw->df = NULL;
 	return ret;
 }

 static void gov_stop(struct devfreq *df)
 {
 	struct memlat_node *node = df->data;
 	struct memlat_hwmon *hw = node->hw;

 	sysfs_remove_group(&df->dev.kobj, node->attr_grp);
 	stop_monitor(df);
 	df->data = node->orig_data;
 	node->orig_data = NULL;
 	hw->df = NULL;
 }

 static int devfreq_memlat_get_freq(struct devfreq *df,
 					unsigned long *freq,
 					u32 *flag)
 {
 	unsigned long mhz;
 	struct memlat_node *node = df->data;

 	mhz = compute_dev_vote(df);
 	*freq = mhz ? (mhz * node->mult_factor) : 0;

 	return 0;
 }

 gov_attr(ratio_ceil, 1U, 1000U);
 gov_attr(freq_thresh_mhz, 300U, 5000U);
 gov_attr(mult_factor, 1U, 10U);

 static struct attribute *dev_attr[] = {
 	&dev_attr_ratio_ceil.attr,
 	&dev_attr_freq_thresh_mhz.attr,
 	&dev_attr_mult_factor.attr,
 	NULL,
 };

 static struct attribute_group dev_attr_group = {
 	.name = "mem_latency",
 	.attrs = dev_attr,
 };

 #define MIN_MS	10U
 #define MAX_MS	500U
 static int devfreq_memlat_ev_handler(struct devfreq *df,
 					unsigned int event, void *data)
 {
 	int ret;
 	unsigned int sample_ms;

 	switch (event) {
 	case DEVFREQ_GOV_START:
 		sample_ms = df->profile->polling_ms;
 		sample_ms = max(MIN_MS, sample_ms);
 		sample_ms = min(MAX_MS, sample_ms);
 		df->profile->polling_ms = sample_ms;

 		ret = gov_start(df);
 		if (ret)
 			return ret;

 		dev_dbg(df->dev.parent,
 			"Enabled Memory Latency governor\n");
 		break;

 	case DEVFREQ_GOV_STOP:
 		gov_stop(df);
 		dev_dbg(df->dev.parent,
 			"Disabled Memory Latency governor\n");
 		break;

 	case DEVFREQ_GOV_INTERVAL:
 		sample_ms = *(unsigned int *)data;
 		sample_ms = max(MIN_MS, sample_ms);
 		sample_ms = min(MAX_MS, sample_ms);
 		devfreq_interval_update(df, &sample_ms);
 		break;
 	}

 	return 0;
 }

 static struct devfreq_governor devfreq_gov_memlat = {
 	.name = "mem_latency",
 	.get_target_freq = devfreq_memlat_get_freq,
 	.event_handler = devfreq_memlat_ev_handler,
 };

 int register_memlat(struct device *dev, struct memlat_hwmon *hw)
 {
 	int ret = 0;
 	struct memlat_node *node;

 	if (!hw->dev && !hw->of_node)
 		return -EINVAL;

 	node = devm_kzalloc(dev, sizeof(*node), GFP_KERNEL);
 	if (!node)
 		return -ENOMEM;

 	node->gov = &devfreq_gov_memlat;
 	node->attr_grp = &dev_attr_group;

 	node->ratio_ceil = 10;
 	node->freq_thresh_mhz = 900;
 	node->mult_factor = 8;
 	node->hw = hw;

 	mutex_lock(&list_lock);
 	list_add_tail(&node->list, &memlat_list);
 	mutex_unlock(&list_lock);

 	mutex_lock(&state_lock);
 	if (!use_cnt)
 		ret = devfreq_add_governor(&devfreq_gov_memlat);
 	if (!ret)
 		use_cnt++;
 	mutex_unlock(&state_lock);

 	if (!ret)
 		dev_info(dev, "Memory Latency governor registered.\n");
 	else
 		dev_err(dev, "Memory Latency governor registration failed!\n");

 	return ret;
 }

 MODULE_DESCRIPTION("HW monitor based dev DDR bandwidth voting driver");
 MODULE_LICENSE("GPL v2");
	/*
	* Copyright (c) 2015, The Linux Foundation. All rights reserved.
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 and
	* only version 2 as published by the Free Software Foundation.
	*
	* This program is distributed in the hope that 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.
	*/

	#define pr_fmt(fmt) "mem_lat: " fmt

	#include <linux/kernel.h>
	#include <linux/sizes.h>
	#include <linux/module.h>
	#include <linux/init.h>
	#include <linux/io.h>
	#include <linux/delay.h>
	#include <linux/ktime.h>
	#include <linux/time.h>
	#include <linux/err.h>
	#include <linux/errno.h>
	#include <linux/mutex.h>
	#include <linux/interrupt.h>
	#include <linux/platform_device.h>
	#include <linux/of.h>
	#include <linux/devfreq.h>
	#include "governor.h"
	#include "governor_memlat.h"

	#include <trace/events/power.h>

	struct memlat_node {
	unsigned int ratio_ceil;
	unsigned int freq_thresh_mhz;
	unsigned int mult_factor;
	bool mon_started;
	struct list_head list;
	void *orig_data;
	struct memlat_hwmon *hw;
	struct devfreq_governor *gov;
	struct attribute_group *attr_grp;
	};

	static LIST_HEAD(memlat_list);
	static DEFINE_MUTEX(list_lock);

	static int use_cnt;
	static DEFINE_MUTEX(state_lock);

	#define show_attr(name) \
	static ssize_t show_##name(struct device *dev, \
	struct device_attribute attr, char buf) \
	{ \
	struct devfreq *df = to_devfreq(dev); \
	struct memlat_node *hw = df->data; \
	return snprintf(buf, PAGE_SIZE, "%u\n", hw->name); \
	}

	#define store_attr(name, _min, _max) \
	static ssize_t store_##name(struct device *dev, \
	struct device_attribute attr, const char buf, \
	size_t count) \
	{ \
	struct devfreq *df = to_devfreq(dev); \
	struct memlat_node *hw = df->data; \
	int ret; \
	unsigned int val; \
	ret = kstrtouint(buf, 10, &val); \
	if (ret) \
	return ret; \
	val = max(val, _min); \
	val = min(val, _max); \
	hw->name = val; \
	return count; \
	}

	#define gov_attr(__attr, min, max) \
	show_attr(__attr) \
	store_attr(__attr, min, max) \
	static DEVICE_ATTR(__attr, 0644, show_##__attr, store_##__attr)

	static unsigned long compute_dev_vote(struct devfreq *df)
	{
	int i, lat_dev;
	struct memlat_node *node = df->data;
	struct memlat_hwmon *hw = node->hw;
	unsigned long max_freq = 0;
	unsigned int ratio;

	hw->get_cnt(hw);

	for (i = 0; i < hw->num_cores; i++) {
	ratio = hw->core_stats[i].inst_count;

	if (hw->core_stats[i].mem_count)
	ratio /= hw->core_stats[i].mem_count;

	trace_memlat_dev_meas(dev_name(df->dev.parent),
	hw->core_stats[i].id,
	hw->core_stats[i].inst_count,
	hw->core_stats[i].mem_count,
	hw->core_stats[i].freq, ratio);

	if (ratio && ratio <= node->ratio_ceil
	&& hw->core_stats[i].freq >= node->freq_thresh_mhz
	&& hw->core_stats[i].freq > max_freq) {
	lat_dev = i;
	max_freq = hw->core_stats[i].freq;
	}
	}

	if (max_freq)
	trace_memlat_dev_update(dev_name(df->dev.parent),
	hw->core_stats[lat_dev].id,
	hw->core_stats[lat_dev].inst_count,
	hw->core_stats[lat_dev].mem_count,
	hw->core_stats[lat_dev].freq,
	max_freq * node->mult_factor);

	return max_freq;
	}

	static struct memlat_node find_memlat_node(struct devfreq df)
	{
	struct memlat_node node, found = NULL;

	mutex_lock(&list_lock);
	list_for_each_entry(node, &memlat_list, list)
	if (node->hw->dev == df->dev.parent \|\|
	node->hw->of_node == df->dev.parent->of_node) {
	found = node;
	break;
	}
	mutex_unlock(&list_lock);

	return found;
	}

	static int start_monitor(struct devfreq *df)
	{
	struct memlat_node *node = df->data;
	struct memlat_hwmon *hw = node->hw;
	struct device *dev = df->dev.parent;
	int ret;

	ret = hw->start_hwmon(hw);

	if (ret) {
	dev_err(dev, "Unable to start HW monitor! (%d)\n", ret);
	return ret;
	}

	devfreq_monitor_start(df);

	node->mon_started = true;

	return 0;
	}

	static void stop_monitor(struct devfreq *df)
	{
	struct memlat_node *node = df->data;
	struct memlat_hwmon *hw = node->hw;

	node->mon_started = false;

	devfreq_monitor_stop(df);
	hw->stop_hwmon(hw);
	}

	static int gov_start(struct devfreq *df)
	{
	int ret = 0;
	struct device *dev = df->dev.parent;
	struct memlat_node *node;
	struct memlat_hwmon *hw;

	node = find_memlat_node(df);
	if (!node) {
	dev_err(dev, "Unable to find HW monitor!\n");
	return -ENODEV;
	}
	hw = node->hw;

	hw->df = df;
	node->orig_data = df->data;
	df->data = node;

	if (start_monitor(df))
	goto err_start;

	ret = sysfs_create_group(&df->dev.kobj, node->attr_grp);
	if (ret)
	goto err_sysfs;

	return 0;

	err_sysfs:
	stop_monitor(df);
	err_start:
	df->data = node->orig_data;
	node->orig_data = NULL;
	hw->df = NULL;
	return ret;
	}

	static void gov_stop(struct devfreq *df)
	{
	struct memlat_node *node = df->data;
	struct memlat_hwmon *hw = node->hw;

	sysfs_remove_group(&df->dev.kobj, node->attr_grp);
	stop_monitor(df);
	df->data = node->orig_data;
	node->orig_data = NULL;
	hw->df = NULL;
	}

	static int devfreq_memlat_get_freq(struct devfreq *df,
	unsigned long *freq,
	u32 *flag)
	{
	unsigned long mhz;
	struct memlat_node *node = df->data;

	mhz = compute_dev_vote(df);
	freq = mhz ? (mhz node->mult_factor) : 0;

	return 0;
	}

	gov_attr(ratio_ceil, 1U, 1000U);
	gov_attr(freq_thresh_mhz, 300U, 5000U);
	gov_attr(mult_factor, 1U, 10U);

	static struct attribute *dev_attr[] = {
	&dev_attr_ratio_ceil.attr,
	&dev_attr_freq_thresh_mhz.attr,
	&dev_attr_mult_factor.attr,
	NULL,
	};

	static struct attribute_group dev_attr_group = {
	.name = "mem_latency",
	.attrs = dev_attr,
	};

	#define MIN_MS 10U
	#define MAX_MS 500U
	static int devfreq_memlat_ev_handler(struct devfreq *df,
	unsigned int event, void *data)
	{
	int ret;
	unsigned int sample_ms;

	switch (event) {
	case DEVFREQ_GOV_START:
	sample_ms = df->profile->polling_ms;
	sample_ms = max(MIN_MS, sample_ms);
	sample_ms = min(MAX_MS, sample_ms);
	df->profile->polling_ms = sample_ms;

	ret = gov_start(df);
	if (ret)
	return ret;

	dev_dbg(df->dev.parent,
	"Enabled Memory Latency governor\n");
	break;

	case DEVFREQ_GOV_STOP:
	gov_stop(df);
	dev_dbg(df->dev.parent,
	"Disabled Memory Latency governor\n");
	break;

	case DEVFREQ_GOV_INTERVAL:
	sample_ms = (unsigned int )data;
	sample_ms = max(MIN_MS, sample_ms);
	sample_ms = min(MAX_MS, sample_ms);
	devfreq_interval_update(df, &sample_ms);
	break;
	}

	return 0;
	}

	static struct devfreq_governor devfreq_gov_memlat = {
	.name = "mem_latency",
	.get_target_freq = devfreq_memlat_get_freq,
	.event_handler = devfreq_memlat_ev_handler,
	};

	int register_memlat(struct device dev, struct memlat_hwmon hw)
	{
	int ret = 0;
	struct memlat_node *node;

	if (!hw->dev && !hw->of_node)
	return -EINVAL;

	node = devm_kzalloc(dev, sizeof(*node), GFP_KERNEL);
	if (!node)
	return -ENOMEM;

	node->gov = &devfreq_gov_memlat;
	node->attr_grp = &dev_attr_group;

	node->ratio_ceil = 10;
	node->freq_thresh_mhz = 900;
	node->mult_factor = 8;
	node->hw = hw;

	mutex_lock(&list_lock);
	list_add_tail(&node->list, &memlat_list);
	mutex_unlock(&list_lock);

	mutex_lock(&state_lock);
	if (!use_cnt)
	ret = devfreq_add_governor(&devfreq_gov_memlat);
	if (!ret)
	use_cnt++;
	mutex_unlock(&state_lock);

	if (!ret)
	dev_info(dev, "Memory Latency governor registered.\n");
	else
	dev_err(dev, "Memory Latency governor registration failed!\n");

	return ret;
	}

	MODULE_DESCRIPTION("HW monitor based dev DDR bandwidth voting driver");
	MODULE_LICENSE("GPL v2");