thermalCommon.cpp - LeafOS-Project/android_hardware_qcom_thermal - Gitiles

 /*
  * Copyright (c) 2020, The Linux Foundation. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *	* Redistributions of source code must retain the above copyright
  *	  notice, this list of conditions and the following disclaimer.
  *	* Redistributions in binary form must reproduce the above
  *	  copyright notice, this list of conditions and the following
  *	  disclaimer in the documentation and/or other materials provided
  *	  with the distribution.
  *	* Neither the name of The Linux Foundation nor the names of its
  *	  contributors may be used to endorse or promote products derived
  *	  from this software without specific prior written permission.
  *
  *
  * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT
  * ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
  * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
  * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
  * IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */

 #include <cstdio>
 #include <cinttypes>
 #include <string>
 #include <dirent.h>
 #include <unordered_map>
 #include <fstream>

 #include <android-base/logging.h>
 #include "thermalCommon.h"

 #define MAX_LENGTH		50
 #define MAX_PATH		(256)
 #define DEFAULT_HYSTERESIS	5000
 #define THERMAL_SYSFS		"/sys/class/thermal/"
 #define TZ_DIR_NAME		"thermal_zone"
 #define TZ_DIR_FMT		"thermal_zone%d"
 #define TEMPERATURE_FILE_FORMAT	"/sys/class/thermal/thermal_zone%d/temp"
 #define POLICY_FILE_FORMAT	"/sys/class/thermal/thermal_zone%d/policy"
 #define TRIP_FILE_FORMAT	"/sys/class/thermal/thermal_zone%d/trip_point_1_temp"
 #define HYST_FILE_FORMAT	"/sys/class/thermal/thermal_zone%d/trip_point_1_hyst"
 #define USER_SPACE_POLICY	"user_space"
 #define TZ_TYPE			"type"
 #define CDEV_DIR_NAME		"cooling_device"
 #define CDEV_DIR_FMT		"cooling_device%d"
 #define CDEV_CUR_STATE_PATH	"/sys/class/thermal/cooling_device%d/cur_state"
 #define CPU_USAGE_FILE		"/proc/stat"
 #define CPU_ONLINE_FILE_FORMAT	"/sys/devices/system/cpu/cpu%d/online"

 namespace android {
 namespace hardware {
 namespace thermal {
 namespace V2_0 {
 namespace implementation {

 static std::unordered_map<std::string, cdevType> cdev_map = {
 	{"thermal-cpufreq-0", cdevType::CPU},
 	{"thermal-cpufreq-1", cdevType::CPU},
 	{"thermal-cpufreq-2", cdevType::CPU},
 	{"thermal-cpufreq-3", cdevType::CPU},
 	{"thermal-cpufreq-4", cdevType::CPU},
 	{"thermal-cpufreq-5", cdevType::CPU},
 	{"thermal-cpufreq-6", cdevType::CPU},
 	{"thermal-cpufreq-7", cdevType::CPU},
 	{"cpufreq-cpu0", cdevType::CPU},
 	{"cpufreq-cpu1", cdevType::CPU},
 	{"cpufreq-cpu2", cdevType::CPU},
 	{"cpufreq-cpu3", cdevType::CPU},
 	{"cpufreq-cpu4", cdevType::CPU},
 	{"cpufreq-cpu5", cdevType::CPU},
 	{"cpufreq-cpu6", cdevType::CPU},
 	{"cpufreq-cpu7", cdevType::CPU},
 	{"thermal-cluster-4-7", cdevType::CPU},
 	{"thermal-cluster-3-7", cdevType::CPU},
 	{"cpu-isolate0", cdevType::CPU},
 	{"cpu-isolate1", cdevType::CPU},
 	{"cpu-isolate2", cdevType::CPU},
 	{"cpu-isolate3", cdevType::CPU},
 	{"cpu-isolate4", cdevType::CPU},
 	{"cpu-isolate5", cdevType::CPU},
 	{"cpu-isolate6", cdevType::CPU},
 	{"cpu-isolate7", cdevType::CPU},
 	{"thermal-pause-1", cdevType::CPU},
 	{"thermal-pause-2", cdevType::CPU},
 	{"thermal-pause-4", cdevType::CPU},
 	{"thermal-pause-8", cdevType::CPU},
 	{"thermal-pause-10", cdevType::CPU},
 	{"thermal-pause-20", cdevType::CPU},
 	{"thermal-pause-40", cdevType::CPU},
 	{"thermal-pause-80", cdevType::CPU},
 	{"thermal-devfreq-0", cdevType::GPU},
 	{"devfreq-3d00000.qcom,kgsl-3d0", cdevType::GPU},
 	{"gpu", cdevType::GPU},
 	{"modem_tj", cdevType::MODEM},
 	{"modem_lte_dsc", cdevType::MODEM},
 	{"modem_nr_dsc", cdevType::MODEM},
 	{"modem_nr_scg_dsc", cdevType::MODEM},
 	{"cdsp", cdevType::NPU},
 	{"cdsp_hw", cdevType::NPU},
 	{"battery", cdevType::BATTERY},
 	{"fan-max31760", cdevType::FAN},
 };

 ThermalCommon::ThermalCommon()
 {
 	LOG(DEBUG) << "Entering " << __func__;
 	ncpus = (int)sysconf(_SC_NPROCESSORS_CONF);
 	if (ncpus < 1)
 		LOG(ERROR) << "Error retrieving number of cores";
 }

 static int writeToFile(std::string_view path, std::string data)
 {
 	std::fstream outFile;

 	outFile.open(std::string(path).c_str(),
 			std::fstream::binary | std::fstream::out);
 	if (outFile.is_open()) {
 		LOG(DEBUG) << "writing: "<< data << " in path:" << path
 			<< std::endl;
 		outFile << data;
 		outFile.close();
 		return data.length();
 	}

 	LOG(ERROR) << "Error opening file: "<< path << std::endl;
 	return -1;
 }

 static int readLineFromFile(std::string_view path, std::string& out)
 {
 	char *fgets_ret;
 	FILE *fd;
 	int rv;
 	char buf[MAX_LENGTH];

 	out.clear();

 	fd = fopen(std::string(path).c_str(), "r");
 	if (fd == NULL) {
 		LOG(ERROR) << "Path:" << std::string(path) << " file open error.err:"
 			<< strerror(errno) << std::endl;
 		return errno;
 	}

 	fgets_ret = fgets(buf, MAX_LENGTH, fd);
 	if (NULL != fgets_ret) {
 		rv = (int)strlen(buf);
 		out.append(buf, rv);
 	} else {
 		rv = ferror(fd);
 	}

 	fclose(fd);
 	out.erase(std::remove(out.begin(), out.end(), '\n'), out.end());
 	LOG(DEBUG) << "Path:" << std::string(path) << " Val:" << out << std::endl;

 	return rv;
 }

 int ThermalCommon::readFromFile(std::string_view path, std::string& out)
 {
 	return readLineFromFile(path, out);
 }

 static int get_tzn(std::string sensor_name)
 {
 	DIR *tdir = NULL;
 	struct dirent *tdirent = NULL;
 	int found = -1;
 	int tzn = 0;
 	char name[MAX_PATH] = {0};
 	char cwd[MAX_PATH] = {0};
 	int ret = 0;

 	if (!getcwd(cwd, sizeof(cwd)))
 		return found;

 	/* Change dir to read the entries. Doesnt work otherwise */
 	ret = chdir(THERMAL_SYSFS);
 	if (ret) {
 		LOG(ERROR) << "Unable to change to " << THERMAL_SYSFS << std::endl;
 		return found;
 	}
 	tdir = opendir(THERMAL_SYSFS);
 	if (!tdir) {
 		LOG(ERROR) << "Unable to open " << THERMAL_SYSFS << std::endl;
 		return found;
 	}

 	while ((tdirent = readdir(tdir))) {
 		std::string buf;

 		if (strncmp(tdirent->d_name, TZ_DIR_NAME,
 			strlen(TZ_DIR_NAME)) != 0)
 			continue;

 		snprintf(name, MAX_PATH, "%s%s/%s", THERMAL_SYSFS,
 				tdirent->d_name, TZ_TYPE);
 		ret = readLineFromFile(std::string_view(name), buf);
 		if (ret <= 0) {
 			LOG(ERROR) <<
 				"get_tzn: sensor name read error for tz:" <<
 				tdirent->d_name << std::endl;
 			continue;
 		}
 		if (!strncmp(buf.c_str(), sensor_name.c_str(),
 					sensor_name.length())) {
 			found = 1;
 			break;
 		}
 	}

 	if (found == 1) {
 		sscanf(tdirent->d_name, TZ_DIR_FMT, &tzn);
 		LOG(DEBUG) << "Sensor: " << sensor_name <<
 			" found at tz: " << tzn << std::endl;
 		found = tzn;
 	}

 	closedir(tdir);
 	/* Restore current working dir */
 	ret = chdir(cwd);

 	return found;
 }

 int ThermalCommon::initialize_sensor(struct target_therm_cfg& cfg, int sens_idx)
 {
 	struct therm_sensor sensor;
 	int idx = 0;

 	sensor.tzn = get_tzn(cfg.sensor_list[sens_idx]);
 	if (sensor.tzn < 0) {
 		LOG(ERROR) << "No thermal zone for sensor: " <<
 			cfg.sensor_list[sens_idx] << ", ret:" <<
 			sensor.tzn << std::endl;
 		return -1;
 	}
 	if (cfg.type == TemperatureType::CPU)
 		sensor.thresh.name = sensor.t.name =
 			std::string("CPU") + std::to_string(sens_idx);
 	else
 		sensor.thresh.name = sensor.t.name = cfg.label;

 	if (cfg.type == TemperatureType::BCL_PERCENTAGE)
 		sensor.mulFactor = 1;
 	else
 		sensor.mulFactor = 1000;

 	sensor.sensor_name = cfg.sensor_list[sens_idx];
 	sensor.positiveThresh = cfg.positive_thresh_ramp;
 	sensor.lastThrottleStatus = sensor.t.throttlingStatus =
 		ThrottlingSeverity::NONE;
 	sensor.thresh.type = sensor.t.type = cfg.type;
 	sensor.thresh.vrThrottlingThreshold =
 	UNKNOWN_TEMPERATURE;
 	for (idx = 0; idx <= (size_t)ThrottlingSeverity::SHUTDOWN; idx++) {
 		sensor.thresh.hotThrottlingThresholds[idx] =
 		sensor.thresh.coldThrottlingThresholds[idx] =
 			UNKNOWN_TEMPERATURE;
 	}

 	if (cfg.throt_thresh != 0 && cfg.positive_thresh_ramp)
 		sensor.thresh.hotThrottlingThresholds[(size_t)ThrottlingSeverity::SEVERE] =
 			cfg.throt_thresh / (float)sensor.mulFactor;
 	else if (cfg.throt_thresh != 0 && !cfg.positive_thresh_ramp)
 		sensor.thresh.coldThrottlingThresholds[(size_t)ThrottlingSeverity::SEVERE] =
 			cfg.throt_thresh / (float)sensor.mulFactor;

 	if (cfg.shutdwn_thresh != 0 && cfg.positive_thresh_ramp)
 		sensor.thresh.hotThrottlingThresholds[(size_t)ThrottlingSeverity::SHUTDOWN] =
 			cfg.shutdwn_thresh / (float)sensor.mulFactor;
 	else if (cfg.shutdwn_thresh != 0 && !cfg.positive_thresh_ramp)
 		sensor.thresh.coldThrottlingThresholds[(size_t)ThrottlingSeverity::SHUTDOWN] =
 			cfg.shutdwn_thresh / (float)sensor.mulFactor;

 	if (cfg.vr_thresh != 0)
 		sensor.thresh.vrThrottlingThreshold =
 			cfg.vr_thresh / (float)sensor.mulFactor;
 	sens.push_back(sensor);
 	//read_temperature((struct therm_sensor *)sensor);

 	return 0;
 }

 int ThermalCommon::initializeCpuSensor(struct target_therm_cfg& cpu_cfg)
 {
 	int cpu = 0;

 	for (;cpu < ncpus; cpu++) {
 		if (initialize_sensor(cpu_cfg, cpu) < 0)
 			return -1;
 	}

 	return 0;
 }

 int ThermalCommon::initThermalZones(std::vector<struct target_therm_cfg>& cfg)
 {
 	std::vector<struct target_therm_cfg>::iterator it;

 	if (cfg.empty()) {
 		LOG(ERROR) << std::string(__func__) +":Invalid input";
 		return -1;
 	}

 	for (it = cfg.begin(); it != cfg.end(); it++)
 	{
 		if (it->type == TemperatureType::CPU) {
 			if (initializeCpuSensor(*it) < 0)
 				return -1;
 			continue;
 		}
 		if (initialize_sensor(*it, 0) < 0) {
 			return -1;
 		}
 	}

 	return sens.size();
 }

 int ThermalCommon::initCdev()
 {
 	DIR *tdir = NULL;
 	struct dirent *tdirent = NULL;
 	int cdevn = 0;
 	char name[MAX_PATH] = {0};
 	char cwd[MAX_PATH] = {0};
 	int ret = 0;

 	if (!getcwd(cwd, sizeof(cwd)))
 		return 0;

 	/* Change dir to read the entries. Doesnt work otherwise */
 	ret = chdir(THERMAL_SYSFS);
 	if (ret) {
 		LOG(ERROR) << "Unable to change to " << THERMAL_SYSFS << std::endl;
 		return 0;
 	}
 	tdir = opendir(THERMAL_SYSFS);
 	if (!tdir) {
 		LOG(ERROR) << "Unable to open " << THERMAL_SYSFS << std::endl;
 		return 0;
 	}

 	while ((tdirent = readdir(tdir))) {
 		std::string buf;
 		struct dirent *tzdirent;
 		std::unordered_map<std::string, cdevType>::iterator it;
 		struct therm_cdev cdevInst;

 		if (strncmp(tdirent->d_name, CDEV_DIR_NAME,
 			strlen(CDEV_DIR_NAME)) != 0)
 			continue;

 		snprintf(name, MAX_PATH, "%s%s/%s", THERMAL_SYSFS,
 				tdirent->d_name, TZ_TYPE);
 		ret = readLineFromFile(std::string_view(name), buf);
 		if (ret <= 0) {
 			LOG(ERROR) <<
 				"init_cdev: cdev type read error for cdev:" <<
 				tdirent->d_name << std::endl;
 		}
 		it = cdev_map.find(buf);
 		if (it == cdev_map.end())
 			continue;
 		sscanf(tdirent->d_name, CDEV_DIR_FMT, &cdevn);
 		LOG(DEBUG) << "cdev: " << it->first <<
 			" found at cdev number: " << cdevn << std::endl;
 		cdevInst.c.name = it->first;
 		cdevInst.c.type = it->second;
 		cdevInst.cdevn = cdevn;
 		read_cdev_state(cdevInst);
 		cdev.push_back(cdevInst);
 	}

 	closedir(tdir);
 	/* Restore current working dir */
 	ret = chdir(cwd);

 	return cdev.size();
 }

 int ThermalCommon::read_cdev_state(struct therm_cdev& cdev)
 {
 	char file_name[MAX_PATH];
 	std::string buf;
 	int ret = 0, ct = 0;
 	bool read_ok = false;

 	snprintf(file_name, sizeof(file_name), CDEV_CUR_STATE_PATH,
 			cdev.cdevn);
 	do {
 		ret = readLineFromFile(std::string(file_name), buf);
 		if (ret <= 0) {
 			LOG(ERROR) << "Cdev state read error:"<< ret <<
 				" for cdev: " << cdev.c.name;
 			return -1;
 		}
 		try {
 			cdev.c.value = std::stoi(buf, nullptr, 0);
 			read_ok = true;
 		}
 		catch (std::exception &err) {
 			LOG(ERROR) << "Cdev read stoi error:" << err.what()
 				<< " cdev:" << cdev.c.name << " ID:"
 				<< cdev.cdevn << " buf:" << buf <<
 				std::endl;
 		}
 		ct++;
 	} while (!read_ok && ct < RETRY_CT);
 	LOG(DEBUG) << "cdev Name:" << cdev.c.name << ". state:" <<
 		cdev.c.value << std::endl;

 	return cdev.c.value;
 }

 int ThermalCommon::estimateSeverity(struct therm_sensor& sensor)
 {
 	int idx = 0;
 	ThrottlingSeverity severity = ThrottlingSeverity::NONE;
 	float temp = sensor.t.value;

 	for (idx = (int)ThrottlingSeverity::SHUTDOWN; idx >= 0; idx--) {
 		/* If a particular threshold is hit already, check if the
 		 * hysteresis is cleared before changing the severity */
 		if (idx == (int)sensor.t.throttlingStatus) {
 			if ((sensor.positiveThresh &&
 				!isnan(sensor.thresh.hotThrottlingThresholds[idx]) &&
 				temp >=
 				(sensor.thresh.hotThrottlingThresholds[idx] -
 				DEFAULT_HYSTERESIS / sensor.mulFactor)) ||
 				(!sensor.positiveThresh &&
 				!isnan(sensor.thresh.coldThrottlingThresholds[idx]) &&
 				temp <=
 				(sensor.thresh.coldThrottlingThresholds[idx] +
 				DEFAULT_HYSTERESIS / sensor.mulFactor)))
 				break;
 			continue;
 		}
 		if ((sensor.positiveThresh &&
 			!isnan(sensor.thresh.hotThrottlingThresholds[idx]) &&
 			temp >=
 			sensor.thresh.hotThrottlingThresholds[idx]) ||
 		 	(!sensor.positiveThresh &&
 			!isnan(sensor.thresh.coldThrottlingThresholds[idx]) &&
 			temp <=
 			sensor.thresh.coldThrottlingThresholds[idx]))
 			break;
 	}
 	if (idx >= 0)
 		severity = (ThrottlingSeverity)(idx);
 	LOG(INFO) << "Sensor Name:" << sensor.t.name << "temp: " <<
 		temp << ". prev severity:" <<
 		(int)sensor.lastThrottleStatus << ". cur severity:" <<
 		(int)sensor.t.throttlingStatus << " New severity:" <<
 		(int)severity << std::endl;
 	if (severity == sensor.t.throttlingStatus)
 		return -1;
 	sensor.lastThrottleStatus = sensor.t.throttlingStatus;
 	sensor.t.throttlingStatus = severity;

 	return (int)severity;
 }

 int ThermalCommon::read_temperature(struct therm_sensor& sensor)
 {
 	char file_name[MAX_PATH];
 	float temp;
 	std::string buf;
 	int ret = 0, ct = 0;
 	bool read_ok = false;

 	do {
 		snprintf(file_name, sizeof(file_name), TEMPERATURE_FILE_FORMAT,
 			sensor.tzn);
 		ret = readLineFromFile(std::string(file_name), buf);
 		if (ret <= 0) {
 			LOG(ERROR) << "Temperature read error:"<< ret <<
 				" for sensor " << sensor.t.name;
 			return -1;
 		}
 		try {
 			sensor.t.value = (float)std::stoi(buf, nullptr, 0) /
 				 (float)sensor.mulFactor;
 			read_ok = true;
 		}
 		catch (std::exception &err) {
 			LOG(ERROR) << "Temperature buf stoi error: "
 				<< err.what()
 				<< " buf:" << buf << " sensor:"
 				<< sensor.t.name << " TZ:" <<
 				sensor.tzn << std::endl;
 		}
 		ct++;
 	} while (!read_ok && ct < RETRY_CT);
 	LOG(DEBUG) << "Sensor Name:" << sensor.t.name << ". Temperature:" <<
 		(float)sensor.t.value << std::endl;

 	return ret;
 }

 void ThermalCommon::initThreshold(struct therm_sensor& sensor)
 {
 	char file_name[MAX_PATH] = "";
 	std::string buf;
 	int ret = 0, idx;
 	ThrottlingSeverity severity = ThrottlingSeverity::NONE;
 	int next_trip, curr_trip, hyst_temp = 0;

 	LOG(DEBUG) << "Entering " <<__func__;
 	if (!sensor.positiveThresh) {
 		LOG(ERROR) << "negative temperature ramp for sensor:"<<
 			sensor.t.name;
 		return;
 	}
 #ifndef ENABLE_THERMAL_NETLINK
 	snprintf(file_name, sizeof(file_name), POLICY_FILE_FORMAT,
 			sensor.tzn);
 	ret = readLineFromFile(std::string(file_name), buf);
 	if (ret <= 0) {
 		LOG(ERROR) << "Policy read error:"<< ret <<
 			" for sensor " << sensor.t.name;
 		return;
 	}
 	if (buf != std::string(USER_SPACE_POLICY)) {
 		LOG(ERROR) << "Policy error:"<< buf << " sensor:" <<
 			sensor.t.name << std::endl;
 		return;
 	}
 #endif
 	next_trip = UNKNOWN_TEMPERATURE;
 	for (idx = 0;idx <= (int)ThrottlingSeverity::SHUTDOWN; idx++) {
 		if (isnan(sensor.thresh.hotThrottlingThresholds[idx])
 			|| idx <= (int)sensor.t.throttlingStatus)
 			continue;

 		next_trip = sensor.thresh.hotThrottlingThresholds[idx] *
 				sensor.mulFactor;
 		break;
 	}

 	if (!isnan(next_trip)) {
 		LOG(DEBUG) << "Sensor: " << sensor.t.name << " high trip:"
 			<< next_trip << std::endl;
 		snprintf(file_name, sizeof(file_name), TRIP_FILE_FORMAT,
 				sensor.tzn);
 		writeToFile(std::string_view(file_name), std::to_string(next_trip));
 	}
 	if (sensor.t.throttlingStatus != ThrottlingSeverity::NONE) {
 		curr_trip = sensor.thresh.hotThrottlingThresholds[
 				(int)sensor.t.throttlingStatus]
 					* sensor.mulFactor;
 		if (!isnan(next_trip))
 			hyst_temp = (next_trip - curr_trip) + DEFAULT_HYSTERESIS;
 		else
 			hyst_temp = DEFAULT_HYSTERESIS;
 		LOG(DEBUG) << "Sensor: " << sensor.t.name << " hysteresis:"
 			<< hyst_temp << std::endl;
 		snprintf(file_name, sizeof(file_name), HYST_FILE_FORMAT,
 				sensor.tzn);
 		writeToFile(std::string_view(file_name), std::to_string(hyst_temp));
 	}

 	return;
 }

 int ThermalCommon::get_cpu_usages(hidl_vec<CpuUsage>& list) {
 	int vals, cpu_num, online;
 	ssize_t read;
 	uint64_t user, nice, system, idle, active, total;
 	char *line = NULL;
 	size_t len = 0;
 	size_t cpu = 0;
 	char file_name[MAX_LENGTH];
 	FILE *file;
 	FILE *cpu_file;

 	list.resize(ncpus);
 	file = fopen(CPU_USAGE_FILE, "r");
 	if (file == NULL) {
 		LOG(ERROR) << "failed to open:" << CPU_USAGE_FILE <<
 			" err:" << strerror(errno);
 		return -errno;
 	}

 	while ((read = getline(&line, &len, file)) != -1) {
 		if (strnlen(line, read) < 4 || strncmp(line, "cpu", 3) != 0 ||
 				!isdigit(line[3])) {
 			free(line);
 			line = NULL;
 			len = 0;
 			continue;
 		}
 		vals = sscanf(line, \
 			"cpu%d %" SCNu64 " %" SCNu64 " %" SCNu64 " %" SCNu64, \
 			&cpu_num, &user, &nice, &system, &idle);

 		free(line);
 		line = NULL;
 		len = 0;

 		if (vals != 5 || cpu == ncpus) {
 			if (vals != 5) {
 				LOG(ERROR) <<
 				"failed to read CPU information from file: "
 				<< strerror(errno);
 			} else {
 				LOG(ERROR) <<
 					"/proc/stat file has incorrect format.";
 			}
 			fclose(file);
 			return errno ? -errno : -EIO;
 		}

 		active = user + nice + system;
 		total = active + idle;

 		// Read online CPU information.
 		snprintf(file_name, MAX_LENGTH, CPU_ONLINE_FILE_FORMAT,
 				cpu_num);
 		cpu_file = fopen(file_name, "r");
 		online = 0;
 		if (cpu_file == NULL) {
 			LOG(ERROR) << "failed to open file:" << file_name <<
 				" err: " << strerror(errno);
 			fclose(file);
 			return -errno;
 		}
 		if (1 != fscanf(cpu_file, "%d", &online)) {
 			LOG(ERROR) << "failed to read CPU online information" << strerror(errno);
 			fclose(file);
 			fclose(cpu_file);
 			return errno ? -errno : -EIO;
 		}
 		fclose(cpu_file);

 		list[cpu_num].name = std::string("CPU") + std::to_string(cpu_num);
 		list[cpu_num].active = active;
 		list[cpu_num].total = total;
 		list[cpu_num].isOnline = online;
 		cpu++;
 	}
 	fclose(file);
 	if (cpu != ncpus) {
 		LOG(ERROR) <<"/proc/stat file has incorrect format.";
 		return -EIO;
 	}
 	return ncpus;
 }

 }  // namespace implementation
 }  // namespace V2_0
 }  // namespace thermal
 }  // namespace hardware
 }  // namespace android
	/*
	* Copyright (c) 2020, The Linux Foundation. All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions are
	* met:
	* * Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* * Redistributions in binary form must reproduce the above
	* copyright notice, this list of conditions and the following
	* disclaimer in the documentation and/or other materials provided
	* with the distribution.
	* * Neither the name of The Linux Foundation nor the names of its
	* contributors may be used to endorse or promote products derived
	* from this software without specific prior written permission.
	*
	*
	* THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
	* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
	* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT
	* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
	* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
	* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
	* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
	* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
	* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
	* OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
	* IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*/

	#include <cstdio>
	#include <cinttypes>
	#include <string>
	#include <dirent.h>
	#include <unordered_map>
	#include <fstream>

	#include <android-base/logging.h>
	#include "thermalCommon.h"

	#define MAX_LENGTH 50
	#define MAX_PATH (256)
	#define DEFAULT_HYSTERESIS 5000
	#define THERMAL_SYSFS "/sys/class/thermal/"
	#define TZ_DIR_NAME "thermal_zone"
	#define TZ_DIR_FMT "thermal_zone%d"
	#define TEMPERATURE_FILE_FORMAT "/sys/class/thermal/thermal_zone%d/temp"
	#define POLICY_FILE_FORMAT "/sys/class/thermal/thermal_zone%d/policy"
	#define TRIP_FILE_FORMAT "/sys/class/thermal/thermal_zone%d/trip_point_1_temp"
	#define HYST_FILE_FORMAT "/sys/class/thermal/thermal_zone%d/trip_point_1_hyst"
	#define USER_SPACE_POLICY "user_space"
	#define TZ_TYPE "type"
	#define CDEV_DIR_NAME "cooling_device"
	#define CDEV_DIR_FMT "cooling_device%d"
	#define CDEV_CUR_STATE_PATH "/sys/class/thermal/cooling_device%d/cur_state"
	#define CPU_USAGE_FILE "/proc/stat"
	#define CPU_ONLINE_FILE_FORMAT "/sys/devices/system/cpu/cpu%d/online"

	namespace android {
	namespace hardware {
	namespace thermal {
	namespace V2_0 {
	namespace implementation {

	static std::unordered_map<std::string, cdevType> cdev_map = {
	{"thermal-cpufreq-0", cdevType::CPU},
	{"thermal-cpufreq-1", cdevType::CPU},
	{"thermal-cpufreq-2", cdevType::CPU},
	{"thermal-cpufreq-3", cdevType::CPU},
	{"thermal-cpufreq-4", cdevType::CPU},
	{"thermal-cpufreq-5", cdevType::CPU},
	{"thermal-cpufreq-6", cdevType::CPU},
	{"thermal-cpufreq-7", cdevType::CPU},
	{"cpufreq-cpu0", cdevType::CPU},
	{"cpufreq-cpu1", cdevType::CPU},
	{"cpufreq-cpu2", cdevType::CPU},
	{"cpufreq-cpu3", cdevType::CPU},
	{"cpufreq-cpu4", cdevType::CPU},
	{"cpufreq-cpu5", cdevType::CPU},
	{"cpufreq-cpu6", cdevType::CPU},
	{"cpufreq-cpu7", cdevType::CPU},
	{"thermal-cluster-4-7", cdevType::CPU},
	{"thermal-cluster-3-7", cdevType::CPU},
	{"cpu-isolate0", cdevType::CPU},
	{"cpu-isolate1", cdevType::CPU},
	{"cpu-isolate2", cdevType::CPU},
	{"cpu-isolate3", cdevType::CPU},
	{"cpu-isolate4", cdevType::CPU},
	{"cpu-isolate5", cdevType::CPU},
	{"cpu-isolate6", cdevType::CPU},
	{"cpu-isolate7", cdevType::CPU},
	{"thermal-pause-1", cdevType::CPU},
	{"thermal-pause-2", cdevType::CPU},
	{"thermal-pause-4", cdevType::CPU},
	{"thermal-pause-8", cdevType::CPU},
	{"thermal-pause-10", cdevType::CPU},
	{"thermal-pause-20", cdevType::CPU},
	{"thermal-pause-40", cdevType::CPU},
	{"thermal-pause-80", cdevType::CPU},
	{"thermal-devfreq-0", cdevType::GPU},
	{"devfreq-3d00000.qcom,kgsl-3d0", cdevType::GPU},
	{"gpu", cdevType::GPU},
	{"modem_tj", cdevType::MODEM},
	{"modem_lte_dsc", cdevType::MODEM},
	{"modem_nr_dsc", cdevType::MODEM},
	{"modem_nr_scg_dsc", cdevType::MODEM},
	{"cdsp", cdevType::NPU},
	{"cdsp_hw", cdevType::NPU},
	{"battery", cdevType::BATTERY},
	{"fan-max31760", cdevType::FAN},
	};

	ThermalCommon::ThermalCommon()
	{
	LOG(DEBUG) << "Entering " << __func__;
	ncpus = (int)sysconf(_SC_NPROCESSORS_CONF);
	if (ncpus < 1)
	LOG(ERROR) << "Error retrieving number of cores";
	}

	static int writeToFile(std::string_view path, std::string data)
	{
	std::fstream outFile;

	outFile.open(std::string(path).c_str(),
	std::fstream::binary \| std::fstream::out);
	if (outFile.is_open()) {
	LOG(DEBUG) << "writing: "<< data << " in path:" << path
	<< std::endl;
	outFile << data;
	outFile.close();
	return data.length();
	}

	LOG(ERROR) << "Error opening file: "<< path << std::endl;
	return -1;
	}

	static int readLineFromFile(std::string_view path, std::string& out)
	{
	char *fgets_ret;
	FILE *fd;
	int rv;
	char buf[MAX_LENGTH];

	out.clear();

	fd = fopen(std::string(path).c_str(), "r");
	if (fd == NULL) {
	LOG(ERROR) << "Path:" << std::string(path) << " file open error.err:"
	<< strerror(errno) << std::endl;
	return errno;
	}

	fgets_ret = fgets(buf, MAX_LENGTH, fd);
	if (NULL != fgets_ret) {
	rv = (int)strlen(buf);
	out.append(buf, rv);
	} else {
	rv = ferror(fd);
	}

	fclose(fd);
	out.erase(std::remove(out.begin(), out.end(), '\n'), out.end());
	LOG(DEBUG) << "Path:" << std::string(path) << " Val:" << out << std::endl;

	return rv;
	}

	int ThermalCommon::readFromFile(std::string_view path, std::string& out)
	{
	return readLineFromFile(path, out);
	}

	static int get_tzn(std::string sensor_name)
	{
	DIR *tdir = NULL;
	struct dirent *tdirent = NULL;
	int found = -1;
	int tzn = 0;
	char name[MAX_PATH] = {0};
	char cwd[MAX_PATH] = {0};
	int ret = 0;

	if (!getcwd(cwd, sizeof(cwd)))
	return found;

	/* Change dir to read the entries. Doesnt work otherwise */
	ret = chdir(THERMAL_SYSFS);
	if (ret) {
	LOG(ERROR) << "Unable to change to " << THERMAL_SYSFS << std::endl;
	return found;
	}
	tdir = opendir(THERMAL_SYSFS);
	if (!tdir) {
	LOG(ERROR) << "Unable to open " << THERMAL_SYSFS << std::endl;
	return found;
	}

	while ((tdirent = readdir(tdir))) {
	std::string buf;

	if (strncmp(tdirent->d_name, TZ_DIR_NAME,
	strlen(TZ_DIR_NAME)) != 0)
	continue;

	snprintf(name, MAX_PATH, "%s%s/%s", THERMAL_SYSFS,
	tdirent->d_name, TZ_TYPE);
	ret = readLineFromFile(std::string_view(name), buf);
	if (ret <= 0) {
	LOG(ERROR) <<
	"get_tzn: sensor name read error for tz:" <<
	tdirent->d_name << std::endl;
	continue;
	}
	if (!strncmp(buf.c_str(), sensor_name.c_str(),
	sensor_name.length())) {
	found = 1;
	break;
	}
	}

	if (found == 1) {
	sscanf(tdirent->d_name, TZ_DIR_FMT, &tzn);
	LOG(DEBUG) << "Sensor: " << sensor_name <<
	" found at tz: " << tzn << std::endl;
	found = tzn;
	}

	closedir(tdir);
	/* Restore current working dir */
	ret = chdir(cwd);

	return found;
	}

	int ThermalCommon::initialize_sensor(struct target_therm_cfg& cfg, int sens_idx)
	{
	struct therm_sensor sensor;
	int idx = 0;

	sensor.tzn = get_tzn(cfg.sensor_list[sens_idx]);
	if (sensor.tzn < 0) {
	LOG(ERROR) << "No thermal zone for sensor: " <<
	cfg.sensor_list[sens_idx] << ", ret:" <<
	sensor.tzn << std::endl;
	return -1;
	}
	if (cfg.type == TemperatureType::CPU)
	sensor.thresh.name = sensor.t.name =
	std::string("CPU") + std::to_string(sens_idx);
	else
	sensor.thresh.name = sensor.t.name = cfg.label;

	if (cfg.type == TemperatureType::BCL_PERCENTAGE)
	sensor.mulFactor = 1;
	else
	sensor.mulFactor = 1000;

	sensor.sensor_name = cfg.sensor_list[sens_idx];
	sensor.positiveThresh = cfg.positive_thresh_ramp;
	sensor.lastThrottleStatus = sensor.t.throttlingStatus =
	ThrottlingSeverity::NONE;
	sensor.thresh.type = sensor.t.type = cfg.type;
	sensor.thresh.vrThrottlingThreshold =
	UNKNOWN_TEMPERATURE;
	for (idx = 0; idx <= (size_t)ThrottlingSeverity::SHUTDOWN; idx++) {
	sensor.thresh.hotThrottlingThresholds[idx] =
	sensor.thresh.coldThrottlingThresholds[idx] =
	UNKNOWN_TEMPERATURE;
	}

	if (cfg.throt_thresh != 0 && cfg.positive_thresh_ramp)
	sensor.thresh.hotThrottlingThresholds[(size_t)ThrottlingSeverity::SEVERE] =
	cfg.throt_thresh / (float)sensor.mulFactor;
	else if (cfg.throt_thresh != 0 && !cfg.positive_thresh_ramp)
	sensor.thresh.coldThrottlingThresholds[(size_t)ThrottlingSeverity::SEVERE] =
	cfg.throt_thresh / (float)sensor.mulFactor;

	if (cfg.shutdwn_thresh != 0 && cfg.positive_thresh_ramp)
	sensor.thresh.hotThrottlingThresholds[(size_t)ThrottlingSeverity::SHUTDOWN] =
	cfg.shutdwn_thresh / (float)sensor.mulFactor;
	else if (cfg.shutdwn_thresh != 0 && !cfg.positive_thresh_ramp)
	sensor.thresh.coldThrottlingThresholds[(size_t)ThrottlingSeverity::SHUTDOWN] =
	cfg.shutdwn_thresh / (float)sensor.mulFactor;

	if (cfg.vr_thresh != 0)
	sensor.thresh.vrThrottlingThreshold =
	cfg.vr_thresh / (float)sensor.mulFactor;
	sens.push_back(sensor);
	//read_temperature((struct therm_sensor *)sensor);

	return 0;
	}

	int ThermalCommon::initializeCpuSensor(struct target_therm_cfg& cpu_cfg)
	{
	int cpu = 0;

	for (;cpu < ncpus; cpu++) {
	if (initialize_sensor(cpu_cfg, cpu) < 0)
	return -1;
	}

	return 0;
	}

	int ThermalCommon::initThermalZones(std::vector<struct target_therm_cfg>& cfg)
	{
	std::vector<struct target_therm_cfg>::iterator it;

	if (cfg.empty()) {
	LOG(ERROR) << std::string(__func__) +":Invalid input";
	return -1;
	}

	for (it = cfg.begin(); it != cfg.end(); it++)
	{
	if (it->type == TemperatureType::CPU) {
	if (initializeCpuSensor(*it) < 0)
	return -1;
	continue;
	}
	if (initialize_sensor(*it, 0) < 0) {
	return -1;
	}
	}

	return sens.size();
	}

	int ThermalCommon::initCdev()
	{
	DIR *tdir = NULL;
	struct dirent *tdirent = NULL;
	int cdevn = 0;
	char name[MAX_PATH] = {0};
	char cwd[MAX_PATH] = {0};
	int ret = 0;

	if (!getcwd(cwd, sizeof(cwd)))
	return 0;

	/* Change dir to read the entries. Doesnt work otherwise */
	ret = chdir(THERMAL_SYSFS);
	if (ret) {
	LOG(ERROR) << "Unable to change to " << THERMAL_SYSFS << std::endl;
	return 0;
	}
	tdir = opendir(THERMAL_SYSFS);
	if (!tdir) {
	LOG(ERROR) << "Unable to open " << THERMAL_SYSFS << std::endl;
	return 0;
	}

	while ((tdirent = readdir(tdir))) {
	std::string buf;
	struct dirent *tzdirent;
	std::unordered_map<std::string, cdevType>::iterator it;
	struct therm_cdev cdevInst;

	if (strncmp(tdirent->d_name, CDEV_DIR_NAME,
	strlen(CDEV_DIR_NAME)) != 0)
	continue;

	snprintf(name, MAX_PATH, "%s%s/%s", THERMAL_SYSFS,
	tdirent->d_name, TZ_TYPE);
	ret = readLineFromFile(std::string_view(name), buf);
	if (ret <= 0) {
	LOG(ERROR) <<
	"init_cdev: cdev type read error for cdev:" <<
	tdirent->d_name << std::endl;
	}
	it = cdev_map.find(buf);
	if (it == cdev_map.end())
	continue;
	sscanf(tdirent->d_name, CDEV_DIR_FMT, &cdevn);
	LOG(DEBUG) << "cdev: " << it->first <<
	" found at cdev number: " << cdevn << std::endl;
	cdevInst.c.name = it->first;
	cdevInst.c.type = it->second;
	cdevInst.cdevn = cdevn;
	read_cdev_state(cdevInst);
	cdev.push_back(cdevInst);
	}

	closedir(tdir);
	/* Restore current working dir */
	ret = chdir(cwd);

	return cdev.size();
	}

	int ThermalCommon::read_cdev_state(struct therm_cdev& cdev)
	{
	char file_name[MAX_PATH];
	std::string buf;
	int ret = 0, ct = 0;
	bool read_ok = false;

	snprintf(file_name, sizeof(file_name), CDEV_CUR_STATE_PATH,
	cdev.cdevn);
	do {
	ret = readLineFromFile(std::string(file_name), buf);
	if (ret <= 0) {
	LOG(ERROR) << "Cdev state read error:"<< ret <<
	" for cdev: " << cdev.c.name;
	return -1;
	}
	try {
	cdev.c.value = std::stoi(buf, nullptr, 0);
	read_ok = true;
	}
	catch (std::exception &err) {
	LOG(ERROR) << "Cdev read stoi error:" << err.what()
	<< " cdev:" << cdev.c.name << " ID:"
	<< cdev.cdevn << " buf:" << buf <<
	std::endl;
	}
	ct++;
	} while (!read_ok && ct < RETRY_CT);
	LOG(DEBUG) << "cdev Name:" << cdev.c.name << ". state:" <<
	cdev.c.value << std::endl;

	return cdev.c.value;
	}

	int ThermalCommon::estimateSeverity(struct therm_sensor& sensor)
	{
	int idx = 0;
	ThrottlingSeverity severity = ThrottlingSeverity::NONE;
	float temp = sensor.t.value;

	for (idx = (int)ThrottlingSeverity::SHUTDOWN; idx >= 0; idx--) {
	/* If a particular threshold is hit already, check if the
	* hysteresis is cleared before changing the severity */
	if (idx == (int)sensor.t.throttlingStatus) {
	if ((sensor.positiveThresh &&
	!isnan(sensor.thresh.hotThrottlingThresholds[idx]) &&
	temp >=
	(sensor.thresh.hotThrottlingThresholds[idx] -
	DEFAULT_HYSTERESIS / sensor.mulFactor)) \|\|
	(!sensor.positiveThresh &&
	!isnan(sensor.thresh.coldThrottlingThresholds[idx]) &&
	temp <=
	(sensor.thresh.coldThrottlingThresholds[idx] +
	DEFAULT_HYSTERESIS / sensor.mulFactor)))
	break;
	continue;
	}
	if ((sensor.positiveThresh &&
	!isnan(sensor.thresh.hotThrottlingThresholds[idx]) &&
	temp >=
	sensor.thresh.hotThrottlingThresholds[idx]) \|\|
	(!sensor.positiveThresh &&
	!isnan(sensor.thresh.coldThrottlingThresholds[idx]) &&
	temp <=
	sensor.thresh.coldThrottlingThresholds[idx]))
	break;
	}
	if (idx >= 0)
	severity = (ThrottlingSeverity)(idx);
	LOG(INFO) << "Sensor Name:" << sensor.t.name << "temp: " <<
	temp << ". prev severity:" <<
	(int)sensor.lastThrottleStatus << ". cur severity:" <<
	(int)sensor.t.throttlingStatus << " New severity:" <<
	(int)severity << std::endl;
	if (severity == sensor.t.throttlingStatus)
	return -1;
	sensor.lastThrottleStatus = sensor.t.throttlingStatus;
	sensor.t.throttlingStatus = severity;

	return (int)severity;
	}

	int ThermalCommon::read_temperature(struct therm_sensor& sensor)
	{
	char file_name[MAX_PATH];
	float temp;
	std::string buf;
	int ret = 0, ct = 0;
	bool read_ok = false;

	do {
	snprintf(file_name, sizeof(file_name), TEMPERATURE_FILE_FORMAT,
	sensor.tzn);
	ret = readLineFromFile(std::string(file_name), buf);
	if (ret <= 0) {
	LOG(ERROR) << "Temperature read error:"<< ret <<
	" for sensor " << sensor.t.name;
	return -1;
	}
	try {
	sensor.t.value = (float)std::stoi(buf, nullptr, 0) /
	(float)sensor.mulFactor;
	read_ok = true;
	}
	catch (std::exception &err) {
	LOG(ERROR) << "Temperature buf stoi error: "
	<< err.what()
	<< " buf:" << buf << " sensor:"
	<< sensor.t.name << " TZ:" <<
	sensor.tzn << std::endl;
	}
	ct++;
	} while (!read_ok && ct < RETRY_CT);
	LOG(DEBUG) << "Sensor Name:" << sensor.t.name << ". Temperature:" <<
	(float)sensor.t.value << std::endl;

	return ret;
	}

	void ThermalCommon::initThreshold(struct therm_sensor& sensor)
	{
	char file_name[MAX_PATH] = "";
	std::string buf;
	int ret = 0, idx;
	ThrottlingSeverity severity = ThrottlingSeverity::NONE;
	int next_trip, curr_trip, hyst_temp = 0;

	LOG(DEBUG) << "Entering " <<__func__;
	if (!sensor.positiveThresh) {
	LOG(ERROR) << "negative temperature ramp for sensor:"<<
	sensor.t.name;
	return;
	}
	#ifndef ENABLE_THERMAL_NETLINK
	snprintf(file_name, sizeof(file_name), POLICY_FILE_FORMAT,
	sensor.tzn);
	ret = readLineFromFile(std::string(file_name), buf);
	if (ret <= 0) {
	LOG(ERROR) << "Policy read error:"<< ret <<
	" for sensor " << sensor.t.name;
	return;
	}
	if (buf != std::string(USER_SPACE_POLICY)) {
	LOG(ERROR) << "Policy error:"<< buf << " sensor:" <<
	sensor.t.name << std::endl;
	return;
	}
	#endif
	next_trip = UNKNOWN_TEMPERATURE;
	for (idx = 0;idx <= (int)ThrottlingSeverity::SHUTDOWN; idx++) {
	if (isnan(sensor.thresh.hotThrottlingThresholds[idx])
	\|\| idx <= (int)sensor.t.throttlingStatus)
	continue;

	next_trip = sensor.thresh.hotThrottlingThresholds[idx] *
	sensor.mulFactor;
	break;
	}

	if (!isnan(next_trip)) {
	LOG(DEBUG) << "Sensor: " << sensor.t.name << " high trip:"
	<< next_trip << std::endl;
	snprintf(file_name, sizeof(file_name), TRIP_FILE_FORMAT,
	sensor.tzn);
	writeToFile(std::string_view(file_name), std::to_string(next_trip));
	}
	if (sensor.t.throttlingStatus != ThrottlingSeverity::NONE) {
	curr_trip = sensor.thresh.hotThrottlingThresholds[
	(int)sensor.t.throttlingStatus]
	* sensor.mulFactor;
	if (!isnan(next_trip))
	hyst_temp = (next_trip - curr_trip) + DEFAULT_HYSTERESIS;
	else
	hyst_temp = DEFAULT_HYSTERESIS;
	LOG(DEBUG) << "Sensor: " << sensor.t.name << " hysteresis:"
	<< hyst_temp << std::endl;
	snprintf(file_name, sizeof(file_name), HYST_FILE_FORMAT,
	sensor.tzn);
	writeToFile(std::string_view(file_name), std::to_string(hyst_temp));
	}

	return;
	}

	int ThermalCommon::get_cpu_usages(hidl_vec<CpuUsage>& list) {
	int vals, cpu_num, online;
	ssize_t read;
	uint64_t user, nice, system, idle, active, total;
	char *line = NULL;
	size_t len = 0;
	size_t cpu = 0;
	char file_name[MAX_LENGTH];
	FILE *file;
	FILE *cpu_file;

	list.resize(ncpus);
	file = fopen(CPU_USAGE_FILE, "r");
	if (file == NULL) {
	LOG(ERROR) << "failed to open:" << CPU_USAGE_FILE <<
	" err:" << strerror(errno);
	return -errno;
	}

	while ((read = getline(&line, &len, file)) != -1) {
	if (strnlen(line, read) < 4 \|\| strncmp(line, "cpu", 3) != 0 \|\|
	!isdigit(line[3])) {
	free(line);
	line = NULL;
	len = 0;
	continue;
	}
	vals = sscanf(line, \
	"cpu%d %" SCNu64 " %" SCNu64 " %" SCNu64 " %" SCNu64, \
	&cpu_num, &user, &nice, &system, &idle);

	free(line);
	line = NULL;
	len = 0;

	if (vals != 5 \|\| cpu == ncpus) {
	if (vals != 5) {
	LOG(ERROR) <<
	"failed to read CPU information from file: "
	<< strerror(errno);
	} else {
	LOG(ERROR) <<
	"/proc/stat file has incorrect format.";
	}
	fclose(file);
	return errno ? -errno : -EIO;
	}

	active = user + nice + system;
	total = active + idle;

	// Read online CPU information.
	snprintf(file_name, MAX_LENGTH, CPU_ONLINE_FILE_FORMAT,
	cpu_num);
	cpu_file = fopen(file_name, "r");
	online = 0;
	if (cpu_file == NULL) {
	LOG(ERROR) << "failed to open file:" << file_name <<
	" err: " << strerror(errno);
	fclose(file);
	return -errno;
	}
	if (1 != fscanf(cpu_file, "%d", &online)) {
	LOG(ERROR) << "failed to read CPU online information" << strerror(errno);
	fclose(file);
	fclose(cpu_file);
	return errno ? -errno : -EIO;
	}
	fclose(cpu_file);

	list[cpu_num].name = std::string("CPU") + std::to_string(cpu_num);
	list[cpu_num].active = active;
	list[cpu_num].total = total;
	list[cpu_num].isOnline = online;
	cpu++;
	}
	fclose(file);
	if (cpu != ncpus) {
	LOG(ERROR) <<"/proc/stat file has incorrect format.";
	return -EIO;
	}
	return ncpus;
	}

	} // namespace implementation
	} // namespace V2_0
	} // namespace thermal
	} // namespace hardware
	} // namespace android