linux/drivers/thermal/thermal_helpers.c
Viresh Kumar 8ea229511e thermal: Add cooling device's statistics in sysfs
This extends the sysfs interface for thermal cooling devices and exposes
some pretty useful statistics. These statistics have proven to be quite
useful specially while doing benchmarks related to the task scheduler,
where we want to make sure that nothing has disrupted the test,
specially the cooling device which may have put constraints on the CPUs.
The information exposed here tells us to what extent the CPUs were
constrained by the thermal framework.

The write-only "reset" file is used to reset the statistics.

The read-only "time_in_state_ms" file shows the time (in msec) spent by the
device in the respective cooling states, and it prints one line per
cooling state.

The read-only "total_trans" file shows single positive integer value
showing the total number of cooling state transitions the device has
gone through since the time the cooling device is registered or the time
when statistics were reset last.

The read-only "trans_table" file shows a two dimensional matrix, where
an entry <i,j> (row i, column j) represents the number of transitions
from State_i to State_j.

This is how the directory structure looks like for a single cooling
device:

$ ls -R /sys/class/thermal/cooling_device0/
/sys/class/thermal/cooling_device0/:
cur_state  max_state  power  stats  subsystem  type  uevent

/sys/class/thermal/cooling_device0/power:
autosuspend_delay_ms  runtime_active_time  runtime_suspended_time
control               runtime_status

/sys/class/thermal/cooling_device0/stats:
reset  time_in_state_ms  total_trans  trans_table

This is tested on ARM 64-bit Hisilicon hikey620 board running Ubuntu and
ARM 64-bit Hisilicon hikey960 board running Android.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
2018-04-02 21:49:01 +08:00

230 lines
5.8 KiB
C

/*
* thermal_helpers.c - helper functions to handle thermal devices
*
* Copyright (C) 2016 Eduardo Valentin <edubezval@gmail.com>
*
* Highly based on original thermal_core.c
* Copyright (C) 2008 Intel Corp
* Copyright (C) 2008 Zhang Rui <rui.zhang@intel.com>
* Copyright (C) 2008 Sujith Thomas <sujith.thomas@intel.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/sysfs.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <trace/events/thermal.h>
#include "thermal_core.h"
int get_tz_trend(struct thermal_zone_device *tz, int trip)
{
enum thermal_trend trend;
if (tz->emul_temperature || !tz->ops->get_trend ||
tz->ops->get_trend(tz, trip, &trend)) {
if (tz->temperature > tz->last_temperature)
trend = THERMAL_TREND_RAISING;
else if (tz->temperature < tz->last_temperature)
trend = THERMAL_TREND_DROPPING;
else
trend = THERMAL_TREND_STABLE;
}
return trend;
}
EXPORT_SYMBOL(get_tz_trend);
struct thermal_instance *
get_thermal_instance(struct thermal_zone_device *tz,
struct thermal_cooling_device *cdev, int trip)
{
struct thermal_instance *pos = NULL;
struct thermal_instance *target_instance = NULL;
mutex_lock(&tz->lock);
mutex_lock(&cdev->lock);
list_for_each_entry(pos, &tz->thermal_instances, tz_node) {
if (pos->tz == tz && pos->trip == trip && pos->cdev == cdev) {
target_instance = pos;
break;
}
}
mutex_unlock(&cdev->lock);
mutex_unlock(&tz->lock);
return target_instance;
}
EXPORT_SYMBOL(get_thermal_instance);
/**
* thermal_zone_get_temp() - returns the temperature of a thermal zone
* @tz: a valid pointer to a struct thermal_zone_device
* @temp: a valid pointer to where to store the resulting temperature.
*
* When a valid thermal zone reference is passed, it will fetch its
* temperature and fill @temp.
*
* Return: On success returns 0, an error code otherwise
*/
int thermal_zone_get_temp(struct thermal_zone_device *tz, int *temp)
{
int ret = -EINVAL;
int count;
int crit_temp = INT_MAX;
enum thermal_trip_type type;
if (!tz || IS_ERR(tz) || !tz->ops->get_temp)
goto exit;
mutex_lock(&tz->lock);
ret = tz->ops->get_temp(tz, temp);
if (IS_ENABLED(CONFIG_THERMAL_EMULATION) && tz->emul_temperature) {
for (count = 0; count < tz->trips; count++) {
ret = tz->ops->get_trip_type(tz, count, &type);
if (!ret && type == THERMAL_TRIP_CRITICAL) {
ret = tz->ops->get_trip_temp(tz, count,
&crit_temp);
break;
}
}
/*
* Only allow emulating a temperature when the real temperature
* is below the critical temperature so that the emulation code
* cannot hide critical conditions.
*/
if (!ret && *temp < crit_temp)
*temp = tz->emul_temperature;
}
mutex_unlock(&tz->lock);
exit:
return ret;
}
EXPORT_SYMBOL_GPL(thermal_zone_get_temp);
void thermal_zone_set_trips(struct thermal_zone_device *tz)
{
int low = -INT_MAX;
int high = INT_MAX;
int trip_temp, hysteresis;
int i, ret;
mutex_lock(&tz->lock);
if (!tz->ops->set_trips || !tz->ops->get_trip_hyst)
goto exit;
for (i = 0; i < tz->trips; i++) {
int trip_low;
tz->ops->get_trip_temp(tz, i, &trip_temp);
tz->ops->get_trip_hyst(tz, i, &hysteresis);
trip_low = trip_temp - hysteresis;
if (trip_low < tz->temperature && trip_low > low)
low = trip_low;
if (trip_temp > tz->temperature && trip_temp < high)
high = trip_temp;
}
/* No need to change trip points */
if (tz->prev_low_trip == low && tz->prev_high_trip == high)
goto exit;
tz->prev_low_trip = low;
tz->prev_high_trip = high;
dev_dbg(&tz->device,
"new temperature boundaries: %d < x < %d\n", low, high);
/*
* Set a temperature window. When this window is left the driver
* must inform the thermal core via thermal_zone_device_update.
*/
ret = tz->ops->set_trips(tz, low, high);
if (ret)
dev_err(&tz->device, "Failed to set trips: %d\n", ret);
exit:
mutex_unlock(&tz->lock);
}
EXPORT_SYMBOL_GPL(thermal_zone_set_trips);
void thermal_cdev_update(struct thermal_cooling_device *cdev)
{
struct thermal_instance *instance;
unsigned long target = 0;
mutex_lock(&cdev->lock);
/* cooling device is updated*/
if (cdev->updated) {
mutex_unlock(&cdev->lock);
return;
}
/* Make sure cdev enters the deepest cooling state */
list_for_each_entry(instance, &cdev->thermal_instances, cdev_node) {
dev_dbg(&cdev->device, "zone%d->target=%lu\n",
instance->tz->id, instance->target);
if (instance->target == THERMAL_NO_TARGET)
continue;
if (instance->target > target)
target = instance->target;
}
if (!cdev->ops->set_cur_state(cdev, target))
thermal_cooling_device_stats_update(cdev, target);
cdev->updated = true;
mutex_unlock(&cdev->lock);
trace_cdev_update(cdev, target);
dev_dbg(&cdev->device, "set to state %lu\n", target);
}
EXPORT_SYMBOL(thermal_cdev_update);
/**
* thermal_zone_get_slope - return the slope attribute of the thermal zone
* @tz: thermal zone device with the slope attribute
*
* Return: If the thermal zone device has a slope attribute, return it, else
* return 1.
*/
int thermal_zone_get_slope(struct thermal_zone_device *tz)
{
if (tz && tz->tzp)
return tz->tzp->slope;
return 1;
}
EXPORT_SYMBOL_GPL(thermal_zone_get_slope);
/**
* thermal_zone_get_offset - return the offset attribute of the thermal zone
* @tz: thermal zone device with the offset attribute
*
* Return: If the thermal zone device has a offset attribute, return it, else
* return 0.
*/
int thermal_zone_get_offset(struct thermal_zone_device *tz)
{
if (tz && tz->tzp)
return tz->tzp->offset;
return 0;
}
EXPORT_SYMBOL_GPL(thermal_zone_get_offset);