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|
// SPDX-License-Identifier: GPL-2.0
/*
* linux/drivers/thermal/cpu_cooling.c
*
* Copyright (C) 2012 Samsung Electronics Co., Ltd(http://www.samsung.com)
*
* Copyright (C) 2012-2018 Linaro Limited.
*
* Authors: Amit Daniel <amit.kachhap@linaro.org>
* Viresh Kumar <viresh.kumar@linaro.org>
*
*/
#include <linux/module.h>
#include <linux/thermal.h>
#include <linux/cpufreq.h>
#include <linux/err.h>
#include <linux/idr.h>
#include <linux/pm_opp.h>
#include <linux/pm_qos.h>
#include <linux/slab.h>
#include <linux/cpu.h>
#include <linux/cpu_cooling.h>
#include <trace/events/thermal.h>
/*
* Cooling state <-> CPUFreq frequency
*
* Cooling states are translated to frequencies throughout this driver and this
* is the relation between them.
*
* Highest cooling state corresponds to lowest possible frequency.
*
* i.e.
* level 0 --> 1st Max Freq
* level 1 --> 2nd Max Freq
* ...
*/
/**
* struct freq_table - frequency table along with power entries
* @frequency: frequency in KHz
* @power: power in mW
*
* This structure is built when the cooling device registers and helps
* in translating frequency to power and vice versa.
*/
struct freq_table {
u32 frequency;
u32 power;
};
/**
* struct time_in_idle - Idle time stats
* @time: previous reading of the absolute time that this cpu was idle
* @timestamp: wall time of the last invocation of get_cpu_idle_time_us()
*/
struct time_in_idle {
u64 time;
u64 timestamp;
};
/**
* struct cpufreq_cooling_device - data for cooling device with cpufreq
* @id: unique integer value corresponding to each cpufreq_cooling_device
* registered.
* @last_load: load measured by the latest call to cpufreq_get_requested_power()
* @cpufreq_state: integer value representing the current state of cpufreq
* cooling devices.
* @max_level: maximum cooling level. One less than total number of valid
* cpufreq frequencies.
* @freq_table: Freq table in descending order of frequencies
* @cdev: thermal_cooling_device pointer to keep track of the
* registered cooling device.
* @policy: cpufreq policy.
* @node: list_head to link all cpufreq_cooling_device together.
* @idle_time: idle time stats
*
* This structure is required for keeping information of each registered
* cpufreq_cooling_device.
*/
struct cpufreq_cooling_device {
int id;
u32 last_load;
unsigned int cpufreq_state;
unsigned int max_level;
struct freq_table *freq_table; /* In descending order */
struct cpufreq_policy *policy;
struct list_head node;
struct time_in_idle *idle_time;
struct dev_pm_qos_request qos_req;
};
static DEFINE_IDA(cpufreq_ida);
static DEFINE_MUTEX(cooling_list_lock);
static LIST_HEAD(cpufreq_cdev_list);
/* Below code defines functions to be used for cpufreq as cooling device */
/**
* get_level: Find the level for a particular frequency
* @cpufreq_cdev: cpufreq_cdev for which the property is required
* @freq: Frequency
*
* Return: level corresponding to the frequency.
*/
static unsigned long get_level(struct cpufreq_cooling_device *cpufreq_cdev,
unsigned int freq)
{
struct freq_table *freq_table = cpufreq_cdev->freq_table;
unsigned long level;
for (level = 1; level <= cpufreq_cdev->max_level; level++)
if (freq > freq_table[level].frequency)
break;
return level - 1;
}
/**
* update_freq_table() - Update the freq table with power numbers
* @cpufreq_cdev: the cpufreq cooling device in which to update the table
* @capacitance: dynamic power coefficient for these cpus
*
* Update the freq table with power numbers. This table will be used in
* cpu_power_to_freq() and cpu_freq_to_power() to convert between power and
* frequency efficiently. Power is stored in mW, frequency in KHz. The
* resulting table is in descending order.
*
* Return: 0 on success, -EINVAL if there are no OPPs for any CPUs,
* or -ENOMEM if we run out of memory.
*/
static int update_freq_table(struct cpufreq_cooling_device *cpufreq_cdev,
u32 capacitance)
{
struct freq_table *freq_table = cpufreq_cdev->freq_table;
struct dev_pm_opp *opp;
struct device *dev = NULL;
int num_opps = 0, cpu = cpufreq_cdev->policy->cpu, i;
dev = get_cpu_device(cpu);
if (unlikely(!dev)) {
pr_warn("No cpu device for cpu %d\n", cpu);
return -ENODEV;
}
num_opps = dev_pm_opp_get_opp_count(dev);
if (num_opps < 0)
return num_opps;
/*
* The cpufreq table is also built from the OPP table and so the count
* should match.
*/
if (num_opps != cpufreq_cdev->max_level + 1) {
dev_warn(dev, "Number of OPPs not matching with max_levels\n");
return -EINVAL;
}
for (i = 0; i <= cpufreq_cdev->max_level; i++) {
unsigned long freq = freq_table[i].frequency * 1000;
u32 freq_mhz = freq_table[i].frequency / 1000;
u64 power;
u32 voltage_mv;
/*
* Find ceil frequency as 'freq' may be slightly lower than OPP
* freq due to truncation while converting to kHz.
*/
opp = dev_pm_opp_find_freq_ceil(dev, &freq);
if (IS_ERR(opp)) {
dev_err(dev, "failed to get opp for %lu frequency\n",
freq);
return -EINVAL;
}
voltage_mv = dev_pm_opp_get_voltage(opp) / 1000;
dev_pm_opp_put(opp);
/*
* Do the multiplication with MHz and millivolt so as
* to not overflow.
*/
power = (u64)capacitance * freq_mhz * voltage_mv * voltage_mv;
do_div(power, 1000000000);
/* power is stored in mW */
freq_table[i].power = power;
}
return 0;
}
static u32 cpu_freq_to_power(struct cpufreq_cooling_device *cpufreq_cdev,
u32 freq)
{
int i;
struct freq_table *freq_table = cpufreq_cdev->freq_table;
for (i = 1; i <= cpufreq_cdev->max_level; i++)
if (freq > freq_table[i].frequency)
break;
return freq_table[i - 1].power;
}
static u32 cpu_power_to_freq(struct cpufreq_cooling_device *cpufreq_cdev,
u32 power)
{
int i;
struct freq_table *freq_table = cpufreq_cdev->freq_table;
for (i = 1; i <= cpufreq_cdev->max_level; i++)
if (power > freq_table[i].power)
break;
return freq_table[i - 1].frequency;
}
/**
* get_load() - get load for a cpu since last updated
* @cpufreq_cdev: &struct cpufreq_cooling_device for this cpu
* @cpu: cpu number
* @cpu_idx: index of the cpu in time_in_idle*
*
* Return: The average load of cpu @cpu in percentage since this
* function was last called.
*/
static u32 get_load(struct cpufreq_cooling_device *cpufreq_cdev, int cpu,
int cpu_idx)
{
u32 load;
u64 now, now_idle, delta_time, delta_idle;
struct time_in_idle *idle_time = &cpufreq_cdev->idle_time[cpu_idx];
now_idle = get_cpu_idle_time(cpu, &now, 0);
delta_idle = now_idle - idle_time->time;
delta_time = now - idle_time->timestamp;
if (delta_time <= delta_idle)
load = 0;
else
load = div64_u64(100 * (delta_time - delta_idle), delta_time);
idle_time->time = now_idle;
idle_time->timestamp = now;
return load;
}
/**
* get_dynamic_power() - calculate the dynamic pow
|