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|
// SPDX-License-Identifier: GPL-2.0
/*
* linux/drivers/thermal/cpufreq_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/cpu.h>
#include <linux/cpufreq.h>
#include <linux/cpu_cooling.h>
#include <linux/device.h>
#include <linux/energy_model.h>
#include <linux/err.h>
#include <linux/export.h>
#include <linux/pm_opp.h>
#include <linux/pm_qos.h>
#include <linux/slab.h>
#include <linux/thermal.h>
#include <linux/units.h>
#include "thermal_trace.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 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
* @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.
* @em: Reference on the Energy Model of the device
* @cdev: thermal_cooling_device pointer to keep track of the
* registered cooling device.
* @policy: cpufreq policy.
* @cooling_ops: cpufreq callbacks to thermal cooling device ops
* @idle_time: idle time stats
* @qos_req: PM QoS contraint to apply
*
* This structure is required for keeping information of each registered
* cpufreq_cooling_device.
*/
struct cpufreq_cooling_device {
u32 last_load;
unsigned int cpufreq_state;
unsigned int max_level;
struct em_perf_domain *em;
struct cpufreq_policy *policy;
struct thermal_cooling_device_ops cooling_ops;
#ifndef CONFIG_SMP
struct time_in_idle *idle_time;
#endif
struct freq_qos_request qos_req;
};
#ifdef CONFIG_THERMAL_GOV_POWER_ALLOCATOR
/**
* 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)
{
int i;
for (i = cpufreq_cdev->max_level - 1; i >= 0; i--) {
if (freq > cpufreq_cdev->em->table[i].frequency)
break;
}
return cpufreq_cdev->max_level - i - 1;
}
static u32 cpu_freq_to_power(struct cpufreq_cooling_device *cpufreq_cdev,
u32 freq)
{
unsigned long power_mw;
int i;
for (i = cpufreq_cdev->max_level - 1; i >= 0; i--) {
if (freq > cpufreq_cdev->em->table[i].frequency)
break;
}
power_mw = cpufreq_cdev->em->table[i + 1].power;
power_mw /= MICROWATT_PER_MILLIWATT;
return power_mw;
}
static u32 cpu_power_to_freq(struct cpufreq_cooling_device *cpufreq_cdev,
u32 power)
{
unsigned long em_power_mw;
int i;
for (i = cpufreq_cdev->max_level; i > 0; i--) {
/* Convert EM power to milli-Watts to make safe comparison */
em_power_mw = cpufreq_cdev->em->table[i].power;
em_power_mw /= MICROWATT_PER_MILLIWATT;
if (power >= em_power_mw)
break;
}
return cpufreq_cdev->em->table[i].frequency;
}
/**
* get_load() - get load for a cpu
* @cpufreq_cdev: struct cpufreq_cooling_device for the cpu
* @cpu: cpu number
* @cpu_idx: index of the cpu in time_in_idle array
*
* Return: The average load of cpu @cpu in percentage since this
* function was last called.
*/
#ifdef CONFIG_SMP
static u32 get_load(struct cpufreq_cooling_device *cpufreq_cdev, int cpu,
int cpu_idx)
{
unsigned long util = sched_cpu_util(cpu);
return (util * 100) / arch_scale_cpu_capacity(cpu);
}
#else /* !CONFIG_SMP */
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;
}
#endif /* CONFIG_SMP */
/**
* get_dynamic_power() - calculate the dynamic power
* @cpufreq_cdev: &cpufreq_cooling_device for this cdev
* @freq: current frequency
*
* Return: the dynamic power consumed by the cpus described by
* @cpufreq_cdev.
*/
static u32 get_dynamic_power(struct cpufreq_cooling_device *cpufreq_cdev,
unsigned long freq)
{
u32 raw_cpu_power;
raw_cpu_power = cpu_freq_to_power(cpufreq_cdev, freq);
return (raw_cpu_power * cpufreq_cdev->last_load) / 100;
}
/**
* cpufreq_get_requested_power() - get the current power
* @cdev: &thermal_cooling_device pointer
* @power: pointer in which to store the resulting power
*
* Calculate the current power consumption of the cpus in milliwatts
* and store it in @power. This function should actually calculate
* the requested power, but it's hard to get the frequency that
* cpufreq would have assigned if there were no thermal limits.
* Instead, we calculate the current power on the assumption that the
* immediate future will look like the immediate past.
*
* We use the current frequency and the average load since this
* function was last called. In reality, there could have been
* multiple opps since this function was last called and that affects
* the load calculation. While it's not perfectly accurate, this
* simplification is good enough and works. REVISIT this, as more
* complex code may be needed if experiments show that it's not
* accurate enough.
*
* Return: 0 on success, this function doesn't fail.
*/
static int cpufreq_get_requested_power(struct thermal_cooling_device *cdev,
u32 *power)
{
unsigned long freq;
int i = 0, cpu;
u32 total_load = 0;
struct cpufreq_cooling_device *cpufreq_cdev = cdev->devdata;
struct cpufreq_policy *policy = cpufreq_cdev->policy;
freq = cpufreq_quick_get(policy->cpu);
for_each_cpu(cpu, policy->related_cpus) {
u32 load;
if (cpu_online(cpu))
load = get_load(cpufreq_cdev, cpu, i);
else
load = 0;
total_load += load;
}
cpufreq_cdev->last_load = total_load;
*power = get_dynamic_power(cpufreq_cdev, freq);
trace_thermal_power_cpu_get_power_simple(policy->cpu, *power);
return 0;
}
/**
* cpufreq_state2power() - convert a cpu cdev state to power consumed
* @cdev: &thermal_cooling_device pointer
* @state: cooling device state to be converted
* @power: pointer in which to store the resulting power
*
* Convert cooling device state @state into power consumption in
* milliwatts assuming 100% load. Store the calculated power in
* @power.
*
* Return: 0 on success, -EINVAL if the cooling device state is bigger
* than maximum allowed.
*/
static int cpufreq_state2power(struct thermal_cooling_device *cdev,
unsigned long state, u32 *power)
{
unsigned int freq, num_cpus, idx;
struct cpufreq_cooling_device *cpufreq_cdev = cdev->devdata;
/* Request state should be less than max_level */
if (state > cpufreq_cdev->max_level)
return -EINVAL;
num_cpus = cpumask_weight(cpufreq_cdev->policy->cpus);
idx = cpufreq_cdev->max_level - state;
freq = cpufreq_cdev->em->table[idx].frequency;
*power = cpu_freq_to_power(cpufreq_cdev, freq) * num_cpus;
return 0;
}
/**
* cpufreq_power2state() - convert power to a cooling device state
* @cdev: &thermal_cooling_device pointer
* @power: power in milliwatts to be converted
* @state: pointer in which to store the resulting state
*
* Calculate a cooling device state for the cpus described by @cdev
* that would allow them to consume at most @power mW and store it in
* @state. Note that this calculation depends on external factors
* such as the CPUs load. Calling this function with the same power
* as input can yield different cooling device states depending on those
* external factors.
*
* Return: 0 on success, this function doesn't fail.
*/
static int cpufreq_power2state(struct thermal_cooling_device *cdev,
u32 power, unsigned long *state)
{
unsigned int target_freq;
u32 last_load, normalised_power;
struct cpufreq_cooling_device *cpufreq_cdev = cdev->devdata;
struct cpufreq_policy *policy = cpufreq_cdev->policy;
last_load = cpufreq_cdev->last_load ?: 1;
normalised_power = (power * 100) / last_load;
target_freq = cpu_power_to_freq(cpufreq_cdev, normalised_power);
*state = get_level(cpufreq_cdev, target_freq);
trace_thermal_power_cpu_limit(policy->related_cpus, target_freq, *state,
power);
return 0;
}
static inline bool em_is_sane(struct cpufreq_cooling_device *cpufreq_cdev,
struct em_perf_domain *em) {
struct cpufreq_policy *policy;
unsigned int nr_levels;
if (!em || em_is_artificial(em))
return false;
policy = cpufreq_cdev->policy;
if (!cpumask_equal(policy->related_cpus, em_span_cpus(em))) {
pr_err("The span of pd %*pbl is misaligned with cpufreq policy %*pbl\n",
cpumask_pr_args(em_span_cpus(em)),
cpumask_pr_args(policy->related_cpus));
return false;
}
nr_levels = cpufreq_cdev->max_level + 1;
if (em_pd_nr_perf_states(em) != nr_levels) {
pr_err("The number of performance states in pd %*pbl (%u) doesn't match the number of cooling levels (%u)\n",
cpumask_pr_args(em_span_cpus(em)),
em_pd_nr_perf_states(em), nr_levels);
return false;
}
return true;
}
#endif /* CONFIG_THERMAL_GOV_POWER_ALLOCATOR */
#ifdef CONFIG_SMP
static inline int allocate_idle_time(struct cpufreq_cooling_device *cpufreq_cdev)
{
return 0;
}
static inline void free_idle_time(struct cpufreq_cooling_device *cpufreq_cdev)
{
}
#else
static int allocate_idle_time(struct cpufreq_cooling_device *cpufreq_cdev)
{
unsigned int num_cpus = cpumask_weight(cpufreq_cdev->policy->related_cpus);
cpufreq_cdev->idle_time = kcalloc(num_cpus,
sizeof(*cpufreq_cdev->idle_time),
GFP_KERNEL);
if (!cpufreq_cdev->idle_time)
return -ENOMEM;
return 0;
}
static void free_idle_time(struct cpufreq_cooling_device *cpufreq_cdev)
{
kfree(cpufreq_cdev->idle_time);
cpufreq_cdev->idle_time = NULL;
}
#endif /* CONFIG_SMP */
static unsigned int get_state_freq(struct cpufreq_cooling_device *cpufreq_cdev,
unsigned long state)
{
struct cpufreq_policy *policy;
unsigned long idx;
#ifdef CONFIG_THERMAL_GOV_POWER_ALLOCATOR
/* Use the Energy Model table if available */
if (cpufreq_cdev->em) {
idx = cpufreq_cdev->max_level - state;
return cpufreq_cdev->em->table[idx].frequency;
}
#endif
/* Otherwise, fallback on the CPUFreq table */
policy = cpufreq_cdev->policy;
if (policy->freq_table_sorted == CPUFREQ_TABLE_SORTED_ASCENDING)
idx = cpufreq_cdev->max_level - state;
else
idx = state;
return policy->freq_table[idx].frequency;
}
/* cpufreq cooling device callback functions are defined below */
/**
* cpufreq_get_max_state - callback function to get the max cooling state.
* @cdev: thermal cooling device pointer.
* @state: fill this variable with the max cooling state.
*
* Callback for the thermal cooling device to return the cpufreq
* max cooling state.
*
* Return: 0 on success, this function doesn't fail.
*/
static int cpufreq_get_max_state(struct thermal_cooling_device *cdev,
unsigned long *state)
{
struct cpufreq_cooling_device *cpufreq_cdev = cdev->devdata;
*state = cpufreq_cdev->max_level;
return 0;
}
/**
* cpufreq_get_cur_state - callback function to get the current cooling state.
* @cdev: thermal cooling device pointer.
* @state: fill this variable with the current cooling state.
*
* Callback for the thermal cooling device to return the cpufreq
* current cooling state.
*
* Return: 0 on success, this function doesn't fail.
*/
static int cpufreq_get_cur_state(struct thermal_cooling_device *cdev,
unsigned long *state)
{
struct cpufreq_cooling_device *cpufreq_cdev = cdev->devdata;
*state = cpufreq_cdev->cpufreq_state;
return 0;
}
/**
* cpufreq_set_cur_state - callback function to set the current cooling state.
* @cdev: thermal cooling device pointer.
* @state: set this variable to the current cooling state.
*
* Callback for the thermal cooling device to change the cpufreq
* current cooling state.
*
* Return: 0 on success, an error code otherwise.
*/
static int cpufreq_set_cur_state(struct thermal_cooling_device *cdev,
unsigned long state)
{
struct cpufreq_cooling_device *cpufreq_cdev = cdev->devdata;
struct cpumask *cpus;
unsigned int frequency;
int ret;
/* Request state should be less than max_level */
if (state > cpufreq_cdev->max_level)
return -EINVAL;
/* Check if the old cooling action is same as new cooling action */
if (cpufreq_cdev->cpufreq_state == state)
return 0;
frequency = get_state_freq(cpufreq_cdev, state);
ret = freq_qos_update_request(&cpufreq_cdev->qos_req, frequency);
if (ret >= 0) {
cpufreq_cdev->cpufreq_state = state;
cpus = cpufreq_cdev->policy->related_cpus;
arch_update_thermal_pressure(cpus, frequency);
ret = 0;
}
return ret;
}
/**
* __cpufreq_cooling_register - helper function to create cpufreq cooling device
* @np: a valid struct device_node to the cooling device tree node
* @policy: cpufreq policy
* Normally this should be same as cpufreq policy->related_cpus.
* @em: Energy Model of the cpufreq policy
*
* This interface function registers the cpufreq cooling device with the name
* "cpufreq-%s". This API can support multiple instances of cpufreq
* cooling devices. It also gives the opportunity to link the cooling device
* with a device tree node, in order to bind it via the thermal DT code.
*
* Return: a valid struct thermal_cooling_device pointer on success,
* on failure, it returns a corresponding ERR_PTR().
*/
static struct thermal_cooling_device *
__cpufreq_cooling_register(struct device_node *np,
struct cpufreq_policy *policy,
struct em_perf_domain *em)
{
struct thermal_cooling_device *cdev;
struct cpufreq_cooling_device *cpufreq_cdev;
unsigned int i;
struct device *dev;
int ret;
struct thermal_cooling_device_ops *cooling_ops;
char *name;
if (IS_ERR_OR_NULL(policy)) {
pr_err("%s: cpufreq policy isn't valid: %p\n", __func__, policy);
return ERR_PTR(-EINVAL);
}
dev = get_cpu_device(policy->cpu);
if (unlikely(!dev)) {
pr_warn("No cpu device for cpu %d\n", policy->cpu);
return ERR_PTR(-ENODEV);
}
i = cpufreq_table_count_valid_entries(policy);
if (!i) {
pr_debug("%s: CPUFreq table not found or has no valid entries\n",
__func__);
return ERR_PTR(-ENODEV);
}
cpufreq_cdev = kzalloc(sizeof(*cpufreq_cdev), GFP_KERNEL);
if (!cpufreq_cdev)
return ERR_PTR(-ENOMEM);
cpufreq_cdev->policy = policy;
ret = allocate_idle_time(cpufreq_cdev);
if (ret) {
cdev = ERR_PTR(ret);
goto free_cdev;
}
/* max_level is an index, not a counter */
cpufreq_cdev->max_level = i - 1;
cooling_ops = &cpufreq_cdev->cooling_ops;
cooling_ops->get_max_state = cpufreq_get_max_state;
cooling_ops->get_cur_state = cpufreq_get_cur_state;
cooling_ops->set_cur_state = cpufreq_set_cur_state;
#ifdef CONFIG_THERMAL_GOV_POWER_ALLOCATOR
if (em_is_sane(cpufreq_cdev, em)) {
cpufreq_cdev->em = em;
cooling_ops->get_requested_power = cpufreq_get_requested_power;
cooling_ops->state2power = cpufreq_state2power;
cooling_ops->power2state = cpufreq_power2state;
} else
#endif
if (policy->freq_table_sorted == CPUFREQ_TABLE_UNSORTED) {
pr_err("%s: unsorted frequency tables are not supported\n",
__func__);
cdev = ERR_PTR(-EINVAL);
goto free_idle_time;
}
ret = freq_qos_add_request(&policy->constraints,
&cpufreq_cdev->qos_req, FREQ_QOS_MAX,
get_state_freq(cpufreq_cdev, 0));
if (ret < 0) {
pr_err("%s: Failed to add freq constraint (%d)\n", __func__,
ret);
cdev = ERR_PTR(ret);
goto free_idle_time;
}
cdev = ERR_PTR(-ENOMEM);
name = kasprintf(GFP_KERNEL, "cpufreq-%s", dev_name(dev));
if (!name)
goto remove_qos_req;
cdev = thermal_of_cooling_device_register(np, name, cpufreq_cdev,
cooling_ops);
kfree(name);
if (IS_ERR(cdev))
goto remove_qos_req;
return cdev;
remove_qos_req:
freq_qos_remove_request(&cpufreq_cdev->qos_req);
free_idle_time:
free_idle_time(cpufreq_cdev);
free_cdev:
kfree(cpufreq_cdev);
return cdev;
}
/**
* cpufreq_cooling_register - function to create cpufreq cooling device.
* @policy: cpufreq policy
*
* This interface function registers the cpufreq cooling device with the name
* "cpufreq-%s". This API can support multiple instances of cpufreq cooling
* devices.
*
* Return: a valid struct thermal_cooling_device pointer on success,
* on failure, it returns a corresponding ERR_PTR().
*/
struct thermal_cooling_device *
cpufreq_cooling_register(struct cpufreq_policy *policy)
{
return __cpufreq_cooling_register(NULL, policy, NULL);
}
EXPORT_SYMBOL_GPL(cpufreq_cooling_register);
/**
* of_cpufreq_cooling_register - function to create cpufreq cooling device.
* @policy: cpufreq policy
*
* This interface function registers the cpufreq cooling device with the name
* "cpufreq-%s". This API can support multiple instances of cpufreq cooling
* devices. Using this API, the cpufreq cooling device will be linked to the
* device tree node provided.
*
* Using this function, the cooling device will implement the power
* extensions by using the Energy Model (if present). The cpus must have
* registered their OPPs using the OPP library.
*
* Return: a valid struct thermal_cooling_device pointer on success,
* and NULL on failure.
*/
struct thermal_cooling_device *
of_cpufreq_cooling_register(struct cpufreq_policy *policy)
{
struct device_node *np = of_get_cpu_node(policy->cpu, NULL);
struct thermal_cooling_device *cdev = NULL;
if (!np) {
pr_err("cpufreq_cooling: OF node not available for cpu%d\n",
policy->cpu);
return NULL;
}
if (of_find_property(np, "#cooling-cells", NULL)) {
struct em_perf_domain *em = em_cpu_get(policy->cpu);
cdev = __cpufreq_cooling_register(np, policy, em);
if (IS_ERR(cdev)) {
pr_err("cpufreq_cooling: cpu%d failed to register as cooling device: %ld\n",
policy->cpu, PTR_ERR(cdev));
cdev = NULL;
}
}
of_node_put(np);
return cdev;
}
EXPORT_SYMBOL_GPL(of_cpufreq_cooling_register);
/**
* cpufreq_cooling_unregister - function to remove cpufreq cooling device.
* @cdev: thermal cooling device pointer.
*
* This interface function unregisters the "cpufreq-%x" cooling device.
*/
void cpufreq_cooling_unregister(struct thermal_cooling_device *cdev)
{
struct cpufreq_cooling_device *cpufreq_cdev;
if (!cdev)
return;
cpufreq_cdev = cdev->devdata;
thermal_cooling_device_unregister(cdev);
freq_qos_remove_request(&cpufreq_cdev->qos_req);
free_idle_time(cpufreq_cdev);
kfree(cpufreq_cdev);
}
EXPORT_SYMBOL_GPL(cpufreq_cooling_unregister);
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