https://github.com/torvalds/linux
Tip revision: 8bb7eca972ad531c9b149c0a51ab43a417385813 authored by Linus Torvalds on 31 October 2021, 20:53:10 UTC
Linux 5.15
Linux 5.15
Tip revision: 8bb7eca
dtpm_cpu.c
// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright 2020 Linaro Limited
*
* Author: Daniel Lezcano <daniel.lezcano@linaro.org>
*
* The DTPM CPU is based on the energy model. It hooks the CPU in the
* DTPM tree which in turns update the power number by propagating the
* power number from the CPU energy model information to the parents.
*
* The association between the power and the performance state, allows
* to set the power of the CPU at the OPP granularity.
*
* The CPU hotplug is supported and the power numbers will be updated
* if a CPU is hot plugged / unplugged.
*/
#include <linux/cpumask.h>
#include <linux/cpufreq.h>
#include <linux/cpuhotplug.h>
#include <linux/dtpm.h>
#include <linux/energy_model.h>
#include <linux/pm_qos.h>
#include <linux/slab.h>
#include <linux/units.h>
static struct dtpm *__parent;
static DEFINE_PER_CPU(struct dtpm *, dtpm_per_cpu);
struct dtpm_cpu {
struct freq_qos_request qos_req;
int cpu;
};
/*
* When a new CPU is inserted at hotplug or boot time, add the power
* contribution and update the dtpm tree.
*/
static int power_add(struct dtpm *dtpm, struct em_perf_domain *em)
{
u64 power_min, power_max;
power_min = em->table[0].power;
power_min *= MICROWATT_PER_MILLIWATT;
power_min += dtpm->power_min;
power_max = em->table[em->nr_perf_states - 1].power;
power_max *= MICROWATT_PER_MILLIWATT;
power_max += dtpm->power_max;
return dtpm_update_power(dtpm, power_min, power_max);
}
/*
* When a CPU is unplugged, remove its power contribution from the
* dtpm tree.
*/
static int power_sub(struct dtpm *dtpm, struct em_perf_domain *em)
{
u64 power_min, power_max;
power_min = em->table[0].power;
power_min *= MICROWATT_PER_MILLIWATT;
power_min = dtpm->power_min - power_min;
power_max = em->table[em->nr_perf_states - 1].power;
power_max *= MICROWATT_PER_MILLIWATT;
power_max = dtpm->power_max - power_max;
return dtpm_update_power(dtpm, power_min, power_max);
}
static u64 set_pd_power_limit(struct dtpm *dtpm, u64 power_limit)
{
struct dtpm_cpu *dtpm_cpu = dtpm->private;
struct em_perf_domain *pd;
struct cpumask cpus;
unsigned long freq;
u64 power;
int i, nr_cpus;
pd = em_cpu_get(dtpm_cpu->cpu);
cpumask_and(&cpus, cpu_online_mask, to_cpumask(pd->cpus));
nr_cpus = cpumask_weight(&cpus);
for (i = 0; i < pd->nr_perf_states; i++) {
power = pd->table[i].power * MICROWATT_PER_MILLIWATT * nr_cpus;
if (power > power_limit)
break;
}
freq = pd->table[i - 1].frequency;
freq_qos_update_request(&dtpm_cpu->qos_req, freq);
power_limit = pd->table[i - 1].power *
MICROWATT_PER_MILLIWATT * nr_cpus;
return power_limit;
}
static u64 get_pd_power_uw(struct dtpm *dtpm)
{
struct dtpm_cpu *dtpm_cpu = dtpm->private;
struct em_perf_domain *pd;
struct cpumask cpus;
unsigned long freq;
int i, nr_cpus;
pd = em_cpu_get(dtpm_cpu->cpu);
freq = cpufreq_quick_get(dtpm_cpu->cpu);
cpumask_and(&cpus, cpu_online_mask, to_cpumask(pd->cpus));
nr_cpus = cpumask_weight(&cpus);
for (i = 0; i < pd->nr_perf_states; i++) {
if (pd->table[i].frequency < freq)
continue;
return pd->table[i].power *
MICROWATT_PER_MILLIWATT * nr_cpus;
}
return 0;
}
static void pd_release(struct dtpm *dtpm)
{
struct dtpm_cpu *dtpm_cpu = dtpm->private;
if (freq_qos_request_active(&dtpm_cpu->qos_req))
freq_qos_remove_request(&dtpm_cpu->qos_req);
kfree(dtpm_cpu);
}
static struct dtpm_ops dtpm_ops = {
.set_power_uw = set_pd_power_limit,
.get_power_uw = get_pd_power_uw,
.release = pd_release,
};
static int cpuhp_dtpm_cpu_offline(unsigned int cpu)
{
struct cpufreq_policy *policy;
struct em_perf_domain *pd;
struct dtpm *dtpm;
policy = cpufreq_cpu_get(cpu);
if (!policy)
return 0;
pd = em_cpu_get(cpu);
if (!pd)
return -EINVAL;
dtpm = per_cpu(dtpm_per_cpu, cpu);
power_sub(dtpm, pd);
if (cpumask_weight(policy->cpus) != 1)
return 0;
for_each_cpu(cpu, policy->related_cpus)
per_cpu(dtpm_per_cpu, cpu) = NULL;
dtpm_unregister(dtpm);
return 0;
}
static int cpuhp_dtpm_cpu_online(unsigned int cpu)
{
struct dtpm *dtpm;
struct dtpm_cpu *dtpm_cpu;
struct cpufreq_policy *policy;
struct em_perf_domain *pd;
char name[CPUFREQ_NAME_LEN];
int ret = -ENOMEM;
policy = cpufreq_cpu_get(cpu);
if (!policy)
return 0;
pd = em_cpu_get(cpu);
if (!pd)
return -EINVAL;
dtpm = per_cpu(dtpm_per_cpu, cpu);
if (dtpm)
return power_add(dtpm, pd);
dtpm = dtpm_alloc(&dtpm_ops);
if (!dtpm)
return -EINVAL;
dtpm_cpu = kzalloc(sizeof(*dtpm_cpu), GFP_KERNEL);
if (!dtpm_cpu)
goto out_kfree_dtpm;
dtpm->private = dtpm_cpu;
dtpm_cpu->cpu = cpu;
for_each_cpu(cpu, policy->related_cpus)
per_cpu(dtpm_per_cpu, cpu) = dtpm;
sprintf(name, "cpu%d", dtpm_cpu->cpu);
ret = dtpm_register(name, dtpm, __parent);
if (ret)
goto out_kfree_dtpm_cpu;
ret = power_add(dtpm, pd);
if (ret)
goto out_dtpm_unregister;
ret = freq_qos_add_request(&policy->constraints,
&dtpm_cpu->qos_req, FREQ_QOS_MAX,
pd->table[pd->nr_perf_states - 1].frequency);
if (ret)
goto out_power_sub;
return 0;
out_power_sub:
power_sub(dtpm, pd);
out_dtpm_unregister:
dtpm_unregister(dtpm);
dtpm_cpu = NULL;
dtpm = NULL;
out_kfree_dtpm_cpu:
for_each_cpu(cpu, policy->related_cpus)
per_cpu(dtpm_per_cpu, cpu) = NULL;
kfree(dtpm_cpu);
out_kfree_dtpm:
kfree(dtpm);
return ret;
}
int dtpm_register_cpu(struct dtpm *parent)
{
__parent = parent;
return cpuhp_setup_state(CPUHP_AP_DTPM_CPU_ONLINE,
"dtpm_cpu:online",
cpuhp_dtpm_cpu_online,
cpuhp_dtpm_cpu_offline);
}