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// 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.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#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>
struct dtpm_cpu {
struct dtpm dtpm;
struct freq_qos_request qos_req;
int cpu;
};
static DEFINE_PER_CPU(struct dtpm_cpu *, dtpm_per_cpu);
static struct dtpm_cpu *to_dtpm_cpu(struct dtpm *dtpm)
{
return container_of(dtpm, struct dtpm_cpu, dtpm);
}
static u64 set_pd_power_limit(struct dtpm *dtpm, u64 power_limit)
{
struct dtpm_cpu *dtpm_cpu = to_dtpm_cpu(dtpm);
struct em_perf_domain *pd = em_cpu_get(dtpm_cpu->cpu);
struct cpumask cpus;
unsigned long freq;
u64 power;
int i, nr_cpus;
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 scale_pd_power_uw(struct cpumask *pd_mask, u64 power)
{
unsigned long max = 0, sum_util = 0;
int cpu;
for_each_cpu_and(cpu, pd_mask, cpu_online_mask) {
/*
* The capacity is the same for all CPUs belonging to
* the same perf domain, so a single call to
* arch_scale_cpu_capacity() is enough. However, we
* need the CPU parameter to be initialized by the
* loop, so the call ends up in this block.
*
* We can initialize 'max' with a cpumask_first() call
* before the loop but the bits computation is not
* worth given the arch_scale_cpu_capacity() just
* returns a value where the resulting assembly code
* will be optimized by the compiler.
*/
max = arch_scale_cpu_capacity(cpu);
sum_util += sched_cpu_util(cpu, max);
}
/*
* In the improbable case where all the CPUs of the perf
* domain are offline, 'max' will be zero and will lead to an
* illegal operation with a zero division.
*/
return max ? (power * ((sum_util << 10) / max)) >> 10 : 0;
}
static u64 get_pd_power_uw(struct dtpm *dtpm)
{
struct dtpm_cpu *dtpm_cpu = to_dtpm_cpu(dtpm);
struct em_perf_domain *pd;
struct cpumask *pd_mask;
unsigned long freq;
int i;
pd = em_cpu_get(dtpm_cpu->cpu);
pd_mask = em_span_cpus(pd);
freq = cpufreq_quick_get(dtpm_cpu->cpu);
for (i = 0; i < pd->nr_perf_states; i++) {
if (pd->table[i].frequency < freq)
continue;
return scale_pd_power_uw(pd_mask, pd->table[i].power *
MICROWATT_PER_MILLIWATT);
}
return 0;
}
static int update_pd_power_uw(struct dtpm *dtpm)
{
struct dtpm_cpu *dtpm_cpu = to_dtpm_cpu(dtpm);
struct em_perf_domain *em = em_cpu_get(dtpm_cpu->cpu);
struct cpumask cpus;
int nr_cpus;
cpumask_and(&cpus, cpu_online_mask, to_cpumask(em->cpus));
nr_cpus = cpumask_weight(&cpus);
dtpm->power_min = em->table[0].power;
dtpm->power_min *= MICROWATT_PER_MILLIWATT;
dtpm->power_min *= nr_cpus;
dtpm->power_max = em->table[em->nr_perf_states - 1].power;
dtpm->power_max *= MICROWATT_PER_MILLIWATT;
dtpm->power_max *= nr_cpus;
return 0;
}
static void pd_release(struct dtpm *dtpm)
{
struct dtpm_cpu *dtpm_cpu = to_dtpm_cpu(dtpm);
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,
.update_power_uw = update_pd_power_uw,
.release = pd_release,
};
static int cpuhp_dtpm_cpu_offline(unsigned int cpu)
{
struct em_perf_domain *pd;
struct dtpm_cpu *dtpm_cpu;
pd = em_cpu_get(cpu);
if (!pd)
return -EINVAL;
dtpm_cpu = per_cpu(dtpm_per_cpu, cpu);
return dtpm_update_power(&dtpm_cpu->dtpm);
}
static int cpuhp_dtpm_cpu_online(unsigned int cpu)
{
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_cpu = per_cpu(dtpm_per_cpu, cpu);
if (dtpm_cpu)
return dtpm_update_power(&dtpm_cpu->dtpm);
dtpm_cpu = kzalloc(sizeof(*dtpm_cpu), GFP_KERNEL);
if (!dtpm_cpu)
return -ENOMEM;
dtpm_init(&dtpm_cpu->dtpm, &dtpm_ops);
dtpm_cpu->cpu = cpu;
for_each_cpu(cpu, policy->related_cpus)
per_cpu(dtpm_per_cpu, cpu) = dtpm_cpu;
snprintf(name, sizeof(name), "cpu%d-cpufreq", dtpm_cpu->cpu);
ret = dtpm_register(name, &dtpm_cpu->dtpm, NULL);
if (ret)
goto out_kfree_dtpm_cpu;
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_dtpm_unregister;
return 0;
out_dtpm_unregister:
dtpm_unregister(&dtpm_cpu->dtpm);
dtpm_cpu = NULL;
out_kfree_dtpm_cpu:
for_each_cpu(cpu, policy->related_cpus)
per_cpu(dtpm_per_cpu, cpu) = NULL;
kfree(dtpm_cpu);
return ret;
}
static int __init dtpm_cpu_init(void)
{
int ret;
/*
* The callbacks at CPU hotplug time are calling
* dtpm_update_power() which in turns calls update_pd_power().
*
* The function update_pd_power() uses the online mask to
* figure out the power consumption limits.
*
* At CPUHP_AP_ONLINE_DYN, the CPU is present in the CPU
* online mask when the cpuhp_dtpm_cpu_online function is
* called, but the CPU is still in the online mask for the
* tear down callback. So the power can not be updated when
* the CPU is unplugged.
*
* At CPUHP_AP_DTPM_CPU_DEAD, the situation is the opposite as
* above. The CPU online mask is not up to date when the CPU
* is plugged in.
*
* For this reason, we need to call the online and offline
* callbacks at different moments when the CPU online mask is
* consistent with the power numbers we want to update.
*/
ret = cpuhp_setup_state(CPUHP_AP_DTPM_CPU_DEAD, "dtpm_cpu:offline",
NULL, cpuhp_dtpm_cpu_offline);
if (ret < 0)
return ret;
ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "dtpm_cpu:online",
cpuhp_dtpm_cpu_online, NULL);
if (ret < 0)
return ret;
return 0;
}
DTPM_DECLARE(dtpm_cpu, dtpm_cpu_init);
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