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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.
- */
- #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);
- }
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