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313 lines
7.4 KiB
313 lines
7.4 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Copyright 2020 Linaro Limited |
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* |
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* Author: Daniel Lezcano <[email protected]> |
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* |
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* The DTPM CPU is based on the energy model. It hooks the CPU in the |
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* DTPM tree which in turns update the power number by propagating the |
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* power number from the CPU energy model information to the parents. |
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* |
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* The association between the power and the performance state, allows |
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* to set the power of the CPU at the OPP granularity. |
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* |
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* The CPU hotplug is supported and the power numbers will be updated |
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* if a CPU is hot plugged / unplugged. |
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*/ |
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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#include <linux/cpumask.h> |
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#include <linux/cpufreq.h> |
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#include <linux/cpuhotplug.h> |
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#include <linux/dtpm.h> |
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#include <linux/energy_model.h> |
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#include <linux/of.h> |
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#include <linux/pm_qos.h> |
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#include <linux/slab.h> |
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#include <linux/units.h> |
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struct dtpm_cpu { |
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struct dtpm dtpm; |
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struct freq_qos_request qos_req; |
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int cpu; |
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}; |
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static DEFINE_PER_CPU(struct dtpm_cpu *, dtpm_per_cpu); |
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static struct dtpm_cpu *to_dtpm_cpu(struct dtpm *dtpm) |
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{ |
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return container_of(dtpm, struct dtpm_cpu, dtpm); |
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} |
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static u64 set_pd_power_limit(struct dtpm *dtpm, u64 power_limit) |
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{ |
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struct dtpm_cpu *dtpm_cpu = to_dtpm_cpu(dtpm); |
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struct em_perf_domain *pd = em_cpu_get(dtpm_cpu->cpu); |
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struct cpumask cpus; |
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unsigned long freq; |
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u64 power; |
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int i, nr_cpus; |
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cpumask_and(&cpus, cpu_online_mask, to_cpumask(pd->cpus)); |
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nr_cpus = cpumask_weight(&cpus); |
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for (i = 0; i < pd->nr_perf_states; i++) { |
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power = pd->table[i].power * MICROWATT_PER_MILLIWATT * nr_cpus; |
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if (power > power_limit) |
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break; |
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} |
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freq = pd->table[i - 1].frequency; |
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freq_qos_update_request(&dtpm_cpu->qos_req, freq); |
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power_limit = pd->table[i - 1].power * |
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MICROWATT_PER_MILLIWATT * nr_cpus; |
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return power_limit; |
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} |
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static u64 scale_pd_power_uw(struct cpumask *pd_mask, u64 power) |
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{ |
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unsigned long max = 0, sum_util = 0; |
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int cpu; |
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for_each_cpu_and(cpu, pd_mask, cpu_online_mask) { |
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/* |
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* The capacity is the same for all CPUs belonging to |
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* the same perf domain, so a single call to |
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* arch_scale_cpu_capacity() is enough. However, we |
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* need the CPU parameter to be initialized by the |
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* loop, so the call ends up in this block. |
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* |
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* We can initialize 'max' with a cpumask_first() call |
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* before the loop but the bits computation is not |
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* worth given the arch_scale_cpu_capacity() just |
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* returns a value where the resulting assembly code |
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* will be optimized by the compiler. |
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*/ |
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max = arch_scale_cpu_capacity(cpu); |
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sum_util += sched_cpu_util(cpu, max); |
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} |
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/* |
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* In the improbable case where all the CPUs of the perf |
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* domain are offline, 'max' will be zero and will lead to an |
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* illegal operation with a zero division. |
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*/ |
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return max ? (power * ((sum_util << 10) / max)) >> 10 : 0; |
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} |
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static u64 get_pd_power_uw(struct dtpm *dtpm) |
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{ |
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struct dtpm_cpu *dtpm_cpu = to_dtpm_cpu(dtpm); |
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struct em_perf_domain *pd; |
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struct cpumask *pd_mask; |
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unsigned long freq; |
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int i; |
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pd = em_cpu_get(dtpm_cpu->cpu); |
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pd_mask = em_span_cpus(pd); |
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freq = cpufreq_quick_get(dtpm_cpu->cpu); |
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for (i = 0; i < pd->nr_perf_states; i++) { |
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if (pd->table[i].frequency < freq) |
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continue; |
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return scale_pd_power_uw(pd_mask, pd->table[i].power * |
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MICROWATT_PER_MILLIWATT); |
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} |
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return 0; |
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} |
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static int update_pd_power_uw(struct dtpm *dtpm) |
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{ |
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struct dtpm_cpu *dtpm_cpu = to_dtpm_cpu(dtpm); |
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struct em_perf_domain *em = em_cpu_get(dtpm_cpu->cpu); |
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struct cpumask cpus; |
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int nr_cpus; |
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cpumask_and(&cpus, cpu_online_mask, to_cpumask(em->cpus)); |
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nr_cpus = cpumask_weight(&cpus); |
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dtpm->power_min = em->table[0].power; |
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dtpm->power_min *= MICROWATT_PER_MILLIWATT; |
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dtpm->power_min *= nr_cpus; |
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dtpm->power_max = em->table[em->nr_perf_states - 1].power; |
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dtpm->power_max *= MICROWATT_PER_MILLIWATT; |
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dtpm->power_max *= nr_cpus; |
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return 0; |
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} |
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static void pd_release(struct dtpm *dtpm) |
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{ |
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struct dtpm_cpu *dtpm_cpu = to_dtpm_cpu(dtpm); |
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struct cpufreq_policy *policy; |
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if (freq_qos_request_active(&dtpm_cpu->qos_req)) |
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freq_qos_remove_request(&dtpm_cpu->qos_req); |
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policy = cpufreq_cpu_get(dtpm_cpu->cpu); |
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if (policy) { |
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for_each_cpu(dtpm_cpu->cpu, policy->related_cpus) |
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per_cpu(dtpm_per_cpu, dtpm_cpu->cpu) = NULL; |
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} |
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kfree(dtpm_cpu); |
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} |
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static struct dtpm_ops dtpm_ops = { |
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.set_power_uw = set_pd_power_limit, |
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.get_power_uw = get_pd_power_uw, |
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.update_power_uw = update_pd_power_uw, |
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.release = pd_release, |
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}; |
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static int cpuhp_dtpm_cpu_offline(unsigned int cpu) |
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{ |
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struct dtpm_cpu *dtpm_cpu; |
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dtpm_cpu = per_cpu(dtpm_per_cpu, cpu); |
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if (dtpm_cpu) |
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dtpm_update_power(&dtpm_cpu->dtpm); |
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return 0; |
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} |
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static int cpuhp_dtpm_cpu_online(unsigned int cpu) |
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{ |
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struct dtpm_cpu *dtpm_cpu; |
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dtpm_cpu = per_cpu(dtpm_per_cpu, cpu); |
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if (dtpm_cpu) |
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return dtpm_update_power(&dtpm_cpu->dtpm); |
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return 0; |
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} |
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static int __dtpm_cpu_setup(int cpu, struct dtpm *parent) |
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{ |
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struct dtpm_cpu *dtpm_cpu; |
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struct cpufreq_policy *policy; |
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struct em_perf_domain *pd; |
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char name[CPUFREQ_NAME_LEN]; |
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int ret = -ENOMEM; |
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dtpm_cpu = per_cpu(dtpm_per_cpu, cpu); |
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if (dtpm_cpu) |
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return 0; |
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policy = cpufreq_cpu_get(cpu); |
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if (!policy) |
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return 0; |
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pd = em_cpu_get(cpu); |
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if (!pd) |
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return -EINVAL; |
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dtpm_cpu = kzalloc(sizeof(*dtpm_cpu), GFP_KERNEL); |
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if (!dtpm_cpu) |
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return -ENOMEM; |
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dtpm_init(&dtpm_cpu->dtpm, &dtpm_ops); |
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dtpm_cpu->cpu = cpu; |
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for_each_cpu(cpu, policy->related_cpus) |
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per_cpu(dtpm_per_cpu, cpu) = dtpm_cpu; |
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snprintf(name, sizeof(name), "cpu%d-cpufreq", dtpm_cpu->cpu); |
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ret = dtpm_register(name, &dtpm_cpu->dtpm, parent); |
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if (ret) |
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goto out_kfree_dtpm_cpu; |
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ret = freq_qos_add_request(&policy->constraints, |
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&dtpm_cpu->qos_req, FREQ_QOS_MAX, |
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pd->table[pd->nr_perf_states - 1].frequency); |
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if (ret) |
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goto out_dtpm_unregister; |
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return 0; |
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out_dtpm_unregister: |
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dtpm_unregister(&dtpm_cpu->dtpm); |
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dtpm_cpu = NULL; |
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out_kfree_dtpm_cpu: |
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for_each_cpu(cpu, policy->related_cpus) |
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per_cpu(dtpm_per_cpu, cpu) = NULL; |
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kfree(dtpm_cpu); |
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return ret; |
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} |
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static int dtpm_cpu_setup(struct dtpm *dtpm, struct device_node *np) |
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{ |
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int cpu; |
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cpu = of_cpu_node_to_id(np); |
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if (cpu < 0) |
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return 0; |
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return __dtpm_cpu_setup(cpu, dtpm); |
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} |
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static int dtpm_cpu_init(void) |
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{ |
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int ret; |
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/* |
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* The callbacks at CPU hotplug time are calling |
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* dtpm_update_power() which in turns calls update_pd_power(). |
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* |
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* The function update_pd_power() uses the online mask to |
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* figure out the power consumption limits. |
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* |
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* At CPUHP_AP_ONLINE_DYN, the CPU is present in the CPU |
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* online mask when the cpuhp_dtpm_cpu_online function is |
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* called, but the CPU is still in the online mask for the |
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* tear down callback. So the power can not be updated when |
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* the CPU is unplugged. |
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* |
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* At CPUHP_AP_DTPM_CPU_DEAD, the situation is the opposite as |
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* above. The CPU online mask is not up to date when the CPU |
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* is plugged in. |
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* |
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* For this reason, we need to call the online and offline |
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* callbacks at different moments when the CPU online mask is |
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* consistent with the power numbers we want to update. |
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*/ |
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ret = cpuhp_setup_state(CPUHP_AP_DTPM_CPU_DEAD, "dtpm_cpu:offline", |
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NULL, cpuhp_dtpm_cpu_offline); |
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if (ret < 0) |
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return ret; |
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ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "dtpm_cpu:online", |
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cpuhp_dtpm_cpu_online, NULL); |
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if (ret < 0) |
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return ret; |
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return 0; |
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} |
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static void dtpm_cpu_exit(void) |
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{ |
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cpuhp_remove_state_nocalls(CPUHP_AP_ONLINE_DYN); |
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cpuhp_remove_state_nocalls(CPUHP_AP_DTPM_CPU_DEAD); |
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} |
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struct dtpm_subsys_ops dtpm_cpu_ops = { |
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.name = KBUILD_MODNAME, |
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.init = dtpm_cpu_init, |
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.exit = dtpm_cpu_exit, |
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.setup = dtpm_cpu_setup, |
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};
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