252 строки
5.9 KiB
C
252 строки
5.9 KiB
C
/*
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* Arch specific cpu topology information
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*
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* Copyright (C) 2016, ARM Ltd.
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* Written by: Juri Lelli, ARM Ltd.
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*
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* Released under the GPLv2 only.
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* SPDX-License-Identifier: GPL-2.0
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*/
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#include <linux/acpi.h>
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#include <linux/arch_topology.h>
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#include <linux/cpu.h>
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#include <linux/cpufreq.h>
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#include <linux/device.h>
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#include <linux/of.h>
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#include <linux/slab.h>
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#include <linux/string.h>
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#include <linux/sched/topology.h>
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static DEFINE_MUTEX(cpu_scale_mutex);
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static DEFINE_PER_CPU(unsigned long, cpu_scale) = SCHED_CAPACITY_SCALE;
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unsigned long topology_get_cpu_scale(struct sched_domain *sd, int cpu)
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{
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return per_cpu(cpu_scale, cpu);
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}
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void topology_set_cpu_scale(unsigned int cpu, unsigned long capacity)
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{
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per_cpu(cpu_scale, cpu) = capacity;
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}
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static ssize_t cpu_capacity_show(struct device *dev,
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struct device_attribute *attr,
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char *buf)
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{
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struct cpu *cpu = container_of(dev, struct cpu, dev);
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return sprintf(buf, "%lu\n", topology_get_cpu_scale(NULL, cpu->dev.id));
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}
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static ssize_t cpu_capacity_store(struct device *dev,
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struct device_attribute *attr,
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const char *buf,
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size_t count)
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{
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struct cpu *cpu = container_of(dev, struct cpu, dev);
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int this_cpu = cpu->dev.id;
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int i;
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unsigned long new_capacity;
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ssize_t ret;
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if (!count)
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return 0;
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ret = kstrtoul(buf, 0, &new_capacity);
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if (ret)
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return ret;
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if (new_capacity > SCHED_CAPACITY_SCALE)
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return -EINVAL;
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mutex_lock(&cpu_scale_mutex);
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for_each_cpu(i, &cpu_topology[this_cpu].core_sibling)
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topology_set_cpu_scale(i, new_capacity);
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mutex_unlock(&cpu_scale_mutex);
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return count;
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}
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static DEVICE_ATTR_RW(cpu_capacity);
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static int register_cpu_capacity_sysctl(void)
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{
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int i;
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struct device *cpu;
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for_each_possible_cpu(i) {
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cpu = get_cpu_device(i);
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if (!cpu) {
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pr_err("%s: too early to get CPU%d device!\n",
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__func__, i);
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continue;
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}
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device_create_file(cpu, &dev_attr_cpu_capacity);
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}
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return 0;
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}
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subsys_initcall(register_cpu_capacity_sysctl);
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static u32 capacity_scale;
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static u32 *raw_capacity;
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static int __init free_raw_capacity(void)
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{
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kfree(raw_capacity);
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raw_capacity = NULL;
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return 0;
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}
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void topology_normalize_cpu_scale(void)
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{
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u64 capacity;
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int cpu;
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if (!raw_capacity)
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return;
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pr_debug("cpu_capacity: capacity_scale=%u\n", capacity_scale);
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mutex_lock(&cpu_scale_mutex);
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for_each_possible_cpu(cpu) {
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pr_debug("cpu_capacity: cpu=%d raw_capacity=%u\n",
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cpu, raw_capacity[cpu]);
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capacity = (raw_capacity[cpu] << SCHED_CAPACITY_SHIFT)
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/ capacity_scale;
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topology_set_cpu_scale(cpu, capacity);
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pr_debug("cpu_capacity: CPU%d cpu_capacity=%lu\n",
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cpu, topology_get_cpu_scale(NULL, cpu));
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}
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mutex_unlock(&cpu_scale_mutex);
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}
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bool __init topology_parse_cpu_capacity(struct device_node *cpu_node, int cpu)
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{
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static bool cap_parsing_failed;
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int ret;
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u32 cpu_capacity;
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if (cap_parsing_failed)
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return false;
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ret = of_property_read_u32(cpu_node, "capacity-dmips-mhz",
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&cpu_capacity);
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if (!ret) {
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if (!raw_capacity) {
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raw_capacity = kcalloc(num_possible_cpus(),
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sizeof(*raw_capacity),
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GFP_KERNEL);
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if (!raw_capacity) {
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pr_err("cpu_capacity: failed to allocate memory for raw capacities\n");
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cap_parsing_failed = true;
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return false;
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}
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}
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capacity_scale = max(cpu_capacity, capacity_scale);
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raw_capacity[cpu] = cpu_capacity;
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pr_debug("cpu_capacity: %pOF cpu_capacity=%u (raw)\n",
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cpu_node, raw_capacity[cpu]);
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} else {
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if (raw_capacity) {
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pr_err("cpu_capacity: missing %pOF raw capacity\n",
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cpu_node);
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pr_err("cpu_capacity: partial information: fallback to 1024 for all CPUs\n");
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}
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cap_parsing_failed = true;
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free_raw_capacity();
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}
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return !ret;
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}
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#ifdef CONFIG_CPU_FREQ
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static cpumask_var_t cpus_to_visit;
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static void parsing_done_workfn(struct work_struct *work);
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static DECLARE_WORK(parsing_done_work, parsing_done_workfn);
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static int
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init_cpu_capacity_callback(struct notifier_block *nb,
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unsigned long val,
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void *data)
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{
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struct cpufreq_policy *policy = data;
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int cpu;
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if (!raw_capacity)
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return 0;
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if (val != CPUFREQ_NOTIFY)
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return 0;
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pr_debug("cpu_capacity: init cpu capacity for CPUs [%*pbl] (to_visit=%*pbl)\n",
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cpumask_pr_args(policy->related_cpus),
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cpumask_pr_args(cpus_to_visit));
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cpumask_andnot(cpus_to_visit, cpus_to_visit, policy->related_cpus);
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for_each_cpu(cpu, policy->related_cpus) {
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raw_capacity[cpu] = topology_get_cpu_scale(NULL, cpu) *
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policy->cpuinfo.max_freq / 1000UL;
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capacity_scale = max(raw_capacity[cpu], capacity_scale);
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}
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if (cpumask_empty(cpus_to_visit)) {
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topology_normalize_cpu_scale();
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free_raw_capacity();
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pr_debug("cpu_capacity: parsing done\n");
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schedule_work(&parsing_done_work);
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}
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return 0;
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}
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static struct notifier_block init_cpu_capacity_notifier = {
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.notifier_call = init_cpu_capacity_callback,
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};
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static int __init register_cpufreq_notifier(void)
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{
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int ret;
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/*
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* on ACPI-based systems we need to use the default cpu capacity
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* until we have the necessary code to parse the cpu capacity, so
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* skip registering cpufreq notifier.
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*/
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if (!acpi_disabled || !raw_capacity)
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return -EINVAL;
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if (!alloc_cpumask_var(&cpus_to_visit, GFP_KERNEL)) {
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pr_err("cpu_capacity: failed to allocate memory for cpus_to_visit\n");
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return -ENOMEM;
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}
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cpumask_copy(cpus_to_visit, cpu_possible_mask);
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ret = cpufreq_register_notifier(&init_cpu_capacity_notifier,
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CPUFREQ_POLICY_NOTIFIER);
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if (ret)
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free_cpumask_var(cpus_to_visit);
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return ret;
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}
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core_initcall(register_cpufreq_notifier);
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static void parsing_done_workfn(struct work_struct *work)
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{
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cpufreq_unregister_notifier(&init_cpu_capacity_notifier,
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CPUFREQ_POLICY_NOTIFIER);
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free_cpumask_var(cpus_to_visit);
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}
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#else
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core_initcall(free_raw_capacity);
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#endif
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