![Greg Kroah-Hartman](/assets/img/avatar_default.png)
arch_topology.c had a SPDX tag in it, so move it to the top of the file like the rest of the kernel files have it. Also remove the redundant license text as it is not needed if the SPDX tag is in the file, as the tag identifies the license in a specific and legally-defined manner. This is done on a quest to remove the 700+ different ways that files in the kernel describe the GPL license text. And there's unneeded stuff like the address (sometimes incorrect) for the FSF which is never needed. No copyright headers or other non-license-description text was removed. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
255 lines
5.9 KiB
C
255 lines
5.9 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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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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#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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DEFINE_PER_CPU(unsigned long, freq_scale) = SCHED_CAPACITY_SCALE;
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void arch_set_freq_scale(struct cpumask *cpus, unsigned long cur_freq,
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unsigned long max_freq)
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{
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unsigned long scale;
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int i;
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scale = (cur_freq << SCHED_CAPACITY_SHIFT) / max_freq;
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for_each_cpu(i, cpus)
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per_cpu(freq_scale, i) = scale;
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}
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static DEFINE_MUTEX(cpu_scale_mutex);
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DEFINE_PER_CPU(unsigned long, cpu_scale) = SCHED_CAPACITY_SCALE;
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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 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 __initdata;
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static void __init parsing_done_workfn(struct work_struct *work);
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static __initdata DECLARE_WORK(parsing_done_work, parsing_done_workfn);
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static int __init
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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 __initdata = {
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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 __init 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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