268 lines
6.0 KiB
C
268 lines
6.0 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* processor_thermal.c - Passive cooling submodule of the ACPI processor driver
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*
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* Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
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* Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
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* Copyright (C) 2004 Dominik Brodowski <linux@brodo.de>
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* Copyright (C) 2004 Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
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* - Added processor hotplug support
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/cpufreq.h>
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#include <linux/acpi.h>
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#include <acpi/processor.h>
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#include <linux/uaccess.h>
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#define PREFIX "ACPI: "
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#define ACPI_PROCESSOR_CLASS "processor"
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#define _COMPONENT ACPI_PROCESSOR_COMPONENT
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ACPI_MODULE_NAME("processor_thermal");
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#ifdef CONFIG_CPU_FREQ
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/* If a passive cooling situation is detected, primarily CPUfreq is used, as it
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* offers (in most cases) voltage scaling in addition to frequency scaling, and
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* thus a cubic (instead of linear) reduction of energy. Also, we allow for
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* _any_ cpufreq driver and not only the acpi-cpufreq driver.
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*/
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#define CPUFREQ_THERMAL_MIN_STEP 0
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#define CPUFREQ_THERMAL_MAX_STEP 3
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static DEFINE_PER_CPU(unsigned int, cpufreq_thermal_reduction_pctg);
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#define reduction_pctg(cpu) \
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per_cpu(cpufreq_thermal_reduction_pctg, phys_package_first_cpu(cpu))
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/*
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* Emulate "per package data" using per cpu data (which should really be
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* provided elsewhere)
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*
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* Note we can lose a CPU on cpu hotunplug, in this case we forget the state
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* temporarily. Fortunately that's not a big issue here (I hope)
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*/
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static int phys_package_first_cpu(int cpu)
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{
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int i;
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int id = topology_physical_package_id(cpu);
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for_each_online_cpu(i)
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if (topology_physical_package_id(i) == id)
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return i;
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return 0;
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}
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static int cpu_has_cpufreq(unsigned int cpu)
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{
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struct cpufreq_policy policy;
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if (!acpi_processor_cpufreq_init || cpufreq_get_policy(&policy, cpu))
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return 0;
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return 1;
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}
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static int cpufreq_get_max_state(unsigned int cpu)
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{
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if (!cpu_has_cpufreq(cpu))
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return 0;
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return CPUFREQ_THERMAL_MAX_STEP;
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}
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static int cpufreq_get_cur_state(unsigned int cpu)
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{
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if (!cpu_has_cpufreq(cpu))
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return 0;
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return reduction_pctg(cpu);
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}
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static int cpufreq_set_cur_state(unsigned int cpu, int state)
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{
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struct cpufreq_policy *policy;
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struct acpi_processor *pr;
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unsigned long max_freq;
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int i, ret;
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if (!cpu_has_cpufreq(cpu))
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return 0;
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reduction_pctg(cpu) = state;
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/*
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* Update all the CPUs in the same package because they all
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* contribute to the temperature and often share the same
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* frequency.
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*/
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for_each_online_cpu(i) {
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if (topology_physical_package_id(i) !=
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topology_physical_package_id(cpu))
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continue;
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pr = per_cpu(processors, i);
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if (unlikely(!freq_qos_request_active(&pr->thermal_req)))
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continue;
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policy = cpufreq_cpu_get(i);
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if (!policy)
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return -EINVAL;
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max_freq = (policy->cpuinfo.max_freq * (100 - reduction_pctg(i) * 20)) / 100;
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cpufreq_cpu_put(policy);
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ret = freq_qos_update_request(&pr->thermal_req, max_freq);
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if (ret < 0) {
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pr_warn("Failed to update thermal freq constraint: CPU%d (%d)\n",
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pr->id, ret);
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}
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}
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return 0;
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}
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void acpi_thermal_cpufreq_init(struct cpufreq_policy *policy)
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{
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unsigned int cpu;
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for_each_cpu(cpu, policy->related_cpus) {
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struct acpi_processor *pr = per_cpu(processors, cpu);
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int ret;
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if (!pr)
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continue;
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ret = freq_qos_add_request(&policy->constraints,
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&pr->thermal_req,
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FREQ_QOS_MAX, INT_MAX);
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if (ret < 0)
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pr_err("Failed to add freq constraint for CPU%d (%d)\n",
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cpu, ret);
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}
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}
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void acpi_thermal_cpufreq_exit(struct cpufreq_policy *policy)
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{
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unsigned int cpu;
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for_each_cpu(cpu, policy->related_cpus) {
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struct acpi_processor *pr = per_cpu(processors, policy->cpu);
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if (pr)
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freq_qos_remove_request(&pr->thermal_req);
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}
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}
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#else /* ! CONFIG_CPU_FREQ */
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static int cpufreq_get_max_state(unsigned int cpu)
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{
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return 0;
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}
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static int cpufreq_get_cur_state(unsigned int cpu)
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{
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return 0;
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}
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static int cpufreq_set_cur_state(unsigned int cpu, int state)
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{
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return 0;
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}
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#endif
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/* thermal cooling device callbacks */
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static int acpi_processor_max_state(struct acpi_processor *pr)
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{
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int max_state = 0;
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/*
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* There exists four states according to
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* cpufreq_thermal_reduction_pctg. 0, 1, 2, 3
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*/
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max_state += cpufreq_get_max_state(pr->id);
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if (pr->flags.throttling)
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max_state += (pr->throttling.state_count -1);
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return max_state;
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}
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static int
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processor_get_max_state(struct thermal_cooling_device *cdev,
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unsigned long *state)
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{
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struct acpi_device *device = cdev->devdata;
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struct acpi_processor *pr;
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if (!device)
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return -EINVAL;
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pr = acpi_driver_data(device);
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if (!pr)
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return -EINVAL;
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*state = acpi_processor_max_state(pr);
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return 0;
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}
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static int
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processor_get_cur_state(struct thermal_cooling_device *cdev,
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unsigned long *cur_state)
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{
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struct acpi_device *device = cdev->devdata;
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struct acpi_processor *pr;
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if (!device)
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return -EINVAL;
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pr = acpi_driver_data(device);
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if (!pr)
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return -EINVAL;
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*cur_state = cpufreq_get_cur_state(pr->id);
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if (pr->flags.throttling)
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*cur_state += pr->throttling.state;
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return 0;
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}
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static int
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processor_set_cur_state(struct thermal_cooling_device *cdev,
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unsigned long state)
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{
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struct acpi_device *device = cdev->devdata;
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struct acpi_processor *pr;
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int result = 0;
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int max_pstate;
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if (!device)
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return -EINVAL;
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pr = acpi_driver_data(device);
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if (!pr)
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return -EINVAL;
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max_pstate = cpufreq_get_max_state(pr->id);
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if (state > acpi_processor_max_state(pr))
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return -EINVAL;
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if (state <= max_pstate) {
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if (pr->flags.throttling && pr->throttling.state)
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result = acpi_processor_set_throttling(pr, 0, false);
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cpufreq_set_cur_state(pr->id, state);
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} else {
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cpufreq_set_cur_state(pr->id, max_pstate);
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result = acpi_processor_set_throttling(pr,
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state - max_pstate, false);
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}
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return result;
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}
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const struct thermal_cooling_device_ops processor_cooling_ops = {
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.get_max_state = processor_get_max_state,
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.get_cur_state = processor_get_cur_state,
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.set_cur_state = processor_set_cur_state,
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};
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