273 lines
6.5 KiB
C
273 lines
6.5 KiB
C
/*
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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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* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or (at
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* your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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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 <asm/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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static unsigned int acpi_thermal_cpufreq_is_init = 0;
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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_thermal_cpufreq_is_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 acpi_thermal_cpufreq_notifier(struct notifier_block *nb,
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unsigned long event, void *data)
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{
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struct cpufreq_policy *policy = data;
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unsigned long max_freq = 0;
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if (event != CPUFREQ_ADJUST)
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goto out;
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max_freq = (
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policy->cpuinfo.max_freq *
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(100 - reduction_pctg(policy->cpu) * 20)
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) / 100;
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cpufreq_verify_within_limits(policy, 0, max_freq);
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out:
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return 0;
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}
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static struct notifier_block acpi_thermal_cpufreq_notifier_block = {
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.notifier_call = acpi_thermal_cpufreq_notifier,
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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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int i;
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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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cpufreq_update_policy(i);
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}
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return 0;
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}
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void acpi_thermal_cpufreq_init(void)
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{
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int i;
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i = cpufreq_register_notifier(&acpi_thermal_cpufreq_notifier_block,
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CPUFREQ_POLICY_NOTIFIER);
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if (!i)
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acpi_thermal_cpufreq_is_init = 1;
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}
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void acpi_thermal_cpufreq_exit(void)
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{
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if (acpi_thermal_cpufreq_is_init)
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cpufreq_unregister_notifier
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(&acpi_thermal_cpufreq_notifier_block,
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CPUFREQ_POLICY_NOTIFIER);
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acpi_thermal_cpufreq_is_init = 0;
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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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