362 lines · c
1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * processor_thermal.c - Passive cooling submodule of the ACPI processor driver4 *5 * Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>6 * Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>7 * Copyright (C) 2004 Dominik Brodowski <linux@brodo.de>8 * Copyright (C) 2004 Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>9 * - Added processor hotplug support10 */11 12#include <linux/kernel.h>13#include <linux/module.h>14#include <linux/init.h>15#include <linux/cpufreq.h>16#include <linux/acpi.h>17#include <acpi/processor.h>18#include <linux/uaccess.h>19 20#include "internal.h"21 22#ifdef CONFIG_CPU_FREQ23 24/* If a passive cooling situation is detected, primarily CPUfreq is used, as it25 * offers (in most cases) voltage scaling in addition to frequency scaling, and26 * thus a cubic (instead of linear) reduction of energy. Also, we allow for27 * _any_ cpufreq driver and not only the acpi-cpufreq driver.28 */29 30#define CPUFREQ_THERMAL_MIN_STEP 031 32static int cpufreq_thermal_max_step __read_mostly = 3;33 34/*35 * Minimum throttle percentage for processor_thermal cooling device.36 * The processor_thermal driver uses it to calculate the percentage amount by37 * which cpu frequency must be reduced for each cooling state. This is also used38 * to calculate the maximum number of throttling steps or cooling states.39 */40static int cpufreq_thermal_reduction_pctg __read_mostly = 20;41 42static DEFINE_PER_CPU(unsigned int, cpufreq_thermal_reduction_step);43 44#define reduction_step(cpu) \45 per_cpu(cpufreq_thermal_reduction_step, phys_package_first_cpu(cpu))46 47/*48 * Emulate "per package data" using per cpu data (which should really be49 * provided elsewhere)50 *51 * Note we can lose a CPU on cpu hotunplug, in this case we forget the state52 * temporarily. Fortunately that's not a big issue here (I hope)53 */54static int phys_package_first_cpu(int cpu)55{56 int i;57 int id = topology_physical_package_id(cpu);58 59 for_each_online_cpu(i)60 if (topology_physical_package_id(i) == id)61 return i;62 return 0;63}64 65static int cpu_has_cpufreq(unsigned int cpu)66{67 struct cpufreq_policy *policy;68 69 if (!acpi_processor_cpufreq_init)70 return 0;71 72 policy = cpufreq_cpu_get(cpu);73 if (policy) {74 cpufreq_cpu_put(policy);75 return 1;76 }77 return 0;78}79 80static int cpufreq_get_max_state(unsigned int cpu)81{82 if (!cpu_has_cpufreq(cpu))83 return 0;84 85 return cpufreq_thermal_max_step;86}87 88static int cpufreq_get_cur_state(unsigned int cpu)89{90 if (!cpu_has_cpufreq(cpu))91 return 0;92 93 return reduction_step(cpu);94}95 96static int cpufreq_set_cur_state(unsigned int cpu, int state)97{98 struct cpufreq_policy *policy;99 struct acpi_processor *pr;100 unsigned long max_freq;101 int i, ret;102 103 if (!cpu_has_cpufreq(cpu))104 return 0;105 106 reduction_step(cpu) = state;107 108 /*109 * Update all the CPUs in the same package because they all110 * contribute to the temperature and often share the same111 * frequency.112 */113 for_each_online_cpu(i) {114 if (topology_physical_package_id(i) !=115 topology_physical_package_id(cpu))116 continue;117 118 pr = per_cpu(processors, i);119 120 if (unlikely(!freq_qos_request_active(&pr->thermal_req)))121 continue;122 123 policy = cpufreq_cpu_get(i);124 if (!policy)125 return -EINVAL;126 127 max_freq = (policy->cpuinfo.max_freq *128 (100 - reduction_step(i) * cpufreq_thermal_reduction_pctg)) / 100;129 130 cpufreq_cpu_put(policy);131 132 ret = freq_qos_update_request(&pr->thermal_req, max_freq);133 if (ret < 0) {134 pr_warn("Failed to update thermal freq constraint: CPU%d (%d)\n",135 pr->id, ret);136 }137 }138 return 0;139}140 141static void acpi_thermal_cpufreq_config(void)142{143 int cpufreq_pctg = acpi_arch_thermal_cpufreq_pctg();144 145 if (!cpufreq_pctg)146 return;147 148 cpufreq_thermal_reduction_pctg = cpufreq_pctg;149 150 /*151 * Derive the MAX_STEP from minimum throttle percentage so that the reduction152 * percentage doesn't end up becoming negative. Also, cap the MAX_STEP so that153 * the CPU performance doesn't become 0.154 */155 cpufreq_thermal_max_step = (100 / cpufreq_pctg) - 2;156}157 158void acpi_thermal_cpufreq_init(struct cpufreq_policy *policy)159{160 unsigned int cpu;161 162 acpi_thermal_cpufreq_config();163 164 for_each_cpu(cpu, policy->related_cpus) {165 struct acpi_processor *pr = per_cpu(processors, cpu);166 int ret;167 168 if (!pr)169 continue;170 171 ret = freq_qos_add_request(&policy->constraints,172 &pr->thermal_req,173 FREQ_QOS_MAX, INT_MAX);174 if (ret < 0) {175 pr_err("Failed to add freq constraint for CPU%d (%d)\n",176 cpu, ret);177 continue;178 }179 180 thermal_cooling_device_update(pr->cdev);181 }182}183 184void acpi_thermal_cpufreq_exit(struct cpufreq_policy *policy)185{186 unsigned int cpu;187 188 for_each_cpu(cpu, policy->related_cpus) {189 struct acpi_processor *pr = per_cpu(processors, cpu);190 191 if (!pr)192 continue;193 194 freq_qos_remove_request(&pr->thermal_req);195 196 thermal_cooling_device_update(pr->cdev);197 }198}199#else /* ! CONFIG_CPU_FREQ */200static int cpufreq_get_max_state(unsigned int cpu)201{202 return 0;203}204 205static int cpufreq_get_cur_state(unsigned int cpu)206{207 return 0;208}209 210static int cpufreq_set_cur_state(unsigned int cpu, int state)211{212 return 0;213}214 215#endif216 217/* thermal cooling device callbacks */218static int acpi_processor_max_state(struct acpi_processor *pr)219{220 int max_state = 0;221 222 /*223 * There exists four states according to224 * cpufreq_thermal_reduction_step. 0, 1, 2, 3225 */226 max_state += cpufreq_get_max_state(pr->id);227 if (pr->flags.throttling)228 max_state += (pr->throttling.state_count -1);229 230 return max_state;231}232static int233processor_get_max_state(struct thermal_cooling_device *cdev,234 unsigned long *state)235{236 struct acpi_device *device = cdev->devdata;237 struct acpi_processor *pr;238 239 if (!device)240 return -EINVAL;241 242 pr = acpi_driver_data(device);243 if (!pr)244 return -EINVAL;245 246 *state = acpi_processor_max_state(pr);247 return 0;248}249 250static int251processor_get_cur_state(struct thermal_cooling_device *cdev,252 unsigned long *cur_state)253{254 struct acpi_device *device = cdev->devdata;255 struct acpi_processor *pr;256 257 if (!device)258 return -EINVAL;259 260 pr = acpi_driver_data(device);261 if (!pr)262 return -EINVAL;263 264 *cur_state = cpufreq_get_cur_state(pr->id);265 if (pr->flags.throttling)266 *cur_state += pr->throttling.state;267 return 0;268}269 270static int271processor_set_cur_state(struct thermal_cooling_device *cdev,272 unsigned long state)273{274 struct acpi_device *device = cdev->devdata;275 struct acpi_processor *pr;276 int result = 0;277 int max_pstate;278 279 if (!device)280 return -EINVAL;281 282 pr = acpi_driver_data(device);283 if (!pr)284 return -EINVAL;285 286 max_pstate = cpufreq_get_max_state(pr->id);287 288 if (state > acpi_processor_max_state(pr))289 return -EINVAL;290 291 if (state <= max_pstate) {292 if (pr->flags.throttling && pr->throttling.state)293 result = acpi_processor_set_throttling(pr, 0, false);294 cpufreq_set_cur_state(pr->id, state);295 } else {296 cpufreq_set_cur_state(pr->id, max_pstate);297 result = acpi_processor_set_throttling(pr,298 state - max_pstate, false);299 }300 return result;301}302 303const struct thermal_cooling_device_ops processor_cooling_ops = {304 .get_max_state = processor_get_max_state,305 .get_cur_state = processor_get_cur_state,306 .set_cur_state = processor_set_cur_state,307};308 309int acpi_processor_thermal_init(struct acpi_processor *pr,310 struct acpi_device *device)311{312 int result = 0;313 314 pr->cdev = thermal_cooling_device_register("Processor", device,315 &processor_cooling_ops);316 if (IS_ERR(pr->cdev)) {317 result = PTR_ERR(pr->cdev);318 return result;319 }320 321 dev_dbg(&device->dev, "registered as cooling_device%d\n",322 pr->cdev->id);323 324 result = sysfs_create_link(&device->dev.kobj,325 &pr->cdev->device.kobj,326 "thermal_cooling");327 if (result) {328 dev_err(&device->dev,329 "Failed to create sysfs link 'thermal_cooling'\n");330 goto err_thermal_unregister;331 }332 333 result = sysfs_create_link(&pr->cdev->device.kobj,334 &device->dev.kobj,335 "device");336 if (result) {337 dev_err(&pr->cdev->device,338 "Failed to create sysfs link 'device'\n");339 goto err_remove_sysfs_thermal;340 }341 342 return 0;343 344err_remove_sysfs_thermal:345 sysfs_remove_link(&device->dev.kobj, "thermal_cooling");346err_thermal_unregister:347 thermal_cooling_device_unregister(pr->cdev);348 349 return result;350}351 352void acpi_processor_thermal_exit(struct acpi_processor *pr,353 struct acpi_device *device)354{355 if (pr->cdev) {356 sysfs_remove_link(&device->dev.kobj, "thermal_cooling");357 sysfs_remove_link(&pr->cdev->device.kobj, "device");358 thermal_cooling_device_unregister(pr->cdev);359 pr->cdev = NULL;360 }361}362