1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * processor_thermal.c - Passive cooling submodule of the ACPI processor driver
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 support
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>
20 #define PREFIX "ACPI: "
22 #define ACPI_PROCESSOR_CLASS "processor"
23 #define _COMPONENT ACPI_PROCESSOR_COMPONENT
24 ACPI_MODULE_NAME("processor_thermal");
26 #ifdef CONFIG_CPU_FREQ
28 /* If a passive cooling situation is detected, primarily CPUfreq is used, as it
29 * offers (in most cases) voltage scaling in addition to frequency scaling, and
30 * thus a cubic (instead of linear) reduction of energy. Also, we allow for
31 * _any_ cpufreq driver and not only the acpi-cpufreq driver.
34 #define CPUFREQ_THERMAL_MIN_STEP 0
35 #define CPUFREQ_THERMAL_MAX_STEP 3
37 static DEFINE_PER_CPU(unsigned int, cpufreq_thermal_reduction_pctg);
39 #define reduction_pctg(cpu) \
40 per_cpu(cpufreq_thermal_reduction_pctg, phys_package_first_cpu(cpu))
43 * Emulate "per package data" using per cpu data (which should really be
46 * Note we can lose a CPU on cpu hotunplug, in this case we forget the state
47 * temporarily. Fortunately that's not a big issue here (I hope)
49 static int phys_package_first_cpu(int cpu)
52 int id = topology_physical_package_id(cpu);
54 for_each_online_cpu(i)
55 if (topology_physical_package_id(i) == id)
60 static int cpu_has_cpufreq(unsigned int cpu)
62 struct cpufreq_policy policy;
63 if (!acpi_processor_cpufreq_init || cpufreq_get_policy(&policy, cpu))
68 static int cpufreq_get_max_state(unsigned int cpu)
70 if (!cpu_has_cpufreq(cpu))
73 return CPUFREQ_THERMAL_MAX_STEP;
76 static int cpufreq_get_cur_state(unsigned int cpu)
78 if (!cpu_has_cpufreq(cpu))
81 return reduction_pctg(cpu);
84 static int cpufreq_set_cur_state(unsigned int cpu, int state)
86 struct cpufreq_policy *policy;
87 struct acpi_processor *pr;
88 unsigned long max_freq;
91 if (!cpu_has_cpufreq(cpu))
94 reduction_pctg(cpu) = state;
97 * Update all the CPUs in the same package because they all
98 * contribute to the temperature and often share the same
101 for_each_online_cpu(i) {
102 if (topology_physical_package_id(i) !=
103 topology_physical_package_id(cpu))
106 pr = per_cpu(processors, i);
108 if (unlikely(!dev_pm_qos_request_active(&pr->thermal_req)))
111 policy = cpufreq_cpu_get(i);
115 max_freq = (policy->cpuinfo.max_freq * (100 - reduction_pctg(i) * 20)) / 100;
117 cpufreq_cpu_put(policy);
119 ret = dev_pm_qos_update_request(&pr->thermal_req, max_freq);
121 pr_warn("Failed to update thermal freq constraint: CPU%d (%d)\n",
128 void acpi_thermal_cpufreq_init(int cpu)
130 struct acpi_processor *pr = per_cpu(processors, cpu);
133 ret = dev_pm_qos_add_request(get_cpu_device(cpu),
134 &pr->thermal_req, DEV_PM_QOS_MAX_FREQUENCY,
137 pr_err("Failed to add freq constraint for CPU%d (%d)\n", cpu,
143 void acpi_thermal_cpufreq_exit(int cpu)
145 struct acpi_processor *pr = per_cpu(processors, cpu);
147 dev_pm_qos_remove_request(&pr->thermal_req);
149 #else /* ! CONFIG_CPU_FREQ */
150 static int cpufreq_get_max_state(unsigned int cpu)
155 static int cpufreq_get_cur_state(unsigned int cpu)
160 static int cpufreq_set_cur_state(unsigned int cpu, int state)
167 /* thermal cooling device callbacks */
168 static int acpi_processor_max_state(struct acpi_processor *pr)
173 * There exists four states according to
174 * cpufreq_thermal_reduction_pctg. 0, 1, 2, 3
176 max_state += cpufreq_get_max_state(pr->id);
177 if (pr->flags.throttling)
178 max_state += (pr->throttling.state_count -1);
183 processor_get_max_state(struct thermal_cooling_device *cdev,
184 unsigned long *state)
186 struct acpi_device *device = cdev->devdata;
187 struct acpi_processor *pr;
192 pr = acpi_driver_data(device);
196 *state = acpi_processor_max_state(pr);
201 processor_get_cur_state(struct thermal_cooling_device *cdev,
202 unsigned long *cur_state)
204 struct acpi_device *device = cdev->devdata;
205 struct acpi_processor *pr;
210 pr = acpi_driver_data(device);
214 *cur_state = cpufreq_get_cur_state(pr->id);
215 if (pr->flags.throttling)
216 *cur_state += pr->throttling.state;
221 processor_set_cur_state(struct thermal_cooling_device *cdev,
224 struct acpi_device *device = cdev->devdata;
225 struct acpi_processor *pr;
232 pr = acpi_driver_data(device);
236 max_pstate = cpufreq_get_max_state(pr->id);
238 if (state > acpi_processor_max_state(pr))
241 if (state <= max_pstate) {
242 if (pr->flags.throttling && pr->throttling.state)
243 result = acpi_processor_set_throttling(pr, 0, false);
244 cpufreq_set_cur_state(pr->id, state);
246 cpufreq_set_cur_state(pr->id, max_pstate);
247 result = acpi_processor_set_throttling(pr,
248 state - max_pstate, false);
253 const struct thermal_cooling_device_ops processor_cooling_ops = {
254 .get_max_state = processor_get_max_state,
255 .get_cur_state = processor_get_cur_state,
256 .set_cur_state = processor_set_cur_state,