1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * processor_thermal.c - Passive cooling submodule of the ACPI processor driver
4 *
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
10 */
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#ifdef CONFIG_CPU_FREQ
21
22/* If a passive cooling situation is detected, primarily CPUfreq is used, as it
23 * offers (in most cases) voltage scaling in addition to frequency scaling, and
24 * thus a cubic (instead of linear) reduction of energy. Also, we allow for
25 * _any_ cpufreq driver and not only the acpi-cpufreq driver.
26 */
27
28#define CPUFREQ_THERMAL_MIN_STEP 0
29#define CPUFREQ_THERMAL_MAX_STEP 3
30
31static DEFINE_PER_CPU(unsigned int, cpufreq_thermal_reduction_pctg);
32
33#define reduction_pctg(cpu) \
34 per_cpu(cpufreq_thermal_reduction_pctg, phys_package_first_cpu(cpu))
35
36/*
37 * Emulate "per package data" using per cpu data (which should really be
38 * provided elsewhere)
39 *
40 * Note we can lose a CPU on cpu hotunplug, in this case we forget the state
41 * temporarily. Fortunately that's not a big issue here (I hope)
42 */
43static int phys_package_first_cpu(int cpu)
44{
45 int i;
46 int id = topology_physical_package_id(cpu);
47
48 for_each_online_cpu(i)
49 if (topology_physical_package_id(i) == id)
50 return i;
51 return 0;
52}
53
54static int cpu_has_cpufreq(unsigned int cpu)
55{
56 struct cpufreq_policy *policy;
57
58 if (!acpi_processor_cpufreq_init)
59 return 0;
60
61 policy = cpufreq_cpu_get(cpu);
62 if (policy) {
63 cpufreq_cpu_put(policy);
64 return 1;
65 }
66 return 0;
67}
68
69static int cpufreq_get_max_state(unsigned int cpu)
70{
71 if (!cpu_has_cpufreq(cpu))
72 return 0;
73
74 return CPUFREQ_THERMAL_MAX_STEP;
75}
76
77static int cpufreq_get_cur_state(unsigned int cpu)
78{
79 if (!cpu_has_cpufreq(cpu))
80 return 0;
81
82 return reduction_pctg(cpu);
83}
84
85static int cpufreq_set_cur_state(unsigned int cpu, int state)
86{
87 struct cpufreq_policy *policy;
88 struct acpi_processor *pr;
89 unsigned long max_freq;
90 int i, ret;
91
92 if (!cpu_has_cpufreq(cpu))
93 return 0;
94
95 reduction_pctg(cpu) = state;
96
97 /*
98 * Update all the CPUs in the same package because they all
99 * contribute to the temperature and often share the same
100 * frequency.
101 */
102 for_each_online_cpu(i) {
103 if (topology_physical_package_id(i) !=
104 topology_physical_package_id(cpu))
105 continue;
106
107 pr = per_cpu(processors, i);
108
109 if (unlikely(!freq_qos_request_active(&pr->thermal_req)))
110 continue;
111
112 policy = cpufreq_cpu_get(cpu: i);
113 if (!policy)
114 return -EINVAL;
115
116 max_freq = (policy->cpuinfo.max_freq * (100 - reduction_pctg(i) * 20)) / 100;
117
118 cpufreq_cpu_put(policy);
119
120 ret = freq_qos_update_request(req: &pr->thermal_req, new_value: max_freq);
121 if (ret < 0) {
122 pr_warn("Failed to update thermal freq constraint: CPU%d (%d)\n",
123 pr->id, ret);
124 }
125 }
126 return 0;
127}
128
129void acpi_thermal_cpufreq_init(struct cpufreq_policy *policy)
130{
131 unsigned int cpu;
132
133 for_each_cpu(cpu, policy->related_cpus) {
134 struct acpi_processor *pr = per_cpu(processors, cpu);
135 int ret;
136
137 if (!pr)
138 continue;
139
140 ret = freq_qos_add_request(qos: &policy->constraints,
141 req: &pr->thermal_req,
142 type: FREQ_QOS_MAX, INT_MAX);
143 if (ret < 0) {
144 pr_err("Failed to add freq constraint for CPU%d (%d)\n",
145 cpu, ret);
146 continue;
147 }
148
149 thermal_cooling_device_update(pr->cdev);
150 }
151}
152
153void acpi_thermal_cpufreq_exit(struct cpufreq_policy *policy)
154{
155 unsigned int cpu;
156
157 for_each_cpu(cpu, policy->related_cpus) {
158 struct acpi_processor *pr = per_cpu(processors, cpu);
159
160 if (!pr)
161 continue;
162
163 freq_qos_remove_request(req: &pr->thermal_req);
164
165 thermal_cooling_device_update(pr->cdev);
166 }
167}
168#else /* ! CONFIG_CPU_FREQ */
169static int cpufreq_get_max_state(unsigned int cpu)
170{
171 return 0;
172}
173
174static int cpufreq_get_cur_state(unsigned int cpu)
175{
176 return 0;
177}
178
179static int cpufreq_set_cur_state(unsigned int cpu, int state)
180{
181 return 0;
182}
183
184#endif
185
186/* thermal cooling device callbacks */
187static int acpi_processor_max_state(struct acpi_processor *pr)
188{
189 int max_state = 0;
190
191 /*
192 * There exists four states according to
193 * cpufreq_thermal_reduction_pctg. 0, 1, 2, 3
194 */
195 max_state += cpufreq_get_max_state(cpu: pr->id);
196 if (pr->flags.throttling)
197 max_state += (pr->throttling.state_count -1);
198
199 return max_state;
200}
201static int
202processor_get_max_state(struct thermal_cooling_device *cdev,
203 unsigned long *state)
204{
205 struct acpi_device *device = cdev->devdata;
206 struct acpi_processor *pr;
207
208 if (!device)
209 return -EINVAL;
210
211 pr = acpi_driver_data(d: device);
212 if (!pr)
213 return -EINVAL;
214
215 *state = acpi_processor_max_state(pr);
216 return 0;
217}
218
219static int
220processor_get_cur_state(struct thermal_cooling_device *cdev,
221 unsigned long *cur_state)
222{
223 struct acpi_device *device = cdev->devdata;
224 struct acpi_processor *pr;
225
226 if (!device)
227 return -EINVAL;
228
229 pr = acpi_driver_data(d: device);
230 if (!pr)
231 return -EINVAL;
232
233 *cur_state = cpufreq_get_cur_state(cpu: pr->id);
234 if (pr->flags.throttling)
235 *cur_state += pr->throttling.state;
236 return 0;
237}
238
239static int
240processor_set_cur_state(struct thermal_cooling_device *cdev,
241 unsigned long state)
242{
243 struct acpi_device *device = cdev->devdata;
244 struct acpi_processor *pr;
245 int result = 0;
246 int max_pstate;
247
248 if (!device)
249 return -EINVAL;
250
251 pr = acpi_driver_data(d: device);
252 if (!pr)
253 return -EINVAL;
254
255 max_pstate = cpufreq_get_max_state(cpu: pr->id);
256
257 if (state > acpi_processor_max_state(pr))
258 return -EINVAL;
259
260 if (state <= max_pstate) {
261 if (pr->flags.throttling && pr->throttling.state)
262 result = acpi_processor_set_throttling(pr, state: 0, force: false);
263 cpufreq_set_cur_state(cpu: pr->id, state);
264 } else {
265 cpufreq_set_cur_state(cpu: pr->id, state: max_pstate);
266 result = acpi_processor_set_throttling(pr,
267 state: state - max_pstate, force: false);
268 }
269 return result;
270}
271
272const struct thermal_cooling_device_ops processor_cooling_ops = {
273 .get_max_state = processor_get_max_state,
274 .get_cur_state = processor_get_cur_state,
275 .set_cur_state = processor_set_cur_state,
276};
277
278int acpi_processor_thermal_init(struct acpi_processor *pr,
279 struct acpi_device *device)
280{
281 int result = 0;
282
283 pr->cdev = thermal_cooling_device_register("Processor", device,
284 &processor_cooling_ops);
285 if (IS_ERR(ptr: pr->cdev)) {
286 result = PTR_ERR(ptr: pr->cdev);
287 return result;
288 }
289
290 dev_dbg(&device->dev, "registered as cooling_device%d\n",
291 pr->cdev->id);
292
293 result = sysfs_create_link(kobj: &device->dev.kobj,
294 target: &pr->cdev->device.kobj,
295 name: "thermal_cooling");
296 if (result) {
297 dev_err(&device->dev,
298 "Failed to create sysfs link 'thermal_cooling'\n");
299 goto err_thermal_unregister;
300 }
301
302 result = sysfs_create_link(kobj: &pr->cdev->device.kobj,
303 target: &device->dev.kobj,
304 name: "device");
305 if (result) {
306 dev_err(&pr->cdev->device,
307 "Failed to create sysfs link 'device'\n");
308 goto err_remove_sysfs_thermal;
309 }
310
311 return 0;
312
313err_remove_sysfs_thermal:
314 sysfs_remove_link(kobj: &device->dev.kobj, name: "thermal_cooling");
315err_thermal_unregister:
316 thermal_cooling_device_unregister(pr->cdev);
317
318 return result;
319}
320
321void acpi_processor_thermal_exit(struct acpi_processor *pr,
322 struct acpi_device *device)
323{
324 if (pr->cdev) {
325 sysfs_remove_link(kobj: &device->dev.kobj, name: "thermal_cooling");
326 sysfs_remove_link(kobj: &pr->cdev->device.kobj, name: "device");
327 thermal_cooling_device_unregister(pr->cdev);
328 pr->cdev = NULL;
329 }
330}
331

source code of linux/drivers/acpi/processor_thermal.c