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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#define PREFIX "ACPI: "
21
22#define ACPI_PROCESSOR_CLASS "processor"
23#define _COMPONENT ACPI_PROCESSOR_COMPONENT
24ACPI_MODULE_NAME("processor_thermal");
25
26#ifdef CONFIG_CPU_FREQ
27
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.
32 */
33
34#define CPUFREQ_THERMAL_MIN_STEP 0
35#define CPUFREQ_THERMAL_MAX_STEP 3
36
37static DEFINE_PER_CPU(unsigned int, cpufreq_thermal_reduction_pctg);
38
39#define reduction_pctg(cpu) \
40 per_cpu(cpufreq_thermal_reduction_pctg, phys_package_first_cpu(cpu))
41
42/*
43 * Emulate "per package data" using per cpu data (which should really be
44 * provided elsewhere)
45 *
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)
48 */
49static int phys_package_first_cpu(int cpu)
50{
51 int i;
52 int id = topology_physical_package_id(cpu);
53
54 for_each_online_cpu(i)
55 if (topology_physical_package_id(i) == id)
56 return i;
57 return 0;
58}
59
60static int cpu_has_cpufreq(unsigned int cpu)
61{
62 struct cpufreq_policy policy;
63 if (!acpi_processor_cpufreq_init || cpufreq_get_policy(&policy, cpu))
64 return 0;
65 return 1;
66}
67
68static int cpufreq_get_max_state(unsigned int cpu)
69{
70 if (!cpu_has_cpufreq(cpu))
71 return 0;
72
73 return CPUFREQ_THERMAL_MAX_STEP;
74}
75
76static int cpufreq_get_cur_state(unsigned int cpu)
77{
78 if (!cpu_has_cpufreq(cpu))
79 return 0;
80
81 return reduction_pctg(cpu);
82}
83
84static int cpufreq_set_cur_state(unsigned int cpu, int state)
85{
86 struct cpufreq_policy *policy;
87 struct acpi_processor *pr;
88 unsigned long max_freq;
89 int i, ret;
90
91 if (!cpu_has_cpufreq(cpu))
92 return 0;
93
94 reduction_pctg(cpu) = state;
95
96 /*
97 * Update all the CPUs in the same package because they all
98 * contribute to the temperature and often share the same
99 * frequency.
100 */
101 for_each_online_cpu(i) {
102 if (topology_physical_package_id(i) !=
103 topology_physical_package_id(cpu))
104 continue;
105
106 pr = per_cpu(processors, i);
107
108 if (unlikely(!freq_qos_request_active(&pr->thermal_req)))
109 continue;
110
111 policy = cpufreq_cpu_get(i);
112 if (!policy)
113 return -EINVAL;
114
115 max_freq = (policy->cpuinfo.max_freq * (100 - reduction_pctg(i) * 20)) / 100;
116
117 cpufreq_cpu_put(policy);
118
119 ret = freq_qos_update_request(&pr->thermal_req, max_freq);
120 if (ret < 0) {
121 pr_warn("Failed to update thermal freq constraint: CPU%d (%d)\n",
122 pr->id, ret);
123 }
124 }
125 return 0;
126}
127
128void acpi_thermal_cpufreq_init(struct cpufreq_policy *policy)
129{
130 unsigned int cpu;
131
132 for_each_cpu(cpu, policy->related_cpus) {
133 struct acpi_processor *pr = per_cpu(processors, cpu);
134 int ret;
135
136 if (!pr)
137 continue;
138
139 ret = freq_qos_add_request(&policy->constraints,
140 &pr->thermal_req,
141 FREQ_QOS_MAX, INT_MAX);
142 if (ret < 0)
143 pr_err("Failed to add freq constraint for CPU%d (%d)\n",
144 cpu, ret);
145 }
146}
147
148void acpi_thermal_cpufreq_exit(struct cpufreq_policy *policy)
149{
150 unsigned int cpu;
151
152 for_each_cpu(cpu, policy->related_cpus) {
153 struct acpi_processor *pr = per_cpu(processors, policy->cpu);
154
155 if (pr)
156 freq_qos_remove_request(&pr->thermal_req);
157 }
158}
159#else /* ! CONFIG_CPU_FREQ */
160static int cpufreq_get_max_state(unsigned int cpu)
161{
162 return 0;
163}
164
165static int cpufreq_get_cur_state(unsigned int cpu)
166{
167 return 0;
168}
169
170static int cpufreq_set_cur_state(unsigned int cpu, int state)
171{
172 return 0;
173}
174
175#endif
176
177/* thermal cooling device callbacks */
178static int acpi_processor_max_state(struct acpi_processor *pr)
179{
180 int max_state = 0;
181
182 /*
183 * There exists four states according to
184 * cpufreq_thermal_reduction_pctg. 0, 1, 2, 3
185 */
186 max_state += cpufreq_get_max_state(pr->id);
187 if (pr->flags.throttling)
188 max_state += (pr->throttling.state_count -1);
189
190 return max_state;
191}
192static int
193processor_get_max_state(struct thermal_cooling_device *cdev,
194 unsigned long *state)
195{
196 struct acpi_device *device = cdev->devdata;
197 struct acpi_processor *pr;
198
199 if (!device)
200 return -EINVAL;
201
202 pr = acpi_driver_data(device);
203 if (!pr)
204 return -EINVAL;
205
206 *state = acpi_processor_max_state(pr);
207 return 0;
208}
209
210static int
211processor_get_cur_state(struct thermal_cooling_device *cdev,
212 unsigned long *cur_state)
213{
214 struct acpi_device *device = cdev->devdata;
215 struct acpi_processor *pr;
216
217 if (!device)
218 return -EINVAL;
219
220 pr = acpi_driver_data(device);
221 if (!pr)
222 return -EINVAL;
223
224 *cur_state = cpufreq_get_cur_state(pr->id);
225 if (pr->flags.throttling)
226 *cur_state += pr->throttling.state;
227 return 0;
228}
229
230static int
231processor_set_cur_state(struct thermal_cooling_device *cdev,
232 unsigned long state)
233{
234 struct acpi_device *device = cdev->devdata;
235 struct acpi_processor *pr;
236 int result = 0;
237 int max_pstate;
238
239 if (!device)
240 return -EINVAL;
241
242 pr = acpi_driver_data(device);
243 if (!pr)
244 return -EINVAL;
245
246 max_pstate = cpufreq_get_max_state(pr->id);
247
248 if (state > acpi_processor_max_state(pr))
249 return -EINVAL;
250
251 if (state <= max_pstate) {
252 if (pr->flags.throttling && pr->throttling.state)
253 result = acpi_processor_set_throttling(pr, 0, false);
254 cpufreq_set_cur_state(pr->id, state);
255 } else {
256 cpufreq_set_cur_state(pr->id, max_pstate);
257 result = acpi_processor_set_throttling(pr,
258 state - max_pstate, false);
259 }
260 return result;
261}
262
263const struct thermal_cooling_device_ops processor_cooling_ops = {
264 .get_max_state = processor_get_max_state,
265 .get_cur_state = processor_get_cur_state,
266 .set_cur_state = processor_set_cur_state,
267};
1/*
2 * processor_thermal.c - Passive cooling submodule of the ACPI processor driver
3 *
4 * Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
5 * Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
6 * Copyright (C) 2004 Dominik Brodowski <linux@brodo.de>
7 * Copyright (C) 2004 Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
8 * - Added processor hotplug support
9 *
10 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
11 *
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License as published by
14 * the Free Software Foundation; either version 2 of the License, or (at
15 * your option) any later version.
16 *
17 * This program is distributed in the hope that it will be useful, but
18 * WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
20 * General Public License for more details.
21 *
22 * You should have received a copy of the GNU General Public License along
23 * with this program; if not, write to the Free Software Foundation, Inc.,
24 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
25 *
26 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
27 */
28
29#include <linux/kernel.h>
30#include <linux/module.h>
31#include <linux/init.h>
32#include <linux/cpufreq.h>
33#include <linux/acpi.h>
34#include <acpi/processor.h>
35#include <asm/uaccess.h>
36
37#define PREFIX "ACPI: "
38
39#define ACPI_PROCESSOR_CLASS "processor"
40#define _COMPONENT ACPI_PROCESSOR_COMPONENT
41ACPI_MODULE_NAME("processor_thermal");
42
43#ifdef CONFIG_CPU_FREQ
44
45/* If a passive cooling situation is detected, primarily CPUfreq is used, as it
46 * offers (in most cases) voltage scaling in addition to frequency scaling, and
47 * thus a cubic (instead of linear) reduction of energy. Also, we allow for
48 * _any_ cpufreq driver and not only the acpi-cpufreq driver.
49 */
50
51#define CPUFREQ_THERMAL_MIN_STEP 0
52#define CPUFREQ_THERMAL_MAX_STEP 3
53
54static DEFINE_PER_CPU(unsigned int, cpufreq_thermal_reduction_pctg);
55static unsigned int acpi_thermal_cpufreq_is_init = 0;
56
57#define reduction_pctg(cpu) \
58 per_cpu(cpufreq_thermal_reduction_pctg, phys_package_first_cpu(cpu))
59
60/*
61 * Emulate "per package data" using per cpu data (which should really be
62 * provided elsewhere)
63 *
64 * Note we can lose a CPU on cpu hotunplug, in this case we forget the state
65 * temporarily. Fortunately that's not a big issue here (I hope)
66 */
67static int phys_package_first_cpu(int cpu)
68{
69 int i;
70 int id = topology_physical_package_id(cpu);
71
72 for_each_online_cpu(i)
73 if (topology_physical_package_id(i) == id)
74 return i;
75 return 0;
76}
77
78static int cpu_has_cpufreq(unsigned int cpu)
79{
80 struct cpufreq_policy policy;
81 if (!acpi_thermal_cpufreq_is_init || cpufreq_get_policy(&policy, cpu))
82 return 0;
83 return 1;
84}
85
86static int acpi_thermal_cpufreq_notifier(struct notifier_block *nb,
87 unsigned long event, void *data)
88{
89 struct cpufreq_policy *policy = data;
90 unsigned long max_freq = 0;
91
92 if (event != CPUFREQ_ADJUST)
93 goto out;
94
95 max_freq = (
96 policy->cpuinfo.max_freq *
97 (100 - reduction_pctg(policy->cpu) * 20)
98 ) / 100;
99
100 cpufreq_verify_within_limits(policy, 0, max_freq);
101
102 out:
103 return 0;
104}
105
106static struct notifier_block acpi_thermal_cpufreq_notifier_block = {
107 .notifier_call = acpi_thermal_cpufreq_notifier,
108};
109
110static int cpufreq_get_max_state(unsigned int cpu)
111{
112 if (!cpu_has_cpufreq(cpu))
113 return 0;
114
115 return CPUFREQ_THERMAL_MAX_STEP;
116}
117
118static int cpufreq_get_cur_state(unsigned int cpu)
119{
120 if (!cpu_has_cpufreq(cpu))
121 return 0;
122
123 return reduction_pctg(cpu);
124}
125
126static int cpufreq_set_cur_state(unsigned int cpu, int state)
127{
128 int i;
129
130 if (!cpu_has_cpufreq(cpu))
131 return 0;
132
133 reduction_pctg(cpu) = state;
134
135 /*
136 * Update all the CPUs in the same package because they all
137 * contribute to the temperature and often share the same
138 * frequency.
139 */
140 for_each_online_cpu(i) {
141 if (topology_physical_package_id(i) ==
142 topology_physical_package_id(cpu))
143 cpufreq_update_policy(i);
144 }
145 return 0;
146}
147
148void acpi_thermal_cpufreq_init(void)
149{
150 int i;
151
152 i = cpufreq_register_notifier(&acpi_thermal_cpufreq_notifier_block,
153 CPUFREQ_POLICY_NOTIFIER);
154 if (!i)
155 acpi_thermal_cpufreq_is_init = 1;
156}
157
158void acpi_thermal_cpufreq_exit(void)
159{
160 if (acpi_thermal_cpufreq_is_init)
161 cpufreq_unregister_notifier
162 (&acpi_thermal_cpufreq_notifier_block,
163 CPUFREQ_POLICY_NOTIFIER);
164
165 acpi_thermal_cpufreq_is_init = 0;
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(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(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(device);
230 if (!pr)
231 return -EINVAL;
232
233 *cur_state = cpufreq_get_cur_state(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(device);
252 if (!pr)
253 return -EINVAL;
254
255 max_pstate = cpufreq_get_max_state(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, 0, false);
263 cpufreq_set_cur_state(pr->id, state);
264 } else {
265 cpufreq_set_cur_state(pr->id, max_pstate);
266 result = acpi_processor_set_throttling(pr,
267 state - max_pstate, 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};