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
31 static 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 */
phys_package_first_cpu(int cpu)43 static 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
cpu_has_cpufreq(unsigned int cpu)54 static 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
cpufreq_get_max_state(unsigned int cpu)69 static 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
cpufreq_get_cur_state(unsigned int cpu)77 static 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
cpufreq_set_cur_state(unsigned int cpu,int state)85 static 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(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(&pr->thermal_req, 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
acpi_thermal_cpufreq_init(struct cpufreq_policy * policy)129 void 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(&policy->constraints,
141 &pr->thermal_req,
142 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
acpi_thermal_cpufreq_exit(struct cpufreq_policy * policy)153 void 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(&pr->thermal_req);
164
165 thermal_cooling_device_update(pr->cdev);
166 }
167 }
168 #else /* ! CONFIG_CPU_FREQ */
cpufreq_get_max_state(unsigned int cpu)169 static int cpufreq_get_max_state(unsigned int cpu)
170 {
171 return 0;
172 }
173
cpufreq_get_cur_state(unsigned int cpu)174 static int cpufreq_get_cur_state(unsigned int cpu)
175 {
176 return 0;
177 }
178
cpufreq_set_cur_state(unsigned int cpu,int state)179 static int cpufreq_set_cur_state(unsigned int cpu, int state)
180 {
181 return 0;
182 }
183
184 #endif
185
186 /* thermal cooling device callbacks */
acpi_processor_max_state(struct acpi_processor * pr)187 static 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 }
201 static int
processor_get_max_state(struct thermal_cooling_device * cdev,unsigned long * state)202 processor_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
219 static int
processor_get_cur_state(struct thermal_cooling_device * cdev,unsigned long * cur_state)220 processor_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
239 static int
processor_set_cur_state(struct thermal_cooling_device * cdev,unsigned long state)240 processor_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
272 const 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
acpi_processor_thermal_init(struct acpi_processor * pr,struct acpi_device * device)278 int 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(pr->cdev)) {
286 result = PTR_ERR(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(&device->dev.kobj,
294 &pr->cdev->device.kobj,
295 "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(&pr->cdev->device.kobj,
303 &device->dev.kobj,
304 "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
313 err_remove_sysfs_thermal:
314 sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
315 err_thermal_unregister:
316 thermal_cooling_device_unregister(pr->cdev);
317
318 return result;
319 }
320
acpi_processor_thermal_exit(struct acpi_processor * pr,struct acpi_device * device)321 void acpi_processor_thermal_exit(struct acpi_processor *pr,
322 struct acpi_device *device)
323 {
324 if (pr->cdev) {
325 sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
326 sysfs_remove_link(&pr->cdev->device.kobj, "device");
327 thermal_cooling_device_unregister(pr->cdev);
328 pr->cdev = NULL;
329 }
330 }
331