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 | */ |
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 | |
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 | |
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 | |
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 | |
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(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 | |
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(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 | |
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(req: &pr->thermal_req); |
164 | |
165 | thermal_cooling_device_update(pr->cdev); |
166 | } |
167 | } |
168 | #else /* ! CONFIG_CPU_FREQ */ |
169 | static int cpufreq_get_max_state(unsigned int cpu) |
170 | { |
171 | return 0; |
172 | } |
173 | |
174 | static int cpufreq_get_cur_state(unsigned int cpu) |
175 | { |
176 | return 0; |
177 | } |
178 | |
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 */ |
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(cpu: pr->id); |
196 | if (pr->flags.throttling) |
197 | max_state += (pr->throttling.state_count -1); |
198 | |
199 | return max_state; |
200 | } |
201 | static int |
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(d: device); |
212 | if (!pr) |
213 | return -EINVAL; |
214 | |
215 | *state = acpi_processor_max_state(pr); |
216 | return 0; |
217 | } |
218 | |
219 | static int |
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(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 | |
239 | static int |
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(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 | |
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 | |
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(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 | |
313 | err_remove_sysfs_thermal: |
314 | sysfs_remove_link(kobj: &device->dev.kobj, name: "thermal_cooling" ); |
315 | err_thermal_unregister: |
316 | thermal_cooling_device_unregister(pr->cdev); |
317 | |
318 | return result; |
319 | } |
320 | |
321 | void 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 | |