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 }
147 }
148
acpi_thermal_cpufreq_exit(struct cpufreq_policy * policy)149 void acpi_thermal_cpufreq_exit(struct cpufreq_policy *policy)
150 {
151 unsigned int cpu;
152
153 for_each_cpu(cpu, policy->related_cpus) {
154 struct acpi_processor *pr = per_cpu(processors, cpu);
155
156 if (pr)
157 freq_qos_remove_request(&pr->thermal_req);
158 }
159 }
160 #else /* ! CONFIG_CPU_FREQ */
cpufreq_get_max_state(unsigned int cpu)161 static int cpufreq_get_max_state(unsigned int cpu)
162 {
163 return 0;
164 }
165
cpufreq_get_cur_state(unsigned int cpu)166 static int cpufreq_get_cur_state(unsigned int cpu)
167 {
168 return 0;
169 }
170
cpufreq_set_cur_state(unsigned int cpu,int state)171 static int cpufreq_set_cur_state(unsigned int cpu, int state)
172 {
173 return 0;
174 }
175
176 #endif
177
178 /* thermal cooling device callbacks */
acpi_processor_max_state(struct acpi_processor * pr)179 static int acpi_processor_max_state(struct acpi_processor *pr)
180 {
181 int max_state = 0;
182
183 /*
184 * There exists four states according to
185 * cpufreq_thermal_reduction_pctg. 0, 1, 2, 3
186 */
187 max_state += cpufreq_get_max_state(pr->id);
188 if (pr->flags.throttling)
189 max_state += (pr->throttling.state_count -1);
190
191 return max_state;
192 }
193 static int
processor_get_max_state(struct thermal_cooling_device * cdev,unsigned long * state)194 processor_get_max_state(struct thermal_cooling_device *cdev,
195 unsigned long *state)
196 {
197 struct acpi_device *device = cdev->devdata;
198 struct acpi_processor *pr;
199
200 if (!device)
201 return -EINVAL;
202
203 pr = acpi_driver_data(device);
204 if (!pr)
205 return -EINVAL;
206
207 *state = acpi_processor_max_state(pr);
208 return 0;
209 }
210
211 static int
processor_get_cur_state(struct thermal_cooling_device * cdev,unsigned long * cur_state)212 processor_get_cur_state(struct thermal_cooling_device *cdev,
213 unsigned long *cur_state)
214 {
215 struct acpi_device *device = cdev->devdata;
216 struct acpi_processor *pr;
217
218 if (!device)
219 return -EINVAL;
220
221 pr = acpi_driver_data(device);
222 if (!pr)
223 return -EINVAL;
224
225 *cur_state = cpufreq_get_cur_state(pr->id);
226 if (pr->flags.throttling)
227 *cur_state += pr->throttling.state;
228 return 0;
229 }
230
231 static int
processor_set_cur_state(struct thermal_cooling_device * cdev,unsigned long state)232 processor_set_cur_state(struct thermal_cooling_device *cdev,
233 unsigned long state)
234 {
235 struct acpi_device *device = cdev->devdata;
236 struct acpi_processor *pr;
237 int result = 0;
238 int max_pstate;
239
240 if (!device)
241 return -EINVAL;
242
243 pr = acpi_driver_data(device);
244 if (!pr)
245 return -EINVAL;
246
247 max_pstate = cpufreq_get_max_state(pr->id);
248
249 if (state > acpi_processor_max_state(pr))
250 return -EINVAL;
251
252 if (state <= max_pstate) {
253 if (pr->flags.throttling && pr->throttling.state)
254 result = acpi_processor_set_throttling(pr, 0, false);
255 cpufreq_set_cur_state(pr->id, state);
256 } else {
257 cpufreq_set_cur_state(pr->id, max_pstate);
258 result = acpi_processor_set_throttling(pr,
259 state - max_pstate, false);
260 }
261 return result;
262 }
263
264 const struct thermal_cooling_device_ops processor_cooling_ops = {
265 .get_max_state = processor_get_max_state,
266 .get_cur_state = processor_get_cur_state,
267 .set_cur_state = processor_set_cur_state,
268 };
269
acpi_processor_thermal_init(struct acpi_processor * pr,struct acpi_device * device)270 int acpi_processor_thermal_init(struct acpi_processor *pr,
271 struct acpi_device *device)
272 {
273 int result = 0;
274
275 pr->cdev = thermal_cooling_device_register("Processor", device,
276 &processor_cooling_ops);
277 if (IS_ERR(pr->cdev)) {
278 result = PTR_ERR(pr->cdev);
279 return result;
280 }
281
282 dev_dbg(&device->dev, "registered as cooling_device%d\n",
283 pr->cdev->id);
284
285 result = sysfs_create_link(&device->dev.kobj,
286 &pr->cdev->device.kobj,
287 "thermal_cooling");
288 if (result) {
289 dev_err(&device->dev,
290 "Failed to create sysfs link 'thermal_cooling'\n");
291 goto err_thermal_unregister;
292 }
293
294 result = sysfs_create_link(&pr->cdev->device.kobj,
295 &device->dev.kobj,
296 "device");
297 if (result) {
298 dev_err(&pr->cdev->device,
299 "Failed to create sysfs link 'device'\n");
300 goto err_remove_sysfs_thermal;
301 }
302
303 return 0;
304
305 err_remove_sysfs_thermal:
306 sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
307 err_thermal_unregister:
308 thermal_cooling_device_unregister(pr->cdev);
309
310 return result;
311 }
312
acpi_processor_thermal_exit(struct acpi_processor * pr,struct acpi_device * device)313 void acpi_processor_thermal_exit(struct acpi_processor *pr,
314 struct acpi_device *device)
315 {
316 if (pr->cdev) {
317 sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
318 sysfs_remove_link(&pr->cdev->device.kobj, "device");
319 thermal_cooling_device_unregister(pr->cdev);
320 pr->cdev = NULL;
321 }
322 }
323