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(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
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(&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
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(&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(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};
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(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
313err_remove_sysfs_thermal:
314	sysfs_remove_link(&device->dev.kobj, "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(&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