summaryrefslogtreecommitdiffstats
path: root/drivers/acpi/processor_thermal.c
blob: 1219adb11ab927cae52b8d106a09c2cb0f17f390 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * processor_thermal.c - Passive cooling submodule of the ACPI processor driver
 *
 *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
 *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
 *  Copyright (C) 2004       Dominik Brodowski <linux@brodo.de>
 *  Copyright (C) 2004  Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
 *  			- Added processor hotplug support
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/cpufreq.h>
#include <linux/acpi.h>
#include <acpi/processor.h>
#include <linux/uaccess.h>

#include "internal.h"

#ifdef CONFIG_CPU_FREQ

/* If a passive cooling situation is detected, primarily CPUfreq is used, as it
 * offers (in most cases) voltage scaling in addition to frequency scaling, and
 * thus a cubic (instead of linear) reduction of energy. Also, we allow for
 * _any_ cpufreq driver and not only the acpi-cpufreq driver.
 */

#define CPUFREQ_THERMAL_MIN_STEP 0

static int cpufreq_thermal_max_step __read_mostly = 3;

/*
 * Minimum throttle percentage for processor_thermal cooling device.
 * The processor_thermal driver uses it to calculate the percentage amount by
 * which cpu frequency must be reduced for each cooling state. This is also used
 * to calculate the maximum number of throttling steps or cooling states.
 */
static int cpufreq_thermal_reduction_pctg __read_mostly = 20;

static DEFINE_PER_CPU(unsigned int, cpufreq_thermal_reduction_step);

#define reduction_step(cpu) \
	per_cpu(cpufreq_thermal_reduction_step, phys_package_first_cpu(cpu))

/*
 * Emulate "per package data" using per cpu data (which should really be
 * provided elsewhere)
 *
 * Note we can lose a CPU on cpu hotunplug, in this case we forget the state
 * temporarily. Fortunately that's not a big issue here (I hope)
 */
static int phys_package_first_cpu(int cpu)
{
	int i;
	int id = topology_physical_package_id(cpu);

	for_each_online_cpu(i)
		if (topology_physical_package_id(i) == id)
			return i;
	return 0;
}

static int cpu_has_cpufreq(unsigned int cpu)
{
	struct cpufreq_policy *policy;

	if (!acpi_processor_cpufreq_init)
		return 0;

	policy = cpufreq_cpu_get(cpu);
	if (policy) {
		cpufreq_cpu_put(policy);
		return 1;
	}
	return 0;
}

static int cpufreq_get_max_state(unsigned int cpu)
{
	if (!cpu_has_cpufreq(cpu))
		return 0;

	return cpufreq_thermal_max_step;
}

static int cpufreq_get_cur_state(unsigned int cpu)
{
	if (!cpu_has_cpufreq(cpu))
		return 0;

	return reduction_step(cpu);
}

static int cpufreq_set_cur_state(unsigned int cpu, int state)
{
	struct cpufreq_policy *policy;
	struct acpi_processor *pr;
	unsigned long max_freq;
	int i, ret;

	if (!cpu_has_cpufreq(cpu))
		return 0;

	reduction_step(cpu) = state;

	/*
	 * Update all the CPUs in the same package because they all
	 * contribute to the temperature and often share the same
	 * frequency.
	 */
	for_each_online_cpu(i) {
		if (topology_physical_package_id(i) !=
		    topology_physical_package_id(cpu))
			continue;

		pr = per_cpu(processors, i);

		if (unlikely(!freq_qos_request_active(&pr->thermal_req)))
			continue;

		policy = cpufreq_cpu_get(i);
		if (!policy)
			return -EINVAL;

		max_freq = (policy->cpuinfo.max_freq *
			    (100 - reduction_step(i) * cpufreq_thermal_reduction_pctg)) / 100;

		cpufreq_cpu_put(policy);

		ret = freq_qos_update_request(&pr->thermal_req, max_freq);
		if (ret < 0) {
			pr_warn("Failed to update thermal freq constraint: CPU%d (%d)\n",
				pr->id, ret);
		}
	}
	return 0;
}

static void acpi_thermal_cpufreq_config(void)
{
	int cpufreq_pctg = acpi_arch_thermal_cpufreq_pctg();

	if (!cpufreq_pctg)
		return;

	cpufreq_thermal_reduction_pctg = cpufreq_pctg;

	/*
	 * Derive the MAX_STEP from minimum throttle percentage so that the reduction
	 * percentage doesn't end up becoming negative. Also, cap the MAX_STEP so that
	 * the CPU performance doesn't become 0.
	 */
	cpufreq_thermal_max_step = (100 / cpufreq_pctg) - 2;
}

void acpi_thermal_cpufreq_init(struct cpufreq_policy *policy)
{
	unsigned int cpu;

	acpi_thermal_cpufreq_config();

	for_each_cpu(cpu, policy->related_cpus) {
		struct acpi_processor *pr = per_cpu(processors, cpu);
		int ret;

		if (!pr)
			continue;

		ret = freq_qos_add_request(&policy->constraints,
					   &pr->thermal_req,
					   FREQ_QOS_MAX, INT_MAX);
		if (ret < 0) {
			pr_err("Failed to add freq constraint for CPU%d (%d)\n",
			       cpu, ret);
			continue;
		}

		thermal_cooling_device_update(pr->cdev);
	}
}

void acpi_thermal_cpufreq_exit(struct cpufreq_policy *policy)
{
	unsigned int cpu;

	for_each_cpu(cpu, policy->related_cpus) {
		struct acpi_processor *pr = per_cpu(processors, cpu);

		if (!pr)
			continue;

		freq_qos_remove_request(&pr->thermal_req);

		thermal_cooling_device_update(pr->cdev);
	}
}
#else				/* ! CONFIG_CPU_FREQ */
static int cpufreq_get_max_state(unsigned int cpu)
{
	return 0;
}

static int cpufreq_get_cur_state(unsigned int cpu)
{
	return 0;
}

static int cpufreq_set_cur_state(unsigned int cpu, int state)
{
	return 0;
}

#endif

/* thermal cooling device callbacks */
static int acpi_processor_max_state(struct acpi_processor *pr)
{
	int max_state = 0;

	/*
	 * There exists four states according to
	 * cpufreq_thermal_reduction_step. 0, 1, 2, 3
	 */
	max_state += cpufreq_get_max_state(pr->id);
	if (pr->flags.throttling)
		max_state += (pr->throttling.state_count -1);

	return max_state;
}
static int
processor_get_max_state(struct thermal_cooling_device *cdev,
			unsigned long *state)
{
	struct acpi_device *device = cdev->devdata;
	struct acpi_processor *pr;

	if (!device)
		return -EINVAL;

	pr = acpi_driver_data(device);
	if (!pr)
		return -EINVAL;

	*state = acpi_processor_max_state(pr);
	return 0;
}

static int
processor_get_cur_state(struct thermal_cooling_device *cdev,
			unsigned long *cur_state)
{
	struct acpi_device *device = cdev->devdata;
	struct acpi_processor *pr;

	if (!device)
		return -EINVAL;

	pr = acpi_driver_data(device);
	if (!pr)
		return -EINVAL;

	*cur_state = cpufreq_get_cur_state(pr->id);
	if (pr->flags.throttling)
		*cur_state += pr->throttling.state;
	return 0;
}

static int
processor_set_cur_state(struct thermal_cooling_device *cdev,
			unsigned long state)
{
	struct acpi_device *device = cdev->devdata;
	struct acpi_processor *pr;
	int result = 0;
	int max_pstate;

	if (!device)
		return -EINVAL;

	pr = acpi_driver_data(device);
	if (!pr)
		return -EINVAL;

	max_pstate = cpufreq_get_max_state(pr->id);

	if (state > acpi_processor_max_state(pr))
		return -EINVAL;

	if (state <= max_pstate) {
		if (pr->flags.throttling && pr->throttling.state)
			result = acpi_processor_set_throttling(pr, 0, false);
		cpufreq_set_cur_state(pr->id, state);
	} else {
		cpufreq_set_cur_state(pr->id, max_pstate);
		result = acpi_processor_set_throttling(pr,
				state - max_pstate, false);
	}
	return result;
}

const struct thermal_cooling_device_ops processor_cooling_ops = {
	.get_max_state = processor_get_max_state,
	.get_cur_state = processor_get_cur_state,
	.set_cur_state = processor_set_cur_state,
};

int acpi_processor_thermal_init(struct acpi_processor *pr,
				struct acpi_device *device)
{
	int result = 0;

	pr->cdev = thermal_cooling_device_register("Processor", device,
						   &processor_cooling_ops);
	if (IS_ERR(pr->cdev)) {
		result = PTR_ERR(pr->cdev);
		return result;
	}

	dev_dbg(&device->dev, "registered as cooling_device%d\n",
		pr->cdev->id);

	result = sysfs_create_link(&device->dev.kobj,
				   &pr->cdev->device.kobj,
				   "thermal_cooling");
	if (result) {
		dev_err(&device->dev,
			"Failed to create sysfs link 'thermal_cooling'\n");
		goto err_thermal_unregister;
	}

	result = sysfs_create_link(&pr->cdev->device.kobj,
				   &device->dev.kobj,
				   "device");
	if (result) {
		dev_err(&pr->cdev->device,
			"Failed to create sysfs link 'device'\n");
		goto err_remove_sysfs_thermal;
	}

	return 0;

err_remove_sysfs_thermal:
	sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
err_thermal_unregister:
	thermal_cooling_device_unregister(pr->cdev);

	return result;
}

void acpi_processor_thermal_exit(struct acpi_processor *pr,
				 struct acpi_device *device)
{
	if (pr->cdev) {
		sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
		sysfs_remove_link(&pr->cdev->device.kobj, "device");
		thermal_cooling_device_unregister(pr->cdev);
		pr->cdev = NULL;
	}
}