summaryrefslogtreecommitdiffstats
path: root/drivers/acpi/processor_thermal.c
blob: 419f651b63f3826097325d02840f7f2e56bce43a (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
/*
 * 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
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or (at
 *  your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful, but
 *  WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/cpufreq.h>
#include <linux/sysdev.h>

#include <asm/uaccess.h>

#include <acpi/acpi_bus.h>
#include <acpi/processor.h>
#include <acpi/acpi_drivers.h>

#define PREFIX "ACPI: "

#define ACPI_PROCESSOR_CLASS            "processor"
#define _COMPONENT              ACPI_PROCESSOR_COMPONENT
ACPI_MODULE_NAME("processor_thermal");

/* --------------------------------------------------------------------------
                                 Limit Interface
   -------------------------------------------------------------------------- */
static int acpi_processor_apply_limit(struct acpi_processor *pr)
{
	int result = 0;
	u16 px = 0;
	u16 tx = 0;


	if (!pr)
		return -EINVAL;

	if (!pr->flags.limit)
		return -ENODEV;

	if (pr->flags.throttling) {
		if (pr->limit.user.tx > tx)
			tx = pr->limit.user.tx;
		if (pr->limit.thermal.tx > tx)
			tx = pr->limit.thermal.tx;

		result = acpi_processor_set_throttling(pr, tx, false);
		if (result)
			goto end;
	}

	pr->limit.state.px = px;
	pr->limit.state.tx = tx;

	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
			  "Processor [%d] limit set to (P%d:T%d)\n", pr->id,
			  pr->limit.state.px, pr->limit.state.tx));

      end:
	if (result)
		printk(KERN_ERR PREFIX "Unable to set limit\n");

	return result;
}

#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
#define CPUFREQ_THERMAL_MAX_STEP 3

static DEFINE_PER_CPU(unsigned int, cpufreq_thermal_reduction_pctg);
static unsigned int acpi_thermal_cpufreq_is_init = 0;

static int cpu_has_cpufreq(unsigned int cpu)
{
	struct cpufreq_policy policy;
	if (!acpi_thermal_cpufreq_is_init || cpufreq_get_policy(&policy, cpu))
		return 0;
	return 1;
}

static int acpi_thermal_cpufreq_increase(unsigned int cpu)
{
	if (!cpu_has_cpufreq(cpu))
		return -ENODEV;

	if (per_cpu(cpufreq_thermal_reduction_pctg, cpu) <
		CPUFREQ_THERMAL_MAX_STEP) {
		per_cpu(cpufreq_thermal_reduction_pctg, cpu)++;
		cpufreq_update_policy(cpu);
		return 0;
	}

	return -ERANGE;
}

static int acpi_thermal_cpufreq_decrease(unsigned int cpu)
{
	if (!cpu_has_cpufreq(cpu))
		return -ENODEV;

	if (per_cpu(cpufreq_thermal_reduction_pctg, cpu) >
		(CPUFREQ_THERMAL_MIN_STEP + 1))
		per_cpu(cpufreq_thermal_reduction_pctg, cpu)--;
	else
		per_cpu(cpufreq_thermal_reduction_pctg, cpu) = 0;
	cpufreq_update_policy(cpu);
	/* We reached max freq again and can leave passive mode */
	return !per_cpu(cpufreq_thermal_reduction_pctg, cpu);
}

static int acpi_thermal_cpufreq_notifier(struct notifier_block *nb,
					 unsigned long event, void *data)
{
	struct cpufreq_policy *policy = data;
	unsigned long max_freq = 0;

	if (event != CPUFREQ_ADJUST)
		goto out;

	max_freq = (
	    policy->cpuinfo.max_freq *
	    (100 - per_cpu(cpufreq_thermal_reduction_pctg, policy->cpu) * 20)
	) / 100;

	cpufreq_verify_within_limits(policy, 0, max_freq);

      out:
	return 0;
}

static struct notifier_block acpi_thermal_cpufreq_notifier_block = {
	.notifier_call = acpi_thermal_cpufreq_notifier,
};

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 per_cpu(cpufreq_thermal_reduction_pctg, cpu);
}

static int cpufreq_set_cur_state(unsigned int cpu, int state)
{
	if (!cpu_has_cpufreq(cpu))
		return 0;

	per_cpu(cpufreq_thermal_reduction_pctg, cpu) = state;
	cpufreq_update_policy(cpu);
	return 0;
}

void acpi_thermal_cpufreq_init(void)
{
	int i;

	for (i = 0; i < nr_cpu_ids; i++)
		if (cpu_present(i))
			per_cpu(cpufreq_thermal_reduction_pctg, i) = 0;

	i = cpufreq_register_notifier(&acpi_thermal_cpufreq_notifier_block,
				      CPUFREQ_POLICY_NOTIFIER);
	if (!i)
		acpi_thermal_cpufreq_is_init = 1;
}

void acpi_thermal_cpufreq_exit(void)
{
	if (acpi_thermal_cpufreq_is_init)
		cpufreq_unregister_notifier
		    (&acpi_thermal_cpufreq_notifier_block,
		     CPUFREQ_POLICY_NOTIFIER);

	acpi_thermal_cpufreq_is_init = 0;
}

#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;
}

static int acpi_thermal_cpufreq_increase(unsigned int cpu)
{
	return -ENODEV;
}
static int acpi_thermal_cpufreq_decrease(unsigned int cpu)
{
	return -ENODEV;
}

#endif

int acpi_processor_get_limit_info(struct acpi_processor *pr)
{

	if (!pr)
		return -EINVAL;

	if (pr->flags.throttling)
		pr->flags.limit = 1;

	return 0;
}

/* thermal coolign 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_ptg. 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 = acpi_driver_data(device);

	if (!device || !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 = acpi_driver_data(device);

	if (!device || !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 = acpi_driver_data(device);
	int result = 0;
	int max_pstate;

	if (!device || !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;
}

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,
};