summaryrefslogtreecommitdiff
path: root/drivers/thermal/devfreq_cooling.c
blob: 7743a78d472397bbf9a10c0b1ac2d7e4b163a6a6 (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
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
/*
 * devfreq_cooling: Thermal cooling device implementation for devices using
 *                  devfreq
 *
 * Copyright (C) 2014-2015 ARM Limited
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed "as is" WITHOUT ANY WARRANTY of any
 * kind, whether express or implied; without even the implied warranty
 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * TODO:
 *    - If OPPs are added or removed after devfreq cooling has
 *      registered, the devfreq cooling won't react to it.
 */

#include <linux/devfreq.h>
#include <linux/devfreq_cooling.h>
#include <linux/export.h>
#include <linux/idr.h>
#include <linux/slab.h>
#include <linux/pm_opp.h>
#include <linux/thermal.h>

#include <trace/events/thermal.h>

static DEFINE_IDA(devfreq_ida);

/**
 * struct devfreq_cooling_device - Devfreq cooling device
 * @id:		unique integer value corresponding to each
 *		devfreq_cooling_device registered.
 * @cdev:	Pointer to associated thermal cooling device.
 * @devfreq:	Pointer to associated devfreq device.
 * @cooling_state:	Current cooling state.
 * @power_table:	Pointer to table with maximum power draw for each
 *			cooling state. State is the index into the table, and
 *			the power is in mW.
 * @freq_table:	Pointer to a table with the frequencies sorted in descending
 *		order.  You can index the table by cooling device state
 * @freq_table_size:	Size of the @freq_table and @power_table
 * @power_ops:	Pointer to devfreq_cooling_power, used to generate the
 *		@power_table.
 */
struct devfreq_cooling_device {
	int id;
	struct thermal_cooling_device *cdev;
	struct devfreq *devfreq;
	unsigned long cooling_state;
	u32 *power_table;
	u32 *freq_table;
	size_t freq_table_size;
	struct devfreq_cooling_power *power_ops;
};

/**
 * partition_enable_opps() - disable all opps above a given state
 * @dfc:	Pointer to devfreq we are operating on
 * @cdev_state:	cooling device state we're setting
 *
 * Go through the OPPs of the device, enabling all OPPs until
 * @cdev_state and disabling those frequencies above it.
 */
static int partition_enable_opps(struct devfreq_cooling_device *dfc,
				 unsigned long cdev_state)
{
	int i;
	struct device *dev = dfc->devfreq->dev.parent;

	for (i = 0; i < dfc->freq_table_size; i++) {
		struct dev_pm_opp *opp;
		int ret = 0;
		unsigned int freq = dfc->freq_table[i];
		bool want_enable = i >= cdev_state ? true : false;

		opp = dev_pm_opp_find_freq_exact(dev, freq, !want_enable);

		if (PTR_ERR(opp) == -ERANGE)
			continue;
		else if (IS_ERR(opp))
			return PTR_ERR(opp);

		dev_pm_opp_put(opp);

		if (want_enable)
			ret = dev_pm_opp_enable(dev, freq);
		else
			ret = dev_pm_opp_disable(dev, freq);

		if (ret)
			return ret;
	}

	return 0;
}

static int devfreq_cooling_get_max_state(struct thermal_cooling_device *cdev,
					 unsigned long *state)
{
	struct devfreq_cooling_device *dfc = cdev->devdata;

	*state = dfc->freq_table_size - 1;

	return 0;
}

static int devfreq_cooling_get_cur_state(struct thermal_cooling_device *cdev,
					 unsigned long *state)
{
	struct devfreq_cooling_device *dfc = cdev->devdata;

	*state = dfc->cooling_state;

	return 0;
}

static int devfreq_cooling_set_cur_state(struct thermal_cooling_device *cdev,
					 unsigned long state)
{
	struct devfreq_cooling_device *dfc = cdev->devdata;
	struct devfreq *df = dfc->devfreq;
	struct device *dev = df->dev.parent;
	int ret;

	if (state == dfc->cooling_state)
		return 0;

	dev_dbg(dev, "Setting cooling state %lu\n", state);

	if (state >= dfc->freq_table_size)
		return -EINVAL;

	ret = partition_enable_opps(dfc, state);
	if (ret)
		return ret;

	dfc->cooling_state = state;

	return 0;
}

/**
 * freq_get_state() - get the cooling state corresponding to a frequency
 * @dfc:	Pointer to devfreq cooling device
 * @freq:	frequency in Hz
 *
 * Return: the cooling state associated with the @freq, or
 * THERMAL_CSTATE_INVALID if it wasn't found.
 */
static unsigned long
freq_get_state(struct devfreq_cooling_device *dfc, unsigned long freq)
{
	int i;

	for (i = 0; i < dfc->freq_table_size; i++) {
		if (dfc->freq_table[i] == freq)
			return i;
	}

	return THERMAL_CSTATE_INVALID;
}

/**
 * get_static_power() - calculate the static power
 * @dfc:	Pointer to devfreq cooling device
 * @freq:	Frequency in Hz
 *
 * Calculate the static power in milliwatts using the supplied
 * get_static_power().  The current voltage is calculated using the
 * OPP library.  If no get_static_power() was supplied, assume the
 * static power is negligible.
 */
static unsigned long
get_static_power(struct devfreq_cooling_device *dfc, unsigned long freq)
{
	struct devfreq *df = dfc->devfreq;
	struct device *dev = df->dev.parent;
	unsigned long voltage;
	struct dev_pm_opp *opp;

	if (!dfc->power_ops->get_static_power)
		return 0;

	opp = dev_pm_opp_find_freq_exact(dev, freq, true);
	if (IS_ERR(opp) && (PTR_ERR(opp) == -ERANGE))
		opp = dev_pm_opp_find_freq_exact(dev, freq, false);

	voltage = dev_pm_opp_get_voltage(opp) / 1000; /* mV */
	dev_pm_opp_put(opp);

	if (voltage == 0) {
		dev_warn_ratelimited(dev,
				     "Failed to get voltage for frequency %lu: %ld\n",
				     freq, IS_ERR(opp) ? PTR_ERR(opp) : 0);
		return 0;
	}

	return dfc->power_ops->get_static_power(df, voltage);
}

/**
 * get_dynamic_power - calculate the dynamic power
 * @dfc:	Pointer to devfreq cooling device
 * @freq:	Frequency in Hz
 * @voltage:	Voltage in millivolts
 *
 * Calculate the dynamic power in milliwatts consumed by the device at
 * frequency @freq and voltage @voltage.  If the get_dynamic_power()
 * was supplied as part of the devfreq_cooling_power struct, then that
 * function is used.  Otherwise, a simple power model (Pdyn = Coeff *
 * Voltage^2 * Frequency) is used.
 */
static unsigned long
get_dynamic_power(struct devfreq_cooling_device *dfc, unsigned long freq,
		  unsigned long voltage)
{
	u64 power;
	u32 freq_mhz;
	struct devfreq_cooling_power *dfc_power = dfc->power_ops;

	if (dfc_power->get_dynamic_power)
		return dfc_power->get_dynamic_power(dfc->devfreq, freq,
						    voltage);

	freq_mhz = freq / 1000000;
	power = (u64)dfc_power->dyn_power_coeff * freq_mhz * voltage * voltage;
	do_div(power, 1000000000);

	return power;
}

static int devfreq_cooling_get_requested_power(struct thermal_cooling_device *cdev,
					       struct thermal_zone_device *tz,
					       u32 *power)
{
	struct devfreq_cooling_device *dfc = cdev->devdata;
	struct devfreq *df = dfc->devfreq;
	struct devfreq_dev_status *status = &df->last_status;
	unsigned long state;
	unsigned long freq = status->current_frequency;
	u32 dyn_power, static_power;

	/* Get dynamic power for state */
	state = freq_get_state(dfc, freq);
	if (state == THERMAL_CSTATE_INVALID)
		return -EAGAIN;

	dyn_power = dfc->power_table[state];

	/* Scale dynamic power for utilization */
	dyn_power = (dyn_power * status->busy_time) / status->total_time;

	/* Get static power */
	static_power = get_static_power(dfc, freq);

	trace_thermal_power_devfreq_get_power(cdev, status, freq, dyn_power,
					      static_power);

	*power = dyn_power + static_power;

	return 0;
}

static int devfreq_cooling_state2power(struct thermal_cooling_device *cdev,
				       struct thermal_zone_device *tz,
				       unsigned long state,
				       u32 *power)
{
	struct devfreq_cooling_device *dfc = cdev->devdata;
	unsigned long freq;
	u32 static_power;

	if (state >= dfc->freq_table_size)
		return -EINVAL;

	freq = dfc->freq_table[state];
	static_power = get_static_power(dfc, freq);

	*power = dfc->power_table[state] + static_power;
	return 0;
}

static int devfreq_cooling_power2state(struct thermal_cooling_device *cdev,
				       struct thermal_zone_device *tz,
				       u32 power, unsigned long *state)
{
	struct devfreq_cooling_device *dfc = cdev->devdata;
	struct devfreq *df = dfc->devfreq;
	struct devfreq_dev_status *status = &df->last_status;
	unsigned long freq = status->current_frequency;
	unsigned long busy_time;
	s32 dyn_power;
	u32 static_power;
	int i;

	static_power = get_static_power(dfc, freq);

	dyn_power = power - static_power;
	dyn_power = dyn_power > 0 ? dyn_power : 0;

	/* Scale dynamic power for utilization */
	busy_time = status->busy_time ?: 1;
	dyn_power = (dyn_power * status->total_time) / busy_time;

	/*
	 * Find the first cooling state that is within the power
	 * budget for dynamic power.
	 */
	for (i = 0; i < dfc->freq_table_size - 1; i++)
		if (dyn_power >= dfc->power_table[i])
			break;

	*state = i;
	trace_thermal_power_devfreq_limit(cdev, freq, *state, power);
	return 0;
}

static struct thermal_cooling_device_ops devfreq_cooling_ops = {
	.get_max_state = devfreq_cooling_get_max_state,
	.get_cur_state = devfreq_cooling_get_cur_state,
	.set_cur_state = devfreq_cooling_set_cur_state,
};

/**
 * devfreq_cooling_gen_tables() - Generate power and freq tables.
 * @dfc: Pointer to devfreq cooling device.
 *
 * Generate power and frequency tables: the power table hold the
 * device's maximum power usage at each cooling state (OPP).  The
 * static and dynamic power using the appropriate voltage and
 * frequency for the state, is acquired from the struct
 * devfreq_cooling_power, and summed to make the maximum power draw.
 *
 * The frequency table holds the frequencies in descending order.
 * That way its indexed by cooling device state.
 *
 * The tables are malloced, and pointers put in dfc.  They must be
 * freed when unregistering the devfreq cooling device.
 *
 * Return: 0 on success, negative error code on failure.
 */
static int devfreq_cooling_gen_tables(struct devfreq_cooling_device *dfc)
{
	struct devfreq *df = dfc->devfreq;
	struct device *dev = df->dev.parent;
	int ret, num_opps;
	unsigned long freq;
	u32 *power_table = NULL;
	u32 *freq_table;
	int i;

	num_opps = dev_pm_opp_get_opp_count(dev);

	if (dfc->power_ops) {
		power_table = kcalloc(num_opps, sizeof(*power_table),
				      GFP_KERNEL);
		if (!power_table)
			return -ENOMEM;
	}

	freq_table = kcalloc(num_opps, sizeof(*freq_table),
			     GFP_KERNEL);
	if (!freq_table) {
		ret = -ENOMEM;
		goto free_power_table;
	}

	for (i = 0, freq = ULONG_MAX; i < num_opps; i++, freq--) {
		unsigned long power_dyn, voltage;
		struct dev_pm_opp *opp;

		opp = dev_pm_opp_find_freq_floor(dev, &freq);
		if (IS_ERR(opp)) {
			ret = PTR_ERR(opp);
			goto free_tables;
		}

		voltage = dev_pm_opp_get_voltage(opp) / 1000; /* mV */
		dev_pm_opp_put(opp);

		if (dfc->power_ops) {
			power_dyn = get_dynamic_power(dfc, freq, voltage);

			dev_dbg(dev, "Dynamic power table: %lu MHz @ %lu mV: %lu = %lu mW\n",
				freq / 1000000, voltage, power_dyn, power_dyn);

			power_table[i] = power_dyn;
		}

		freq_table[i] = freq;
	}

	if (dfc->power_ops)
		dfc->power_table = power_table;

	dfc->freq_table = freq_table;
	dfc->freq_table_size = num_opps;

	return 0;

free_tables:
	kfree(freq_table);
free_power_table:
	kfree(power_table);

	return ret;
}

/**
 * of_devfreq_cooling_register_power() - Register devfreq cooling device,
 *                                      with OF and power information.
 * @np:	Pointer to OF device_node.
 * @df:	Pointer to devfreq device.
 * @dfc_power:	Pointer to devfreq_cooling_power.
 *
 * Register a devfreq cooling device.  The available OPPs must be
 * registered on the device.
 *
 * If @dfc_power is provided, the cooling device is registered with the
 * power extensions.  For the power extensions to work correctly,
 * devfreq should use the simple_ondemand governor, other governors
 * are not currently supported.
 */
struct thermal_cooling_device *
of_devfreq_cooling_register_power(struct device_node *np, struct devfreq *df,
				  struct devfreq_cooling_power *dfc_power)
{
	struct thermal_cooling_device *cdev;
	struct devfreq_cooling_device *dfc;
	char dev_name[THERMAL_NAME_LENGTH];
	int err;

	dfc = kzalloc(sizeof(*dfc), GFP_KERNEL);
	if (!dfc)
		return ERR_PTR(-ENOMEM);

	dfc->devfreq = df;

	if (dfc_power) {
		dfc->power_ops = dfc_power;

		devfreq_cooling_ops.get_requested_power =
			devfreq_cooling_get_requested_power;
		devfreq_cooling_ops.state2power = devfreq_cooling_state2power;
		devfreq_cooling_ops.power2state = devfreq_cooling_power2state;
	}

	err = devfreq_cooling_gen_tables(dfc);
	if (err)
		goto free_dfc;

	err = ida_simple_get(&devfreq_ida, 0, 0, GFP_KERNEL);
	if (err < 0)
		goto free_tables;
	dfc->id = err;

	snprintf(dev_name, sizeof(dev_name), "thermal-devfreq-%d", dfc->id);

	cdev = thermal_of_cooling_device_register(np, dev_name, dfc,
						  &devfreq_cooling_ops);
	if (IS_ERR(cdev)) {
		err = PTR_ERR(cdev);
		dev_err(df->dev.parent,
			"Failed to register devfreq cooling device (%d)\n",
			err);
		goto release_ida;
	}

	dfc->cdev = cdev;

	return cdev;

release_ida:
	ida_simple_remove(&devfreq_ida, dfc->id);
free_tables:
	kfree(dfc->power_table);
	kfree(dfc->freq_table);
free_dfc:
	kfree(dfc);

	return ERR_PTR(err);
}
EXPORT_SYMBOL_GPL(of_devfreq_cooling_register_power);

/**
 * of_devfreq_cooling_register() - Register devfreq cooling device,
 *                                with OF information.
 * @np: Pointer to OF device_node.
 * @df: Pointer to devfreq device.
 */
struct thermal_cooling_device *
of_devfreq_cooling_register(struct device_node *np, struct devfreq *df)
{
	return of_devfreq_cooling_register_power(np, df, NULL);
}
EXPORT_SYMBOL_GPL(of_devfreq_cooling_register);

/**
 * devfreq_cooling_register() - Register devfreq cooling device.
 * @df: Pointer to devfreq device.
 */
struct thermal_cooling_device *devfreq_cooling_register(struct devfreq *df)
{
	return of_devfreq_cooling_register(NULL, df);
}
EXPORT_SYMBOL_GPL(devfreq_cooling_register);

/**
 * devfreq_cooling_unregister() - Unregister devfreq cooling device.
 * @dfc: Pointer to devfreq cooling device to unregister.
 */
void devfreq_cooling_unregister(struct thermal_cooling_device *cdev)
{
	struct devfreq_cooling_device *dfc;

	if (!cdev)
		return;

	dfc = cdev->devdata;

	thermal_cooling_device_unregister(dfc->cdev);
	ida_simple_remove(&devfreq_ida, dfc->id);
	kfree(dfc->power_table);
	kfree(dfc->freq_table);

	kfree(dfc);
}
EXPORT_SYMBOL_GPL(devfreq_cooling_unregister);