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1/*
2 * devfreq_cooling: Thermal cooling device implementation for devices using
3 * devfreq
4 *
5 * Copyright (C) 2014-2015 ARM Limited
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 *
11 * This program is distributed "as is" WITHOUT ANY WARRANTY of any
12 * kind, whether express or implied; without even the implied warranty
13 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * TODO:
17 * - If OPPs are added or removed after devfreq cooling has
18 * registered, the devfreq cooling won't react to it.
19 */
20
21#include <linux/devfreq.h>
22#include <linux/devfreq_cooling.h>
23#include <linux/export.h>
24#include <linux/idr.h>
25#include <linux/slab.h>
26#include <linux/pm_opp.h>
27#include <linux/thermal.h>
28
29#include <trace/events/thermal.h>
30
31#define SCALE_ERROR_MITIGATION 100
32
33static DEFINE_IDA(devfreq_ida);
34
35/**
36 * struct devfreq_cooling_device - Devfreq cooling device
37 * @id: unique integer value corresponding to each
38 * devfreq_cooling_device registered.
39 * @cdev: Pointer to associated thermal cooling device.
40 * @devfreq: Pointer to associated devfreq device.
41 * @cooling_state: Current cooling state.
42 * @power_table: Pointer to table with maximum power draw for each
43 * cooling state. State is the index into the table, and
44 * the power is in mW.
45 * @freq_table: Pointer to a table with the frequencies sorted in descending
46 * order. You can index the table by cooling device state
47 * @freq_table_size: Size of the @freq_table and @power_table
48 * @power_ops: Pointer to devfreq_cooling_power, used to generate the
49 * @power_table.
50 * @res_util: Resource utilization scaling factor for the power.
51 * It is multiplied by 100 to minimize the error. It is used
52 * for estimation of the power budget instead of using
53 * 'utilization' (which is 'busy_time / 'total_time').
54 * The 'res_util' range is from 100 to (power_table[state] * 100)
55 * for the corresponding 'state'.
56 */
57struct devfreq_cooling_device {
58 int id;
59 struct thermal_cooling_device *cdev;
60 struct devfreq *devfreq;
61 unsigned long cooling_state;
62 u32 *power_table;
63 u32 *freq_table;
64 size_t freq_table_size;
65 struct devfreq_cooling_power *power_ops;
66 u32 res_util;
67 int capped_state;
68};
69
70/**
71 * partition_enable_opps() - disable all opps above a given state
72 * @dfc: Pointer to devfreq we are operating on
73 * @cdev_state: cooling device state we're setting
74 *
75 * Go through the OPPs of the device, enabling all OPPs until
76 * @cdev_state and disabling those frequencies above it.
77 */
78static int partition_enable_opps(struct devfreq_cooling_device *dfc,
79 unsigned long cdev_state)
80{
81 int i;
82 struct device *dev = dfc->devfreq->dev.parent;
83
84 for (i = 0; i < dfc->freq_table_size; i++) {
85 struct dev_pm_opp *opp;
86 int ret = 0;
87 unsigned int freq = dfc->freq_table[i];
88 bool want_enable = i >= cdev_state ? true : false;
89
90 opp = dev_pm_opp_find_freq_exact(dev, freq, !want_enable);
91
92 if (PTR_ERR(opp) == -ERANGE)
93 continue;
94 else if (IS_ERR(opp))
95 return PTR_ERR(opp);
96
97 dev_pm_opp_put(opp);
98
99 if (want_enable)
100 ret = dev_pm_opp_enable(dev, freq);
101 else
102 ret = dev_pm_opp_disable(dev, freq);
103
104 if (ret)
105 return ret;
106 }
107
108 return 0;
109}
110
111static int devfreq_cooling_get_max_state(struct thermal_cooling_device *cdev,
112 unsigned long *state)
113{
114 struct devfreq_cooling_device *dfc = cdev->devdata;
115
116 *state = dfc->freq_table_size - 1;
117
118 return 0;
119}
120
121static int devfreq_cooling_get_cur_state(struct thermal_cooling_device *cdev,
122 unsigned long *state)
123{
124 struct devfreq_cooling_device *dfc = cdev->devdata;
125
126 *state = dfc->cooling_state;
127
128 return 0;
129}
130
131static int devfreq_cooling_set_cur_state(struct thermal_cooling_device *cdev,
132 unsigned long state)
133{
134 struct devfreq_cooling_device *dfc = cdev->devdata;
135 struct devfreq *df = dfc->devfreq;
136 struct device *dev = df->dev.parent;
137 int ret;
138
139 if (state == dfc->cooling_state)
140 return 0;
141
142 dev_dbg(dev, "Setting cooling state %lu\n", state);
143
144 if (state >= dfc->freq_table_size)
145 return -EINVAL;
146
147 ret = partition_enable_opps(dfc, state);
148 if (ret)
149 return ret;
150
151 dfc->cooling_state = state;
152
153 return 0;
154}
155
156/**
157 * freq_get_state() - get the cooling state corresponding to a frequency
158 * @dfc: Pointer to devfreq cooling device
159 * @freq: frequency in Hz
160 *
161 * Return: the cooling state associated with the @freq, or
162 * THERMAL_CSTATE_INVALID if it wasn't found.
163 */
164static unsigned long
165freq_get_state(struct devfreq_cooling_device *dfc, unsigned long freq)
166{
167 int i;
168
169 for (i = 0; i < dfc->freq_table_size; i++) {
170 if (dfc->freq_table[i] == freq)
171 return i;
172 }
173
174 return THERMAL_CSTATE_INVALID;
175}
176
177static unsigned long get_voltage(struct devfreq *df, unsigned long freq)
178{
179 struct device *dev = df->dev.parent;
180 unsigned long voltage;
181 struct dev_pm_opp *opp;
182
183 opp = dev_pm_opp_find_freq_exact(dev, freq, true);
184 if (PTR_ERR(opp) == -ERANGE)
185 opp = dev_pm_opp_find_freq_exact(dev, freq, false);
186
187 if (IS_ERR(opp)) {
188 dev_err_ratelimited(dev, "Failed to find OPP for frequency %lu: %ld\n",
189 freq, PTR_ERR(opp));
190 return 0;
191 }
192
193 voltage = dev_pm_opp_get_voltage(opp) / 1000; /* mV */
194 dev_pm_opp_put(opp);
195
196 if (voltage == 0) {
197 dev_err_ratelimited(dev,
198 "Failed to get voltage for frequency %lu\n",
199 freq);
200 }
201
202 return voltage;
203}
204
205/**
206 * get_static_power() - calculate the static power
207 * @dfc: Pointer to devfreq cooling device
208 * @freq: Frequency in Hz
209 *
210 * Calculate the static power in milliwatts using the supplied
211 * get_static_power(). The current voltage is calculated using the
212 * OPP library. If no get_static_power() was supplied, assume the
213 * static power is negligible.
214 */
215static unsigned long
216get_static_power(struct devfreq_cooling_device *dfc, unsigned long freq)
217{
218 struct devfreq *df = dfc->devfreq;
219 unsigned long voltage;
220
221 if (!dfc->power_ops->get_static_power)
222 return 0;
223
224 voltage = get_voltage(df, freq);
225
226 if (voltage == 0)
227 return 0;
228
229 return dfc->power_ops->get_static_power(df, voltage);
230}
231
232/**
233 * get_dynamic_power - calculate the dynamic power
234 * @dfc: Pointer to devfreq cooling device
235 * @freq: Frequency in Hz
236 * @voltage: Voltage in millivolts
237 *
238 * Calculate the dynamic power in milliwatts consumed by the device at
239 * frequency @freq and voltage @voltage. If the get_dynamic_power()
240 * was supplied as part of the devfreq_cooling_power struct, then that
241 * function is used. Otherwise, a simple power model (Pdyn = Coeff *
242 * Voltage^2 * Frequency) is used.
243 */
244static unsigned long
245get_dynamic_power(struct devfreq_cooling_device *dfc, unsigned long freq,
246 unsigned long voltage)
247{
248 u64 power;
249 u32 freq_mhz;
250 struct devfreq_cooling_power *dfc_power = dfc->power_ops;
251
252 if (dfc_power->get_dynamic_power)
253 return dfc_power->get_dynamic_power(dfc->devfreq, freq,
254 voltage);
255
256 freq_mhz = freq / 1000000;
257 power = (u64)dfc_power->dyn_power_coeff * freq_mhz * voltage * voltage;
258 do_div(power, 1000000000);
259
260 return power;
261}
262
263
264static inline unsigned long get_total_power(struct devfreq_cooling_device *dfc,
265 unsigned long freq,
266 unsigned long voltage)
267{
268 return get_static_power(dfc, freq) + get_dynamic_power(dfc, freq,
269 voltage);
270}
271
272
273static int devfreq_cooling_get_requested_power(struct thermal_cooling_device *cdev,
274 struct thermal_zone_device *tz,
275 u32 *power)
276{
277 struct devfreq_cooling_device *dfc = cdev->devdata;
278 struct devfreq *df = dfc->devfreq;
279 struct devfreq_dev_status *status = &df->last_status;
280 unsigned long state;
281 unsigned long freq = status->current_frequency;
282 unsigned long voltage;
283 u32 dyn_power = 0;
284 u32 static_power = 0;
285 int res;
286
287 state = freq_get_state(dfc, freq);
288 if (state == THERMAL_CSTATE_INVALID) {
289 res = -EAGAIN;
290 goto fail;
291 }
292
293 if (dfc->power_ops->get_real_power) {
294 voltage = get_voltage(df, freq);
295 if (voltage == 0) {
296 res = -EINVAL;
297 goto fail;
298 }
299
300 res = dfc->power_ops->get_real_power(df, power, freq, voltage);
301 if (!res) {
302 state = dfc->capped_state;
303 dfc->res_util = dfc->power_table[state];
304 dfc->res_util *= SCALE_ERROR_MITIGATION;
305
306 if (*power > 1)
307 dfc->res_util /= *power;
308 } else {
309 goto fail;
310 }
311 } else {
312 dyn_power = dfc->power_table[state];
313
314 /* Scale dynamic power for utilization */
315 dyn_power *= status->busy_time;
316 dyn_power /= status->total_time;
317 /* Get static power */
318 static_power = get_static_power(dfc, freq);
319
320 *power = dyn_power + static_power;
321 }
322
323 trace_thermal_power_devfreq_get_power(cdev, status, freq, dyn_power,
324 static_power, *power);
325
326 return 0;
327fail:
328 /* It is safe to set max in this case */
329 dfc->res_util = SCALE_ERROR_MITIGATION;
330 return res;
331}
332
333static int devfreq_cooling_state2power(struct thermal_cooling_device *cdev,
334 struct thermal_zone_device *tz,
335 unsigned long state,
336 u32 *power)
337{
338 struct devfreq_cooling_device *dfc = cdev->devdata;
339 unsigned long freq;
340 u32 static_power;
341
342 if (state >= dfc->freq_table_size)
343 return -EINVAL;
344
345 freq = dfc->freq_table[state];
346 static_power = get_static_power(dfc, freq);
347
348 *power = dfc->power_table[state] + static_power;
349 return 0;
350}
351
352static int devfreq_cooling_power2state(struct thermal_cooling_device *cdev,
353 struct thermal_zone_device *tz,
354 u32 power, unsigned long *state)
355{
356 struct devfreq_cooling_device *dfc = cdev->devdata;
357 struct devfreq *df = dfc->devfreq;
358 struct devfreq_dev_status *status = &df->last_status;
359 unsigned long freq = status->current_frequency;
360 unsigned long busy_time;
361 s32 dyn_power;
362 u32 static_power;
363 s32 est_power;
364 int i;
365
366 if (dfc->power_ops->get_real_power) {
367 /* Scale for resource utilization */
368 est_power = power * dfc->res_util;
369 est_power /= SCALE_ERROR_MITIGATION;
370 } else {
371 static_power = get_static_power(dfc, freq);
372
373 dyn_power = power - static_power;
374 dyn_power = dyn_power > 0 ? dyn_power : 0;
375
376 /* Scale dynamic power for utilization */
377 busy_time = status->busy_time ?: 1;
378 est_power = (dyn_power * status->total_time) / busy_time;
379 }
380
381 /*
382 * Find the first cooling state that is within the power
383 * budget for dynamic power.
384 */
385 for (i = 0; i < dfc->freq_table_size - 1; i++)
386 if (est_power >= dfc->power_table[i])
387 break;
388
389 *state = i;
390 dfc->capped_state = i;
391 trace_thermal_power_devfreq_limit(cdev, freq, *state, power);
392 return 0;
393}
394
395static struct thermal_cooling_device_ops devfreq_cooling_ops = {
396 .get_max_state = devfreq_cooling_get_max_state,
397 .get_cur_state = devfreq_cooling_get_cur_state,
398 .set_cur_state = devfreq_cooling_set_cur_state,
399};
400
401/**
402 * devfreq_cooling_gen_tables() - Generate power and freq tables.
403 * @dfc: Pointer to devfreq cooling device.
404 *
405 * Generate power and frequency tables: the power table hold the
406 * device's maximum power usage at each cooling state (OPP). The
407 * static and dynamic power using the appropriate voltage and
408 * frequency for the state, is acquired from the struct
409 * devfreq_cooling_power, and summed to make the maximum power draw.
410 *
411 * The frequency table holds the frequencies in descending order.
412 * That way its indexed by cooling device state.
413 *
414 * The tables are malloced, and pointers put in dfc. They must be
415 * freed when unregistering the devfreq cooling device.
416 *
417 * Return: 0 on success, negative error code on failure.
418 */
419static int devfreq_cooling_gen_tables(struct devfreq_cooling_device *dfc)
420{
421 struct devfreq *df = dfc->devfreq;
422 struct device *dev = df->dev.parent;
423 int ret, num_opps;
424 unsigned long freq;
425 u32 *power_table = NULL;
426 u32 *freq_table;
427 int i;
428
429 num_opps = dev_pm_opp_get_opp_count(dev);
430
431 if (dfc->power_ops) {
432 power_table = kcalloc(num_opps, sizeof(*power_table),
433 GFP_KERNEL);
434 if (!power_table)
435 return -ENOMEM;
436 }
437
438 freq_table = kcalloc(num_opps, sizeof(*freq_table),
439 GFP_KERNEL);
440 if (!freq_table) {
441 ret = -ENOMEM;
442 goto free_power_table;
443 }
444
445 for (i = 0, freq = ULONG_MAX; i < num_opps; i++, freq--) {
446 unsigned long power, voltage;
447 struct dev_pm_opp *opp;
448
449 opp = dev_pm_opp_find_freq_floor(dev, &freq);
450 if (IS_ERR(opp)) {
451 ret = PTR_ERR(opp);
452 goto free_tables;
453 }
454
455 voltage = dev_pm_opp_get_voltage(opp) / 1000; /* mV */
456 dev_pm_opp_put(opp);
457
458 if (dfc->power_ops) {
459 if (dfc->power_ops->get_real_power)
460 power = get_total_power(dfc, freq, voltage);
461 else
462 power = get_dynamic_power(dfc, freq, voltage);
463
464 dev_dbg(dev, "Power table: %lu MHz @ %lu mV: %lu = %lu mW\n",
465 freq / 1000000, voltage, power, power);
466
467 power_table[i] = power;
468 }
469
470 freq_table[i] = freq;
471 }
472
473 if (dfc->power_ops)
474 dfc->power_table = power_table;
475
476 dfc->freq_table = freq_table;
477 dfc->freq_table_size = num_opps;
478
479 return 0;
480
481free_tables:
482 kfree(freq_table);
483free_power_table:
484 kfree(power_table);
485
486 return ret;
487}
488
489/**
490 * of_devfreq_cooling_register_power() - Register devfreq cooling device,
491 * with OF and power information.
492 * @np: Pointer to OF device_node.
493 * @df: Pointer to devfreq device.
494 * @dfc_power: Pointer to devfreq_cooling_power.
495 *
496 * Register a devfreq cooling device. The available OPPs must be
497 * registered on the device.
498 *
499 * If @dfc_power is provided, the cooling device is registered with the
500 * power extensions. For the power extensions to work correctly,
501 * devfreq should use the simple_ondemand governor, other governors
502 * are not currently supported.
503 */
504struct thermal_cooling_device *
505of_devfreq_cooling_register_power(struct device_node *np, struct devfreq *df,
506 struct devfreq_cooling_power *dfc_power)
507{
508 struct thermal_cooling_device *cdev;
509 struct devfreq_cooling_device *dfc;
510 char dev_name[THERMAL_NAME_LENGTH];
511 int err;
512
513 dfc = kzalloc(sizeof(*dfc), GFP_KERNEL);
514 if (!dfc)
515 return ERR_PTR(-ENOMEM);
516
517 dfc->devfreq = df;
518
519 if (dfc_power) {
520 dfc->power_ops = dfc_power;
521
522 devfreq_cooling_ops.get_requested_power =
523 devfreq_cooling_get_requested_power;
524 devfreq_cooling_ops.state2power = devfreq_cooling_state2power;
525 devfreq_cooling_ops.power2state = devfreq_cooling_power2state;
526 }
527
528 err = devfreq_cooling_gen_tables(dfc);
529 if (err)
530 goto free_dfc;
531
532 err = ida_simple_get(&devfreq_ida, 0, 0, GFP_KERNEL);
533 if (err < 0)
534 goto free_tables;
535 dfc->id = err;
536
537 snprintf(dev_name, sizeof(dev_name), "thermal-devfreq-%d", dfc->id);
538
539 cdev = thermal_of_cooling_device_register(np, dev_name, dfc,
540 &devfreq_cooling_ops);
541 if (IS_ERR(cdev)) {
542 err = PTR_ERR(cdev);
543 dev_err(df->dev.parent,
544 "Failed to register devfreq cooling device (%d)\n",
545 err);
546 goto release_ida;
547 }
548
549 dfc->cdev = cdev;
550
551 return cdev;
552
553release_ida:
554 ida_simple_remove(&devfreq_ida, dfc->id);
555free_tables:
556 kfree(dfc->power_table);
557 kfree(dfc->freq_table);
558free_dfc:
559 kfree(dfc);
560
561 return ERR_PTR(err);
562}
563EXPORT_SYMBOL_GPL(of_devfreq_cooling_register_power);
564
565/**
566 * of_devfreq_cooling_register() - Register devfreq cooling device,
567 * with OF information.
568 * @np: Pointer to OF device_node.
569 * @df: Pointer to devfreq device.
570 */
571struct thermal_cooling_device *
572of_devfreq_cooling_register(struct device_node *np, struct devfreq *df)
573{
574 return of_devfreq_cooling_register_power(np, df, NULL);
575}
576EXPORT_SYMBOL_GPL(of_devfreq_cooling_register);
577
578/**
579 * devfreq_cooling_register() - Register devfreq cooling device.
580 * @df: Pointer to devfreq device.
581 */
582struct thermal_cooling_device *devfreq_cooling_register(struct devfreq *df)
583{
584 return of_devfreq_cooling_register(NULL, df);
585}
586EXPORT_SYMBOL_GPL(devfreq_cooling_register);
587
588/**
589 * devfreq_cooling_unregister() - Unregister devfreq cooling device.
590 * @dfc: Pointer to devfreq cooling device to unregister.
591 */
592void devfreq_cooling_unregister(struct thermal_cooling_device *cdev)
593{
594 struct devfreq_cooling_device *dfc;
595
596 if (!cdev)
597 return;
598
599 dfc = cdev->devdata;
600
601 thermal_cooling_device_unregister(dfc->cdev);
602 ida_simple_remove(&devfreq_ida, dfc->id);
603 kfree(dfc->power_table);
604 kfree(dfc->freq_table);
605
606 kfree(dfc);
607}
608EXPORT_SYMBOL_GPL(devfreq_cooling_unregister);