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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * devfreq_cooling: Thermal cooling device implementation for devices using
4 * devfreq
5 *
6 * Copyright (C) 2014-2015 ARM Limited
7 *
8 * TODO:
9 * - If OPPs are added or removed after devfreq cooling has
10 * registered, the devfreq cooling won't react to it.
11 */
12
13#include <linux/devfreq.h>
14#include <linux/devfreq_cooling.h>
15#include <linux/energy_model.h>
16#include <linux/export.h>
17#include <linux/slab.h>
18#include <linux/pm_opp.h>
19#include <linux/pm_qos.h>
20#include <linux/thermal.h>
21#include <linux/units.h>
22
23#include "thermal_trace.h"
24
25#define SCALE_ERROR_MITIGATION 100
26
27/**
28 * struct devfreq_cooling_device - Devfreq cooling device
29 * devfreq_cooling_device registered.
30 * @cdev: Pointer to associated thermal cooling device.
31 * @cooling_ops: devfreq callbacks to thermal cooling device ops
32 * @devfreq: Pointer to associated devfreq device.
33 * @cooling_state: Current cooling state.
34 * @freq_table: Pointer to a table with the frequencies sorted in descending
35 * order. You can index the table by cooling device state
36 * @max_state: It is the last index, that is, one less than the number of the
37 * OPPs
38 * @power_ops: Pointer to devfreq_cooling_power, a more precised model.
39 * @res_util: Resource utilization scaling factor for the power.
40 * It is multiplied by 100 to minimize the error. It is used
41 * for estimation of the power budget instead of using
42 * 'utilization' (which is 'busy_time' / 'total_time').
43 * The 'res_util' range is from 100 to power * 100 for the
44 * corresponding 'state'.
45 * @capped_state: index to cooling state with in dynamic power budget
46 * @req_max_freq: PM QoS request for limiting the maximum frequency
47 * of the devfreq device.
48 * @em_pd: Energy Model for the associated Devfreq device
49 */
50struct devfreq_cooling_device {
51 struct thermal_cooling_device *cdev;
52 struct thermal_cooling_device_ops cooling_ops;
53 struct devfreq *devfreq;
54 unsigned long cooling_state;
55 u32 *freq_table;
56 size_t max_state;
57 struct devfreq_cooling_power *power_ops;
58 u32 res_util;
59 int capped_state;
60 struct dev_pm_qos_request req_max_freq;
61 struct em_perf_domain *em_pd;
62};
63
64static int devfreq_cooling_get_max_state(struct thermal_cooling_device *cdev,
65 unsigned long *state)
66{
67 struct devfreq_cooling_device *dfc = cdev->devdata;
68
69 *state = dfc->max_state;
70
71 return 0;
72}
73
74static int devfreq_cooling_get_cur_state(struct thermal_cooling_device *cdev,
75 unsigned long *state)
76{
77 struct devfreq_cooling_device *dfc = cdev->devdata;
78
79 *state = dfc->cooling_state;
80
81 return 0;
82}
83
84static int devfreq_cooling_set_cur_state(struct thermal_cooling_device *cdev,
85 unsigned long state)
86{
87 struct devfreq_cooling_device *dfc = cdev->devdata;
88 struct devfreq *df = dfc->devfreq;
89 struct device *dev = df->dev.parent;
90 struct em_perf_state *table;
91 unsigned long freq;
92 int perf_idx;
93
94 if (state == dfc->cooling_state)
95 return 0;
96
97 dev_dbg(dev, "Setting cooling state %lu\n", state);
98
99 if (state > dfc->max_state)
100 return -EINVAL;
101
102 if (dfc->em_pd) {
103 perf_idx = dfc->max_state - state;
104
105 rcu_read_lock();
106 table = em_perf_state_from_pd(dfc->em_pd);
107 freq = table[perf_idx].frequency * 1000;
108 rcu_read_unlock();
109 } else {
110 freq = dfc->freq_table[state];
111 }
112
113 dev_pm_qos_update_request(&dfc->req_max_freq,
114 DIV_ROUND_UP(freq, HZ_PER_KHZ));
115
116 dfc->cooling_state = state;
117
118 return 0;
119}
120
121/**
122 * get_perf_idx() - get the performance index corresponding to a frequency
123 * @em_pd: Pointer to device's Energy Model
124 * @freq: frequency in kHz
125 *
126 * Return: the performance index associated with the @freq, or
127 * -EINVAL if it wasn't found.
128 */
129static int get_perf_idx(struct em_perf_domain *em_pd, unsigned long freq)
130{
131 struct em_perf_state *table;
132 int i, idx = -EINVAL;
133
134 rcu_read_lock();
135 table = em_perf_state_from_pd(em_pd);
136 for (i = 0; i < em_pd->nr_perf_states; i++) {
137 if (table[i].frequency != freq)
138 continue;
139
140 idx = i;
141 break;
142 }
143 rcu_read_unlock();
144
145 return idx;
146}
147
148static unsigned long get_voltage(struct devfreq *df, unsigned long freq)
149{
150 struct device *dev = df->dev.parent;
151 unsigned long voltage;
152 struct dev_pm_opp *opp;
153
154 opp = dev_pm_opp_find_freq_exact(dev, freq, true);
155 if (PTR_ERR(opp) == -ERANGE)
156 opp = dev_pm_opp_find_freq_exact(dev, freq, false);
157
158 if (IS_ERR(opp)) {
159 dev_err_ratelimited(dev, "Failed to find OPP for frequency %lu: %ld\n",
160 freq, PTR_ERR(opp));
161 return 0;
162 }
163
164 voltage = dev_pm_opp_get_voltage(opp) / 1000; /* mV */
165 dev_pm_opp_put(opp);
166
167 if (voltage == 0) {
168 dev_err_ratelimited(dev,
169 "Failed to get voltage for frequency %lu\n",
170 freq);
171 }
172
173 return voltage;
174}
175
176static void _normalize_load(struct devfreq_dev_status *status)
177{
178 if (status->total_time > 0xfffff) {
179 status->total_time >>= 10;
180 status->busy_time >>= 10;
181 }
182
183 status->busy_time <<= 10;
184 status->busy_time /= status->total_time ? : 1;
185
186 status->busy_time = status->busy_time ? : 1;
187 status->total_time = 1024;
188}
189
190static int devfreq_cooling_get_requested_power(struct thermal_cooling_device *cdev,
191 u32 *power)
192{
193 struct devfreq_cooling_device *dfc = cdev->devdata;
194 struct devfreq *df = dfc->devfreq;
195 struct devfreq_dev_status status;
196 struct em_perf_state *table;
197 unsigned long state;
198 unsigned long freq;
199 unsigned long voltage;
200 int res, perf_idx;
201
202 mutex_lock(&df->lock);
203 status = df->last_status;
204 mutex_unlock(&df->lock);
205
206 freq = status.current_frequency;
207
208 if (dfc->power_ops && dfc->power_ops->get_real_power) {
209 voltage = get_voltage(df, freq);
210 if (voltage == 0) {
211 res = -EINVAL;
212 goto fail;
213 }
214
215 res = dfc->power_ops->get_real_power(df, power, freq, voltage);
216 if (!res) {
217 state = dfc->max_state - dfc->capped_state;
218
219 /* Convert EM power into milli-Watts first */
220 rcu_read_lock();
221 table = em_perf_state_from_pd(dfc->em_pd);
222 dfc->res_util = table[state].power;
223 rcu_read_unlock();
224
225 dfc->res_util /= MICROWATT_PER_MILLIWATT;
226
227 dfc->res_util *= SCALE_ERROR_MITIGATION;
228
229 if (*power > 1)
230 dfc->res_util /= *power;
231 } else {
232 goto fail;
233 }
234 } else {
235 /* Energy Model frequencies are in kHz */
236 perf_idx = get_perf_idx(dfc->em_pd, freq / 1000);
237 if (perf_idx < 0) {
238 res = -EAGAIN;
239 goto fail;
240 }
241
242 _normalize_load(&status);
243
244 /* Convert EM power into milli-Watts first */
245 rcu_read_lock();
246 table = em_perf_state_from_pd(dfc->em_pd);
247 *power = table[perf_idx].power;
248 rcu_read_unlock();
249
250 *power /= MICROWATT_PER_MILLIWATT;
251 /* Scale power for utilization */
252 *power *= status.busy_time;
253 *power >>= 10;
254 }
255
256 trace_thermal_power_devfreq_get_power(cdev, &status, freq, *power);
257
258 return 0;
259fail:
260 /* It is safe to set max in this case */
261 dfc->res_util = SCALE_ERROR_MITIGATION;
262 return res;
263}
264
265static int devfreq_cooling_state2power(struct thermal_cooling_device *cdev,
266 unsigned long state, u32 *power)
267{
268 struct devfreq_cooling_device *dfc = cdev->devdata;
269 struct em_perf_state *table;
270 int perf_idx;
271
272 if (state > dfc->max_state)
273 return -EINVAL;
274
275 perf_idx = dfc->max_state - state;
276
277 rcu_read_lock();
278 table = em_perf_state_from_pd(dfc->em_pd);
279 *power = table[perf_idx].power;
280 rcu_read_unlock();
281
282 *power /= MICROWATT_PER_MILLIWATT;
283
284 return 0;
285}
286
287static int devfreq_cooling_power2state(struct thermal_cooling_device *cdev,
288 u32 power, unsigned long *state)
289{
290 struct devfreq_cooling_device *dfc = cdev->devdata;
291 struct devfreq *df = dfc->devfreq;
292 struct devfreq_dev_status status;
293 unsigned long freq, em_power_mw;
294 struct em_perf_state *table;
295 s32 est_power;
296 int i;
297
298 mutex_lock(&df->lock);
299 status = df->last_status;
300 mutex_unlock(&df->lock);
301
302 freq = status.current_frequency;
303
304 if (dfc->power_ops && dfc->power_ops->get_real_power) {
305 /* Scale for resource utilization */
306 est_power = power * dfc->res_util;
307 est_power /= SCALE_ERROR_MITIGATION;
308 } else {
309 /* Scale dynamic power for utilization */
310 _normalize_load(&status);
311 est_power = power << 10;
312 est_power /= status.busy_time;
313 }
314
315 /*
316 * Find the first cooling state that is within the power
317 * budget. The EM power table is sorted ascending.
318 */
319 rcu_read_lock();
320 table = em_perf_state_from_pd(dfc->em_pd);
321 for (i = dfc->max_state; i > 0; i--) {
322 /* Convert EM power to milli-Watts to make safe comparison */
323 em_power_mw = table[i].power;
324 em_power_mw /= MICROWATT_PER_MILLIWATT;
325 if (est_power >= em_power_mw)
326 break;
327 }
328 rcu_read_unlock();
329
330 *state = dfc->max_state - i;
331 dfc->capped_state = *state;
332
333 trace_thermal_power_devfreq_limit(cdev, freq, *state, power);
334 return 0;
335}
336
337/**
338 * devfreq_cooling_gen_tables() - Generate frequency table.
339 * @dfc: Pointer to devfreq cooling device.
340 * @num_opps: Number of OPPs
341 *
342 * Generate frequency table which holds the frequencies in descending
343 * order. That way its indexed by cooling device state. This is for
344 * compatibility with drivers which do not register Energy Model.
345 *
346 * Return: 0 on success, negative error code on failure.
347 */
348static int devfreq_cooling_gen_tables(struct devfreq_cooling_device *dfc,
349 int num_opps)
350{
351 struct devfreq *df = dfc->devfreq;
352 struct device *dev = df->dev.parent;
353 unsigned long freq;
354 int i;
355
356 dfc->freq_table = kcalloc(num_opps, sizeof(*dfc->freq_table),
357 GFP_KERNEL);
358 if (!dfc->freq_table)
359 return -ENOMEM;
360
361 for (i = 0, freq = ULONG_MAX; i < num_opps; i++, freq--) {
362 struct dev_pm_opp *opp;
363
364 opp = dev_pm_opp_find_freq_floor(dev, &freq);
365 if (IS_ERR(opp)) {
366 kfree(dfc->freq_table);
367 return PTR_ERR(opp);
368 }
369
370 dev_pm_opp_put(opp);
371 dfc->freq_table[i] = freq;
372 }
373
374 return 0;
375}
376
377/**
378 * of_devfreq_cooling_register_power() - Register devfreq cooling device,
379 * with OF and power information.
380 * @np: Pointer to OF device_node.
381 * @df: Pointer to devfreq device.
382 * @dfc_power: Pointer to devfreq_cooling_power.
383 *
384 * Register a devfreq cooling device. The available OPPs must be
385 * registered on the device.
386 *
387 * If @dfc_power is provided, the cooling device is registered with the
388 * power extensions. For the power extensions to work correctly,
389 * devfreq should use the simple_ondemand governor, other governors
390 * are not currently supported.
391 */
392struct thermal_cooling_device *
393of_devfreq_cooling_register_power(struct device_node *np, struct devfreq *df,
394 struct devfreq_cooling_power *dfc_power)
395{
396 struct thermal_cooling_device *cdev;
397 struct device *dev = df->dev.parent;
398 struct devfreq_cooling_device *dfc;
399 struct em_perf_domain *em;
400 struct thermal_cooling_device_ops *ops;
401 char *name;
402 int err, num_opps;
403
404
405 dfc = kzalloc(sizeof(*dfc), GFP_KERNEL);
406 if (!dfc)
407 return ERR_PTR(-ENOMEM);
408
409 dfc->devfreq = df;
410
411 ops = &dfc->cooling_ops;
412 ops->get_max_state = devfreq_cooling_get_max_state;
413 ops->get_cur_state = devfreq_cooling_get_cur_state;
414 ops->set_cur_state = devfreq_cooling_set_cur_state;
415
416 em = em_pd_get(dev);
417 if (em && !em_is_artificial(em)) {
418 dfc->em_pd = em;
419 ops->get_requested_power =
420 devfreq_cooling_get_requested_power;
421 ops->state2power = devfreq_cooling_state2power;
422 ops->power2state = devfreq_cooling_power2state;
423
424 dfc->power_ops = dfc_power;
425
426 num_opps = em_pd_nr_perf_states(dfc->em_pd);
427 } else {
428 /* Backward compatibility for drivers which do not use IPA */
429 dev_dbg(dev, "missing proper EM for cooling device\n");
430
431 num_opps = dev_pm_opp_get_opp_count(dev);
432
433 err = devfreq_cooling_gen_tables(dfc, num_opps);
434 if (err)
435 goto free_dfc;
436 }
437
438 if (num_opps <= 0) {
439 err = -EINVAL;
440 goto free_dfc;
441 }
442
443 /* max_state is an index, not a counter */
444 dfc->max_state = num_opps - 1;
445
446 err = dev_pm_qos_add_request(dev, &dfc->req_max_freq,
447 DEV_PM_QOS_MAX_FREQUENCY,
448 PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE);
449 if (err < 0)
450 goto free_table;
451
452 err = -ENOMEM;
453 name = kasprintf(GFP_KERNEL, "devfreq-%s", dev_name(dev));
454 if (!name)
455 goto remove_qos_req;
456
457 cdev = thermal_of_cooling_device_register(np, name, dfc, ops);
458 kfree(name);
459
460 if (IS_ERR(cdev)) {
461 err = PTR_ERR(cdev);
462 dev_err(dev,
463 "Failed to register devfreq cooling device (%d)\n",
464 err);
465 goto remove_qos_req;
466 }
467
468 dfc->cdev = cdev;
469
470 return cdev;
471
472remove_qos_req:
473 dev_pm_qos_remove_request(&dfc->req_max_freq);
474free_table:
475 kfree(dfc->freq_table);
476free_dfc:
477 kfree(dfc);
478
479 return ERR_PTR(err);
480}
481EXPORT_SYMBOL_GPL(of_devfreq_cooling_register_power);
482
483/**
484 * of_devfreq_cooling_register() - Register devfreq cooling device,
485 * with OF information.
486 * @np: Pointer to OF device_node.
487 * @df: Pointer to devfreq device.
488 */
489struct thermal_cooling_device *
490of_devfreq_cooling_register(struct device_node *np, struct devfreq *df)
491{
492 return of_devfreq_cooling_register_power(np, df, NULL);
493}
494EXPORT_SYMBOL_GPL(of_devfreq_cooling_register);
495
496/**
497 * devfreq_cooling_register() - Register devfreq cooling device.
498 * @df: Pointer to devfreq device.
499 */
500struct thermal_cooling_device *devfreq_cooling_register(struct devfreq *df)
501{
502 return of_devfreq_cooling_register(NULL, df);
503}
504EXPORT_SYMBOL_GPL(devfreq_cooling_register);
505
506/**
507 * devfreq_cooling_em_register() - Register devfreq cooling device with
508 * power information and automatically register Energy Model (EM)
509 * @df: Pointer to devfreq device.
510 * @dfc_power: Pointer to devfreq_cooling_power.
511 *
512 * Register a devfreq cooling device and automatically register EM. The
513 * available OPPs must be registered for the device.
514 *
515 * If @dfc_power is provided, the cooling device is registered with the
516 * power extensions. It is using the simple Energy Model which requires
517 * "dynamic-power-coefficient" a devicetree property. To not break drivers
518 * which miss that DT property, the function won't bail out when the EM
519 * registration failed. The cooling device will be registered if everything
520 * else is OK.
521 */
522struct thermal_cooling_device *
523devfreq_cooling_em_register(struct devfreq *df,
524 struct devfreq_cooling_power *dfc_power)
525{
526 struct thermal_cooling_device *cdev;
527 struct device *dev;
528 int ret;
529
530 if (IS_ERR_OR_NULL(df))
531 return ERR_PTR(-EINVAL);
532
533 dev = df->dev.parent;
534
535 ret = dev_pm_opp_of_register_em(dev, NULL);
536 if (ret)
537 dev_dbg(dev, "Unable to register EM for devfreq cooling device (%d)\n",
538 ret);
539
540 cdev = of_devfreq_cooling_register_power(dev->of_node, df, dfc_power);
541
542 if (IS_ERR_OR_NULL(cdev))
543 em_dev_unregister_perf_domain(dev);
544
545 return cdev;
546}
547EXPORT_SYMBOL_GPL(devfreq_cooling_em_register);
548
549/**
550 * devfreq_cooling_unregister() - Unregister devfreq cooling device.
551 * @cdev: Pointer to devfreq cooling device to unregister.
552 *
553 * Unregisters devfreq cooling device and related Energy Model if it was
554 * present.
555 */
556void devfreq_cooling_unregister(struct thermal_cooling_device *cdev)
557{
558 struct devfreq_cooling_device *dfc;
559 struct device *dev;
560
561 if (IS_ERR_OR_NULL(cdev))
562 return;
563
564 dfc = cdev->devdata;
565 dev = dfc->devfreq->dev.parent;
566
567 thermal_cooling_device_unregister(dfc->cdev);
568 dev_pm_qos_remove_request(&dfc->req_max_freq);
569
570 em_dev_unregister_perf_domain(dev);
571
572 kfree(dfc->freq_table);
573 kfree(dfc);
574}
575EXPORT_SYMBOL_GPL(devfreq_cooling_unregister);