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