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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 | ||
30 | static DEFINE_MUTEX(devfreq_lock); | |
31 | static 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 | */ | |
49 | struct 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 | */ | |
70 | static 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 | */ | |
89 | static 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 | */ | |
104 | static 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 | opp = dev_pm_opp_find_freq_exact(dev, freq, !want_enable); | |
117 | ||
118 | if (PTR_ERR(opp) == -ERANGE) | |
119 | continue; | |
120 | else if (IS_ERR(opp)) | |
121 | return PTR_ERR(opp); | |
122 | ||
123 | dev_pm_opp_put(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 | ||
137 | static 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 | ||
147 | static 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 | ||
157 | static 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 | */ | |
190 | static unsigned long | |
191 | freq_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 | */ | |
213 | static unsigned long | |
214 | get_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 | opp = dev_pm_opp_find_freq_exact(dev, freq, true); | |
225 | if (IS_ERR(opp) && (PTR_ERR(opp) == -ERANGE)) | |
226 | opp = dev_pm_opp_find_freq_exact(dev, freq, false); | |
227 | ||
228 | voltage = dev_pm_opp_get_voltage(opp) / 1000; /* mV */ | |
229 | dev_pm_opp_put(opp); | |
230 | ||
231 | if (voltage == 0) { | |
232 | dev_warn_ratelimited(dev, | |
233 | "Failed to get voltage for frequency %lu: %ld\n", | |
234 | freq, IS_ERR(opp) ? PTR_ERR(opp) : 0); | |
235 | return 0; | |
236 | } | |
237 | ||
238 | return dfc->power_ops->get_static_power(df, voltage); | |
239 | } | |
240 | ||
241 | /** | |
242 | * get_dynamic_power - calculate the dynamic power | |
243 | * @dfc: Pointer to devfreq cooling device | |
244 | * @freq: Frequency in Hz | |
245 | * @voltage: Voltage in millivolts | |
246 | * | |
247 | * Calculate the dynamic power in milliwatts consumed by the device at | |
248 | * frequency @freq and voltage @voltage. If the get_dynamic_power() | |
249 | * was supplied as part of the devfreq_cooling_power struct, then that | |
250 | * function is used. Otherwise, a simple power model (Pdyn = Coeff * | |
251 | * Voltage^2 * Frequency) is used. | |
252 | */ | |
253 | static unsigned long | |
254 | get_dynamic_power(struct devfreq_cooling_device *dfc, unsigned long freq, | |
255 | unsigned long voltage) | |
256 | { | |
257 | u64 power; | |
258 | u32 freq_mhz; | |
259 | struct devfreq_cooling_power *dfc_power = dfc->power_ops; | |
260 | ||
261 | if (dfc_power->get_dynamic_power) | |
262 | return dfc_power->get_dynamic_power(dfc->devfreq, freq, | |
263 | voltage); | |
264 | ||
265 | freq_mhz = freq / 1000000; | |
266 | power = (u64)dfc_power->dyn_power_coeff * freq_mhz * voltage * voltage; | |
267 | do_div(power, 1000000000); | |
268 | ||
269 | return power; | |
270 | } | |
271 | ||
272 | static int devfreq_cooling_get_requested_power(struct thermal_cooling_device *cdev, | |
273 | struct thermal_zone_device *tz, | |
274 | u32 *power) | |
275 | { | |
276 | struct devfreq_cooling_device *dfc = cdev->devdata; | |
277 | struct devfreq *df = dfc->devfreq; | |
278 | struct devfreq_dev_status *status = &df->last_status; | |
279 | unsigned long state; | |
280 | unsigned long freq = status->current_frequency; | |
281 | u32 dyn_power, static_power; | |
282 | ||
283 | /* Get dynamic power for state */ | |
284 | state = freq_get_state(dfc, freq); | |
285 | if (state == THERMAL_CSTATE_INVALID) | |
286 | return -EAGAIN; | |
287 | ||
288 | dyn_power = dfc->power_table[state]; | |
289 | ||
290 | /* Scale dynamic power for utilization */ | |
291 | dyn_power = (dyn_power * status->busy_time) / status->total_time; | |
292 | ||
293 | /* Get static power */ | |
294 | static_power = get_static_power(dfc, freq); | |
295 | ||
296 | trace_thermal_power_devfreq_get_power(cdev, status, freq, dyn_power, | |
297 | static_power); | |
298 | ||
299 | *power = dyn_power + static_power; | |
300 | ||
301 | return 0; | |
302 | } | |
303 | ||
304 | static int devfreq_cooling_state2power(struct thermal_cooling_device *cdev, | |
305 | struct thermal_zone_device *tz, | |
306 | unsigned long state, | |
307 | u32 *power) | |
308 | { | |
309 | struct devfreq_cooling_device *dfc = cdev->devdata; | |
310 | unsigned long freq; | |
311 | u32 static_power; | |
312 | ||
313 | if (state >= dfc->freq_table_size) | |
314 | return -EINVAL; | |
315 | ||
316 | freq = dfc->freq_table[state]; | |
317 | static_power = get_static_power(dfc, freq); | |
318 | ||
319 | *power = dfc->power_table[state] + static_power; | |
320 | return 0; | |
321 | } | |
322 | ||
323 | static int devfreq_cooling_power2state(struct thermal_cooling_device *cdev, | |
324 | struct thermal_zone_device *tz, | |
325 | u32 power, unsigned long *state) | |
326 | { | |
327 | struct devfreq_cooling_device *dfc = cdev->devdata; | |
328 | struct devfreq *df = dfc->devfreq; | |
329 | struct devfreq_dev_status *status = &df->last_status; | |
330 | unsigned long freq = status->current_frequency; | |
331 | unsigned long busy_time; | |
332 | s32 dyn_power; | |
333 | u32 static_power; | |
334 | int i; | |
335 | ||
336 | static_power = get_static_power(dfc, freq); | |
337 | ||
338 | dyn_power = power - static_power; | |
339 | dyn_power = dyn_power > 0 ? dyn_power : 0; | |
340 | ||
341 | /* Scale dynamic power for utilization */ | |
342 | busy_time = status->busy_time ?: 1; | |
343 | dyn_power = (dyn_power * status->total_time) / busy_time; | |
344 | ||
345 | /* | |
346 | * Find the first cooling state that is within the power | |
347 | * budget for dynamic power. | |
348 | */ | |
349 | for (i = 0; i < dfc->freq_table_size - 1; i++) | |
350 | if (dyn_power >= dfc->power_table[i]) | |
351 | break; | |
352 | ||
353 | *state = i; | |
354 | trace_thermal_power_devfreq_limit(cdev, freq, *state, power); | |
355 | return 0; | |
356 | } | |
357 | ||
358 | static struct thermal_cooling_device_ops devfreq_cooling_ops = { | |
359 | .get_max_state = devfreq_cooling_get_max_state, | |
360 | .get_cur_state = devfreq_cooling_get_cur_state, | |
361 | .set_cur_state = devfreq_cooling_set_cur_state, | |
362 | }; | |
363 | ||
364 | /** | |
365 | * devfreq_cooling_gen_tables() - Generate power and freq tables. | |
366 | * @dfc: Pointer to devfreq cooling device. | |
367 | * | |
368 | * Generate power and frequency tables: the power table hold the | |
369 | * device's maximum power usage at each cooling state (OPP). The | |
370 | * static and dynamic power using the appropriate voltage and | |
371 | * frequency for the state, is acquired from the struct | |
372 | * devfreq_cooling_power, and summed to make the maximum power draw. | |
373 | * | |
374 | * The frequency table holds the frequencies in descending order. | |
375 | * That way its indexed by cooling device state. | |
376 | * | |
377 | * The tables are malloced, and pointers put in dfc. They must be | |
378 | * freed when unregistering the devfreq cooling device. | |
379 | * | |
380 | * Return: 0 on success, negative error code on failure. | |
381 | */ | |
382 | static int devfreq_cooling_gen_tables(struct devfreq_cooling_device *dfc) | |
383 | { | |
384 | struct devfreq *df = dfc->devfreq; | |
385 | struct device *dev = df->dev.parent; | |
386 | int ret, num_opps; | |
387 | unsigned long freq; | |
388 | u32 *power_table = NULL; | |
389 | u32 *freq_table; | |
390 | int i; | |
391 | ||
392 | num_opps = dev_pm_opp_get_opp_count(dev); | |
393 | ||
394 | if (dfc->power_ops) { | |
395 | power_table = kcalloc(num_opps, sizeof(*power_table), | |
396 | GFP_KERNEL); | |
397 | if (!power_table) | |
398 | return -ENOMEM; | |
399 | } | |
400 | ||
401 | freq_table = kcalloc(num_opps, sizeof(*freq_table), | |
402 | GFP_KERNEL); | |
403 | if (!freq_table) { | |
404 | ret = -ENOMEM; | |
405 | goto free_power_table; | |
406 | } | |
407 | ||
408 | for (i = 0, freq = ULONG_MAX; i < num_opps; i++, freq--) { | |
409 | unsigned long power_dyn, voltage; | |
410 | struct dev_pm_opp *opp; | |
411 | ||
412 | opp = dev_pm_opp_find_freq_floor(dev, &freq); | |
413 | if (IS_ERR(opp)) { | |
414 | ret = PTR_ERR(opp); | |
415 | goto free_tables; | |
416 | } | |
417 | ||
418 | voltage = dev_pm_opp_get_voltage(opp) / 1000; /* mV */ | |
419 | dev_pm_opp_put(opp); | |
420 | ||
421 | if (dfc->power_ops) { | |
422 | power_dyn = get_dynamic_power(dfc, freq, voltage); | |
423 | ||
424 | dev_dbg(dev, "Dynamic power table: %lu MHz @ %lu mV: %lu = %lu mW\n", | |
425 | freq / 1000000, voltage, power_dyn, power_dyn); | |
426 | ||
427 | power_table[i] = power_dyn; | |
428 | } | |
429 | ||
430 | freq_table[i] = freq; | |
431 | } | |
432 | ||
433 | if (dfc->power_ops) | |
434 | dfc->power_table = power_table; | |
435 | ||
436 | dfc->freq_table = freq_table; | |
437 | dfc->freq_table_size = num_opps; | |
438 | ||
439 | return 0; | |
440 | ||
441 | free_tables: | |
442 | kfree(freq_table); | |
443 | free_power_table: | |
444 | kfree(power_table); | |
445 | ||
446 | return ret; | |
447 | } | |
448 | ||
449 | /** | |
450 | * of_devfreq_cooling_register_power() - Register devfreq cooling device, | |
451 | * with OF and power information. | |
452 | * @np: Pointer to OF device_node. | |
453 | * @df: Pointer to devfreq device. | |
454 | * @dfc_power: Pointer to devfreq_cooling_power. | |
455 | * | |
456 | * Register a devfreq cooling device. The available OPPs must be | |
457 | * registered on the device. | |
458 | * | |
459 | * If @dfc_power is provided, the cooling device is registered with the | |
460 | * power extensions. For the power extensions to work correctly, | |
461 | * devfreq should use the simple_ondemand governor, other governors | |
462 | * are not currently supported. | |
463 | */ | |
464 | struct thermal_cooling_device * | |
465 | of_devfreq_cooling_register_power(struct device_node *np, struct devfreq *df, | |
466 | struct devfreq_cooling_power *dfc_power) | |
467 | { | |
468 | struct thermal_cooling_device *cdev; | |
469 | struct devfreq_cooling_device *dfc; | |
470 | char dev_name[THERMAL_NAME_LENGTH]; | |
471 | int err; | |
472 | ||
473 | dfc = kzalloc(sizeof(*dfc), GFP_KERNEL); | |
474 | if (!dfc) | |
475 | return ERR_PTR(-ENOMEM); | |
476 | ||
477 | dfc->devfreq = df; | |
478 | ||
479 | if (dfc_power) { | |
480 | dfc->power_ops = dfc_power; | |
481 | ||
482 | devfreq_cooling_ops.get_requested_power = | |
483 | devfreq_cooling_get_requested_power; | |
484 | devfreq_cooling_ops.state2power = devfreq_cooling_state2power; | |
485 | devfreq_cooling_ops.power2state = devfreq_cooling_power2state; | |
486 | } | |
487 | ||
488 | err = devfreq_cooling_gen_tables(dfc); | |
489 | if (err) | |
490 | goto free_dfc; | |
491 | ||
492 | err = get_idr(&devfreq_idr, &dfc->id); | |
493 | if (err) | |
494 | goto free_tables; | |
495 | ||
496 | snprintf(dev_name, sizeof(dev_name), "thermal-devfreq-%d", dfc->id); | |
497 | ||
498 | cdev = thermal_of_cooling_device_register(np, dev_name, dfc, | |
499 | &devfreq_cooling_ops); | |
500 | if (IS_ERR(cdev)) { | |
501 | err = PTR_ERR(cdev); | |
502 | dev_err(df->dev.parent, | |
503 | "Failed to register devfreq cooling device (%d)\n", | |
504 | err); | |
505 | goto release_idr; | |
506 | } | |
507 | ||
508 | dfc->cdev = cdev; | |
509 | ||
510 | return cdev; | |
511 | ||
512 | release_idr: | |
513 | release_idr(&devfreq_idr, dfc->id); | |
514 | free_tables: | |
515 | kfree(dfc->power_table); | |
516 | kfree(dfc->freq_table); | |
517 | free_dfc: | |
518 | kfree(dfc); | |
519 | ||
520 | return ERR_PTR(err); | |
521 | } | |
522 | EXPORT_SYMBOL_GPL(of_devfreq_cooling_register_power); | |
523 | ||
524 | /** | |
525 | * of_devfreq_cooling_register() - Register devfreq cooling device, | |
526 | * with OF information. | |
527 | * @np: Pointer to OF device_node. | |
528 | * @df: Pointer to devfreq device. | |
529 | */ | |
530 | struct thermal_cooling_device * | |
531 | of_devfreq_cooling_register(struct device_node *np, struct devfreq *df) | |
532 | { | |
533 | return of_devfreq_cooling_register_power(np, df, NULL); | |
534 | } | |
535 | EXPORT_SYMBOL_GPL(of_devfreq_cooling_register); | |
536 | ||
537 | /** | |
538 | * devfreq_cooling_register() - Register devfreq cooling device. | |
539 | * @df: Pointer to devfreq device. | |
540 | */ | |
541 | struct thermal_cooling_device *devfreq_cooling_register(struct devfreq *df) | |
542 | { | |
543 | return of_devfreq_cooling_register(NULL, df); | |
544 | } | |
545 | EXPORT_SYMBOL_GPL(devfreq_cooling_register); | |
546 | ||
547 | /** | |
548 | * devfreq_cooling_unregister() - Unregister devfreq cooling device. | |
549 | * @dfc: Pointer to devfreq cooling device to unregister. | |
550 | */ | |
551 | void devfreq_cooling_unregister(struct thermal_cooling_device *cdev) | |
552 | { | |
553 | struct devfreq_cooling_device *dfc; | |
554 | ||
555 | if (!cdev) | |
556 | return; | |
557 | ||
558 | dfc = cdev->devdata; | |
559 | ||
560 | thermal_cooling_device_unregister(dfc->cdev); | |
561 | release_idr(&devfreq_idr, dfc->id); | |
562 | kfree(dfc->power_table); | |
563 | kfree(dfc->freq_table); | |
564 | ||
565 | kfree(dfc); | |
566 | } | |
567 | EXPORT_SYMBOL_GPL(devfreq_cooling_unregister); |