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 | */ |
50 | struct 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 | |
64 | static 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 | |
74 | static 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 | |
84 | static 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(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(req: &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 | */ |
129 | static 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(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 | |
148 | static 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, available: true); |
155 | if (PTR_ERR(ptr: opp) == -ERANGE) |
156 | opp = dev_pm_opp_find_freq_exact(dev, freq, available: false); |
157 | |
158 | if (IS_ERR(ptr: 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 | |
176 | static 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 | |
190 | static 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(lock: &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(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(em_pd: dfc->em_pd, freq: freq / 1000); |
237 | if (perf_idx < 0) { |
238 | res = -EAGAIN; |
239 | goto fail; |
240 | } |
241 | |
242 | _normalize_load(status: &status); |
243 | |
244 | /* Convert EM power into milli-Watts first */ |
245 | rcu_read_lock(); |
246 | table = em_perf_state_from_pd(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: &status, freq, power: *power); |
257 | |
258 | return 0; |
259 | fail: |
260 | /* It is safe to set max in this case */ |
261 | dfc->res_util = SCALE_ERROR_MITIGATION; |
262 | return res; |
263 | } |
264 | |
265 | static 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(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 | |
287 | static 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(lock: &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: &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(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, cdev_state: *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 | */ |
348 | static 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(n: num_opps, size: 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: &freq); |
365 | if (IS_ERR(ptr: opp)) { |
366 | kfree(objp: dfc->freq_table); |
367 | return PTR_ERR(ptr: 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 | */ |
392 | struct thermal_cooling_device * |
393 | of_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(size: sizeof(*dfc), GFP_KERNEL); |
406 | if (!dfc) |
407 | return ERR_PTR(error: -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(pd: 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, req: &dfc->req_max_freq, |
447 | type: 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, fmt: "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(objp: name); |
459 | |
460 | if (IS_ERR(ptr: cdev)) { |
461 | err = PTR_ERR(ptr: 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 | |
472 | remove_qos_req: |
473 | dev_pm_qos_remove_request(req: &dfc->req_max_freq); |
474 | free_table: |
475 | kfree(objp: dfc->freq_table); |
476 | free_dfc: |
477 | kfree(objp: dfc); |
478 | |
479 | return ERR_PTR(error: err); |
480 | } |
481 | EXPORT_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 | */ |
489 | struct thermal_cooling_device * |
490 | of_devfreq_cooling_register(struct device_node *np, struct devfreq *df) |
491 | { |
492 | return of_devfreq_cooling_register_power(np, df, NULL); |
493 | } |
494 | EXPORT_SYMBOL_GPL(of_devfreq_cooling_register); |
495 | |
496 | /** |
497 | * devfreq_cooling_register() - Register devfreq cooling device. |
498 | * @df: Pointer to devfreq device. |
499 | */ |
500 | struct thermal_cooling_device *devfreq_cooling_register(struct devfreq *df) |
501 | { |
502 | return of_devfreq_cooling_register(NULL, df); |
503 | } |
504 | EXPORT_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 | */ |
522 | struct thermal_cooling_device * |
523 | devfreq_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(ptr: df)) |
531 | return ERR_PTR(error: -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(ptr: cdev)) |
543 | em_dev_unregister_perf_domain(dev); |
544 | |
545 | return cdev; |
546 | } |
547 | EXPORT_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 | */ |
556 | void 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(ptr: 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(req: &dfc->req_max_freq); |
569 | |
570 | em_dev_unregister_perf_domain(dev); |
571 | |
572 | kfree(objp: dfc->freq_table); |
573 | kfree(objp: dfc); |
574 | } |
575 | EXPORT_SYMBOL_GPL(devfreq_cooling_unregister); |
576 | |