GNU Linux-libre 5.19-rc6-gnu
[releases.git] / drivers / thermal / devfreq_cooling.c
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 <trace/events/thermal.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  * @devfreq:    Pointer to associated devfreq device.
32  * @cooling_state:      Current cooling state.
33  * @freq_table: Pointer to a table with the frequencies sorted in descending
34  *              order.  You can index the table by cooling device state
35  * @max_state:  It is the last index, that is, one less than the number of the
36  *              OPPs
37  * @power_ops:  Pointer to devfreq_cooling_power, a more precised model.
38  * @res_util:   Resource utilization scaling factor for the power.
39  *              It is multiplied by 100 to minimize the error. It is used
40  *              for estimation of the power budget instead of using
41  *              'utilization' (which is 'busy_time' / 'total_time').
42  *              The 'res_util' range is from 100 to power * 100 for the
43  *              corresponding 'state'.
44  * @capped_state:       index to cooling state with in dynamic power budget
45  * @req_max_freq:       PM QoS request for limiting the maximum frequency
46  *                      of the devfreq device.
47  * @em_pd:              Energy Model for the associated Devfreq device
48  */
49 struct devfreq_cooling_device {
50         struct thermal_cooling_device *cdev;
51         struct devfreq *devfreq;
52         unsigned long cooling_state;
53         u32 *freq_table;
54         size_t max_state;
55         struct devfreq_cooling_power *power_ops;
56         u32 res_util;
57         int capped_state;
58         struct dev_pm_qos_request req_max_freq;
59         struct em_perf_domain *em_pd;
60 };
61
62 static int devfreq_cooling_get_max_state(struct thermal_cooling_device *cdev,
63                                          unsigned long *state)
64 {
65         struct devfreq_cooling_device *dfc = cdev->devdata;
66
67         *state = dfc->max_state;
68
69         return 0;
70 }
71
72 static int devfreq_cooling_get_cur_state(struct thermal_cooling_device *cdev,
73                                          unsigned long *state)
74 {
75         struct devfreq_cooling_device *dfc = cdev->devdata;
76
77         *state = dfc->cooling_state;
78
79         return 0;
80 }
81
82 static int devfreq_cooling_set_cur_state(struct thermal_cooling_device *cdev,
83                                          unsigned long state)
84 {
85         struct devfreq_cooling_device *dfc = cdev->devdata;
86         struct devfreq *df = dfc->devfreq;
87         struct device *dev = df->dev.parent;
88         unsigned long freq;
89         int perf_idx;
90
91         if (state == dfc->cooling_state)
92                 return 0;
93
94         dev_dbg(dev, "Setting cooling state %lu\n", state);
95
96         if (state > dfc->max_state)
97                 return -EINVAL;
98
99         if (dfc->em_pd) {
100                 perf_idx = dfc->max_state - state;
101                 freq = dfc->em_pd->table[perf_idx].frequency * 1000;
102         } else {
103                 freq = dfc->freq_table[state];
104         }
105
106         dev_pm_qos_update_request(&dfc->req_max_freq,
107                                   DIV_ROUND_UP(freq, HZ_PER_KHZ));
108
109         dfc->cooling_state = state;
110
111         return 0;
112 }
113
114 /**
115  * get_perf_idx() - get the performance index corresponding to a frequency
116  * @em_pd:      Pointer to device's Energy Model
117  * @freq:       frequency in kHz
118  *
119  * Return: the performance index associated with the @freq, or
120  * -EINVAL if it wasn't found.
121  */
122 static int get_perf_idx(struct em_perf_domain *em_pd, unsigned long freq)
123 {
124         int i;
125
126         for (i = 0; i < em_pd->nr_perf_states; i++) {
127                 if (em_pd->table[i].frequency == freq)
128                         return i;
129         }
130
131         return -EINVAL;
132 }
133
134 static unsigned long get_voltage(struct devfreq *df, unsigned long freq)
135 {
136         struct device *dev = df->dev.parent;
137         unsigned long voltage;
138         struct dev_pm_opp *opp;
139
140         opp = dev_pm_opp_find_freq_exact(dev, freq, true);
141         if (PTR_ERR(opp) == -ERANGE)
142                 opp = dev_pm_opp_find_freq_exact(dev, freq, false);
143
144         if (IS_ERR(opp)) {
145                 dev_err_ratelimited(dev, "Failed to find OPP for frequency %lu: %ld\n",
146                                     freq, PTR_ERR(opp));
147                 return 0;
148         }
149
150         voltage = dev_pm_opp_get_voltage(opp) / 1000; /* mV */
151         dev_pm_opp_put(opp);
152
153         if (voltage == 0) {
154                 dev_err_ratelimited(dev,
155                                     "Failed to get voltage for frequency %lu\n",
156                                     freq);
157         }
158
159         return voltage;
160 }
161
162 static void _normalize_load(struct devfreq_dev_status *status)
163 {
164         if (status->total_time > 0xfffff) {
165                 status->total_time >>= 10;
166                 status->busy_time >>= 10;
167         }
168
169         status->busy_time <<= 10;
170         status->busy_time /= status->total_time ? : 1;
171
172         status->busy_time = status->busy_time ? : 1;
173         status->total_time = 1024;
174 }
175
176 static int devfreq_cooling_get_requested_power(struct thermal_cooling_device *cdev,
177                                                u32 *power)
178 {
179         struct devfreq_cooling_device *dfc = cdev->devdata;
180         struct devfreq *df = dfc->devfreq;
181         struct devfreq_dev_status status;
182         unsigned long state;
183         unsigned long freq;
184         unsigned long voltage;
185         int res, perf_idx;
186
187         mutex_lock(&df->lock);
188         status = df->last_status;
189         mutex_unlock(&df->lock);
190
191         freq = status.current_frequency;
192
193         if (dfc->power_ops && dfc->power_ops->get_real_power) {
194                 voltage = get_voltage(df, freq);
195                 if (voltage == 0) {
196                         res = -EINVAL;
197                         goto fail;
198                 }
199
200                 res = dfc->power_ops->get_real_power(df, power, freq, voltage);
201                 if (!res) {
202                         state = dfc->capped_state;
203                         dfc->res_util = dfc->em_pd->table[state].power;
204                         dfc->res_util *= SCALE_ERROR_MITIGATION;
205
206                         if (*power > 1)
207                                 dfc->res_util /= *power;
208                 } else {
209                         goto fail;
210                 }
211         } else {
212                 /* Energy Model frequencies are in kHz */
213                 perf_idx = get_perf_idx(dfc->em_pd, freq / 1000);
214                 if (perf_idx < 0) {
215                         res = -EAGAIN;
216                         goto fail;
217                 }
218
219                 _normalize_load(&status);
220
221                 /* Scale power for utilization */
222                 *power = dfc->em_pd->table[perf_idx].power;
223                 *power *= status.busy_time;
224                 *power >>= 10;
225         }
226
227         trace_thermal_power_devfreq_get_power(cdev, &status, freq, *power);
228
229         return 0;
230 fail:
231         /* It is safe to set max in this case */
232         dfc->res_util = SCALE_ERROR_MITIGATION;
233         return res;
234 }
235
236 static int devfreq_cooling_state2power(struct thermal_cooling_device *cdev,
237                                        unsigned long state, u32 *power)
238 {
239         struct devfreq_cooling_device *dfc = cdev->devdata;
240         int perf_idx;
241
242         if (state > dfc->max_state)
243                 return -EINVAL;
244
245         perf_idx = dfc->max_state - state;
246         *power = dfc->em_pd->table[perf_idx].power;
247
248         return 0;
249 }
250
251 static int devfreq_cooling_power2state(struct thermal_cooling_device *cdev,
252                                        u32 power, unsigned long *state)
253 {
254         struct devfreq_cooling_device *dfc = cdev->devdata;
255         struct devfreq *df = dfc->devfreq;
256         struct devfreq_dev_status status;
257         unsigned long freq;
258         s32 est_power;
259         int i;
260
261         mutex_lock(&df->lock);
262         status = df->last_status;
263         mutex_unlock(&df->lock);
264
265         freq = status.current_frequency;
266
267         if (dfc->power_ops && dfc->power_ops->get_real_power) {
268                 /* Scale for resource utilization */
269                 est_power = power * dfc->res_util;
270                 est_power /= SCALE_ERROR_MITIGATION;
271         } else {
272                 /* Scale dynamic power for utilization */
273                 _normalize_load(&status);
274                 est_power = power << 10;
275                 est_power /= status.busy_time;
276         }
277
278         /*
279          * Find the first cooling state that is within the power
280          * budget. The EM power table is sorted ascending.
281          */
282         for (i = dfc->max_state; i > 0; i--)
283                 if (est_power >= dfc->em_pd->table[i].power)
284                         break;
285
286         *state = dfc->max_state - i;
287         dfc->capped_state = *state;
288
289         trace_thermal_power_devfreq_limit(cdev, freq, *state, power);
290         return 0;
291 }
292
293 static struct thermal_cooling_device_ops devfreq_cooling_ops = {
294         .get_max_state = devfreq_cooling_get_max_state,
295         .get_cur_state = devfreq_cooling_get_cur_state,
296         .set_cur_state = devfreq_cooling_set_cur_state,
297 };
298
299 /**
300  * devfreq_cooling_gen_tables() - Generate frequency table.
301  * @dfc:        Pointer to devfreq cooling device.
302  * @num_opps:   Number of OPPs
303  *
304  * Generate frequency table which holds the frequencies in descending
305  * order. That way its indexed by cooling device state. This is for
306  * compatibility with drivers which do not register Energy Model.
307  *
308  * Return: 0 on success, negative error code on failure.
309  */
310 static int devfreq_cooling_gen_tables(struct devfreq_cooling_device *dfc,
311                                       int num_opps)
312 {
313         struct devfreq *df = dfc->devfreq;
314         struct device *dev = df->dev.parent;
315         unsigned long freq;
316         int i;
317
318         dfc->freq_table = kcalloc(num_opps, sizeof(*dfc->freq_table),
319                              GFP_KERNEL);
320         if (!dfc->freq_table)
321                 return -ENOMEM;
322
323         for (i = 0, freq = ULONG_MAX; i < num_opps; i++, freq--) {
324                 struct dev_pm_opp *opp;
325
326                 opp = dev_pm_opp_find_freq_floor(dev, &freq);
327                 if (IS_ERR(opp)) {
328                         kfree(dfc->freq_table);
329                         return PTR_ERR(opp);
330                 }
331
332                 dev_pm_opp_put(opp);
333                 dfc->freq_table[i] = freq;
334         }
335
336         return 0;
337 }
338
339 /**
340  * of_devfreq_cooling_register_power() - Register devfreq cooling device,
341  *                                      with OF and power information.
342  * @np: Pointer to OF device_node.
343  * @df: Pointer to devfreq device.
344  * @dfc_power:  Pointer to devfreq_cooling_power.
345  *
346  * Register a devfreq cooling device.  The available OPPs must be
347  * registered on the device.
348  *
349  * If @dfc_power is provided, the cooling device is registered with the
350  * power extensions.  For the power extensions to work correctly,
351  * devfreq should use the simple_ondemand governor, other governors
352  * are not currently supported.
353  */
354 struct thermal_cooling_device *
355 of_devfreq_cooling_register_power(struct device_node *np, struct devfreq *df,
356                                   struct devfreq_cooling_power *dfc_power)
357 {
358         struct thermal_cooling_device *cdev;
359         struct device *dev = df->dev.parent;
360         struct devfreq_cooling_device *dfc;
361         struct em_perf_domain *em;
362         struct thermal_cooling_device_ops *ops;
363         char *name;
364         int err, num_opps;
365
366         ops = kmemdup(&devfreq_cooling_ops, sizeof(*ops), GFP_KERNEL);
367         if (!ops)
368                 return ERR_PTR(-ENOMEM);
369
370         dfc = kzalloc(sizeof(*dfc), GFP_KERNEL);
371         if (!dfc) {
372                 err = -ENOMEM;
373                 goto free_ops;
374         }
375
376         dfc->devfreq = df;
377
378         em = em_pd_get(dev);
379         if (em && !em_is_artificial(em)) {
380                 dfc->em_pd = em;
381                 ops->get_requested_power =
382                         devfreq_cooling_get_requested_power;
383                 ops->state2power = devfreq_cooling_state2power;
384                 ops->power2state = devfreq_cooling_power2state;
385
386                 dfc->power_ops = dfc_power;
387
388                 num_opps = em_pd_nr_perf_states(dfc->em_pd);
389         } else {
390                 /* Backward compatibility for drivers which do not use IPA */
391                 dev_dbg(dev, "missing proper EM for cooling device\n");
392
393                 num_opps = dev_pm_opp_get_opp_count(dev);
394
395                 err = devfreq_cooling_gen_tables(dfc, num_opps);
396                 if (err)
397                         goto free_dfc;
398         }
399
400         if (num_opps <= 0) {
401                 err = -EINVAL;
402                 goto free_dfc;
403         }
404
405         /* max_state is an index, not a counter */
406         dfc->max_state = num_opps - 1;
407
408         err = dev_pm_qos_add_request(dev, &dfc->req_max_freq,
409                                      DEV_PM_QOS_MAX_FREQUENCY,
410                                      PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE);
411         if (err < 0)
412                 goto free_table;
413
414         err = -ENOMEM;
415         name = kasprintf(GFP_KERNEL, "devfreq-%s", dev_name(dev));
416         if (!name)
417                 goto remove_qos_req;
418
419         cdev = thermal_of_cooling_device_register(np, name, dfc, ops);
420         kfree(name);
421
422         if (IS_ERR(cdev)) {
423                 err = PTR_ERR(cdev);
424                 dev_err(dev,
425                         "Failed to register devfreq cooling device (%d)\n",
426                         err);
427                 goto remove_qos_req;
428         }
429
430         dfc->cdev = cdev;
431
432         return cdev;
433
434 remove_qos_req:
435         dev_pm_qos_remove_request(&dfc->req_max_freq);
436 free_table:
437         kfree(dfc->freq_table);
438 free_dfc:
439         kfree(dfc);
440 free_ops:
441         kfree(ops);
442
443         return ERR_PTR(err);
444 }
445 EXPORT_SYMBOL_GPL(of_devfreq_cooling_register_power);
446
447 /**
448  * of_devfreq_cooling_register() - Register devfreq cooling device,
449  *                                with OF information.
450  * @np: Pointer to OF device_node.
451  * @df: Pointer to devfreq device.
452  */
453 struct thermal_cooling_device *
454 of_devfreq_cooling_register(struct device_node *np, struct devfreq *df)
455 {
456         return of_devfreq_cooling_register_power(np, df, NULL);
457 }
458 EXPORT_SYMBOL_GPL(of_devfreq_cooling_register);
459
460 /**
461  * devfreq_cooling_register() - Register devfreq cooling device.
462  * @df: Pointer to devfreq device.
463  */
464 struct thermal_cooling_device *devfreq_cooling_register(struct devfreq *df)
465 {
466         return of_devfreq_cooling_register(NULL, df);
467 }
468 EXPORT_SYMBOL_GPL(devfreq_cooling_register);
469
470 /**
471  * devfreq_cooling_em_register() - Register devfreq cooling device with
472  *              power information and automatically register Energy Model (EM)
473  * @df:         Pointer to devfreq device.
474  * @dfc_power:  Pointer to devfreq_cooling_power.
475  *
476  * Register a devfreq cooling device and automatically register EM. The
477  * available OPPs must be registered for the device.
478  *
479  * If @dfc_power is provided, the cooling device is registered with the
480  * power extensions. It is using the simple Energy Model which requires
481  * "dynamic-power-coefficient" a devicetree property. To not break drivers
482  * which miss that DT property, the function won't bail out when the EM
483  * registration failed. The cooling device will be registered if everything
484  * else is OK.
485  */
486 struct thermal_cooling_device *
487 devfreq_cooling_em_register(struct devfreq *df,
488                             struct devfreq_cooling_power *dfc_power)
489 {
490         struct thermal_cooling_device *cdev;
491         struct device *dev;
492         int ret;
493
494         if (IS_ERR_OR_NULL(df))
495                 return ERR_PTR(-EINVAL);
496
497         dev = df->dev.parent;
498
499         ret = dev_pm_opp_of_register_em(dev, NULL);
500         if (ret)
501                 dev_dbg(dev, "Unable to register EM for devfreq cooling device (%d)\n",
502                         ret);
503
504         cdev = of_devfreq_cooling_register_power(dev->of_node, df, dfc_power);
505
506         if (IS_ERR_OR_NULL(cdev))
507                 em_dev_unregister_perf_domain(dev);
508
509         return cdev;
510 }
511 EXPORT_SYMBOL_GPL(devfreq_cooling_em_register);
512
513 /**
514  * devfreq_cooling_unregister() - Unregister devfreq cooling device.
515  * @cdev: Pointer to devfreq cooling device to unregister.
516  *
517  * Unregisters devfreq cooling device and related Energy Model if it was
518  * present.
519  */
520 void devfreq_cooling_unregister(struct thermal_cooling_device *cdev)
521 {
522         struct devfreq_cooling_device *dfc;
523         const struct thermal_cooling_device_ops *ops;
524         struct device *dev;
525
526         if (IS_ERR_OR_NULL(cdev))
527                 return;
528
529         ops = cdev->ops;
530         dfc = cdev->devdata;
531         dev = dfc->devfreq->dev.parent;
532
533         thermal_cooling_device_unregister(dfc->cdev);
534         dev_pm_qos_remove_request(&dfc->req_max_freq);
535
536         em_dev_unregister_perf_domain(dev);
537
538         kfree(dfc->freq_table);
539         kfree(dfc);
540         kfree(ops);
541 }
542 EXPORT_SYMBOL_GPL(devfreq_cooling_unregister);