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  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Copyright 2023 Linaro Limited
  4 *
  5 * Author: Daniel Lezcano <daniel.lezcano@linaro.org>
  6 *
  7 * Thermal subsystem debug support
  8 */
  9#include <linux/debugfs.h>
 10#include <linux/ktime.h>
 11#include <linux/list.h>
 12#include <linux/minmax.h>
 13#include <linux/mutex.h>
 14#include <linux/thermal.h>
 15
 16#include "thermal_core.h"
 17
 18static struct dentry *d_root;
 19static struct dentry *d_cdev;
 20static struct dentry *d_tz;
 21
 22/*
 23 * Length of the string containing the thermal zone id or the cooling
 24 * device id, including the ending nul character. We can reasonably
 25 * assume there won't be more than 256 thermal zones as the maximum
 26 * observed today is around 32.
 27 */
 28#define IDSLENGTH 4
 29
 30/*
 31 * The cooling device transition list is stored in a hash table where
 32 * the size is CDEVSTATS_HASH_SIZE. The majority of cooling devices
 33 * have dozen of states but some can have much more, so a hash table
 34 * is more adequate in this case, because the cost of browsing the entire
 35 * list when storing the transitions may not be negligible.
 36 */
 37#define CDEVSTATS_HASH_SIZE 16
 38
 39/**
 40 * struct cdev_debugfs - per cooling device statistics structure
 41 * A cooling device can have a high number of states. Showing the
 42 * transitions on a matrix based representation can be overkill given
 43 * most of the transitions won't happen and we end up with a matrix
 44 * filled with zero. Instead, we show the transitions which actually
 45 * happened.
 46 *
 47 * Every transition updates the current_state and the timestamp. The
 48 * transitions and the durations are stored in lists.
 49 *
 50 * @total: the number of transitions for this cooling device
 51 * @current_state: the current cooling device state
 52 * @timestamp: the state change timestamp
 53 * @transitions: an array of lists containing the state transitions
 54 * @durations: an array of lists containing the residencies of each state
 55 */
 56struct cdev_debugfs {
 57	u32 total;
 58	int current_state;
 59	ktime_t timestamp;
 60	struct list_head transitions[CDEVSTATS_HASH_SIZE];
 61	struct list_head durations[CDEVSTATS_HASH_SIZE];
 62};
 63
 64/**
 65 * struct cdev_record - Common structure for cooling device entry
 66 *
 67 * The following common structure allows to store the information
 68 * related to the transitions and to the state residencies. They are
 69 * identified with a id which is associated to a value. It is used as
 70 * nodes for the "transitions" and "durations" above.
 71 *
 72 * @node: node to insert the structure in a list
 73 * @id: identifier of the value which can be a state or a transition
 74 * @residency: a ktime_t representing a state residency duration
 75 * @count: a number of occurrences
 76 */
 77struct cdev_record {
 78	struct list_head node;
 79	int id;
 80	union {
 81                ktime_t residency;
 82                u64 count;
 83        };
 84};
 85
 86/**
 87 * struct trip_stats - Thermal trip statistics
 88 *
 89 * The trip_stats structure has the relevant information to show the
 90 * statistics related to temperature going above a trip point.
 91 *
 92 * @timestamp: the trip crossing timestamp
 93 * @duration: total time when the zone temperature was above the trip point
 94 * @count: the number of times the zone temperature was above the trip point
 95 * @max: maximum recorded temperature above the trip point
 96 * @min: minimum recorded temperature above the trip point
 97 * @avg: average temperature above the trip point
 98 */
 99struct trip_stats {
100	ktime_t timestamp;
101	ktime_t duration;
102	int count;
103	int max;
104	int min;
105	int avg;
106};
107
108/**
109 * struct tz_episode - A mitigation episode information
110 *
111 * The tz_episode structure describes a mitigation episode. A
112 * mitigation episode begins the trip point with the lower temperature
113 * is crossed the way up and ends when it is crossed the way
114 * down. During this episode we can have multiple trip points crossed
115 * the way up and down if there are multiple trip described in the
116 * firmware after the lowest temperature trip point.
117 *
118 * @timestamp: first trip point crossed the way up
119 * @duration: total duration of the mitigation episode
120 * @node: a list element to be added to the list of tz events
121 * @trip_stats: per trip point statistics, flexible array
122 */
123struct tz_episode {
124	ktime_t timestamp;
125	ktime_t duration;
126	struct list_head node;
127	struct trip_stats trip_stats[];
128};
129
130/**
131 * struct tz_debugfs - Store all mitigation episodes for a thermal zone
132 *
133 * The tz_debugfs structure contains the list of the mitigation
134 * episodes and has to track which trip point has been crossed in
135 * order to handle correctly nested trip point mitigation episodes.
136 *
137 * We keep the history of the trip point crossed in an array and as we
138 * can go back and forth inside this history, eg. trip 0,1,2,1,2,1,0,
139 * we keep track of the current position in the history array.
140 *
141 * @tz_episodes: a list of thermal mitigation episodes
142 * @trips_crossed: an array of trip points crossed by id
143 * @nr_trips: the number of trip points currently being crossed
144 */
145struct tz_debugfs {
146	struct list_head tz_episodes;
147	int *trips_crossed;
148	int nr_trips;
149};
150
151/**
152 * struct thermal_debugfs - High level structure for a thermal object in debugfs
153 *
154 * The thermal_debugfs structure is the common structure used by the
155 * cooling device or the thermal zone to store the statistics.
156 *
157 * @d_top: top directory of the thermal object directory
158 * @lock: per object lock to protect the internals
159 *
160 * @cdev_dbg: a cooling device debug structure
161 * @tz_dbg: a thermal zone debug structure
162 */
163struct thermal_debugfs {
164	struct dentry *d_top;
165	struct mutex lock;
166	union {
167		struct cdev_debugfs cdev_dbg;
168		struct tz_debugfs tz_dbg;
169	};
170};
171
172void thermal_debug_init(void)
173{
174	d_root = debugfs_create_dir("thermal", NULL);
175	if (!d_root)
176		return;
177
178	d_cdev = debugfs_create_dir("cooling_devices", d_root);
179	if (!d_cdev)
180		return;
181
182	d_tz = debugfs_create_dir("thermal_zones", d_root);
183}
184
185static struct thermal_debugfs *thermal_debugfs_add_id(struct dentry *d, int id)
186{
187	struct thermal_debugfs *thermal_dbg;
188	char ids[IDSLENGTH];
189
190	thermal_dbg = kzalloc(sizeof(*thermal_dbg), GFP_KERNEL);
191	if (!thermal_dbg)
192		return NULL;
193
194	mutex_init(&thermal_dbg->lock);
195
196	snprintf(ids, IDSLENGTH, "%d", id);
197
198	thermal_dbg->d_top = debugfs_create_dir(ids, d);
199	if (!thermal_dbg->d_top) {
200		kfree(thermal_dbg);
201		return NULL;
202	}
203
204	return thermal_dbg;
205}
206
207static void thermal_debugfs_remove_id(struct thermal_debugfs *thermal_dbg)
208{
209	if (!thermal_dbg)
210		return;
211
212	debugfs_remove(thermal_dbg->d_top);
213
214	kfree(thermal_dbg);
215}
216
217static struct cdev_record *
218thermal_debugfs_cdev_record_alloc(struct thermal_debugfs *thermal_dbg,
219				  struct list_head *lists, int id)
220{
221	struct cdev_record *cdev_record;
222
223	cdev_record = kzalloc(sizeof(*cdev_record), GFP_KERNEL);
224	if (!cdev_record)
225		return NULL;
226
227	cdev_record->id = id;
228	INIT_LIST_HEAD(&cdev_record->node);
229	list_add_tail(&cdev_record->node,
230		      &lists[cdev_record->id % CDEVSTATS_HASH_SIZE]);
231
232	return cdev_record;
233}
234
235static struct cdev_record *
236thermal_debugfs_cdev_record_find(struct thermal_debugfs *thermal_dbg,
237				 struct list_head *lists, int id)
238{
239	struct cdev_record *entry;
240
241	list_for_each_entry(entry, &lists[id % CDEVSTATS_HASH_SIZE], node)
242		if (entry->id == id)
243			return entry;
244
245	return NULL;
246}
247
248static struct cdev_record *
249thermal_debugfs_cdev_record_get(struct thermal_debugfs *thermal_dbg,
250				struct list_head *lists, int id)
251{
252	struct cdev_record *cdev_record;
253
254	cdev_record = thermal_debugfs_cdev_record_find(thermal_dbg, lists, id);
255	if (cdev_record)
256		return cdev_record;
257
258	return thermal_debugfs_cdev_record_alloc(thermal_dbg, lists, id);
259}
260
261static void thermal_debugfs_cdev_clear(struct cdev_debugfs *cdev_dbg)
262{
263	int i;
264	struct cdev_record *entry, *tmp;
265
266	for (i = 0; i < CDEVSTATS_HASH_SIZE; i++) {
267
268		list_for_each_entry_safe(entry, tmp,
269					 &cdev_dbg->transitions[i], node) {
270			list_del(&entry->node);
271			kfree(entry);
272		}
273
274		list_for_each_entry_safe(entry, tmp,
275					 &cdev_dbg->durations[i], node) {
276			list_del(&entry->node);
277			kfree(entry);
278		}
279	}
280
281	cdev_dbg->total = 0;
282}
283
284static void *cdev_seq_start(struct seq_file *s, loff_t *pos)
285{
286	struct thermal_debugfs *thermal_dbg = s->private;
287
288	mutex_lock(&thermal_dbg->lock);
289
290	return (*pos < CDEVSTATS_HASH_SIZE) ? pos : NULL;
291}
292
293static void *cdev_seq_next(struct seq_file *s, void *v, loff_t *pos)
294{
295	(*pos)++;
296
297	return (*pos < CDEVSTATS_HASH_SIZE) ? pos : NULL;
298}
299
300static void cdev_seq_stop(struct seq_file *s, void *v)
301{
302	struct thermal_debugfs *thermal_dbg = s->private;
303
304	mutex_unlock(&thermal_dbg->lock);
305}
306
307static int cdev_tt_seq_show(struct seq_file *s, void *v)
308{
309	struct thermal_debugfs *thermal_dbg = s->private;
310	struct cdev_debugfs *cdev_dbg = &thermal_dbg->cdev_dbg;
311	struct list_head *transitions = cdev_dbg->transitions;
312	struct cdev_record *entry;
313	int i = *(loff_t *)v;
314
315	if (!i)
316		seq_puts(s, "Transition\tOccurences\n");
317
318	list_for_each_entry(entry, &transitions[i], node) {
319		/*
320		 * Assuming maximum cdev states is 1024, the longer
321		 * string for a transition would be "1024->1024\0"
322		 */
323		char buffer[11];
324
325		snprintf(buffer, ARRAY_SIZE(buffer), "%d->%d",
326			 entry->id >> 16, entry->id & 0xFFFF);
327
328		seq_printf(s, "%-10s\t%-10llu\n", buffer, entry->count);
329	}
330
331	return 0;
332}
333
334static const struct seq_operations tt_sops = {
335	.start = cdev_seq_start,
336	.next = cdev_seq_next,
337	.stop = cdev_seq_stop,
338	.show = cdev_tt_seq_show,
339};
340
341DEFINE_SEQ_ATTRIBUTE(tt);
342
343static int cdev_dt_seq_show(struct seq_file *s, void *v)
344{
345	struct thermal_debugfs *thermal_dbg = s->private;
346	struct cdev_debugfs *cdev_dbg = &thermal_dbg->cdev_dbg;
347	struct list_head *durations = cdev_dbg->durations;
348	struct cdev_record *entry;
349	int i = *(loff_t *)v;
350
351	if (!i)
352		seq_puts(s, "State\tResidency\n");
353
354	list_for_each_entry(entry, &durations[i], node) {
355		s64 duration = ktime_to_ms(entry->residency);
356
357		if (entry->id == cdev_dbg->current_state)
358			duration += ktime_ms_delta(ktime_get(),
359						   cdev_dbg->timestamp);
360
361		seq_printf(s, "%-5d\t%-10llu\n", entry->id, duration);
362	}
363
364	return 0;
365}
366
367static const struct seq_operations dt_sops = {
368	.start = cdev_seq_start,
369	.next = cdev_seq_next,
370	.stop = cdev_seq_stop,
371	.show = cdev_dt_seq_show,
372};
373
374DEFINE_SEQ_ATTRIBUTE(dt);
375
376static int cdev_clear_set(void *data, u64 val)
377{
378	struct thermal_debugfs *thermal_dbg = data;
379
380	if (!val)
381		return -EINVAL;
382
383	mutex_lock(&thermal_dbg->lock);
384
385	thermal_debugfs_cdev_clear(&thermal_dbg->cdev_dbg);
386
387	mutex_unlock(&thermal_dbg->lock);
388
389	return 0;
390}
391
392DEFINE_DEBUGFS_ATTRIBUTE(cdev_clear_fops, NULL, cdev_clear_set, "%llu\n");
393
394/**
395 * thermal_debug_cdev_state_update - Update a cooling device state change
396 *
397 * Computes a transition and the duration of the previous state residency.
398 *
399 * @cdev : a pointer to a cooling device
400 * @new_state: an integer corresponding to the new cooling device state
401 */
402void thermal_debug_cdev_state_update(const struct thermal_cooling_device *cdev,
403				     int new_state)
404{
405	struct thermal_debugfs *thermal_dbg = cdev->debugfs;
406	struct cdev_debugfs *cdev_dbg;
407	struct cdev_record *cdev_record;
408	int transition, old_state;
409
410	if (!thermal_dbg || (thermal_dbg->cdev_dbg.current_state == new_state))
411		return;
412
413	mutex_lock(&thermal_dbg->lock);
414
415	cdev_dbg = &thermal_dbg->cdev_dbg;
416
417	old_state = cdev_dbg->current_state;
418
419	/*
420	 * Get the old state information in the durations list. If
421	 * this one does not exist, a new allocated one will be
422	 * returned. Recompute the total duration in the old state and
423	 * get a new timestamp for the new state.
424	 */
425	cdev_record = thermal_debugfs_cdev_record_get(thermal_dbg,
426						      cdev_dbg->durations,
427						      old_state);
428	if (cdev_record) {
429		ktime_t now = ktime_get();
430		ktime_t delta = ktime_sub(now, cdev_dbg->timestamp);
431		cdev_record->residency = ktime_add(cdev_record->residency, delta);
432		cdev_dbg->timestamp = now;
433	}
434
435	cdev_dbg->current_state = new_state;
436	transition = (old_state << 16) | new_state;
437
438	/*
439	 * Get the transition in the transitions list. If this one
440	 * does not exist, a new allocated one will be returned.
441	 * Increment the occurrence of this transition which is stored
442	 * in the value field.
443	 */
444	cdev_record = thermal_debugfs_cdev_record_get(thermal_dbg,
445						      cdev_dbg->transitions,
446						      transition);
447	if (cdev_record)
448		cdev_record->count++;
449
450	cdev_dbg->total++;
451
452	mutex_unlock(&thermal_dbg->lock);
453}
454
455/**
456 * thermal_debug_cdev_add - Add a cooling device debugfs entry
457 *
458 * Allocates a cooling device object for debug, initializes the
459 * statistics and create the entries in sysfs.
460 * @cdev: a pointer to a cooling device
461 */
462void thermal_debug_cdev_add(struct thermal_cooling_device *cdev)
463{
464	struct thermal_debugfs *thermal_dbg;
465	struct cdev_debugfs *cdev_dbg;
466	int i;
467
468	thermal_dbg = thermal_debugfs_add_id(d_cdev, cdev->id);
469	if (!thermal_dbg)
470		return;
471
472	cdev_dbg = &thermal_dbg->cdev_dbg;
473
474	for (i = 0; i < CDEVSTATS_HASH_SIZE; i++) {
475		INIT_LIST_HEAD(&cdev_dbg->transitions[i]);
476		INIT_LIST_HEAD(&cdev_dbg->durations[i]);
477	}
478
479	cdev_dbg->current_state = 0;
480	cdev_dbg->timestamp = ktime_get();
481
482	debugfs_create_file("trans_table", 0400, thermal_dbg->d_top,
483			    thermal_dbg, &tt_fops);
484
485	debugfs_create_file("time_in_state_ms", 0400, thermal_dbg->d_top,
486			    thermal_dbg, &dt_fops);
487
488	debugfs_create_file("clear", 0200, thermal_dbg->d_top,
489			    thermal_dbg, &cdev_clear_fops);
490
491	debugfs_create_u32("total_trans", 0400, thermal_dbg->d_top,
492			   &cdev_dbg->total);
493
494	cdev->debugfs = thermal_dbg;
495}
496
497/**
498 * thermal_debug_cdev_remove - Remove a cooling device debugfs entry
499 *
500 * Frees the statistics memory data and remove the debugfs entry
501 *
502 * @cdev: a pointer to a cooling device
503 */
504void thermal_debug_cdev_remove(struct thermal_cooling_device *cdev)
505{
506	struct thermal_debugfs *thermal_dbg = cdev->debugfs;
507
508	if (!thermal_dbg)
509		return;
510
511	mutex_lock(&thermal_dbg->lock);
512
513	thermal_debugfs_cdev_clear(&thermal_dbg->cdev_dbg);
514	cdev->debugfs = NULL;
515
516	mutex_unlock(&thermal_dbg->lock);
517
518	thermal_debugfs_remove_id(thermal_dbg);
519}
520
521static struct tz_episode *thermal_debugfs_tz_event_alloc(struct thermal_zone_device *tz,
522							ktime_t now)
523{
524	struct tz_episode *tze;
525	int i;
526
527	tze = kzalloc(struct_size(tze, trip_stats, tz->num_trips), GFP_KERNEL);
528	if (!tze)
529		return NULL;
530
531	INIT_LIST_HEAD(&tze->node);
532	tze->timestamp = now;
533
534	for (i = 0; i < tz->num_trips; i++) {
535		tze->trip_stats[i].min = INT_MAX;
536		tze->trip_stats[i].max = INT_MIN;
537	}
538
539	return tze;
540}
541
542void thermal_debug_tz_trip_up(struct thermal_zone_device *tz,
543			      const struct thermal_trip *trip)
544{
545	struct tz_episode *tze;
546	struct tz_debugfs *tz_dbg;
547	struct thermal_debugfs *thermal_dbg = tz->debugfs;
548	int temperature = tz->temperature;
549	int trip_id = thermal_zone_trip_id(tz, trip);
550	ktime_t now = ktime_get();
551
552	if (!thermal_dbg)
553		return;
554
555	mutex_lock(&thermal_dbg->lock);
556
557	tz_dbg = &thermal_dbg->tz_dbg;
558
559	/*
560	 * The mitigation is starting. A mitigation can contain
561	 * several episodes where each of them is related to a
562	 * temperature crossing a trip point. The episodes are
563	 * nested. That means when the temperature is crossing the
564	 * first trip point, the duration begins to be measured. If
565	 * the temperature continues to increase and reaches the
566	 * second trip point, the duration of the first trip must be
567	 * also accumulated.
568	 *
569	 * eg.
570	 *
571	 * temp
572	 *   ^
573	 *   |             --------
574	 * trip 2         /        \         ------
575	 *   |           /|        |\      /|      |\
576	 * trip 1       / |        | `----  |      | \
577	 *   |         /| |        |        |      | |\
578	 * trip 0     / | |        |        |      | | \
579	 *   |       /| | |        |        |      | | |\
580	 *   |      / | | |        |        |      | | | `--
581	 *   |     /  | | |        |        |      | | |
582	 *   |-----   | | |        |        |      | | |
583	 *   |        | | |        |        |      | | |
584	 *    --------|-|-|--------|--------|------|-|-|------------------> time
585	 *            | | |<--t2-->|        |<-t2'>| | |
586	 *            | |                            | |
587	 *            | |<------------t1------------>| |
588	 *            |                                |
589	 *            |<-------------t0--------------->|
590	 *
591	 */
592	if (!tz_dbg->nr_trips) {
593		tze = thermal_debugfs_tz_event_alloc(tz, now);
594		if (!tze)
595			goto unlock;
596
597		list_add(&tze->node, &tz_dbg->tz_episodes);
598	}
599
600	/*
601	 * Each time a trip point is crossed the way up, the trip_id
602	 * is stored in the trip_crossed array and the nr_trips is
603	 * incremented. A nr_trips equal to zero means we are entering
604	 * a mitigation episode.
605	 *
606	 * The trip ids may not be in the ascending order but the
607	 * result in the array trips_crossed will be in the ascending
608	 * temperature order. The function detecting when a trip point
609	 * is crossed the way down will handle the very rare case when
610	 * the trip points may have been reordered during this
611	 * mitigation episode.
612	 */
613	tz_dbg->trips_crossed[tz_dbg->nr_trips++] = trip_id;
614
615	tze = list_first_entry(&tz_dbg->tz_episodes, struct tz_episode, node);
616	tze->trip_stats[trip_id].timestamp = now;
617	tze->trip_stats[trip_id].max = max(tze->trip_stats[trip_id].max, temperature);
618	tze->trip_stats[trip_id].min = min(tze->trip_stats[trip_id].min, temperature);
619	tze->trip_stats[trip_id].avg = tze->trip_stats[trip_id].avg +
620		(temperature - tze->trip_stats[trip_id].avg) /
621		tze->trip_stats[trip_id].count;
622
623unlock:
624	mutex_unlock(&thermal_dbg->lock);
625}
626
627void thermal_debug_tz_trip_down(struct thermal_zone_device *tz,
628				const struct thermal_trip *trip)
629{
630	struct thermal_debugfs *thermal_dbg = tz->debugfs;
631	struct tz_episode *tze;
632	struct tz_debugfs *tz_dbg;
633	ktime_t delta, now = ktime_get();
634	int trip_id = thermal_zone_trip_id(tz, trip);
635	int i;
636
637	if (!thermal_dbg)
638		return;
639
640	mutex_lock(&thermal_dbg->lock);
641
642	tz_dbg = &thermal_dbg->tz_dbg;
643
644	/*
645	 * The temperature crosses the way down but there was not
646	 * mitigation detected before. That may happen when the
647	 * temperature is greater than a trip point when registering a
648	 * thermal zone, which is a common use case as the kernel has
649	 * no mitigation mechanism yet at boot time.
650	 */
651	if (!tz_dbg->nr_trips)
652		goto out;
653
654	for (i = tz_dbg->nr_trips - 1; i >= 0; i--) {
655		if (tz_dbg->trips_crossed[i] == trip_id)
656			break;
657	}
658
659	if (i < 0)
660		goto out;
661
662	tz_dbg->nr_trips--;
663
664	if (i < tz_dbg->nr_trips)
665		tz_dbg->trips_crossed[i] = tz_dbg->trips_crossed[tz_dbg->nr_trips];
666
667	tze = list_first_entry(&tz_dbg->tz_episodes, struct tz_episode, node);
668
669	delta = ktime_sub(now, tze->trip_stats[trip_id].timestamp);
670
671	tze->trip_stats[trip_id].duration =
672		ktime_add(delta, tze->trip_stats[trip_id].duration);
673
674	/*
675	 * This event closes the mitigation as we are crossing the
676	 * last trip point the way down.
677	 */
678	if (!tz_dbg->nr_trips)
679		tze->duration = ktime_sub(now, tze->timestamp);
680
681out:
682	mutex_unlock(&thermal_dbg->lock);
683}
684
685void thermal_debug_update_temp(struct thermal_zone_device *tz)
686{
687	struct thermal_debugfs *thermal_dbg = tz->debugfs;
688	struct tz_episode *tze;
689	struct tz_debugfs *tz_dbg;
690	int trip_id, i;
691
692	if (!thermal_dbg)
693		return;
694
695	mutex_lock(&thermal_dbg->lock);
696
697	tz_dbg = &thermal_dbg->tz_dbg;
698
699	if (!tz_dbg->nr_trips)
700		goto out;
701
702	for (i = 0; i < tz_dbg->nr_trips; i++) {
703		trip_id = tz_dbg->trips_crossed[i];
704		tze = list_first_entry(&tz_dbg->tz_episodes, struct tz_episode, node);
705		tze->trip_stats[trip_id].count++;
706		tze->trip_stats[trip_id].max = max(tze->trip_stats[trip_id].max, tz->temperature);
707		tze->trip_stats[trip_id].min = min(tze->trip_stats[trip_id].min, tz->temperature);
708		tze->trip_stats[trip_id].avg = tze->trip_stats[trip_id].avg +
709			(tz->temperature - tze->trip_stats[trip_id].avg) /
710			tze->trip_stats[trip_id].count;
711	}
712out:
713	mutex_unlock(&thermal_dbg->lock);
714}
715
716static void *tze_seq_start(struct seq_file *s, loff_t *pos)
717{
718	struct thermal_zone_device *tz = s->private;
719	struct thermal_debugfs *thermal_dbg = tz->debugfs;
720	struct tz_debugfs *tz_dbg = &thermal_dbg->tz_dbg;
721
722	mutex_lock(&thermal_dbg->lock);
723
724	return seq_list_start(&tz_dbg->tz_episodes, *pos);
725}
726
727static void *tze_seq_next(struct seq_file *s, void *v, loff_t *pos)
728{
729	struct thermal_zone_device *tz = s->private;
730	struct thermal_debugfs *thermal_dbg = tz->debugfs;
731	struct tz_debugfs *tz_dbg = &thermal_dbg->tz_dbg;
732
733	return seq_list_next(v, &tz_dbg->tz_episodes, pos);
734}
735
736static void tze_seq_stop(struct seq_file *s, void *v)
737{
738	struct thermal_zone_device *tz = s->private;
739	struct thermal_debugfs *thermal_dbg = tz->debugfs;
740
741	mutex_unlock(&thermal_dbg->lock);
742}
743
744static int tze_seq_show(struct seq_file *s, void *v)
745{
746	struct thermal_zone_device *tz = s->private;
747	struct thermal_trip *trip;
748	struct tz_episode *tze;
749	const char *type;
750	int trip_id;
751
752	tze = list_entry((struct list_head *)v, struct tz_episode, node);
753
754	seq_printf(s, ",-Mitigation at %lluus, duration=%llums\n",
755		   ktime_to_us(tze->timestamp),
756		   ktime_to_ms(tze->duration));
757
758	seq_printf(s, "| trip |     type | temp(°mC) | hyst(°mC) |  duration  |  avg(°mC) |  min(°mC) |  max(°mC) |\n");
759
760	for_each_trip(tz, trip) {
761		/*
762		 * There is no possible mitigation happening at the
763		 * critical trip point, so the stats will be always
764		 * zero, skip this trip point
765		 */
766		if (trip->type == THERMAL_TRIP_CRITICAL)
767			continue;
768
769		if (trip->type == THERMAL_TRIP_PASSIVE)
770			type = "passive";
771		else if (trip->type == THERMAL_TRIP_ACTIVE)
772			type = "active";
773		else
774			type = "hot";
775
776		trip_id = thermal_zone_trip_id(tz, trip);
777
778		seq_printf(s, "| %*d | %*s | %*d | %*d | %*lld | %*d | %*d | %*d |\n",
779			   4 , trip_id,
780			   8, type,
781			   9, trip->temperature,
782			   9, trip->hysteresis,
783			   10, ktime_to_ms(tze->trip_stats[trip_id].duration),
784			   9, tze->trip_stats[trip_id].avg,
785			   9, tze->trip_stats[trip_id].min,
786			   9, tze->trip_stats[trip_id].max);
787	}
788
789	return 0;
790}
791
792static const struct seq_operations tze_sops = {
793	.start = tze_seq_start,
794	.next = tze_seq_next,
795	.stop = tze_seq_stop,
796	.show = tze_seq_show,
797};
798
799DEFINE_SEQ_ATTRIBUTE(tze);
800
801void thermal_debug_tz_add(struct thermal_zone_device *tz)
802{
803	struct thermal_debugfs *thermal_dbg;
804	struct tz_debugfs *tz_dbg;
805
806	thermal_dbg = thermal_debugfs_add_id(d_tz, tz->id);
807	if (!thermal_dbg)
808		return;
809
810	tz_dbg = &thermal_dbg->tz_dbg;
811
812	tz_dbg->trips_crossed = kzalloc(sizeof(int) * tz->num_trips, GFP_KERNEL);
813	if (!tz_dbg->trips_crossed) {
814		thermal_debugfs_remove_id(thermal_dbg);
815		return;
816	}
817
818	INIT_LIST_HEAD(&tz_dbg->tz_episodes);
819
820	debugfs_create_file("mitigations", 0400, thermal_dbg->d_top, tz, &tze_fops);
821
822	tz->debugfs = thermal_dbg;
823}
824
825void thermal_debug_tz_remove(struct thermal_zone_device *tz)
826{
827	struct thermal_debugfs *thermal_dbg = tz->debugfs;
828
829	if (!thermal_dbg)
830		return;
831
832	mutex_lock(&thermal_dbg->lock);
833
834	tz->debugfs = NULL;
835
836	mutex_unlock(&thermal_dbg->lock);
837
838	thermal_debugfs_remove_id(thermal_dbg);
839}