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-rw-r--r--drivers/thermal/thermal_debugfs.c839
1 files changed, 839 insertions, 0 deletions
diff --git a/drivers/thermal/thermal_debugfs.c b/drivers/thermal/thermal_debugfs.c
new file mode 100644
index 000000000000..c617e8b9f0dd
--- /dev/null
+++ b/drivers/thermal/thermal_debugfs.c
@@ -0,0 +1,839 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2023 Linaro Limited
+ *
+ * Author: Daniel Lezcano <daniel.lezcano@linaro.org>
+ *
+ * Thermal subsystem debug support
+ */
+#include <linux/debugfs.h>
+#include <linux/ktime.h>
+#include <linux/list.h>
+#include <linux/minmax.h>
+#include <linux/mutex.h>
+#include <linux/thermal.h>
+
+#include "thermal_core.h"
+
+static struct dentry *d_root;
+static struct dentry *d_cdev;
+static struct dentry *d_tz;
+
+/*
+ * Length of the string containing the thermal zone id or the cooling
+ * device id, including the ending nul character. We can reasonably
+ * assume there won't be more than 256 thermal zones as the maximum
+ * observed today is around 32.
+ */
+#define IDSLENGTH 4
+
+/*
+ * The cooling device transition list is stored in a hash table where
+ * the size is CDEVSTATS_HASH_SIZE. The majority of cooling devices
+ * have dozen of states but some can have much more, so a hash table
+ * is more adequate in this case, because the cost of browsing the entire
+ * list when storing the transitions may not be negligible.
+ */
+#define CDEVSTATS_HASH_SIZE 16
+
+/**
+ * struct cdev_debugfs - per cooling device statistics structure
+ * A cooling device can have a high number of states. Showing the
+ * transitions on a matrix based representation can be overkill given
+ * most of the transitions won't happen and we end up with a matrix
+ * filled with zero. Instead, we show the transitions which actually
+ * happened.
+ *
+ * Every transition updates the current_state and the timestamp. The
+ * transitions and the durations are stored in lists.
+ *
+ * @total: the number of transitions for this cooling device
+ * @current_state: the current cooling device state
+ * @timestamp: the state change timestamp
+ * @transitions: an array of lists containing the state transitions
+ * @durations: an array of lists containing the residencies of each state
+ */
+struct cdev_debugfs {
+ u32 total;
+ int current_state;
+ ktime_t timestamp;
+ struct list_head transitions[CDEVSTATS_HASH_SIZE];
+ struct list_head durations[CDEVSTATS_HASH_SIZE];
+};
+
+/**
+ * struct cdev_record - Common structure for cooling device entry
+ *
+ * The following common structure allows to store the information
+ * related to the transitions and to the state residencies. They are
+ * identified with a id which is associated to a value. It is used as
+ * nodes for the "transitions" and "durations" above.
+ *
+ * @node: node to insert the structure in a list
+ * @id: identifier of the value which can be a state or a transition
+ * @residency: a ktime_t representing a state residency duration
+ * @count: a number of occurrences
+ */
+struct cdev_record {
+ struct list_head node;
+ int id;
+ union {
+ ktime_t residency;
+ u64 count;
+ };
+};
+
+/**
+ * struct trip_stats - Thermal trip statistics
+ *
+ * The trip_stats structure has the relevant information to show the
+ * statistics related to temperature going above a trip point.
+ *
+ * @timestamp: the trip crossing timestamp
+ * @duration: total time when the zone temperature was above the trip point
+ * @count: the number of times the zone temperature was above the trip point
+ * @max: maximum recorded temperature above the trip point
+ * @min: minimum recorded temperature above the trip point
+ * @avg: average temperature above the trip point
+ */
+struct trip_stats {
+ ktime_t timestamp;
+ ktime_t duration;
+ int count;
+ int max;
+ int min;
+ int avg;
+};
+
+/**
+ * struct tz_episode - A mitigation episode information
+ *
+ * The tz_episode structure describes a mitigation episode. A
+ * mitigation episode begins the trip point with the lower temperature
+ * is crossed the way up and ends when it is crossed the way
+ * down. During this episode we can have multiple trip points crossed
+ * the way up and down if there are multiple trip described in the
+ * firmware after the lowest temperature trip point.
+ *
+ * @timestamp: first trip point crossed the way up
+ * @duration: total duration of the mitigation episode
+ * @node: a list element to be added to the list of tz events
+ * @trip_stats: per trip point statistics, flexible array
+ */
+struct tz_episode {
+ ktime_t timestamp;
+ ktime_t duration;
+ struct list_head node;
+ struct trip_stats trip_stats[];
+};
+
+/**
+ * struct tz_debugfs - Store all mitigation episodes for a thermal zone
+ *
+ * The tz_debugfs structure contains the list of the mitigation
+ * episodes and has to track which trip point has been crossed in
+ * order to handle correctly nested trip point mitigation episodes.
+ *
+ * We keep the history of the trip point crossed in an array and as we
+ * can go back and forth inside this history, eg. trip 0,1,2,1,2,1,0,
+ * we keep track of the current position in the history array.
+ *
+ * @tz_episodes: a list of thermal mitigation episodes
+ * @trips_crossed: an array of trip points crossed by id
+ * @nr_trips: the number of trip points currently being crossed
+ */
+struct tz_debugfs {
+ struct list_head tz_episodes;
+ int *trips_crossed;
+ int nr_trips;
+};
+
+/**
+ * struct thermal_debugfs - High level structure for a thermal object in debugfs
+ *
+ * The thermal_debugfs structure is the common structure used by the
+ * cooling device or the thermal zone to store the statistics.
+ *
+ * @d_top: top directory of the thermal object directory
+ * @lock: per object lock to protect the internals
+ *
+ * @cdev_dbg: a cooling device debug structure
+ * @tz_dbg: a thermal zone debug structure
+ */
+struct thermal_debugfs {
+ struct dentry *d_top;
+ struct mutex lock;
+ union {
+ struct cdev_debugfs cdev_dbg;
+ struct tz_debugfs tz_dbg;
+ };
+};
+
+void thermal_debug_init(void)
+{
+ d_root = debugfs_create_dir("thermal", NULL);
+ if (!d_root)
+ return;
+
+ d_cdev = debugfs_create_dir("cooling_devices", d_root);
+ if (!d_cdev)
+ return;
+
+ d_tz = debugfs_create_dir("thermal_zones", d_root);
+}
+
+static struct thermal_debugfs *thermal_debugfs_add_id(struct dentry *d, int id)
+{
+ struct thermal_debugfs *thermal_dbg;
+ char ids[IDSLENGTH];
+
+ thermal_dbg = kzalloc(sizeof(*thermal_dbg), GFP_KERNEL);
+ if (!thermal_dbg)
+ return NULL;
+
+ mutex_init(&thermal_dbg->lock);
+
+ snprintf(ids, IDSLENGTH, "%d", id);
+
+ thermal_dbg->d_top = debugfs_create_dir(ids, d);
+ if (!thermal_dbg->d_top) {
+ kfree(thermal_dbg);
+ return NULL;
+ }
+
+ return thermal_dbg;
+}
+
+static void thermal_debugfs_remove_id(struct thermal_debugfs *thermal_dbg)
+{
+ if (!thermal_dbg)
+ return;
+
+ debugfs_remove(thermal_dbg->d_top);
+
+ kfree(thermal_dbg);
+}
+
+static struct cdev_record *
+thermal_debugfs_cdev_record_alloc(struct thermal_debugfs *thermal_dbg,
+ struct list_head *lists, int id)
+{
+ struct cdev_record *cdev_record;
+
+ cdev_record = kzalloc(sizeof(*cdev_record), GFP_KERNEL);
+ if (!cdev_record)
+ return NULL;
+
+ cdev_record->id = id;
+ INIT_LIST_HEAD(&cdev_record->node);
+ list_add_tail(&cdev_record->node,
+ &lists[cdev_record->id % CDEVSTATS_HASH_SIZE]);
+
+ return cdev_record;
+}
+
+static struct cdev_record *
+thermal_debugfs_cdev_record_find(struct thermal_debugfs *thermal_dbg,
+ struct list_head *lists, int id)
+{
+ struct cdev_record *entry;
+
+ list_for_each_entry(entry, &lists[id % CDEVSTATS_HASH_SIZE], node)
+ if (entry->id == id)
+ return entry;
+
+ return NULL;
+}
+
+static struct cdev_record *
+thermal_debugfs_cdev_record_get(struct thermal_debugfs *thermal_dbg,
+ struct list_head *lists, int id)
+{
+ struct cdev_record *cdev_record;
+
+ cdev_record = thermal_debugfs_cdev_record_find(thermal_dbg, lists, id);
+ if (cdev_record)
+ return cdev_record;
+
+ return thermal_debugfs_cdev_record_alloc(thermal_dbg, lists, id);
+}
+
+static void thermal_debugfs_cdev_clear(struct cdev_debugfs *cdev_dbg)
+{
+ int i;
+ struct cdev_record *entry, *tmp;
+
+ for (i = 0; i < CDEVSTATS_HASH_SIZE; i++) {
+
+ list_for_each_entry_safe(entry, tmp,
+ &cdev_dbg->transitions[i], node) {
+ list_del(&entry->node);
+ kfree(entry);
+ }
+
+ list_for_each_entry_safe(entry, tmp,
+ &cdev_dbg->durations[i], node) {
+ list_del(&entry->node);
+ kfree(entry);
+ }
+ }
+
+ cdev_dbg->total = 0;
+}
+
+static void *cdev_seq_start(struct seq_file *s, loff_t *pos)
+{
+ struct thermal_debugfs *thermal_dbg = s->private;
+
+ mutex_lock(&thermal_dbg->lock);
+
+ return (*pos < CDEVSTATS_HASH_SIZE) ? pos : NULL;
+}
+
+static void *cdev_seq_next(struct seq_file *s, void *v, loff_t *pos)
+{
+ (*pos)++;
+
+ return (*pos < CDEVSTATS_HASH_SIZE) ? pos : NULL;
+}
+
+static void cdev_seq_stop(struct seq_file *s, void *v)
+{
+ struct thermal_debugfs *thermal_dbg = s->private;
+
+ mutex_unlock(&thermal_dbg->lock);
+}
+
+static int cdev_tt_seq_show(struct seq_file *s, void *v)
+{
+ struct thermal_debugfs *thermal_dbg = s->private;
+ struct cdev_debugfs *cdev_dbg = &thermal_dbg->cdev_dbg;
+ struct list_head *transitions = cdev_dbg->transitions;
+ struct cdev_record *entry;
+ int i = *(loff_t *)v;
+
+ if (!i)
+ seq_puts(s, "Transition\tOccurences\n");
+
+ list_for_each_entry(entry, &transitions[i], node) {
+ /*
+ * Assuming maximum cdev states is 1024, the longer
+ * string for a transition would be "1024->1024\0"
+ */
+ char buffer[11];
+
+ snprintf(buffer, ARRAY_SIZE(buffer), "%d->%d",
+ entry->id >> 16, entry->id & 0xFFFF);
+
+ seq_printf(s, "%-10s\t%-10llu\n", buffer, entry->count);
+ }
+
+ return 0;
+}
+
+static const struct seq_operations tt_sops = {
+ .start = cdev_seq_start,
+ .next = cdev_seq_next,
+ .stop = cdev_seq_stop,
+ .show = cdev_tt_seq_show,
+};
+
+DEFINE_SEQ_ATTRIBUTE(tt);
+
+static int cdev_dt_seq_show(struct seq_file *s, void *v)
+{
+ struct thermal_debugfs *thermal_dbg = s->private;
+ struct cdev_debugfs *cdev_dbg = &thermal_dbg->cdev_dbg;
+ struct list_head *durations = cdev_dbg->durations;
+ struct cdev_record *entry;
+ int i = *(loff_t *)v;
+
+ if (!i)
+ seq_puts(s, "State\tResidency\n");
+
+ list_for_each_entry(entry, &durations[i], node) {
+ s64 duration = ktime_to_ms(entry->residency);
+
+ if (entry->id == cdev_dbg->current_state)
+ duration += ktime_ms_delta(ktime_get(),
+ cdev_dbg->timestamp);
+
+ seq_printf(s, "%-5d\t%-10llu\n", entry->id, duration);
+ }
+
+ return 0;
+}
+
+static const struct seq_operations dt_sops = {
+ .start = cdev_seq_start,
+ .next = cdev_seq_next,
+ .stop = cdev_seq_stop,
+ .show = cdev_dt_seq_show,
+};
+
+DEFINE_SEQ_ATTRIBUTE(dt);
+
+static int cdev_clear_set(void *data, u64 val)
+{
+ struct thermal_debugfs *thermal_dbg = data;
+
+ if (!val)
+ return -EINVAL;
+
+ mutex_lock(&thermal_dbg->lock);
+
+ thermal_debugfs_cdev_clear(&thermal_dbg->cdev_dbg);
+
+ mutex_unlock(&thermal_dbg->lock);
+
+ return 0;
+}
+
+DEFINE_DEBUGFS_ATTRIBUTE(cdev_clear_fops, NULL, cdev_clear_set, "%llu\n");
+
+/**
+ * thermal_debug_cdev_state_update - Update a cooling device state change
+ *
+ * Computes a transition and the duration of the previous state residency.
+ *
+ * @cdev : a pointer to a cooling device
+ * @new_state: an integer corresponding to the new cooling device state
+ */
+void thermal_debug_cdev_state_update(const struct thermal_cooling_device *cdev,
+ int new_state)
+{
+ struct thermal_debugfs *thermal_dbg = cdev->debugfs;
+ struct cdev_debugfs *cdev_dbg;
+ struct cdev_record *cdev_record;
+ int transition, old_state;
+
+ if (!thermal_dbg || (thermal_dbg->cdev_dbg.current_state == new_state))
+ return;
+
+ mutex_lock(&thermal_dbg->lock);
+
+ cdev_dbg = &thermal_dbg->cdev_dbg;
+
+ old_state = cdev_dbg->current_state;
+
+ /*
+ * Get the old state information in the durations list. If
+ * this one does not exist, a new allocated one will be
+ * returned. Recompute the total duration in the old state and
+ * get a new timestamp for the new state.
+ */
+ cdev_record = thermal_debugfs_cdev_record_get(thermal_dbg,
+ cdev_dbg->durations,
+ old_state);
+ if (cdev_record) {
+ ktime_t now = ktime_get();
+ ktime_t delta = ktime_sub(now, cdev_dbg->timestamp);
+ cdev_record->residency = ktime_add(cdev_record->residency, delta);
+ cdev_dbg->timestamp = now;
+ }
+
+ cdev_dbg->current_state = new_state;
+ transition = (old_state << 16) | new_state;
+
+ /*
+ * Get the transition in the transitions list. If this one
+ * does not exist, a new allocated one will be returned.
+ * Increment the occurrence of this transition which is stored
+ * in the value field.
+ */
+ cdev_record = thermal_debugfs_cdev_record_get(thermal_dbg,
+ cdev_dbg->transitions,
+ transition);
+ if (cdev_record)
+ cdev_record->count++;
+
+ cdev_dbg->total++;
+
+ mutex_unlock(&thermal_dbg->lock);
+}
+
+/**
+ * thermal_debug_cdev_add - Add a cooling device debugfs entry
+ *
+ * Allocates a cooling device object for debug, initializes the
+ * statistics and create the entries in sysfs.
+ * @cdev: a pointer to a cooling device
+ */
+void thermal_debug_cdev_add(struct thermal_cooling_device *cdev)
+{
+ struct thermal_debugfs *thermal_dbg;
+ struct cdev_debugfs *cdev_dbg;
+ int i;
+
+ thermal_dbg = thermal_debugfs_add_id(d_cdev, cdev->id);
+ if (!thermal_dbg)
+ return;
+
+ cdev_dbg = &thermal_dbg->cdev_dbg;
+
+ for (i = 0; i < CDEVSTATS_HASH_SIZE; i++) {
+ INIT_LIST_HEAD(&cdev_dbg->transitions[i]);
+ INIT_LIST_HEAD(&cdev_dbg->durations[i]);
+ }
+
+ cdev_dbg->current_state = 0;
+ cdev_dbg->timestamp = ktime_get();
+
+ debugfs_create_file("trans_table", 0400, thermal_dbg->d_top,
+ thermal_dbg, &tt_fops);
+
+ debugfs_create_file("time_in_state_ms", 0400, thermal_dbg->d_top,
+ thermal_dbg, &dt_fops);
+
+ debugfs_create_file("clear", 0200, thermal_dbg->d_top,
+ thermal_dbg, &cdev_clear_fops);
+
+ debugfs_create_u32("total_trans", 0400, thermal_dbg->d_top,
+ &cdev_dbg->total);
+
+ cdev->debugfs = thermal_dbg;
+}
+
+/**
+ * thermal_debug_cdev_remove - Remove a cooling device debugfs entry
+ *
+ * Frees the statistics memory data and remove the debugfs entry
+ *
+ * @cdev: a pointer to a cooling device
+ */
+void thermal_debug_cdev_remove(struct thermal_cooling_device *cdev)
+{
+ struct thermal_debugfs *thermal_dbg = cdev->debugfs;
+
+ if (!thermal_dbg)
+ return;
+
+ mutex_lock(&thermal_dbg->lock);
+
+ thermal_debugfs_cdev_clear(&thermal_dbg->cdev_dbg);
+ cdev->debugfs = NULL;
+
+ mutex_unlock(&thermal_dbg->lock);
+
+ thermal_debugfs_remove_id(thermal_dbg);
+}
+
+static struct tz_episode *thermal_debugfs_tz_event_alloc(struct thermal_zone_device *tz,
+ ktime_t now)
+{
+ struct tz_episode *tze;
+ int i;
+
+ tze = kzalloc(struct_size(tze, trip_stats, tz->num_trips), GFP_KERNEL);
+ if (!tze)
+ return NULL;
+
+ INIT_LIST_HEAD(&tze->node);
+ tze->timestamp = now;
+
+ for (i = 0; i < tz->num_trips; i++) {
+ tze->trip_stats[i].min = INT_MAX;
+ tze->trip_stats[i].max = INT_MIN;
+ }
+
+ return tze;
+}
+
+void thermal_debug_tz_trip_up(struct thermal_zone_device *tz,
+ const struct thermal_trip *trip)
+{
+ struct tz_episode *tze;
+ struct tz_debugfs *tz_dbg;
+ struct thermal_debugfs *thermal_dbg = tz->debugfs;
+ int temperature = tz->temperature;
+ int trip_id = thermal_zone_trip_id(tz, trip);
+ ktime_t now = ktime_get();
+
+ if (!thermal_dbg)
+ return;
+
+ mutex_lock(&thermal_dbg->lock);
+
+ tz_dbg = &thermal_dbg->tz_dbg;
+
+ /*
+ * The mitigation is starting. A mitigation can contain
+ * several episodes where each of them is related to a
+ * temperature crossing a trip point. The episodes are
+ * nested. That means when the temperature is crossing the
+ * first trip point, the duration begins to be measured. If
+ * the temperature continues to increase and reaches the
+ * second trip point, the duration of the first trip must be
+ * also accumulated.
+ *
+ * eg.
+ *
+ * temp
+ * ^
+ * | --------
+ * trip 2 / \ ------
+ * | /| |\ /| |\
+ * trip 1 / | | `---- | | \
+ * | /| | | | | |\
+ * trip 0 / | | | | | | \
+ * | /| | | | | | | |\
+ * | / | | | | | | | | `--
+ * | / | | | | | | | |
+ * |----- | | | | | | | |
+ * | | | | | | | | |
+ * --------|-|-|--------|--------|------|-|-|------------------> time
+ * | | |<--t2-->| |<-t2'>| | |
+ * | | | |
+ * | |<------------t1------------>| |
+ * | |
+ * |<-------------t0--------------->|
+ *
+ */
+ if (!tz_dbg->nr_trips) {
+ tze = thermal_debugfs_tz_event_alloc(tz, now);
+ if (!tze)
+ goto unlock;
+
+ list_add(&tze->node, &tz_dbg->tz_episodes);
+ }
+
+ /*
+ * Each time a trip point is crossed the way up, the trip_id
+ * is stored in the trip_crossed array and the nr_trips is
+ * incremented. A nr_trips equal to zero means we are entering
+ * a mitigation episode.
+ *
+ * The trip ids may not be in the ascending order but the
+ * result in the array trips_crossed will be in the ascending
+ * temperature order. The function detecting when a trip point
+ * is crossed the way down will handle the very rare case when
+ * the trip points may have been reordered during this
+ * mitigation episode.
+ */
+ tz_dbg->trips_crossed[tz_dbg->nr_trips++] = trip_id;
+
+ tze = list_first_entry(&tz_dbg->tz_episodes, struct tz_episode, node);
+ tze->trip_stats[trip_id].timestamp = now;
+ tze->trip_stats[trip_id].max = max(tze->trip_stats[trip_id].max, temperature);
+ tze->trip_stats[trip_id].min = min(tze->trip_stats[trip_id].min, temperature);
+ tze->trip_stats[trip_id].avg = tze->trip_stats[trip_id].avg +
+ (temperature - tze->trip_stats[trip_id].avg) /
+ tze->trip_stats[trip_id].count;
+
+unlock:
+ mutex_unlock(&thermal_dbg->lock);
+}
+
+void thermal_debug_tz_trip_down(struct thermal_zone_device *tz,
+ const struct thermal_trip *trip)
+{
+ struct thermal_debugfs *thermal_dbg = tz->debugfs;
+ struct tz_episode *tze;
+ struct tz_debugfs *tz_dbg;
+ ktime_t delta, now = ktime_get();
+ int trip_id = thermal_zone_trip_id(tz, trip);
+ int i;
+
+ if (!thermal_dbg)
+ return;
+
+ mutex_lock(&thermal_dbg->lock);
+
+ tz_dbg = &thermal_dbg->tz_dbg;
+
+ /*
+ * The temperature crosses the way down but there was not
+ * mitigation detected before. That may happen when the
+ * temperature is greater than a trip point when registering a
+ * thermal zone, which is a common use case as the kernel has
+ * no mitigation mechanism yet at boot time.
+ */
+ if (!tz_dbg->nr_trips)
+ goto out;
+
+ for (i = tz_dbg->nr_trips - 1; i >= 0; i--) {
+ if (tz_dbg->trips_crossed[i] == trip_id)
+ break;
+ }
+
+ if (i < 0)
+ goto out;
+
+ tz_dbg->nr_trips--;
+
+ if (i < tz_dbg->nr_trips)
+ tz_dbg->trips_crossed[i] = tz_dbg->trips_crossed[tz_dbg->nr_trips];
+
+ tze = list_first_entry(&tz_dbg->tz_episodes, struct tz_episode, node);
+
+ delta = ktime_sub(now, tze->trip_stats[trip_id].timestamp);
+
+ tze->trip_stats[trip_id].duration =
+ ktime_add(delta, tze->trip_stats[trip_id].duration);
+
+ /*
+ * This event closes the mitigation as we are crossing the
+ * last trip point the way down.
+ */
+ if (!tz_dbg->nr_trips)
+ tze->duration = ktime_sub(now, tze->timestamp);
+
+out:
+ mutex_unlock(&thermal_dbg->lock);
+}
+
+void thermal_debug_update_temp(struct thermal_zone_device *tz)
+{
+ struct thermal_debugfs *thermal_dbg = tz->debugfs;
+ struct tz_episode *tze;
+ struct tz_debugfs *tz_dbg;
+ int trip_id, i;
+
+ if (!thermal_dbg)
+ return;
+
+ mutex_lock(&thermal_dbg->lock);
+
+ tz_dbg = &thermal_dbg->tz_dbg;
+
+ if (!tz_dbg->nr_trips)
+ goto out;
+
+ for (i = 0; i < tz_dbg->nr_trips; i++) {
+ trip_id = tz_dbg->trips_crossed[i];
+ tze = list_first_entry(&tz_dbg->tz_episodes, struct tz_episode, node);
+ tze->trip_stats[trip_id].count++;
+ tze->trip_stats[trip_id].max = max(tze->trip_stats[trip_id].max, tz->temperature);
+ tze->trip_stats[trip_id].min = min(tze->trip_stats[trip_id].min, tz->temperature);
+ tze->trip_stats[trip_id].avg = tze->trip_stats[trip_id].avg +
+ (tz->temperature - tze->trip_stats[trip_id].avg) /
+ tze->trip_stats[trip_id].count;
+ }
+out:
+ mutex_unlock(&thermal_dbg->lock);
+}
+
+static void *tze_seq_start(struct seq_file *s, loff_t *pos)
+{
+ struct thermal_zone_device *tz = s->private;
+ struct thermal_debugfs *thermal_dbg = tz->debugfs;
+ struct tz_debugfs *tz_dbg = &thermal_dbg->tz_dbg;
+
+ mutex_lock(&thermal_dbg->lock);
+
+ return seq_list_start(&tz_dbg->tz_episodes, *pos);
+}
+
+static void *tze_seq_next(struct seq_file *s, void *v, loff_t *pos)
+{
+ struct thermal_zone_device *tz = s->private;
+ struct thermal_debugfs *thermal_dbg = tz->debugfs;
+ struct tz_debugfs *tz_dbg = &thermal_dbg->tz_dbg;
+
+ return seq_list_next(v, &tz_dbg->tz_episodes, pos);
+}
+
+static void tze_seq_stop(struct seq_file *s, void *v)
+{
+ struct thermal_zone_device *tz = s->private;
+ struct thermal_debugfs *thermal_dbg = tz->debugfs;
+
+ mutex_unlock(&thermal_dbg->lock);
+}
+
+static int tze_seq_show(struct seq_file *s, void *v)
+{
+ struct thermal_zone_device *tz = s->private;
+ struct thermal_trip *trip;
+ struct tz_episode *tze;
+ const char *type;
+ int trip_id;
+
+ tze = list_entry((struct list_head *)v, struct tz_episode, node);
+
+ seq_printf(s, ",-Mitigation at %lluus, duration=%llums\n",
+ ktime_to_us(tze->timestamp),
+ ktime_to_ms(tze->duration));
+
+ seq_printf(s, "| trip | type | temp(°mC) | hyst(°mC) | duration | avg(°mC) | min(°mC) | max(°mC) |\n");
+
+ for_each_trip(tz, trip) {
+ /*
+ * There is no possible mitigation happening at the
+ * critical trip point, so the stats will be always
+ * zero, skip this trip point
+ */
+ if (trip->type == THERMAL_TRIP_CRITICAL)
+ continue;
+
+ if (trip->type == THERMAL_TRIP_PASSIVE)
+ type = "passive";
+ else if (trip->type == THERMAL_TRIP_ACTIVE)
+ type = "active";
+ else
+ type = "hot";
+
+ trip_id = thermal_zone_trip_id(tz, trip);
+
+ seq_printf(s, "| %*d | %*s | %*d | %*d | %*lld | %*d | %*d | %*d |\n",
+ 4 , trip_id,
+ 8, type,
+ 9, trip->temperature,
+ 9, trip->hysteresis,
+ 10, ktime_to_ms(tze->trip_stats[trip_id].duration),
+ 9, tze->trip_stats[trip_id].avg,
+ 9, tze->trip_stats[trip_id].min,
+ 9, tze->trip_stats[trip_id].max);
+ }
+
+ return 0;
+}
+
+static const struct seq_operations tze_sops = {
+ .start = tze_seq_start,
+ .next = tze_seq_next,
+ .stop = tze_seq_stop,
+ .show = tze_seq_show,
+};
+
+DEFINE_SEQ_ATTRIBUTE(tze);
+
+void thermal_debug_tz_add(struct thermal_zone_device *tz)
+{
+ struct thermal_debugfs *thermal_dbg;
+ struct tz_debugfs *tz_dbg;
+
+ thermal_dbg = thermal_debugfs_add_id(d_tz, tz->id);
+ if (!thermal_dbg)
+ return;
+
+ tz_dbg = &thermal_dbg->tz_dbg;
+
+ tz_dbg->trips_crossed = kzalloc(sizeof(int) * tz->num_trips, GFP_KERNEL);
+ if (!tz_dbg->trips_crossed) {
+ thermal_debugfs_remove_id(thermal_dbg);
+ return;
+ }
+
+ INIT_LIST_HEAD(&tz_dbg->tz_episodes);
+
+ debugfs_create_file("mitigations", 0400, thermal_dbg->d_top, tz, &tze_fops);
+
+ tz->debugfs = thermal_dbg;
+}
+
+void thermal_debug_tz_remove(struct thermal_zone_device *tz)
+{
+ struct thermal_debugfs *thermal_dbg = tz->debugfs;
+
+ if (!thermal_dbg)
+ return;
+
+ mutex_lock(&thermal_dbg->lock);
+
+ tz->debugfs = NULL;
+
+ mutex_unlock(&thermal_dbg->lock);
+
+ thermal_debugfs_remove_id(thermal_dbg);
+}