// SPDX-License-Identifier: GPL-2.0 /* * Copyright 2023 Linaro Limited * * Author: Daniel Lezcano * * Thermal subsystem debug support */ #include #include #include #include #include #include #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); }