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linux/drivers/thermal/thermal_core.h
Rafael J. Wysocki 6d5537d40c thermal: core: Use trip lists for trip crossing detection 
Modify the thermal core to use three lists of trip points:

 trips_high, containing trips with thresholds strictly above the current
 thermal zone temperature,

 trips_reached, containing trips with thresholds at or below the current
 zone temperature,

 trips_invalid, containing trips with temperature equal to
 THERMAL_ZONE_INVALID,

where the first two lists are always sorted by the current trip
threshold.

For each trip in trips_high, there is no mitigation under way and
the trip threshold is equal to its temperature.  In turn, for each
trip in trips_reached, there is mitigation under way and the trip
threshold is equal to its low temperature.  The trips in trips_invalid,
of course, need not be taken into consideration.

The idea is to make __thermal_zone_device_update() walk trips_high and
trips_reached instead of walking the entire table of trip points in a
thermal zone.  Usually, it will only need to walk a few entries in one
of the lists and check one entry in the other list, depending on the
direction of the zone temperature changes, because crossing many trips
by the zone temperature in one go between two consecutive temperature
checks should be unlikely (if it occurs often, the thermal zone
temperature should probably be checked more often either or there
are too many trips).

This also helps to eliminate one temporary trip list used for trip
crossing notification (only one temporary list is needed for this
purpose instead of two) and the remaining temporary list may be sorted
by the current trip threshold value, like the trips_reached list, so
the additional notify_temp field in struct thermal_trip_desc is not
necessary any more.

Moreover, since the trips_reached and trips_high lists are sorted,
the "low" and "high" values needed by thermal_zone_set_trips() can be
determined in a straightforward way by looking at one end of each list.

Of course, additional work is needed in some places in order to
maintain the ordering of the lists, but it is limited to situations
that should be rare, like updating a trip point temperature or
hysteresis, thermal zone initialization, or system resume.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Link: https://patch.msgid.link/2003443.usQuhbGJ8B@rjwysocki.net
[ rjw: Added a comment to thermal_zone_handle_trips() ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2024-10-24 17:15:07 +02:00

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/* SPDX-License-Identifier: GPL-2.0 */
/*
* thermal_core.h
*
* Copyright (C) 2012 Intel Corp
* Author: Durgadoss R <durgadoss.r@intel.com>
*/
#ifndef __THERMAL_CORE_H__
#define __THERMAL_CORE_H__
#include <linux/cleanup.h>
#include <linux/device.h>
#include <linux/thermal.h>
#include "thermal_netlink.h"
#include "thermal_thresholds.h"
#include "thermal_debugfs.h"
struct thermal_attr {
struct device_attribute attr;
char name[THERMAL_NAME_LENGTH];
};
struct thermal_trip_attrs {
struct thermal_attr type;
struct thermal_attr temp;
struct thermal_attr hyst;
};
struct thermal_trip_desc {
struct thermal_trip trip;
struct thermal_trip_attrs trip_attrs;
struct list_head list_node;
struct list_head thermal_instances;
int threshold;
};
/**
* struct thermal_governor - structure that holds thermal governor information
* @name: name of the governor
* @bind_to_tz: callback called when binding to a thermal zone. If it
* returns 0, the governor is bound to the thermal zone,
* otherwise it fails.
* @unbind_from_tz: callback called when a governor is unbound from a
* thermal zone.
* @trip_crossed: called for trip points that have just been crossed
* @manage: called on thermal zone temperature updates
* @update_tz: callback called when thermal zone internals have changed, e.g.
* thermal cooling instance was added/removed
* @governor_list: node in thermal_governor_list (in thermal_core.c)
*/
struct thermal_governor {
const char *name;
int (*bind_to_tz)(struct thermal_zone_device *tz);
void (*unbind_from_tz)(struct thermal_zone_device *tz);
void (*trip_crossed)(struct thermal_zone_device *tz,
const struct thermal_trip *trip,
bool crossed_up);
void (*manage)(struct thermal_zone_device *tz);
void (*update_tz)(struct thermal_zone_device *tz,
enum thermal_notify_event reason);
struct list_head governor_list;
};
#define TZ_STATE_FLAG_SUSPENDED BIT(0)
#define TZ_STATE_FLAG_RESUMING BIT(1)
#define TZ_STATE_FLAG_INIT BIT(2)
#define TZ_STATE_FLAG_EXIT BIT(3)
#define TZ_STATE_READY 0
/**
* struct thermal_zone_device - structure for a thermal zone
* @id: unique id number for each thermal zone
* @type: the thermal zone device type
* @device: &struct device for this thermal zone
* @removal: removal completion
* @resume: resume completion
* @trips_high: trips above the current zone temperature
* @trips_reached: trips below or at the current zone temperature
* @trips_invalid: trips with invalid temperature
* @mode: current mode of this thermal zone
* @devdata: private pointer for device private data
* @num_trips: number of trip points the thermal zone supports
* @passive_delay_jiffies: number of jiffies to wait between polls when
* performing passive cooling.
* @polling_delay_jiffies: number of jiffies to wait between polls when
* checking whether trip points have been crossed (0 for
* interrupt driven systems)
* @recheck_delay_jiffies: delay after a failed attempt to determine the zone
* temperature before trying again
* @temperature: current temperature. This is only for core code,
* drivers should use thermal_zone_get_temp() to get the
* current temperature
* @last_temperature: previous temperature read
* @emul_temperature: emulated temperature when using CONFIG_THERMAL_EMULATION
* @passive: 1 if you've crossed a passive trip point, 0 otherwise.
* @prev_low_trip: the low current temperature if you've crossed a passive
trip point.
* @prev_high_trip: the above current temperature if you've crossed a
passive trip point.
* @ops: operations this &thermal_zone_device supports
* @tzp: thermal zone parameters
* @governor: pointer to the governor for this thermal zone
* @governor_data: private pointer for governor data
* @ida: &struct ida to generate unique id for this zone's cooling
* devices
* @lock: lock to protect thermal_instances list
* @node: node in thermal_tz_list (in thermal_core.c)
* @poll_queue: delayed work for polling
* @notify_event: Last notification event
* @state: current state of the thermal zone
* @trips: array of struct thermal_trip objects
*/
struct thermal_zone_device {
int id;
char type[THERMAL_NAME_LENGTH];
struct device device;
struct completion removal;
struct completion resume;
struct attribute_group trips_attribute_group;
struct list_head trips_high;
struct list_head trips_reached;
struct list_head trips_invalid;
enum thermal_device_mode mode;
void *devdata;
int num_trips;
unsigned long passive_delay_jiffies;
unsigned long polling_delay_jiffies;
unsigned long recheck_delay_jiffies;
int temperature;
int last_temperature;
int emul_temperature;
int passive;
int prev_low_trip;
int prev_high_trip;
struct thermal_zone_device_ops ops;
struct thermal_zone_params *tzp;
struct thermal_governor *governor;
void *governor_data;
struct ida ida;
struct mutex lock;
struct list_head node;
struct delayed_work poll_queue;
enum thermal_notify_event notify_event;
u8 state;
#ifdef CONFIG_THERMAL_DEBUGFS
struct thermal_debugfs *debugfs;
#endif
struct list_head user_thresholds;
struct thermal_trip_desc trips[] __counted_by(num_trips);
};
DEFINE_GUARD(thermal_zone, struct thermal_zone_device *, mutex_lock(&_T->lock),
mutex_unlock(&_T->lock))
DEFINE_GUARD(thermal_zone_reverse, struct thermal_zone_device *,
mutex_unlock(&_T->lock), mutex_lock(&_T->lock))
/* Initial thermal zone temperature. */
#define THERMAL_TEMP_INIT INT_MIN
/*
* Default and maximum delay after a failed thermal zone temperature check
* before attempting to check it again (in jiffies).
*/
#define THERMAL_RECHECK_DELAY msecs_to_jiffies(250)
#define THERMAL_MAX_RECHECK_DELAY (120 * HZ)
/* Default Thermal Governor */
#if defined(CONFIG_THERMAL_DEFAULT_GOV_STEP_WISE)
#define DEFAULT_THERMAL_GOVERNOR "step_wise"
#elif defined(CONFIG_THERMAL_DEFAULT_GOV_FAIR_SHARE)
#define DEFAULT_THERMAL_GOVERNOR "fair_share"
#elif defined(CONFIG_THERMAL_DEFAULT_GOV_USER_SPACE)
#define DEFAULT_THERMAL_GOVERNOR "user_space"
#elif defined(CONFIG_THERMAL_DEFAULT_GOV_POWER_ALLOCATOR)
#define DEFAULT_THERMAL_GOVERNOR "power_allocator"
#elif defined(CONFIG_THERMAL_DEFAULT_GOV_BANG_BANG)
#define DEFAULT_THERMAL_GOVERNOR "bang_bang"
#endif
/* Initial state of a cooling device during binding */
#define THERMAL_NO_TARGET -1UL
/* Init section thermal table */
extern struct thermal_governor *__governor_thermal_table[];
extern struct thermal_governor *__governor_thermal_table_end[];
#define THERMAL_TABLE_ENTRY(table, name) \
static typeof(name) *__thermal_table_entry_##name \
__used __section("__" #table "_thermal_table") = &name
#define THERMAL_GOVERNOR_DECLARE(name) THERMAL_TABLE_ENTRY(governor, name)
#define for_each_governor_table(__governor) \
for (__governor = __governor_thermal_table; \
__governor < __governor_thermal_table_end; \
__governor++)
int for_each_thermal_zone(int (*cb)(struct thermal_zone_device *, void *),
void *);
int for_each_thermal_cooling_device(int (*cb)(struct thermal_cooling_device *,
void *), void *);
int for_each_thermal_governor(int (*cb)(struct thermal_governor *, void *),
void *thermal_governor);
struct thermal_zone_device *thermal_zone_get_by_id(int id);
DEFINE_CLASS(thermal_zone_get_by_id, struct thermal_zone_device *,
if (_T) put_device(&_T->device), thermal_zone_get_by_id(id), int id)
static inline bool cdev_is_power_actor(struct thermal_cooling_device *cdev)
{
return cdev->ops->get_requested_power && cdev->ops->state2power &&
cdev->ops->power2state;
}
void thermal_cdev_update(struct thermal_cooling_device *);
void thermal_cdev_update_nocheck(struct thermal_cooling_device *cdev);
void __thermal_cdev_update(struct thermal_cooling_device *cdev);
int get_tz_trend(struct thermal_zone_device *tz, const struct thermal_trip *trip);
/*
* This structure is used to describe the behavior of
* a certain cooling device on a certain trip point
* in a certain thermal zone
*/
struct thermal_instance {
int id;
char name[THERMAL_NAME_LENGTH];
struct thermal_cooling_device *cdev;
const struct thermal_trip *trip;
bool initialized;
unsigned long upper; /* Highest cooling state for this trip point */
unsigned long lower; /* Lowest cooling state for this trip point */
unsigned long target; /* expected cooling state */
char attr_name[THERMAL_NAME_LENGTH];
struct device_attribute attr;
char weight_attr_name[THERMAL_NAME_LENGTH];
struct device_attribute weight_attr;
struct list_head trip_node; /* node in trip->thermal_instances */
struct list_head cdev_node; /* node in cdev->thermal_instances */
unsigned int weight; /* The weight of the cooling device */
bool upper_no_limit;
};
#define to_thermal_zone(_dev) \
container_of(_dev, struct thermal_zone_device, device)
#define to_cooling_device(_dev) \
container_of(_dev, struct thermal_cooling_device, device)
int thermal_register_governor(struct thermal_governor *);
void thermal_unregister_governor(struct thermal_governor *);
int thermal_zone_device_set_policy(struct thermal_zone_device *, char *);
int thermal_build_list_of_policies(char *buf);
void __thermal_zone_device_update(struct thermal_zone_device *tz,
enum thermal_notify_event event);
void thermal_zone_device_critical_reboot(struct thermal_zone_device *tz);
void thermal_governor_update_tz(struct thermal_zone_device *tz,
enum thermal_notify_event reason);
/* Helpers */
#define for_each_trip_desc(__tz, __td) \
for (__td = __tz->trips; __td - __tz->trips < __tz->num_trips; __td++)
#define trip_to_trip_desc(__trip) \
container_of(__trip, struct thermal_trip_desc, trip)
const char *thermal_trip_type_name(enum thermal_trip_type trip_type);
void thermal_zone_set_trips(struct thermal_zone_device *tz, int low, int high);
int thermal_zone_trip_id(const struct thermal_zone_device *tz,
const struct thermal_trip *trip);
int __thermal_zone_get_temp(struct thermal_zone_device *tz, int *temp);
void thermal_zone_set_trip_hyst(struct thermal_zone_device *tz,
struct thermal_trip *trip, int hyst);
/* sysfs I/F */
int thermal_zone_create_device_groups(struct thermal_zone_device *tz);
void thermal_zone_destroy_device_groups(struct thermal_zone_device *);
void thermal_cooling_device_setup_sysfs(struct thermal_cooling_device *);
void thermal_cooling_device_destroy_sysfs(struct thermal_cooling_device *cdev);
void thermal_cooling_device_stats_reinit(struct thermal_cooling_device *cdev);
/* used only at binding time */
ssize_t trip_point_show(struct device *, struct device_attribute *, char *);
ssize_t weight_show(struct device *, struct device_attribute *, char *);
ssize_t weight_store(struct device *, struct device_attribute *, const char *,
size_t);
#ifdef CONFIG_THERMAL_STATISTICS
void thermal_cooling_device_stats_update(struct thermal_cooling_device *cdev,
unsigned long new_state);
#else
static inline void
thermal_cooling_device_stats_update(struct thermal_cooling_device *cdev,
unsigned long new_state) {}
#endif /* CONFIG_THERMAL_STATISTICS */
#endif /* __THERMAL_CORE_H__ */
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