path: root/include/linux/cpufreq.h

/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * linux/include/linux/cpufreq.h
 *
 * Copyright (C) 2001 Russell King
 *           (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
 */
#ifndef _LINUX_CPUFREQ_H
#define _LINUX_CPUFREQ_H

#include <linux/clk.h>
#include <linux/cpu.h>
#include <linux/cpumask.h>
#include <linux/completion.h>
#include <linux/kobject.h>
#include <linux/notifier.h>
#include <linux/of.h>
#include <linux/pm_opp.h>
#include <linux/pm_qos.h>
#include <linux/spinlock.h>
#include <linux/sysfs.h>
#include <linux/minmax.h>

/*********************************************************************
 *                        CPUFREQ INTERFACE                          *
 *********************************************************************/
/*
 * Frequency values here are CPU kHz
 *
 * Maximum transition latency is in nanoseconds - if it's unknown,
 * CPUFREQ_ETERNAL shall be used.
 */

#define CPUFREQ_ETERNAL			(-1)
#define CPUFREQ_NAME_LEN		16
/* Print length for names. Extra 1 space for accommodating '\n' in prints */
#define CPUFREQ_NAME_PLEN		(CPUFREQ_NAME_LEN + 1)

struct cpufreq_governor;

enum cpufreq_table_sorting {
	CPUFREQ_TABLE_UNSORTED,
	CPUFREQ_TABLE_SORTED_ASCENDING,
	CPUFREQ_TABLE_SORTED_DESCENDING
};

struct cpufreq_cpuinfo {
	unsigned int		max_freq;
	unsigned int		min_freq;

	/* in 10^(-9) s = nanoseconds */
	unsigned int		transition_latency;
};

struct cpufreq_policy {
	/* CPUs sharing clock, require sw coordination */
	cpumask_var_t		cpus;	/* Online CPUs only */
	cpumask_var_t		related_cpus; /* Online + Offline CPUs */
	cpumask_var_t		real_cpus; /* Related and present */

	unsigned int		shared_type; /* ACPI: ANY or ALL affected CPUs
						should set cpufreq */
	unsigned int		cpu;    /* cpu managing this policy, must be online */

	struct clk		*clk;
	struct cpufreq_cpuinfo	cpuinfo;/* see above */

	unsigned int		min;    /* in kHz */
	unsigned int		max;    /* in kHz */
	unsigned int		cur;    /* in kHz, only needed if cpufreq
					 * governors are used */
	unsigned int		suspend_freq; /* freq to set during suspend */

	unsigned int		policy; /* see above */
	unsigned int		last_policy; /* policy before unplug */
	struct cpufreq_governor	*governor; /* see below */
	void			*governor_data;
	char			last_governor[CPUFREQ_NAME_LEN]; /* last governor used */

	struct work_struct	update; /* if update_policy() needs to be
					 * called, but you're in IRQ context */

	struct freq_constraints	constraints;
	struct freq_qos_request	*min_freq_req;
	struct freq_qos_request	*max_freq_req;

	struct cpufreq_frequency_table	*freq_table;
	enum cpufreq_table_sorting freq_table_sorted;

	struct list_head        policy_list;
	struct kobject		kobj;
	struct completion	kobj_unregister;

	/*
	 * The rules for this semaphore:
	 * - Any routine that wants to read from the policy structure will
	 *   do a down_read on this semaphore.
	 * - Any routine that will write to the policy structure and/or may take away
	 *   the policy altogether (eg. CPU hotplug), will hold this lock in write
	 *   mode before doing so.
	 */
	struct rw_semaphore	rwsem;

	/*
	 * Fast switch flags:
	 * - fast_switch_possible should be set by the driver if it can
	 *   guarantee that frequency can be changed on any CPU sharing the
	 *   policy and that the change will affect all of the policy CPUs then.
	 * - fast_switch_enabled is to be set by governors that support fast
	 *   frequency switching with the help of cpufreq_enable_fast_switch().
	 */
	bool			fast_switch_possible;
	bool			fast_switch_enabled;

	/*
	 * Set if the CPUFREQ_GOV_STRICT_TARGET flag is set for the current
	 * governor.
	 */
	bool			strict_target;

	/*
	 * Set if inefficient frequencies were found in the frequency table.
	 * This indicates if the relation flag CPUFREQ_RELATION_E can be
	 * honored.
	 */
	bool			efficiencies_available;

	/*
	 * Preferred average time interval between consecutive invocations of
	 * the driver to set the frequency for this policy.  To be set by the
	 * scaling driver (0, which is the default, means no preference).
	 */
	unsigned int		transition_delay_us;

	/*
	 * Remote DVFS flag (Not added to the driver structure as we don't want
	 * to access another structure from scheduler hotpath).
	 *
	 * Should be set if CPUs can do DVFS on behalf of other CPUs from
	 * different cpufreq policies.
	 */
	bool			dvfs_possible_from_any_cpu;

	/* Per policy boost enabled flag. */
	bool			boost_enabled;

	 /* Cached frequency lookup from cpufreq_driver_resolve_freq. */
	unsigned int cached_target_freq;
	unsigned int cached_resolved_idx;

	/* Synchronization for frequency transitions */
	bool			transition_ongoing; /* Tracks transition status */
	spinlock_t		transition_lock;
	wait_queue_head_t	transition_wait;
	struct task_struct	*transition_task; /* Task which is doing the transition */

	/* cpufreq-stats */
	struct cpufreq_stats	*stats;

	/* For cpufreq driver's internal use */
	void			*driver_data;

	/* Pointer to the cooling device if used for thermal mitigation */
	struct thermal_cooling_device *cdev;

	struct notifier_block nb_min;
	struct notifier_block nb_max;
};

/*
 * Used for passing new cpufreq policy data to the cpufreq driver's ->verify()
 * callback for sanitization.  That callback is only expected to modify the min
 * and max values, if necessary, and specifically it must not update the
 * frequency table.
 */
struct cpufreq_policy_data {
	struct cpufreq_cpuinfo		cpuinfo;
	struct cpufreq_frequency_table	*freq_table;
	unsigned int			cpu;
	unsigned int			min;    /* in kHz */
	unsigned int			max;    /* in kHz */
};

struct cpufreq_freqs {
	struct cpufreq_policy *policy;
	unsigned int old;
	unsigned