/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * drivers/cpufreq/cpufreq_governor.h
 *
 * Header file for CPUFreq governors common code
 *
 * Copyright    (C) 2001 Russell King
 *              (C) 2003 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>.
 *              (C) 2003 Jun Nakajima <jun.nakajima@intel.com>
 *              (C) 2009 Alexander Clouter <alex@digriz.org.uk>
 *              (c) 2012 Viresh Kumar <viresh.kumar@linaro.org>
 */

#ifndef _CPUFREQ_GOVERNOR_H
#define _CPUFREQ_GOVERNOR_H

#include <linux/atomic.h>
#include <linux/irq_work.h>
#include <linux/cpufreq.h>
#include <linux/sched/cpufreq.h>
#include <linux/kernel_stat.h>
#include <linux/module.h>
#include <linux/mutex.h>

/* Ondemand Sampling types */
enum {OD_NORMAL_SAMPLE, OD_SUB_SAMPLE};

/*
 * Abbreviations:
 * dbs: used as a shortform for demand based switching It helps to keep variable
 *      names smaller, simpler
 * cdbs: common dbs
 * od_*: On-demand governor
 * cs_*: Conservative governor
 */

/* Governor demand based switching data (per-policy or global). */
struct dbs_data {
        struct gov_attr_set attr_set;
        struct dbs_governor *gov;
        void *tuners;
        unsigned int ignore_nice_load;
        unsigned int sampling_rate;
        unsigned int sampling_down_factor;
        unsigned int up_threshold;
        unsigned int io_is_busy;
};

static inline struct dbs_data *to_dbs_data(struct gov_attr_set *attr_set)
{
        return container_of(attr_set, struct dbs_data, attr_set);
}

#define gov_show_one(_gov, file_name)                                   \
static ssize_t file_name##_show                                         \
(struct gov_attr_set *attr_set, char *buf)                              \
{                                                                       \
        struct dbs_data *dbs_data = to_dbs_data(attr_set);              \
        struct _gov##_dbs_tuners *tuners = dbs_data->tuners;            \
        return sprintf(buf, "%u\n", tuners->file_name);                 \
}

#define gov_show_one_common(file_name)                                  \
static ssize_t file_name##_show                                         \
(struct gov_attr_set *attr_set, char *buf)                              \
{                                                                       \
        struct dbs_data *dbs_data = to_dbs_data(attr_set);              \
        return sprintf(buf, "%u\n", dbs_data->file_name);               \
}

#define gov_attr_ro(_name)                                              \
static struct governor_attr _name = __ATTR_RO(_name)

#define gov_attr_rw(_name)                                              \
static struct governor_attr _name = __ATTR_RW(_name)

/* Common to all CPUs of a policy */
struct policy_dbs_info {
        struct cpufreq_policy *policy;
        /*
         * Per policy mutex that serializes load evaluation from limit-change
         * and work-handler.
         */
        struct mutex update_mutex;

        u64 last_sample_time;
        s64 sample_delay_ns;
        atomic_t work_count;
        struct irq_work irq_work;
        struct work_struct work;
        /* dbs_data may be shared between multiple policy objects */
        struct dbs_data *dbs_data;
        struct list_head list;
        /* Multiplier for increasing sample delay temporarily. */
        unsigned int rate_mult;
        unsigned int idle_periods;      /* For conservative */
        /* Status indicators */
        bool is_shared;         /* This object is used by multiple CPUs */
        bool work_in_progress;  /* Work is being queued up or in progress */
};

static inline void gov_update_sample_delay(struct policy_dbs_info *policy_dbs,
                                           unsigned int delay_us)
{
        policy_dbs->sample_delay_ns = delay_us * NSEC_PER_USEC;
}

/* Per cpu structures */
struct cpu_dbs_info {
        u64 prev_cpu_idle;
        u64 prev_update_time;
        u64 prev_cpu_nice;
        /*
         * Used to keep track of load in the previous interval. However, when
         * explicitly set to zero, it is used as a flag to ensure that we copy
         * the previous load to the current interval only once, upon the first
         * wake-up from idle.
         */
        unsigned int prev_load;
        struct update_util_data update_util;
        struct policy_dbs_info *policy_dbs;
};

/* Common Governor data across policies */
struct dbs_governor {
        struct cpufreq_governor gov;
        struct kobj_type kobj_type;

        /*
         * Common data for platforms that don't set
         * CPUFREQ_HAVE_GOVERNOR_PER_POLICY
         */
        struct dbs_data *gdbs_data;

        unsigned int (*gov_dbs_update)(struct cpufreq_policy *policy);
        struct policy_dbs_info *(*alloc)(void);
        void (*free)(struct policy_dbs_info *policy_dbs);
        int (*init)(struct dbs_data *dbs_data);
        void (*exit)(struct dbs_data *dbs_data);
        void (*start)(struct cpufreq_policy *policy);
        void (*limits)(struct cpufreq_policy *policy);
};

static inline struct dbs_governor *dbs_governor_of(struct cpufreq_policy *policy)
{
        return container_of(policy->governor, struct dbs_governor, gov);
}

/* Governor callback routines */
int cpufreq_dbs_governor_init(struct cpufreq_policy *policy);
void cpufreq_dbs_governor_exit(struct cpufreq_policy *policy);
int cpufreq_dbs_governor_start(struct cpufreq_policy *policy);
void cpufreq_dbs_governor_stop(struct cpufreq_policy *policy);
void cpufreq_dbs_governor_limits(struct cpufreq_policy *policy);

#define CPUFREQ_DBS_GOVERNOR_INITIALIZER(_name_)                        \
        {                                                               \
                .name = _name_,                                         \
                .flags = CPUFREQ_GOV_DYNAMIC_SWITCHING,                 \
                .owner = THIS_MODULE,                                   \
                .init = cpufreq_dbs_governor_init,                      \
                .exit = cpufreq_dbs_governor_exit,                      \
                .start = cpufreq_dbs_governor_start,                    \
                .stop = cpufreq_dbs_governor_stop,                      \
                .limits = cpufreq_dbs_governor_limits,                  \
        }

/* Governor specific operations */
struct od_ops {
        unsigned int (*powersave_bias_target)(struct cpufreq_policy *policy,
                        unsigned int freq_next, unsigned int relation);
};

unsigned int dbs_update(struct cpufreq_policy *policy);
void od_register_powersave_bias_handler(unsigned int (*f)
                (struct cpufreq_policy *, unsigned int, unsigned int),
                unsigned int powersave_bias);
void od_unregister_powersave_bias_handler(void);
ssize_t sampling_rate_store(struct gov_attr_set *attr_set, const char *buf,
                            size_t count);
void gov_update_cpu_data(struct dbs_data *dbs_data);
#endif /* _CPUFREQ_GOVERNOR_H */