// SPDX-License-Identifier: GPL-2.0
/*
 * CPUFreq governor based on scheduler-provided CPU utilization data.
 *
 * Copyright (C) 2016, Intel Corporation
 * Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
 */
/*
 *
 * Copyright (c) 2019 MediaTek Inc.
 *
 */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/sched/cputime.h>
#include <sched/sched.h>
#include "cpufreq.h"
#if IS_ENABLED(CONFIG_MTK_GEARLESS_SUPPORT)
#include "mtk_energy_model/v2/energy_model.h"
#else
#include "mtk_energy_model/v1/energy_model.h"
#endif
#include "common.h"
#include <linux/tick.h>
#include <linux/sched/cpufreq.h>
#include <linux/sched/clock.h>
#include <trace/events/power.h>
#include <trace/hooks/sched.h>
#include <linux/sched/topology.h>
#include <trace/hooks/cpufreq.h>
#include <linux/sched/cpufreq.h>
#include <linux/kthread.h>
#include <uapi/linux/sched/types.h>
#include <thermal_interface.h>

#define CREATE_TRACE_POINTS
#include "sugov_trace.h"

#define IOWAIT_BOOST_MIN	(SCHED_CAPACITY_SCALE / 8)

struct sugov_cpu {
	struct update_util_data	update_util;
	struct sugov_policy	*sg_policy;
	unsigned int		cpu;

	bool			iowait_boost_pending;
	unsigned int		iowait_boost;
	u64			last_update;
	unsigned long		util;
	unsigned long		bw_dl;
	unsigned long		max;

	/* The field below is for single-CPU policies only: */
#if IS_ENABLED(CONFIG_NO_HZ_COMMON)
	unsigned long		saved_idle_calls;
#endif
};

static DEFINE_PER_CPU(struct sugov_cpu, sugov_cpu);

/************************ Governor internals ***********************/

static bool sugov_should_update_freq(struct sugov_policy *sg_policy, u64 time)
{
	s64 delta_ns;

	/*
	 * Since cpufreq_update_util() is called with rq->lock held for
	 * the @target_cpu, our per-CPU data is fully serialized.
	 *
	 * However, drivers cannot in general deal with cross-CPU
	 * requests, so while get_next_freq() will work, our
	 * sugov_update_commit() call may not for the fast switching platforms.
	 *
	 * Hence stop here for remote requests if they aren't supported
	 * by the hardware, as calculating the frequency is pointless if
	 * we cannot in fact act on it.
	 *
	 * This is needed on the slow switching platforms too to prevent CPUs
	 * going offline from leaving stale IRQ work items behind.
	 */
	if (!cpufreq_this_cpu_can_update(sg_policy->policy))
		return false;

	if (unlikely(sg_policy->limits_changed)) {
		sg_policy->limits_changed = false;
		sg_policy->need_freq_update = true;
		return true;
	}

	/* No need to recalculate next freq for min_rate_limit_us
	 * at least. However we might still decide to further rate
	 * limit once frequency change direction is decided, according
	 * to the separate rate limits.
	 */

	delta_ns = time - sg_policy->last_freq_update_time;
	return delta_ns >= READ_ONCE(sg_policy->min_rate_limit_ns);
}

static bool sugov_up_down_rate_limit(struct sugov_policy *sg_policy, u64 time,
				     unsigned int next_freq)
{
	s64 delta_ns;

	delta_ns = time - sg_policy->last_freq_update_time;

	if (next_freq > sg_policy->next_freq &&
	    delta_ns < sg_policy->up_rate_delay_ns)
		return true;

	if (next_freq < sg_policy->next_freq &&
	    delta_ns < sg_policy->down_rate_delay_ns)
		return true;

	return false;
}

static bool sugov_update_next_freq(struct sugov_policy *sg_policy, u64 time,
				   unsigned int next_freq)
{
	if (sugov_up_down_rate_limit(sg_policy, time, next_freq))
		return false;

	if (sg_policy->need_freq_update)
		sg_policy->need_freq_update = false;
	else if (sg_policy->next_freq == next_freq)
		return false;

	sg_policy->next_freq = next_freq;
	sg_policy->last_freq_update_time = time;

	return true;
}

static void sugov_deferred_update(struct sugov_policy *sg_policy)
{
	if (!sg_policy->work_in_progress) {
		sg_policy->work_in_progress = true;
		irq_work_queue(&sg_policy->irq_work);
	}
}

/**
 * get_next_freq - Compute a new frequency for a given cpufreq policy.
 * @sg_policy: schedutil policy object to compute the new frequency for.
 * @util: Current CPU utilization.
 * @max: CPU capacity.
 *
 * If the utilization is frequency-invariant, choose the new frequency to be
 * proportional to it, that is
 *
 * next_freq = C * max_freq * util / max
 *
 * Otherwise, approximate the would-be frequency-invariant utilization by
 * util_raw * (curr_freq / max_freq) which leads to
 *
 * next_freq = C * curr_freq * util_raw / max
 *
 * Take C = 1.25 for the frequency tipping point at (util / max) = 0.8.
 *
 * The lowest driver-supported frequency which is equal or greater than the raw
 * next_freq (as calculated above) is returned, subject to policy min/max and
 * cpufreq driver limitations.
 */
static unsigned int get_next_freq(struct sugov_policy *sg_policy,
				  unsigned long util, unsigned long max)
{
	struct cpufreq_policy *policy = sg_policy->policy;
	unsigned int freq = policy->cpuinfo.max_freq;
	unsigned long next_freq = 0;

	mtk_map_util_freq((void *)sg_policy, util, freq, policy->related_cpus, &next_freq);
	if (next_freq) {
		freq = next_freq;
	} else {
		freq = map_util_freq(util, freq, max);
		if (freq == sg_policy->cached_raw_freq && !sg_policy->need_freq_update)
			return sg_policy->next_freq;
		sg_policy->cached_raw_freq = freq;
		freq = cpufreq_driver_resolve_freq(policy, freq);
	}

	return freq;
}

/*
 * This function computes an effective utilization for the given CPU, to be
 * used for frequency selection given the linear relation: f = u * f_max.
 *
 * The scheduler tracks the following metrics:
 *
 *   cpu_util_{cfs,rt,dl,irq}()
 *   cpu_bw_dl()
 *
 * Where the cfs,rt and dl util numbers are tracked with the same metric and
 * synchronized windows and are thus directly comparable.
 *
 * The cfs,rt,dl utilization are the running times measured with rq->clock_task
 * which excludes things like IRQ and steal-time. These latter are then accrued
 * in the irq utilization.
 *
 * The DL bandwidth number otoh is not a measured metric but a value computed
 * based on the task model parameters and gives the minimal utilization
 * required to meet deadlines.
 */
unsigned long mtk_cpu_util(int cpu, struct util_rq *util_rq,
				 unsigned long max, enum cpu_util_type type,
				 struct task_struct *p,
				 unsigned long min_cap, unsigned long max_cap)
{
	unsigned long util_cfs, dl_util, util, irq;
	unsigned long util_ori;
	//bool sbb_trigger = false;
	struct rq *rq = cpu_rq(cpu);

	if (util_rq->base) {
		util_rq->dl_util = cpu_util_dl(rq);
		util_rq->irq_util = cpu_util_irq(rq);
		util_rq->rt_util = cpu_util_rt(rq);
		util_rq->bw_dl_util = cpu_bw_dl(rq);
		util_rq->base = 0;
	}
	util_cfs = util_rq->util_cfs;

	if (!uclamp_is_used() &&
	    type == FREQUENCY_UTIL && rt_rq_is_runnable(&rq->rt)) {
		return max;
	}

	/*
	 * Early check to see if IRQ/steal time saturates the CPU, can be
	 * because of inaccuracies in how we track these -- see
	 * update_irq_load_avg().
	 */
	irq = util_rq->irq_util;
	if (unlikely(irq >= max))
		return max;

	/*
	 * Because the time spend on RT/DL tasks is visible as 'lost' time to
	 * CFS tasks and we use the same metric to track the effective
	 * utilization (PELT windows are synchronized) we can directly add them
	 * to obtain the CPU's actual utilization.
	 *
	 * CFS and RT utilization can be boosted or capped, depending on
	 * utilization clamp constraints requested by currently RUNNABLE
	 * tasks.
	 * When there are no CFS RUNNABLE tasks, clamps are released and
	 * frequency will be gracefully reduced with the utilization decay.
	 */
	util = util_cfs + util_rq->rt_util;
	util_ori = util;

	if (type == FREQUENCY_UTIL) {
		/*if ((rq->curr->android_vendor_data1[T_SBB_FLG] || is_busy_tick_boost_all() ||
				rq->curr->sched_task_group->android_vendor_data1[TG_SBB_FLG]) &&
				p == (struct task_struct *)UINTPTR_MAX &&
				rq->android_vendor_data1[RQ_SBB_ACTIVE]) {
			util = util * rq->android_vendor_data1[RQ_SBB_BOOST_FACTOR];
			sbb_trigger = true;
		}*/
		if (p == (struct task_struct *)UINTPTR_MAX)
			p = NULL;
		util = mtk_uclamp_rq_util_with(rq, util, p, min_cap, max_cap);
		/*if (sbb_trigger && trace_sugov_ext_sbb_enabled())
			trace_sugov_ext_sbb(rq->cpu, rq->curr->pid,
			rq->android_vendor_data1[RQ_SBB_BOOST_FACTOR], util_ori, util,
			rq->android_vendor_data1[RQ_SBB_CPU_UTILIZE], get_sbb_active_ratio());*/
	}


	dl_util = util_rq->dl_util;

	/*
	 * For frequency selection we do not make cpu_util_dl() a permanent part
	 * of this sum because we want to use cpu_bw_dl() later on, but we need
	 * to check if the CFS+RT+DL sum is saturated (ie. no idle time) such
	 * that we select f_max when there is no idle time.
	 *
	 * NOTE: numerical errors or stop class might cause us to not quite hit
	 * saturation when we should -- something for later.
	 */
	if (util + dl_util >= max)
		return max;

	/*
	 * OTOH, for energy computation we need the estimated running time, so
	 * include util_dl and ignore dl_bw.
	 */
	if (type == ENERGY_UTIL)
		util += dl_util;

	/*
	 * There is still idle time; further improve the number by using the
	 * irq metric. Because IRQ/steal time is hidden from the task clock we
	 * need to scale the task numbers:
	 *
	 *              max - irq
	 *   U' = irq + --------- * U
	 *                 max
	 */
	util = scale_irq_capacity(util, irq, max);
	util += irq;

	/*
	 * Bandwidth required by DEADLINE must always be granted while, for
	 * FAIR and RT, we use blocked utilization of IDLE CPUs as a mechanism
	 * to gracefully reduce the frequency when no tasks show up for longer
	 * periods of time.
	 *
	 * Ideally we would like to set bw_dl as min/guaranteed freq and util +
	 * bw_dl as requested freq. However, cpufreq is not yet ready for such
	 * an interface. So, we only do the latter for now.
	 */
	if (type == FREQUENCY_UTIL)
		util += util_rq->bw_dl_util;

	return min(max, util);
}
EXPORT_SYMBOL(mtk_cpu_util);

static void sugov_get_util(struct sugov_cpu *sg_cpu)
{
	struct rq *rq = cpu_rq(sg_cpu->cpu);
	unsigned long max = capacity_orig_of(sg_cpu->cpu);
	struct util_rq util_rq_sugov;

	sg_cpu->max = max;
	sg_cpu->bw_dl = cpu_bw_dl(rq);

	util_rq_sugov.util_cfs = cpu_util_cfs(sg_cpu->cpu);
	util_rq_sugov.base = 1;
	sg_cpu->util = mtk_cpu_util(sg_cpu->cpu, &util_rq_sugov, max, FREQUENCY_UTIL,
							(struct task_struct *)UINTPTR_MAX,
							0, SCHED_CAPACITY_SCALE);
}

/**
 * sugov_iowait_reset() - Reset the IO boost status of a CPU.
 * @sg_cpu: the sugov data for the CPU to boost
 * @time: the update time from the caller
 * @set_iowait_boost: true if an IO boost has been requested
 *
 * The IO wait boost of a task is disabled after a tick since the last update
 * of a CPU. If a new IO wait boost is requested after more then a tick, then
 * we enable the boost starting from IOWAIT_BOOST_MIN, which improves energy
 * efficiency by ignoring sporadic wakeups from IO.
 */
static bool sugov_iowait_reset(struct sugov_cpu *sg_cpu, u64 time,
			       bool set_iowait_boost)
{
	s64 delta_ns = time - sg_cpu->last_update;

	/* Reset boost only if a tick has elapsed since last request */
	if (delta_ns <= TICK_NSEC)
		return false;

	sg_cpu->iowait_boost = set_iowait_boost ? IOWAIT_BOOST_MIN : 0;
	sg_cpu->iowait_boost_pending = set_iowait_boost;

	return true;
}

/**
 * sugov_iowait_boost() - Updates the IO boost status of a CPU.
 * @sg_cpu: the sugov data for the CPU to boost
 * @time: the update time from the caller
 * @flags: SCHED_CPUFREQ_IOWAIT if the task is waking up after an IO wait
 *
 * Each time a task wakes up after an IO operation, the CPU utilization can be
 * boosted to a certain utilization which doubles at each "frequent and
 * successive" wakeup from IO, ranging from IOWAIT_BOOST_MIN to the utilization
 * of the maximum OPP.
 *
 * To keep doubling, an IO boost has to be requested at least once per tick,
 * otherwise we restart from the utilization of the minimum OPP.
 */
static void sugov_iowait_boost(struct sugov_cpu *sg_cpu, u64 time,
			       unsigned int flags)
{
	bool set_iowait_boost = flags & SCHED_CPUFREQ_IOWAIT;

	/* Reset boost if the CPU appears to have been idle enough */
	if (sg_cpu->iowait_boost &&
	    sugov_iowait_reset(sg_cpu, time, set_iowait_boost))
		return;

	/* Boost only tasks waking up after IO */
	if (!set_iowait_boost)
		return;

	/* Ensure boost doubles only one time at each request */
	if (sg_cpu->iowait_boost_pending)
		return;
	sg_cpu->iowait_boost_pending = true;

	/* Double the boost at each request */
	if (sg_cpu->iowait_boost) {
		sg_cpu->iowait_boost =
			min_t(unsigned int, sg_cpu->iowait_boost << 1, SCHED_CAPACITY_SCALE);
		return;
	}

	/* First wakeup after IO: start with minimum boost */
	sg_cpu->iowait_boost = IOWAIT_BOOST_MIN;
}

/**
 * sugov_iowait_apply() - Apply the IO boost to a CPU.
 * @sg_cpu: the sugov data for the cpu to boost
 * @time: the update time from the caller
 *
 * A CPU running a task which woken up after an IO operation can have its
 * utilization boosted to speed up the completion of those IO operations.
 * The IO boost value is increased each time a task wakes up from IO, in
 * sugov_iowait_apply(), and it's instead decreased by this function,
 * each time an increase has not been requested (!iowait_boost_pending).
 *
 * A CPU which also appears to have been idle for at least one tick has also
 * its IO boost utilization reset.
 *
 * This mechanism is designed to boost high frequently IO waiting tasks, while
 * being more conservative on tasks which does sporadic IO operations.
 */
static void sugov_iowait_apply(struct sugov_cpu *sg_cpu, u64 time)
{
	unsigned long boost;

	/* No boost currently required */
	if (!sg_cpu->iowait_boost)
		return;

	/* Reset boost if the CPU appears to have been idle enough */
	if (sugov_iowait_reset(sg_cpu, time, false))
		return;

	if (!sg_cpu->iowait_boost_pending) {
		/*
		 * No boost pending; reduce the boost value.
		 */
		sg_cpu->iowait_boost >>= 1;
		if (sg_cpu->iowait_boost < IOWAIT_BOOST_MIN) {
			sg_cpu->iowait_boost = 0;
			return;
		}
	}

	sg_cpu->iowait_boost_pending = false;

	/*
	 * sg_cpu->util is already in capacity scale; convert iowait_boost
	 * into the same scale so we can compare.
	 */
	boost = (sg_cpu->iowait_boost * sg_cpu->max) >> SCHED_CAPACITY_SHIFT;
	if (sg_cpu->util < boost)
		sg_cpu->util = boost;
}

/*
 * Make sugov_should_update_freq() ignore the rate limit when DL
 * has increased the utilization.
 */
static inline void ignore_dl_rate_limit(struct sugov_cpu *sg_cpu)
{
	if (cpu_bw_dl(cpu_rq(sg_cpu->cpu)) > sg_cpu->bw_dl)
		sg_cpu->sg_policy->limits_changed = true;
}

#if IS_ENABLED(CONFIG_MTK_OPP_MIN)
void mtk_set_cpu_min_opp(int cpu, unsigned long min_util)
{
	int gear_id, min_opp;

	gear_id = topology_physical_package_id(cpu);
	min_util = map_util_perf(min_util);
	min_opp = pd_get_util_opp(cpu, min_util);
	set_cpu_min_opp(gear_id, min_opp);
}

void mtk_set_cpu_min_opp_single(struct sugov_cpu *sg_cpu)
{
	int cpu = sg_cpu->cpu;
	struct rq *rq = cpu_rq(cpu);
	unsigned long min_util;

	min_util = READ_ONCE(rq->uclamp[UCLAMP_MIN].value);
	mtk_set_cpu_min_opp(cpu, min_util);
}

void mtk_set_cpu_min_opp_shared(struct sugov_cpu *sg_cpu)
{
	int cpu, i;
	unsigned long min_util = 0, util;
	struct sugov_policy *sg_policy = sg_cpu->sg_policy;
	struct cpufreq_policy *policy = sg_policy->policy;

	for_each_cpu(i, policy->cpus) {
		struct rq *rq = cpu_rq(i);

		util = READ_ONCE(rq->uclamp[UCLAMP_MIN].value);
		min_util = max(min_util, util);
	}


	cpu = cpumask_first(policy->cpus);
	mtk_set_cpu_min_opp(cpu, min_util);
}
#else

void mtk_set_cpu_min_opp_single(struct sugov_cpu *sg_cpu)
{
}

void mtk_set_cpu_min_opp_shared(struct sugov_cpu *sg_cpu)
{
}

#endif

static void sugov_update_single(struct update_util_data *hook, u64 time,
				unsigned int flags)
{
	struct sugov_cpu *sg_cpu = container_of(hook, struct sugov_cpu, update_util);
	struct sugov_policy *sg_policy = sg_cpu->sg_policy;
	struct rq *rq;
	unsigned long umin, umax;
	unsigned int next_f;
#if IS_ENABLED(CONFIG_MTK_IRQ_MONITOR_DEBUG)
	u64 ts[2];
#endif


	raw_spin_lock(&sg_policy->update_lock);

	sugov_iowait_boost(sg_cpu, time, flags);
	sg_cpu->last_update = time;

	ignore_dl_rate_limit(sg_cpu);

	if (!sugov_should_update_freq(sg_policy, time)) {
		raw_spin_unlock(&sg_policy->update_lock);
		return;
	}

	/* Critical Task aware thermal throttling, notify thermal */
	mtk_set_cpu_min_opp_single(sg_cpu);

	sugov_get_util(sg_cpu);
	sugov_iowait_apply(sg_cpu, time);

	if (trace_sugov_ext_util_enabled()) {
		rq = cpu_rq(sg_cpu->cpu);

		umin = rq->uclamp[UCLAMP_MIN].value;
		umax = rq->uclamp[UCLAMP_MAX].value;
		trace_sugov_ext_util(sg_cpu->cpu, sg_cpu->util, umin, umax);
	}

	next_f = get_next_freq(sg_policy, sg_cpu->util, sg_cpu->max);

	if (!sugov_update_next_freq(sg_policy, time, next_f)) {
		raw_spin_unlock(&sg_policy->update_lock);
		return;
	}

	/*
	 * This code runs under rq->lock for the target CPU, so it won't run
	 * concurrently on two different CPUs for the same target and it is not
	 * necessary to acquire the lock in the fast switch case.
	 */
	if (sg_policy->policy->fast_switch_enabled) {
#if IS_ENABLED(CONFIG_MTK_IRQ_MONITOR_DEBUG)
		ts[0] = sched_clock();
#endif
		cpufreq_driver_fast_switch(sg_policy->policy, next_f);
#if IS_ENABLED(CONFIG_MTK_IRQ_MONITOR_DEBUG)
		ts[1] = sched_clock();

		if ((ts[1] - ts[0] > 500000ULL) && in_hardirq()) {
			printk_deferred("%s duration %llu, ts[0]=%llu, ts[1]=%llu\n",
				__func__, ts[1] - ts[0], ts[0], ts[1]);
		}
#endif
	} else
		sugov_deferred_update(sg_policy);

	raw_spin_unlock(&sg_policy->update_lock);
}

static unsigned int sugov_next_freq_shared(struct sugov_cpu *sg_cpu, u64 time)
{
	struct sugov_policy *sg_policy = sg_cpu->sg_policy;
	struct cpufreq_policy *policy = sg_policy->policy;
	struct rq *rq;
	unsigned long umin, umax;
	unsigned long util = 0, max = 1;
	unsigned int j;

	for_each_cpu(j, policy->cpus) {
		struct sugov_cpu *j_sg_cpu = &per_cpu(sugov_cpu, j);
		unsigned long j_util, j_max;

		sugov_get_util(j_sg_cpu);
		sugov_iowait_apply(j_sg_cpu, time);
		j_util = j_sg_cpu->util;
		j_max = j_sg_cpu->max;

		if (trace_sugov_ext_util_enabled()) {
			rq = cpu_rq(j);

			umin = rq->uclamp[UCLAMP_MIN].value;
			umax = rq->uclamp[UCLAMP_MAX].value;
			trace_sugov_ext_util(j, j_util, umin, umax);
		}

		if (j_util * max >= j_max * util) {
			util = j_util;
			max = j_max;
		}
	}

	return get_next_freq(sg_policy, util, max);
}

static void
sugov_update_shared(struct update_util_data *hook, u64 time, unsigned int flags)
{
	struct sugov_cpu *sg_cpu = container_of(hook, struct sugov_cpu, update_util);
	struct sugov_policy *sg_policy = sg_cpu->sg_policy;
	unsigned int next_f;
#if IS_ENABLED(CONFIG_MTK_IRQ_MONITOR_DEBUG)
	u64 ts[2];
#endif

	raw_spin_lock(&sg_policy->update_lock);

	sugov_iowait_boost(sg_cpu, time, flags);
	sg_cpu->last_update = time;

	ignore_dl_rate_limit(sg_cpu);

	if (sugov_should_update_freq(sg_policy, time)) {
		next_f = sugov_next_freq_shared(sg_cpu, time);

		if (!sugov_update_next_freq(sg_policy, time, next_f))
			goto unlock;

		if (sg_policy->policy->fast_switch_enabled) {
#if IS_ENABLED(CONFIG_MTK_IRQ_MONITOR_DEBUG)
			ts[0] = sched_clock();
#endif
			cpufreq_driver_fast_switch(sg_policy->policy, next_f);
#if IS_ENABLED(CONFIG_MTK_IRQ_MONITOR_DEBUG)
			ts[1] = sched_clock();

			if ((ts[1] - ts[0] > 500000ULL) && in_hardirq()) {
				printk_deferred("%s duration %llu, ts[0]=%llu, ts[1]=%llu\n",
					__func__, ts[1] - ts[0], ts[0], ts[1]);
			}
#endif
		} else
			sugov_deferred_update(sg_policy);
	}
unlock:
	/* Critical Task aware thermal throttling, notify thermal */
	mtk_set_cpu_min_opp_shared(sg_cpu);

	raw_spin_unlock(&sg_policy->update_lock);
}

static void sugov_work(struct kthread_work *work)
{
	struct sugov_policy *sg_policy = container_of(work, struct sugov_policy, work);
	unsigned int freq;
	unsigned long flags;

	/*
	 * Hold sg_policy->update_lock shortly to handle the case where:
	 * in case sg_policy->next_freq is read here, and then updated by
	 * sugov_deferred_update() just before work_in_progress is set to false
	 * here, we may miss queueing the new update.
	 *
	 * Note: If a work was queued after the update_lock is released,
	 * sugov_work() will just be called again by kthread_work code; and the
	 * request will be proceed before the sugov thread sleeps.
	 */
	raw_spin_lock_irqsave(&sg_policy->update_lock, flags);
	freq = sg_policy->next_freq;
	sg_policy->work_in_progress = false;
	raw_spin_unlock_irqrestore(&sg_policy->update_lock, flags);

	mutex_lock(&sg_policy->work_lock);
	__cpufreq_driver_target(sg_policy->policy, freq, CPUFREQ_RELATION_L);
	mutex_unlock(&sg_policy->work_lock);
}

bool check_freq_update_for_time(struct update_util_data *hook, u64 time)
{
	struct sugov_cpu *sg_cpu = container_of(hook, struct sugov_cpu, update_util);

	return sg_cpu->last_update == time;
}
EXPORT_SYMBOL(check_freq_update_for_time);

static void sugov_irq_work(struct irq_work *irq_work)
{
	struct sugov_policy *sg_policy;

	sg_policy = container_of(irq_work, struct sugov_policy, irq_work);

	kthread_queue_work(&sg_policy->worker, &sg_policy->work);
}

/************************** sysfs interface ************************/

static struct sugov_tunables *global_tunables;
static DEFINE_MUTEX(global_tunables_lock);

static inline struct sugov_tunables *to_sugov_tunables(struct gov_attr_set *attr_set)
{
	return container_of(attr_set, struct sugov_tunables, attr_set);
}

static DEFINE_MUTEX(min_rate_lock);

static void update_min_rate_limit_ns(struct sugov_policy *sg_policy)
{
	mutex_lock(&min_rate_lock);
	WRITE_ONCE(sg_policy->min_rate_limit_ns, min(sg_policy->up_rate_delay_ns,
					   sg_policy->down_rate_delay_ns));
	mutex_unlock(&min_rate_lock);
}

static ssize_t up_rate_limit_us_show(struct gov_attr_set *attr_set, char *buf)
{
	struct sugov_tunables *tunables = to_sugov_tunables(attr_set);

	return sprintf(buf, "%u\n", tunables->up_rate_limit_us);
}

static ssize_t down_rate_limit_us_show(struct gov_attr_set *attr_set, char *buf)
{
	struct sugov_tunables *tunables = to_sugov_tunables(attr_set);

	return sprintf(buf, "%u\n", tunables->down_rate_limit_us);
}

static ssize_t
up_rate_limit_us_store(struct gov_attr_set *attr_set, const char *buf, size_t count)
{
	struct sugov_tunables *tunables = to_sugov_tunables(attr_set);
	struct sugov_policy *sg_policy;
	unsigned int rate_limit_us;

	if (kstrtouint(buf, 10, &rate_limit_us))
		return -EINVAL;

	tunables->up_rate_limit_us = rate_limit_us;

	list_for_each_entry(sg_policy, &attr_set->policy_list, tunables_hook) {
		sg_policy->up_rate_delay_ns = rate_limit_us * NSEC_PER_USEC;
		update_min_rate_limit_ns(sg_policy);
	}

	return count;
}

static ssize_t
down_rate_limit_us_store(struct gov_attr_set *attr_set, const char *buf, size_t count)
{
	struct sugov_tunables *tunables = to_sugov_tunables(attr_set);
	struct sugov_policy *sg_policy;
	unsigned int rate_limit_us;

	if (kstrtouint(buf, 10, &rate_limit_us))
		return -EINVAL;

	tunables->down_rate_limit_us = rate_limit_us;

	list_for_each_entry(sg_policy, &attr_set->policy_list, tunables_hook) {
		sg_policy->down_rate_delay_ns = rate_limit_us * NSEC_PER_USEC;
		update_min_rate_limit_ns(sg_policy);
	}

	return count;
}

static struct governor_attr up_rate_limit_us = __ATTR_RW(up_rate_limit_us);
static struct governor_attr down_rate_limit_us = __ATTR_RW(down_rate_limit_us);

static struct attribute *sugov_attrs[] = {
	&up_rate_limit_us.attr,
	&down_rate_limit_us.attr,
	NULL
};
ATTRIBUTE_GROUPS(sugov);

static void sugov_tunables_free(struct kobject *kobj)
{
	struct gov_attr_set *attr_set = container_of(kobj, struct gov_attr_set, kobj);

	kfree(to_sugov_tunables(attr_set));
}

static struct kobj_type sugov_tunables_ktype = {
	.default_groups = sugov_groups,
	.sysfs_ops = &governor_sysfs_ops,
	.release = &sugov_tunables_free,
};

/********************** cpufreq governor interface *********************/

struct cpufreq_governor mtk_gov;

static struct sugov_policy *sugov_policy_alloc(struct cpufreq_policy *policy)
{
	struct sugov_policy *sg_policy;

	sg_policy = kzalloc(sizeof(*sg_policy), GFP_KERNEL);
	if (!sg_policy)
		return NULL;

	sg_policy->policy = policy;
	raw_spin_lock_init(&sg_policy->update_lock);
	return sg_policy;
}

static void sugov_policy_free(struct sugov_policy *sg_policy)
{
	kfree(sg_policy);
}

static int sugov_kthread_create(struct sugov_policy *sg_policy)
{
	struct task_struct *thread;
	struct sched_attr attr = {
		.size		= sizeof(struct sched_attr),
		.sched_policy	= SCHED_DEADLINE,
		.sched_flags	= SCHED_FLAG_SUGOV,
		.sched_nice	= 0,
		.sched_priority	= 0,
		/*
		 * Fake (unused) bandwidth; workaround to "fix"
		 * priority inheritance.
		 */
		.sched_runtime	=  1000000,
		.sched_deadline = 10000000,
		.sched_period	= 10000000,
	};
	struct cpufreq_policy *policy = sg_policy->policy;
	int ret;

	/* kthread only required for slow path */
	if (policy->fast_switch_enabled)
		return 0;

	kthread_init_work(&sg_policy->work, sugov_work);
	kthread_init_worker(&sg_policy->worker);
	thread = kthread_create(kthread_worker_fn, &sg_policy->worker,
				"sugov:%d",
				cpumask_first(policy->related_cpus));
	if (IS_ERR(thread)) {
		pr_info("failed to create sugov thread: %ld\n", PTR_ERR(thread));
		return PTR_ERR(thread);
	}

	ret = sched_setattr_nocheck(thread, &attr);
	if (ret) {
		kthread_stop(thread);
		pr_info("%s: failed to set SCHED_DEADLINE\n", __func__);
		return ret;
	}

	sg_policy->thread = thread;
	kthread_bind_mask(thread, policy->related_cpus);
	init_irq_work(&sg_policy->irq_work, sugov_irq_work);
	mutex_init(&sg_policy->work_lock);

	wake_up_process(thread);

	return 0;
}

static void sugov_kthread_stop(struct sugov_policy *sg_policy)
{
	/* kthread only required for slow path */
	if (sg_policy->policy->fast_switch_enabled)
		return;

	kthread_flush_worker(&sg_policy->worker);
	kthread_stop(sg_policy->thread);
	mutex_destroy(&sg_policy->work_lock);
}

static struct sugov_tunables *sugov_tunables_alloc(struct sugov_policy *sg_policy)
{
	struct sugov_tunables *tunables;

	tunables = kzalloc(sizeof(*tunables), GFP_KERNEL);
	if (tunables) {
		gov_attr_set_init(&tunables->attr_set, &sg_policy->tunables_hook);
		if (!have_governor_per_policy())
			global_tunables = tunables;
	}
	return tunables;
}

static void sugov_clear_global_tunables(void)
{
	if (!have_governor_per_policy())
		global_tunables = NULL;
}

static int sugov_init(struct cpufreq_policy *policy)
{
	struct sugov_policy *sg_policy;
	struct sugov_tunables *tunables;
	int ret = 0;

	/* State should be equivalent to EXIT */
	if (policy->governor_data)
		return -EBUSY;

	cpufreq_enable_fast_switch(policy);

	sg_policy = sugov_policy_alloc(policy);
	if (!sg_policy) {
		ret = -ENOMEM;
		goto disable_fast_switch;
	}

	ret = sugov_kthread_create(sg_policy);
	if (ret)
		goto free_sg_policy;

	mutex_lock(&global_tunables_lock);

	if (global_tunables) {
		if (WARN_ON(have_governor_per_policy())) {
			ret = -EINVAL;
			goto stop_kthread;
		}
		policy->governor_data = sg_policy;
		sg_policy->tunables = global_tunables;

		gov_attr_set_get(&global_tunables->attr_set, &sg_policy->tunables_hook);
		goto out;
	}

	tunables = sugov_tunables_alloc(sg_policy);
	if (!tunables) {
		ret = -ENOMEM;
		goto stop_kthread;
	}

	tunables->up_rate_limit_us = cpufreq_policy_transition_delay_us(policy);
	tunables->down_rate_limit_us = cpufreq_policy_transition_delay_us(policy);

	policy->governor_data = sg_policy;
	sg_policy->tunables = tunables;

	ret = kobject_init_and_add(&tunables->attr_set.kobj, &sugov_tunables_ktype,
				   get_governor_parent_kobj(policy), "%s",
				   mtk_gov.name);
	if (ret)
		goto fail;

	policy->dvfs_possible_from_any_cpu = 1;

out:
	mutex_unlock(&global_tunables_lock);
	return 0;

fail:
	kobject_put(&tunables->attr_set.kobj);
	policy->governor_data = NULL;
	sugov_clear_global_tunables();

stop_kthread:
	sugov_kthread_stop(sg_policy);
	mutex_unlock(&global_tunables_lock);

free_sg_policy:
	sugov_policy_free(sg_policy);

disable_fast_switch:
	cpufreq_disable_fast_switch(policy);

	pr_info("initialization failed (error %d)\n", ret);
	return ret;
}

static void sugov_exit(struct cpufreq_policy *policy)
{
	struct sugov_policy *sg_policy = policy->governor_data;
	struct sugov_tunables *tunables = sg_policy->tunables;
	unsigned int count;

	mutex_lock(&global_tunables_lock);

	count = gov_attr_set_put(&tunables->attr_set, &sg_policy->tunables_hook);
	policy->governor_data = NULL;
	if (!count)
		sugov_clear_global_tunables();

	mutex_unlock(&global_tunables_lock);

	sugov_kthread_stop(sg_policy);
	sugov_policy_free(sg_policy);
	cpufreq_disable_fast_switch(policy);
}

static int sugov_start(struct cpufreq_policy *policy)
{
	struct sugov_policy *sg_policy = policy->governor_data;
	unsigned int cpu;

	sg_policy->up_rate_delay_ns =
		sg_policy->tunables->up_rate_limit_us * NSEC_PER_USEC;
	sg_policy->down_rate_delay_ns =
		sg_policy->tunables->down_rate_limit_us * NSEC_PER_USEC;
	update_min_rate_limit_ns(sg_policy);
	sg_policy->last_freq_update_time	= 0;
	sg_policy->next_freq			= 0;
	sg_policy->work_in_progress		= false;
	sg_policy->limits_changed		= false;
	sg_policy->need_freq_update		= false;
	sg_policy->cached_raw_freq		= 0;

	for_each_cpu(cpu, policy->cpus) {
		struct sugov_cpu *sg_cpu = &per_cpu(sugov_cpu, cpu);

		memset(sg_cpu, 0, sizeof(*sg_cpu));
		sg_cpu->cpu			= cpu;
		sg_cpu->sg_policy		= sg_policy;
	}

	for_each_cpu(cpu, policy->cpus) {
		struct sugov_cpu *sg_cpu = &per_cpu(sugov_cpu, cpu);

		cpufreq_add_update_util_hook(cpu, &sg_cpu->update_util,
					     policy_is_shared(policy) ?
							sugov_update_shared :
							sugov_update_single);
	}
	return 0;
}

static void sugov_stop(struct cpufreq_policy *policy)
{
	struct sugov_policy *sg_policy = policy->governor_data;
	unsigned int cpu;

	for_each_cpu(cpu, policy->cpus)
		cpufreq_remove_update_util_hook(cpu);

	synchronize_rcu();

	if (!policy->fast_switch_enabled) {
		irq_work_sync(&sg_policy->irq_work);
		kthread_cancel_work_sync(&sg_policy->work);
	}
}

static void sugov_limits(struct cpufreq_policy *policy)
{
	struct sugov_policy *sg_policy = policy->governor_data;

	if (!policy->fast_switch_enabled) {
		mutex_lock(&sg_policy->work_lock);
		cpufreq_policy_apply_limits(policy);
		mutex_unlock(&sg_policy->work_lock);
	}

	sg_policy->limits_changed = true;
}

struct cpufreq_governor mtk_gov = {
	.name			= "sugov_ext",
	.owner			= THIS_MODULE,
	.init			= sugov_init,
	.exit			= sugov_exit,
	.start			= sugov_start,
	.stop			= sugov_stop,
	.limits			= sugov_limits,
};

static int __init cpufreq_mtk_init(void)
{
	int ret = 0;
	struct proc_dir_entry *dir;

	ret = mtk_static_power_init();
	if (ret) {
#if IS_ENABLED(CONFIG_MTK_GEARLESS_SUPPORT)
		pr_info("%s: failed to init MTK EM, ret: %d, %p, %p\n",
			__func__, ret, mtk_em_pd_ptr_private, mtk_em_pd_ptr_public);
#else
		pr_info("%s: failed to init MTK EM, ret: %d\n",
			__func__, ret);
#endif
		return ret;
	}

	dir = proc_mkdir("mtk_scheduler", NULL);
	if (!dir)
		return -ENOMEM;

	ret = init_opp_cap_info(dir);
	if (ret)
		return ret;
#if IS_ENABLED(CONFIG_NONLINEAR_FREQ_CTL)
	//ret = register_trace_android_vh_cpufreq_fast_switch(mtk_cpufreq_fast_switch, NULL);
	//if (ret)
	//	pr_info("register android_vh_cpufreq_fast_switch failed\n");

	//ret = register_trace_android_vh_arch_set_freq_scale(
	//		mtk_arch_set_freq_scale, NULL);
	//if (ret)
	//	pr_info("register android_vh_arch_set_freq_scale failed\n");
	//else
	//	topology_clear_scale_freq_source(SCALE_FREQ_SOURCE_ARCH, cpu_possible_mask);
#endif

	return cpufreq_register_governor(&mtk_gov);
}

static void __exit cpufreq_mtk_exit(void)
{
	clear_opp_cap_info();
	cpufreq_unregister_governor(&mtk_gov);
}

module_init(cpufreq_mtk_init);
module_exit(cpufreq_mtk_exit);

MODULE_LICENSE("GPL");
