// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright 2020 Martin Blumenstingl <martin.blumenstingl@googlemail.com>
 *
 * Based on panfrost_devfreq.c:
 *   Copyright 2019 Collabora ltd.
 */
#include <linux/clk.h>
#include <linux/devfreq.h>
#include <linux/devfreq_cooling.h>
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/pm_opp.h>
#include <linux/property.h>

#include "lima_device.h"
#include "lima_devfreq.h"

static void lima_devfreq_update_utilization(struct lima_devfreq *devfreq)
{
        ktime_t now, last;

        now = ktime_get();
        last = devfreq->time_last_update;

        if (devfreq->busy_count > 0)
                devfreq->busy_time += ktime_sub(now, last);
        else
                devfreq->idle_time += ktime_sub(now, last);

        devfreq->time_last_update = now;
}

static int lima_devfreq_target(struct device *dev, unsigned long *freq,
                               u32 flags)
{
        struct dev_pm_opp *opp;

        opp = devfreq_recommended_opp(dev, freq, flags);
        if (IS_ERR(opp))
                return PTR_ERR(opp);
        dev_pm_opp_put(opp);

        return dev_pm_opp_set_rate(dev, *freq);
}

static void lima_devfreq_reset(struct lima_devfreq *devfreq)
{
        devfreq->busy_time = 0;
        devfreq->idle_time = 0;
        devfreq->time_last_update = ktime_get();
}

static int lima_devfreq_get_dev_status(struct device *dev,
                                       struct devfreq_dev_status *status)
{
        struct lima_device *ldev = dev_get_drvdata(dev);
        struct lima_devfreq *devfreq = &ldev->devfreq;
        unsigned long irqflags;

        status->current_frequency = clk_get_rate(ldev->clk_gpu);

        spin_lock_irqsave(&devfreq->lock, irqflags);

        lima_devfreq_update_utilization(devfreq);

        status->total_time = ktime_to_ns(ktime_add(devfreq->busy_time,
                                                   devfreq->idle_time));
        status->busy_time = ktime_to_ns(devfreq->busy_time);

        lima_devfreq_reset(devfreq);

        spin_unlock_irqrestore(&devfreq->lock, irqflags);

        dev_dbg(ldev->dev, "busy %lu total %lu %lu %% freq %lu MHz\n",
                status->busy_time, status->total_time,
                status->busy_time / (status->total_time / 100),
                status->current_frequency / 1000 / 1000);

        return 0;
}

static struct devfreq_dev_profile lima_devfreq_profile = {
        .timer = DEVFREQ_TIMER_DELAYED,
        .polling_ms = 50, /* ~3 frames */
        .target = lima_devfreq_target,
        .get_dev_status = lima_devfreq_get_dev_status,
};

void lima_devfreq_fini(struct lima_device *ldev)
{
        struct lima_devfreq *devfreq = &ldev->devfreq;

        if (devfreq->cooling) {
                devfreq_cooling_unregister(devfreq->cooling);
                devfreq->cooling = NULL;
        }

        if (devfreq->devfreq) {
                devm_devfreq_remove_device(ldev->dev, devfreq->devfreq);
                devfreq->devfreq = NULL;
        }
}

int lima_devfreq_init(struct lima_device *ldev)
{
        struct thermal_cooling_device *cooling;
        struct device *dev = ldev->dev;
        struct devfreq *devfreq;
        struct lima_devfreq *ldevfreq = &ldev->devfreq;
        struct dev_pm_opp *opp;
        unsigned long cur_freq;
        int ret;
        const char *regulator_names[] = { "mali", NULL };

        if (!device_property_present(dev, "operating-points-v2"))
                /* Optional, continue without devfreq */
                return 0;

        spin_lock_init(&ldevfreq->lock);

        /*
         * clkname is set separately so it is not affected by the optional
         * regulator setting which may return error.
         */
        ret = devm_pm_opp_set_clkname(dev, "core");
        if (ret)
                return ret;

        ret = devm_pm_opp_set_regulators(dev, regulator_names);
        if (ret) {
                /* Continue if the optional regulator is missing */
                if (ret != -ENODEV)
                        return ret;
        }

        ret = devm_pm_opp_of_add_table(dev);
        if (ret)
                return ret;

        lima_devfreq_reset(ldevfreq);

        cur_freq = clk_get_rate(ldev->clk_gpu);

        opp = devfreq_recommended_opp(dev, &cur_freq, 0);
        if (IS_ERR(opp))
                return PTR_ERR(opp);

        lima_devfreq_profile.initial_freq = cur_freq;
        dev_pm_opp_put(opp);

        /*
         * Setup default thresholds for the simple_ondemand governor.
         * The values are chosen based on experiments.
         */
        ldevfreq->gov_data.upthreshold = 30;
        ldevfreq->gov_data.downdifferential = 5;

        devfreq = devm_devfreq_add_device(dev, &lima_devfreq_profile,
                                          DEVFREQ_GOV_SIMPLE_ONDEMAND,
                                          &ldevfreq->gov_data);
        if (IS_ERR(devfreq)) {
                dev_err(dev, "Couldn't initialize GPU devfreq\n");
                return PTR_ERR(devfreq);
        }

        ldevfreq->devfreq = devfreq;

        cooling = of_devfreq_cooling_register(dev->of_node, devfreq);
        if (IS_ERR(cooling))
                dev_info(dev, "Failed to register cooling device\n");
        else
                ldevfreq->cooling = cooling;

        return 0;
}

void lima_devfreq_record_busy(struct lima_devfreq *devfreq)
{
        unsigned long irqflags;

        if (!devfreq->devfreq)
                return;

        spin_lock_irqsave(&devfreq->lock, irqflags);

        lima_devfreq_update_utilization(devfreq);

        devfreq->busy_count++;

        spin_unlock_irqrestore(&devfreq->lock, irqflags);
}

void lima_devfreq_record_idle(struct lima_devfreq *devfreq)
{
        unsigned long irqflags;

        if (!devfreq->devfreq)
                return;

        spin_lock_irqsave(&devfreq->lock, irqflags);

        lima_devfreq_update_utilization(devfreq);

        WARN_ON(--devfreq->busy_count < 0);

        spin_unlock_irqrestore(&devfreq->lock, irqflags);
}

int lima_devfreq_resume(struct lima_devfreq *devfreq)
{
        unsigned long irqflags;

        if (!devfreq->devfreq)
                return 0;

        spin_lock_irqsave(&devfreq->lock, irqflags);

        lima_devfreq_reset(devfreq);

        spin_unlock_irqrestore(&devfreq->lock, irqflags);

        return devfreq_resume_device(devfreq->devfreq);
}

int lima_devfreq_suspend(struct lima_devfreq *devfreq)
{
        if (!devfreq->devfreq)
                return 0;

        return devfreq_suspend_device(devfreq->devfreq);
}