// 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);
}