drivers/gpu/drm/lima/lima_devfreq.c

Source file repositories/reference/linux-study-clean/drivers/gpu/drm/lima/lima_devfreq.c

File Facts

System
Linux kernel
Corpus path
drivers/gpu/drm/lima/lima_devfreq.c
Extension
.c
Size
5382 bytes
Lines
233
Domain
Driver Families
Bucket
drivers/gpu
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

// 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)

Annotation

Implementation Notes