drivers/gpu/drm/evdi/evdi_platform_dev.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2020 DisplayLink (UK) Ltd.
 *
 * This program is free software; you can redistribute  it and/or modify it
 * under  the terms of  the GNU General  Public License as published by the
 * Free Software Foundation;  either version 2 of the  License, or (at your
 * option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */

#include "evdi_platform_dev.h"
#include <linux/dma-mapping.h>
#include <linux/platform_device.h>
#include <linux/slab.h>

#include "evdi_platform_drv.h"
#include "evdi_debug.h"
#include "evdi_drm_drv.h"

struct evdi_platform_device_data {
	struct drm_device *drm_dev;
	struct device *parent;
	bool symlinked;
};

struct platform_device *evdi_platform_dev_create(struct platform_device_info *info)
{
	struct platform_device *platform_dev = NULL;

	platform_dev = platform_device_register_full(info);
	if (dma_set_mask(&platform_dev->dev, DMA_BIT_MASK(64))) {
		EVDI_WARN("Unable to change dma mask to 64 bit. ");
		EVDI_WARN("Sticking with 32 bit\n");
	}

	EVDI_INFO("Evdi platform_device create\n");

	return platform_dev;
}

void evdi_platform_dev_destroy(struct platform_device *dev)
{
	platform_device_unregister(dev);
	EVDI_INFO("Evdi platform_device destroy\n");
}

int evdi_platform_device_probe(struct platform_device *pdev)
{
	struct drm_device *dev;
	struct evdi_platform_device_data *data;

	EVDI_CHECKPT();
	data = kzalloc(sizeof(struct evdi_platform_device_data), GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	dev = evdi_drm_device_create(&pdev->dev);
	if (IS_ERR_OR_NULL(dev))
		goto err_free;

	data->drm_dev = dev;
	data->symlinked = false;
	platform_set_drvdata(pdev, data);
	return PTR_ERR_OR_ZERO(dev);

err_free:
	kfree(data);
	return PTR_ERR_OR_ZERO(dev);
}

int evdi_platform_device_remove(struct platform_device *pdev)
{
	struct evdi_platform_device_data *data = platform_get_drvdata(pdev);

	EVDI_CHECKPT();

	evdi_drm_device_remove(data->drm_dev);
	kfree(data);
	return 0;
}

bool evdi_platform_device_is_free(struct platform_device *pdev)
{
	struct evdi_platform_device_data *data = platform_get_drvdata(pdev);
	struct evdi_device *evdi = data->drm_dev->dev_private;

	if (evdi && !evdi_painter_is_connected(evdi->painter) &&
	    !data->symlinked)
		return true;
	return false;
}

void evdi_platform_device_link(struct platform_device *pdev,
				      struct device *parent)
{
	struct evdi_platform_device_data *data = NULL;
	int ret = 0;

	if (!parent || !pdev)
		return;

	data = platform_get_drvdata(pdev);
	if (!evdi_platform_device_is_free(pdev)) {
		EVDI_FATAL("Device is already attached can't symlink again\n");
		return;
	}

	ret = sysfs_create_link(&pdev->dev.kobj, &parent->kobj, "device");
	if (ret) {
		EVDI_FATAL("Failed to create sysfs link from evdi to parent device\n");
	} else {
		data->symlinked = true;
		data->parent = parent;
	}
}

void evdi_platform_device_unlink_if_linked_with(struct platform_device *pdev,
				struct device *parent)
{
	struct evdi_platform_device_data *data = platform_get_drvdata(pdev);

	if (parent && data->parent == parent) {
		sysfs_remove_link(&pdev->dev.kobj, "device");
		data->symlinked = false;
		data->parent = NULL;
		EVDI_INFO("Detached from parent device\n");
	}
}