u-boot/drivers/dma/dma-uclass.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * Direct Memory Access U-Class driver
 *
 * (C) Copyright 2015
 *     Texas Instruments Incorporated, <www.ti.com>
 *
 * Author: Mugunthan V N <mugunthanvnm@ti.com>
 */

#include <common.h>
#include <dma.h>
#include <dm.h>
#include <dm/uclass-internal.h>
#include <dm/device-internal.h>
#include <errno.h>

int dma_get_device(u32 transfer_type, struct udevice **devp)
{
	struct udevice *dev;
	int ret;

	for (ret = uclass_first_device(UCLASS_DMA, &dev); dev && !ret;
	     ret = uclass_next_device(&dev)) {
		struct dma_dev_priv *uc_priv;

		uc_priv = dev_get_uclass_priv(dev);
		if (uc_priv->supported & transfer_type)
			break;
	}

	if (!dev) {
		pr_err("No DMA device found that supports %x type\n",
		      transfer_type);
		return -EPROTONOSUPPORT;
	}

	*devp = dev;

	return ret;
}

int dma_memcpy(void *dst, void *src, size_t len)
{
	struct udevice *dev;
	const struct dma_ops *ops;
	int ret;

	ret = dma_get_device(DMA_SUPPORTS_MEM_TO_MEM, &dev);
	if (ret < 0)
		return ret;

	ops = device_get_ops(dev);
	if (!ops->transfer)
		return -ENOSYS;

	/* Invalidate the area, so no writeback into the RAM races with DMA */
	invalidate_dcache_range((unsigned long)dst, (unsigned long)dst +
				roundup(len, ARCH_DMA_MINALIGN));

	return ops->transfer(dev, DMA_MEM_TO_MEM, dst, src, len);
}

UCLASS_DRIVER(dma) = {
	.id		= UCLASS_DMA,
	.name		= "dma",
	.flags		= DM_UC_FLAG_SEQ_ALIAS,
	.per_device_auto_alloc_size = sizeof(struct dma_dev_priv),
};