arch/loongarch/kernel/dma.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
 */
#include <linux/acpi.h>
#include <linux/dma-direct.h>

void acpi_arch_dma_setup(struct device *dev)
{
	int ret;
	u64 mask, end = 0;
	const struct bus_dma_region *map = NULL;

	ret = acpi_dma_get_range(dev, &map);
	if (!ret && map) {
		const struct bus_dma_region *r = map;

		for (end = 0; r->size; r++) {
			if (r->dma_start + r->size - 1 > end)
				end = r->dma_start + r->size - 1;
		}

		mask = DMA_BIT_MASK(ilog2(end) + 1);
		dev->bus_dma_limit = end;
		dev->dma_range_map = map;
		dev->coherent_dma_mask = min(dev->coherent_dma_mask, mask);
		*dev->dma_mask = min(*dev->dma_mask, mask);
	}

}