1// SPDX-License-Identifier: GPL-2.0-only
2#include <linux/acpi.h>
3#include <linux/acpi_iort.h>
4#include <linux/device.h>
5#include <linux/dma-direct.h>
6
7void acpi_arch_dma_setup(struct device *dev)
8{
9	int ret;
10	u64 end, mask;
11	u64 size = 0;
12	const struct bus_dma_region *map = NULL;
13
14	/*
15	 * If @dev is expected to be DMA-capable then the bus code that created
16	 * it should have initialised its dma_mask pointer by this point. For
17	 * now, we'll continue the legacy behaviour of coercing it to the
18	 * coherent mask if not, but we'll no longer do so quietly.
19	 */
20	if (!dev->dma_mask) {
21		dev_warn(dev, "DMA mask not set\n");
22		dev->dma_mask = &dev->coherent_dma_mask;
23	}
24
25	if (dev->coherent_dma_mask)
26		size = max(dev->coherent_dma_mask, dev->coherent_dma_mask + 1);
27	else
28		size = 1ULL << 32;
29
30	ret = acpi_dma_get_range(dev, &map);
31	if (!ret && map) {
32		const struct bus_dma_region *r = map;
33
34		for (end = 0; r->size; r++) {
35			if (r->dma_start + r->size - 1 > end)
36				end = r->dma_start + r->size - 1;
37		}
38
39		size = end + 1;
40		dev->dma_range_map = map;
41	}
42
43	if (ret == -ENODEV)
44		ret = iort_dma_get_ranges(dev, &size);
45	if (!ret) {
46		/*
47		 * Limit coherent and dma mask based on size retrieved from
48		 * firmware.
49		 */
50		end = size - 1;
51		mask = DMA_BIT_MASK(ilog2(end) + 1);
52		dev->bus_dma_limit = end;
53		dev->coherent_dma_mask = min(dev->coherent_dma_mask, mask);
54		*dev->dma_mask = min(*dev->dma_mask, mask);
55	}
56}
57