summaryrefslogtreecommitdiffstats
path: root/arch/sh/kernel/dma-nommu.c
blob: 47fee3b6e29c1311ac2f36779ff5560c8d98cb28 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
/*
 * DMA mapping support for platforms lacking IOMMUs.
 *
 * Copyright (C) 2009  Paul Mundt
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 */
#include <linux/dma-mapping.h>
#include <linux/io.h>

static dma_addr_t nommu_map_page(struct device *dev, struct page *page,
				 unsigned long offset, size_t size,
				 enum dma_data_direction dir,
				 unsigned long attrs)
{
	dma_addr_t addr = page_to_phys(page) + offset;

	WARN_ON(size == 0);

	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
		dma_cache_sync(dev, page_address(page) + offset, size, dir);

	return addr;
}

static int nommu_map_sg(struct device *dev, struct scatterlist *sg,
			int nents, enum dma_data_direction dir,
			unsigned long attrs)
{
	struct scatterlist *s;
	int i;

	WARN_ON(nents == 0 || sg[0].length == 0);

	for_each_sg(sg, s, nents, i) {
		BUG_ON(!sg_page(s));

		if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
			dma_cache_sync(dev, sg_virt(s), s->length, dir);

		s->dma_address = sg_phys(s);
		s->dma_length = s->length;
	}

	return nents;
}

#ifdef CONFIG_DMA_NONCOHERENT
static void nommu_sync_single(struct device *dev, dma_addr_t addr,
			      size_t size, enum dma_data_direction dir)
{
	dma_cache_sync(dev, phys_to_virt(addr), size, dir);
}

static void nommu_sync_sg(struct device *dev, struct scatterlist *sg,
			  int nelems, enum dma_data_direction dir)
{
	struct scatterlist *s;
	int i;

	for_each_sg(sg, s, nelems, i)
		dma_cache_sync(dev, sg_virt(s), s->length, dir);
}
#endif

struct dma_map_ops nommu_dma_ops = {
	.alloc			= dma_generic_alloc_coherent,
	.free			= dma_generic_free_coherent,
	.map_page		= nommu_map_page,
	.map_sg			= nommu_map_sg,
#ifdef CONFIG_DMA_NONCOHERENT
	.sync_single_for_device	= nommu_sync_single,
	.sync_sg_for_device	= nommu_sync_sg,
#endif
	.is_phys		= 1,
};

void __init no_iommu_init(void)
{
	if (dma_ops)
		return;
	dma_ops = &nommu_dma_ops;
}