1/*
 2 * DMA mapping support for platforms lacking IOMMUs.
 3 *
 4 * Copyright (C) 2009  Paul Mundt
 5 *
 6 * This file is subject to the terms and conditions of the GNU General Public
 7 * License.  See the file "COPYING" in the main directory of this archive
 8 * for more details.
 9 */
10#include <linux/dma-mapping.h>
11#include <linux/io.h>
12
13static dma_addr_t nommu_map_page(struct device *dev, struct page *page,
14				 unsigned long offset, size_t size,
15				 enum dma_data_direction dir,
16				 struct dma_attrs *attrs)
17{
18	dma_addr_t addr = page_to_phys(page) + offset;
19
20	WARN_ON(size == 0);
21	dma_cache_sync(dev, page_address(page) + offset, size, dir);
 
 
22
23	return addr;
24}
25
26static int nommu_map_sg(struct device *dev, struct scatterlist *sg,
27			int nents, enum dma_data_direction dir,
28			struct dma_attrs *attrs)
29{
30	struct scatterlist *s;
31	int i;
32
33	WARN_ON(nents == 0 || sg[0].length == 0);
34
35	for_each_sg(sg, s, nents, i) {
36		BUG_ON(!sg_page(s));
37
38		dma_cache_sync(dev, sg_virt(s), s->length, dir);
 
39
40		s->dma_address = sg_phys(s);
41		s->dma_length = s->length;
42	}
43
44	return nents;
45}
46
47#ifdef CONFIG_DMA_NONCOHERENT
48static void nommu_sync_single(struct device *dev, dma_addr_t addr,
49			      size_t size, enum dma_data_direction dir)
50{
51	dma_cache_sync(dev, phys_to_virt(addr), size, dir);
52}
53
54static void nommu_sync_sg(struct device *dev, struct scatterlist *sg,
55			  int nelems, enum dma_data_direction dir)
56{
57	struct scatterlist *s;
58	int i;
59
60	for_each_sg(sg, s, nelems, i)
61		dma_cache_sync(dev, sg_virt(s), s->length, dir);
62}
63#endif
64
65struct dma_map_ops nommu_dma_ops = {
66	.alloc			= dma_generic_alloc_coherent,
67	.free			= dma_generic_free_coherent,
68	.map_page		= nommu_map_page,
69	.map_sg			= nommu_map_sg,
70#ifdef CONFIG_DMA_NONCOHERENT
71	.sync_single_for_device	= nommu_sync_single,
72	.sync_sg_for_device	= nommu_sync_sg,
73#endif
74	.is_phys		= 1,
75};
76
77void __init no_iommu_init(void)
78{
79	if (dma_ops)
80		return;
81	dma_ops = &nommu_dma_ops;
82}

 1/*
 2 * DMA mapping support for platforms lacking IOMMUs.
 3 *
 4 * Copyright (C) 2009  Paul Mundt
 5 *
 6 * This file is subject to the terms and conditions of the GNU General Public
 7 * License.  See the file "COPYING" in the main directory of this archive
 8 * for more details.
 9 */
10#include <linux/dma-mapping.h>
11#include <linux/io.h>
12
13static dma_addr_t nommu_map_page(struct device *dev, struct page *page,
14				 unsigned long offset, size_t size,
15				 enum dma_data_direction dir,
16				 unsigned long attrs)
17{
18	dma_addr_t addr = page_to_phys(page) + offset;
19
20	WARN_ON(size == 0);
21
22	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
23		dma_cache_sync(dev, page_address(page) + offset, size, dir);
24
25	return addr;
26}
27
28static int nommu_map_sg(struct device *dev, struct scatterlist *sg,
29			int nents, enum dma_data_direction dir,
30			unsigned long attrs)
31{
32	struct scatterlist *s;
33	int i;
34
35	WARN_ON(nents == 0 || sg[0].length == 0);
36
37	for_each_sg(sg, s, nents, i) {
38		BUG_ON(!sg_page(s));
39
40		if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
41			dma_cache_sync(dev, sg_virt(s), s->length, dir);
42
43		s->dma_address = sg_phys(s);
44		s->dma_length = s->length;
45	}
46
47	return nents;
48}
49
50#ifdef CONFIG_DMA_NONCOHERENT
51static void nommu_sync_single(struct device *dev, dma_addr_t addr,
52			      size_t size, enum dma_data_direction dir)
53{
54	dma_cache_sync(dev, phys_to_virt(addr), size, dir);
55}
56
57static void nommu_sync_sg(struct device *dev, struct scatterlist *sg,
58			  int nelems, enum dma_data_direction dir)
59{
60	struct scatterlist *s;
61	int i;
62
63	for_each_sg(sg, s, nelems, i)
64		dma_cache_sync(dev, sg_virt(s), s->length, dir);
65}
66#endif
67
68struct dma_map_ops nommu_dma_ops = {
69	.alloc			= dma_generic_alloc_coherent,
70	.free			= dma_generic_free_coherent,
71	.map_page		= nommu_map_page,
72	.map_sg			= nommu_map_sg,
73#ifdef CONFIG_DMA_NONCOHERENT
74	.sync_single_for_device	= nommu_sync_single,
75	.sync_sg_for_device	= nommu_sync_sg,
76#endif
77	.is_phys		= 1,
78};
79
80void __init no_iommu_init(void)
81{
82	if (dma_ops)
83		return;
84	dma_ops = &nommu_dma_ops;
85}