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73c926be PM |
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 | ||
13 | static 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 | ||
26 | static 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 | ||
01be5d63 | 47 | #ifdef CONFIG_DMA_NONCOHERENT |
73c926be PM |
48 | static 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 | ||
54 | static 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 | } | |
01be5d63 | 63 | #endif |
73c926be PM |
64 | |
65 | struct dma_map_ops nommu_dma_ops = { | |
f32154c9 PM |
66 | .alloc_coherent = dma_generic_alloc_coherent, |
67 | .free_coherent = dma_generic_free_coherent, | |
73c926be PM |
68 | .map_page = nommu_map_page, |
69 | .map_sg = nommu_map_sg, | |
01be5d63 | 70 | #ifdef CONFIG_DMA_NONCOHERENT |
73c926be PM |
71 | .sync_single_for_device = nommu_sync_single, |
72 | .sync_sg_for_device = nommu_sync_sg, | |
01be5d63 | 73 | #endif |
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74 | .is_phys = 1, |
75 | }; | |
76 | ||
77 | void __init no_iommu_init(void) | |
78 | { | |
79 | if (dma_ops) | |
80 | return; | |
81 | dma_ops = &nommu_dma_ops; | |
82 | } |