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Commit | Line | Data |
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1da177e4 LT |
1 | /* Fallback functions when the main IOMMU code is not compiled in. This |
2 | code is roughly equivalent to i386. */ | |
3 | #include <linux/mm.h> | |
4 | #include <linux/init.h> | |
5 | #include <linux/pci.h> | |
6 | #include <linux/string.h> | |
7 | #include <asm/proto.h> | |
8 | #include <asm/processor.h> | |
17a941d8 | 9 | #include <asm/dma.h> |
1da177e4 | 10 | |
17a941d8 MBY |
11 | static int |
12 | check_addr(char *name, struct device *hwdev, dma_addr_t bus, size_t size) | |
1da177e4 | 13 | { |
17a941d8 MBY |
14 | if (hwdev && bus + size > *hwdev->dma_mask) { |
15 | printk(KERN_ERR | |
16 | "nommu_%s: overflow %Lx+%lu of device mask %Lx\n", | |
17 | name, (long long)bus, size, (long long)*hwdev->dma_mask); | |
18 | return 0; | |
1da177e4 | 19 | } |
17a941d8 MBY |
20 | return 1; |
21 | } | |
1da177e4 | 22 | |
17a941d8 MBY |
23 | static dma_addr_t |
24 | nommu_map_single(struct device *hwdev, void *ptr, size_t size, | |
25 | int direction) | |
26 | { | |
27 | dma_addr_t bus = virt_to_bus(ptr); | |
28 | if (!check_addr("map_single", hwdev, bus, size)) | |
29 | return bad_dma_address; | |
30 | return bus; | |
1da177e4 | 31 | } |
1da177e4 | 32 | |
17a941d8 MBY |
33 | void nommu_unmap_single(struct device *dev, dma_addr_t addr,size_t size, |
34 | int direction) | |
1da177e4 | 35 | { |
1da177e4 | 36 | } |
1da177e4 | 37 | |
17a941d8 MBY |
38 | /* Map a set of buffers described by scatterlist in streaming |
39 | * mode for DMA. This is the scatter-gather version of the | |
40 | * above pci_map_single interface. Here the scatter gather list | |
41 | * elements are each tagged with the appropriate dma address | |
42 | * and length. They are obtained via sg_dma_{address,length}(SG). | |
43 | * | |
44 | * NOTE: An implementation may be able to use a smaller number of | |
45 | * DMA address/length pairs than there are SG table elements. | |
46 | * (for example via virtual mapping capabilities) | |
47 | * The routine returns the number of addr/length pairs actually | |
48 | * used, at most nents. | |
49 | * | |
50 | * Device ownership issues as mentioned above for pci_map_single are | |
51 | * the same here. | |
52 | */ | |
53 | int nommu_map_sg(struct device *hwdev, struct scatterlist *sg, | |
54 | int nents, int direction) | |
1da177e4 | 55 | { |
17a941d8 | 56 | int i; |
1da177e4 | 57 | |
17a941d8 MBY |
58 | BUG_ON(direction == DMA_NONE); |
59 | for (i = 0; i < nents; i++ ) { | |
60 | struct scatterlist *s = &sg[i]; | |
61 | BUG_ON(!s->page); | |
62 | s->dma_address = virt_to_bus(page_address(s->page) +s->offset); | |
63 | if (!check_addr("map_sg", hwdev, s->dma_address, s->length)) | |
64 | return 0; | |
65 | s->dma_length = s->length; | |
66 | } | |
67 | return nents; | |
68 | } | |
1da177e4 | 69 | |
17a941d8 MBY |
70 | /* Unmap a set of streaming mode DMA translations. |
71 | * Again, cpu read rules concerning calls here are the same as for | |
72 | * pci_unmap_single() above. | |
73 | */ | |
74 | void nommu_unmap_sg(struct device *dev, struct scatterlist *sg, | |
75 | int nents, int dir) | |
1da177e4 | 76 | { |
1da177e4 | 77 | } |
1da177e4 | 78 | |
17a941d8 MBY |
79 | struct dma_mapping_ops nommu_dma_ops = { |
80 | .map_single = nommu_map_single, | |
81 | .unmap_single = nommu_unmap_single, | |
82 | .map_sg = nommu_map_sg, | |
83 | .unmap_sg = nommu_unmap_sg, | |
84 | .is_phys = 1, | |
85 | }; | |
1da177e4 | 86 | |
17a941d8 MBY |
87 | void __init no_iommu_init(void) |
88 | { | |
89 | if (dma_ops) | |
90 | return; | |
17a941d8 | 91 | dma_ops = &nommu_dma_ops; |
17a941d8 | 92 | } |