Commit | Line | Data |
---|---|---|
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> | |
8fa3d6fc | 7 | #include <linux/dma-mapping.h> |
b922f53b | 8 | #include <linux/scatterlist.h> |
8fa3d6fc | 9 | |
395624fc | 10 | #include <asm/gart.h> |
1da177e4 | 11 | #include <asm/processor.h> |
17a941d8 | 12 | #include <asm/dma.h> |
1da177e4 | 13 | |
17a941d8 MBY |
14 | static int |
15 | check_addr(char *name, struct device *hwdev, dma_addr_t bus, size_t size) | |
1da177e4 | 16 | { |
17a941d8 | 17 | if (hwdev && bus + size > *hwdev->dma_mask) { |
8fa3d6fc | 18 | if (*hwdev->dma_mask >= DMA_32BIT_MASK) |
f0fdabf8 | 19 | printk(KERN_ERR |
8fa3d6fc AM |
20 | "nommu_%s: overflow %Lx+%zu of device mask %Lx\n", |
21 | name, (long long)bus, size, | |
22 | (long long)*hwdev->dma_mask); | |
17a941d8 | 23 | return 0; |
1da177e4 | 24 | } |
17a941d8 MBY |
25 | return 1; |
26 | } | |
1da177e4 | 27 | |
17a941d8 | 28 | static dma_addr_t |
2be62149 | 29 | nommu_map_single(struct device *hwdev, phys_addr_t paddr, size_t size, |
17a941d8 MBY |
30 | int direction) |
31 | { | |
2be62149 | 32 | dma_addr_t bus = paddr; |
17a941d8 MBY |
33 | if (!check_addr("map_single", hwdev, bus, size)) |
34 | return bad_dma_address; | |
35 | return bus; | |
1da177e4 | 36 | } |
1da177e4 | 37 | |
1da177e4 | 38 | |
17a941d8 MBY |
39 | /* Map a set of buffers described by scatterlist in streaming |
40 | * mode for DMA. This is the scatter-gather version of the | |
41 | * above pci_map_single interface. Here the scatter gather list | |
42 | * elements are each tagged with the appropriate dma address | |
43 | * and length. They are obtained via sg_dma_{address,length}(SG). | |
44 | * | |
45 | * NOTE: An implementation may be able to use a smaller number of | |
46 | * DMA address/length pairs than there are SG table elements. | |
47 | * (for example via virtual mapping capabilities) | |
48 | * The routine returns the number of addr/length pairs actually | |
49 | * used, at most nents. | |
50 | * | |
51 | * Device ownership issues as mentioned above for pci_map_single are | |
52 | * the same here. | |
53 | */ | |
1048fa52 | 54 | static int nommu_map_sg(struct device *hwdev, struct scatterlist *sg, |
17a941d8 | 55 | int nents, int direction) |
1da177e4 | 56 | { |
b922f53b | 57 | struct scatterlist *s; |
17a941d8 | 58 | int i; |
1da177e4 | 59 | |
b922f53b | 60 | for_each_sg(sg, s, nents, i) { |
58b053e4 JA |
61 | BUG_ON(!sg_page(s)); |
62 | s->dma_address = virt_to_bus(sg_virt(s)); | |
17a941d8 MBY |
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 | |
9f9ab46d GC |
70 | /* Make sure we keep the same behaviour */ |
71 | static int nommu_mapping_error(dma_addr_t dma_addr) | |
72 | { | |
73 | #ifdef CONFIG_X86_32 | |
74 | return 0; | |
75 | #else | |
76 | return (dma_addr == bad_dma_address); | |
77 | #endif | |
78 | } | |
79 | ||
80 | ||
e6584504 | 81 | const struct dma_mapping_ops nommu_dma_ops = { |
17a941d8 | 82 | .map_single = nommu_map_single, |
17a941d8 | 83 | .map_sg = nommu_map_sg, |
9f9ab46d | 84 | .mapping_error = nommu_mapping_error, |
17a941d8 MBY |
85 | .is_phys = 1, |
86 | }; | |
1da177e4 | 87 | |
17a941d8 MBY |
88 | void __init no_iommu_init(void) |
89 | { | |
90 | if (dma_ops) | |
91 | return; | |
a166222c MBY |
92 | |
93 | force_iommu = 0; /* no HW IOMMU */ | |
17a941d8 | 94 | dma_ops = &nommu_dma_ops; |
17a941d8 | 95 | } |