| 1 | /* Fallback functions when the main IOMMU code is not compiled in. This |
| 2 | code is roughly equivalent to i386. */ |
| 3 | #include <linux/dma-mapping.h> |
| 4 | #include <linux/scatterlist.h> |
| 5 | #include <linux/string.h> |
| 6 | #include <linux/init.h> |
| 7 | #include <linux/gfp.h> |
| 8 | #include <linux/pci.h> |
| 9 | #include <linux/mm.h> |
| 10 | |
| 11 | #include <asm/processor.h> |
| 12 | #include <asm/iommu.h> |
| 13 | #include <asm/dma.h> |
| 14 | |
| 15 | static int |
| 16 | check_addr(char *name, struct device *hwdev, dma_addr_t bus, size_t size) |
| 17 | { |
| 18 | if (hwdev && !dma_capable(hwdev, bus, size)) { |
| 19 | if (*hwdev->dma_mask >= DMA_BIT_MASK(32)) |
| 20 | printk(KERN_ERR |
| 21 | "nommu_%s: overflow %Lx+%zu of device mask %Lx\n", |
| 22 | name, (long long)bus, size, |
| 23 | (long long)*hwdev->dma_mask); |
| 24 | return 0; |
| 25 | } |
| 26 | return 1; |
| 27 | } |
| 28 | |
| 29 | static dma_addr_t nommu_map_page(struct device *dev, struct page *page, |
| 30 | unsigned long offset, size_t size, |
| 31 | enum dma_data_direction dir, |
| 32 | struct dma_attrs *attrs) |
| 33 | { |
| 34 | dma_addr_t bus = page_to_phys(page) + offset; |
| 35 | WARN_ON(size == 0); |
| 36 | if (!check_addr("map_single", dev, bus, size)) |
| 37 | return DMA_ERROR_CODE; |
| 38 | flush_write_buffers(); |
| 39 | return bus; |
| 40 | } |
| 41 | |
| 42 | /* Map a set of buffers described by scatterlist in streaming |
| 43 | * mode for DMA. This is the scatter-gather version of the |
| 44 | * above pci_map_single interface. Here the scatter gather list |
| 45 | * elements are each tagged with the appropriate dma address |
| 46 | * and length. They are obtained via sg_dma_{address,length}(SG). |
| 47 | * |
| 48 | * NOTE: An implementation may be able to use a smaller number of |
| 49 | * DMA address/length pairs than there are SG table elements. |
| 50 | * (for example via virtual mapping capabilities) |
| 51 | * The routine returns the number of addr/length pairs actually |
| 52 | * used, at most nents. |
| 53 | * |
| 54 | * Device ownership issues as mentioned above for pci_map_single are |
| 55 | * the same here. |
| 56 | */ |
| 57 | static int nommu_map_sg(struct device *hwdev, struct scatterlist *sg, |
| 58 | int nents, enum dma_data_direction dir, |
| 59 | struct dma_attrs *attrs) |
| 60 | { |
| 61 | struct scatterlist *s; |
| 62 | int i; |
| 63 | |
| 64 | WARN_ON(nents == 0 || sg[0].length == 0); |
| 65 | |
| 66 | for_each_sg(sg, s, nents, i) { |
| 67 | BUG_ON(!sg_page(s)); |
| 68 | s->dma_address = sg_phys(s); |
| 69 | if (!check_addr("map_sg", hwdev, s->dma_address, s->length)) |
| 70 | return 0; |
| 71 | s->dma_length = s->length; |
| 72 | } |
| 73 | flush_write_buffers(); |
| 74 | return nents; |
| 75 | } |
| 76 | |
| 77 | static void nommu_free_coherent(struct device *dev, size_t size, void *vaddr, |
| 78 | dma_addr_t dma_addr) |
| 79 | { |
| 80 | free_pages((unsigned long)vaddr, get_order(size)); |
| 81 | } |
| 82 | |
| 83 | static void nommu_sync_single_for_device(struct device *dev, |
| 84 | dma_addr_t addr, size_t size, |
| 85 | enum dma_data_direction dir) |
| 86 | { |
| 87 | flush_write_buffers(); |
| 88 | } |
| 89 | |
| 90 | |
| 91 | static void nommu_sync_sg_for_device(struct device *dev, |
| 92 | struct scatterlist *sg, int nelems, |
| 93 | enum dma_data_direction dir) |
| 94 | { |
| 95 | flush_write_buffers(); |
| 96 | } |
| 97 | |
| 98 | struct dma_map_ops nommu_dma_ops = { |
| 99 | .alloc_coherent = dma_generic_alloc_coherent, |
| 100 | .free_coherent = nommu_free_coherent, |
| 101 | .map_sg = nommu_map_sg, |
| 102 | .map_page = nommu_map_page, |
| 103 | .sync_single_for_device = nommu_sync_single_for_device, |
| 104 | .sync_sg_for_device = nommu_sync_sg_for_device, |
| 105 | .is_phys = 1, |
| 106 | }; |