Paul Mundt | 73c926b | 2009-10-20 12:55:56 +0900 | [diff] [blame] | 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 | |
Paul Mundt | 01be5d6 | 2009-10-27 10:35:02 +0900 | [diff] [blame] | 47 | #ifdef CONFIG_DMA_NONCOHERENT |
Paul Mundt | 73c926b | 2009-10-20 12:55:56 +0900 | [diff] [blame] | 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 | } |
Paul Mundt | 01be5d6 | 2009-10-27 10:35:02 +0900 | [diff] [blame] | 63 | #endif |
Paul Mundt | 73c926b | 2009-10-20 12:55:56 +0900 | [diff] [blame] | 64 | |
| 65 | struct dma_map_ops nommu_dma_ops = { |
Andrzej Pietrasiewicz | 552c0d3 | 2011-12-14 12:11:13 +0100 | [diff] [blame] | 66 | .alloc = dma_generic_alloc_coherent, |
| 67 | .free = dma_generic_free_coherent, |
Paul Mundt | 73c926b | 2009-10-20 12:55:56 +0900 | [diff] [blame] | 68 | .map_page = nommu_map_page, |
| 69 | .map_sg = nommu_map_sg, |
Paul Mundt | 01be5d6 | 2009-10-27 10:35:02 +0900 | [diff] [blame] | 70 | #ifdef CONFIG_DMA_NONCOHERENT |
Paul Mundt | 73c926b | 2009-10-20 12:55:56 +0900 | [diff] [blame] | 71 | .sync_single_for_device = nommu_sync_single, |
| 72 | .sync_sg_for_device = nommu_sync_sg, |
Paul Mundt | 01be5d6 | 2009-10-27 10:35:02 +0900 | [diff] [blame] | 73 | #endif |
Paul Mundt | 73c926b | 2009-10-20 12:55:56 +0900 | [diff] [blame] | 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 | } |