Christian Borntraeger | a8463d4 | 2016-02-02 21:46:32 -0800 | [diff] [blame] | 1 | /* |
| 2 | * lib/dma-noop.c |
| 3 | * |
| 4 | * Simple DMA noop-ops that map 1:1 with memory |
| 5 | */ |
| 6 | #include <linux/export.h> |
| 7 | #include <linux/mm.h> |
| 8 | #include <linux/dma-mapping.h> |
| 9 | #include <linux/scatterlist.h> |
| 10 | |
| 11 | static void *dma_noop_alloc(struct device *dev, size_t size, |
| 12 | dma_addr_t *dma_handle, gfp_t gfp, |
Krzysztof Kozlowski | 00085f1 | 2016-08-03 13:46:00 -0700 | [diff] [blame] | 13 | unsigned long attrs) |
Christian Borntraeger | a8463d4 | 2016-02-02 21:46:32 -0800 | [diff] [blame] | 14 | { |
| 15 | void *ret; |
| 16 | |
| 17 | ret = (void *)__get_free_pages(gfp, get_order(size)); |
| 18 | if (ret) |
| 19 | *dma_handle = virt_to_phys(ret); |
| 20 | return ret; |
| 21 | } |
| 22 | |
| 23 | static void dma_noop_free(struct device *dev, size_t size, |
| 24 | void *cpu_addr, dma_addr_t dma_addr, |
Krzysztof Kozlowski | 00085f1 | 2016-08-03 13:46:00 -0700 | [diff] [blame] | 25 | unsigned long attrs) |
Christian Borntraeger | a8463d4 | 2016-02-02 21:46:32 -0800 | [diff] [blame] | 26 | { |
| 27 | free_pages((unsigned long)cpu_addr, get_order(size)); |
| 28 | } |
| 29 | |
| 30 | static dma_addr_t dma_noop_map_page(struct device *dev, struct page *page, |
| 31 | unsigned long offset, size_t size, |
| 32 | enum dma_data_direction dir, |
Krzysztof Kozlowski | 00085f1 | 2016-08-03 13:46:00 -0700 | [diff] [blame] | 33 | unsigned long attrs) |
Christian Borntraeger | a8463d4 | 2016-02-02 21:46:32 -0800 | [diff] [blame] | 34 | { |
| 35 | return page_to_phys(page) + offset; |
| 36 | } |
| 37 | |
| 38 | static int dma_noop_map_sg(struct device *dev, struct scatterlist *sgl, int nents, |
Krzysztof Kozlowski | 00085f1 | 2016-08-03 13:46:00 -0700 | [diff] [blame] | 39 | enum dma_data_direction dir, |
| 40 | unsigned long attrs) |
Christian Borntraeger | a8463d4 | 2016-02-02 21:46:32 -0800 | [diff] [blame] | 41 | { |
| 42 | int i; |
| 43 | struct scatterlist *sg; |
| 44 | |
| 45 | for_each_sg(sgl, sg, nents, i) { |
| 46 | void *va; |
| 47 | |
| 48 | BUG_ON(!sg_page(sg)); |
| 49 | va = sg_virt(sg); |
| 50 | sg_dma_address(sg) = (dma_addr_t)virt_to_phys(va); |
| 51 | sg_dma_len(sg) = sg->length; |
| 52 | } |
| 53 | |
| 54 | return nents; |
| 55 | } |
| 56 | |
| 57 | static int dma_noop_mapping_error(struct device *dev, dma_addr_t dma_addr) |
| 58 | { |
| 59 | return 0; |
| 60 | } |
| 61 | |
| 62 | static int dma_noop_supported(struct device *dev, u64 mask) |
| 63 | { |
| 64 | return 1; |
| 65 | } |
| 66 | |
| 67 | struct dma_map_ops dma_noop_ops = { |
| 68 | .alloc = dma_noop_alloc, |
| 69 | .free = dma_noop_free, |
| 70 | .map_page = dma_noop_map_page, |
| 71 | .map_sg = dma_noop_map_sg, |
| 72 | .mapping_error = dma_noop_mapping_error, |
| 73 | .dma_supported = dma_noop_supported, |
| 74 | }; |
| 75 | |
| 76 | EXPORT_SYMBOL(dma_noop_ops); |