blob: 3d766e78fbe26663e0de166fbe26d9b21b19ca89
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, |
13 | unsigned long attrs) |
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, |
25 | unsigned long attrs) |
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, |
33 | unsigned long attrs) |
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, |
39 | enum dma_data_direction dir, |
40 | unsigned long attrs) |
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); |
77 |