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545d2927 CH |
1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* | |
3 | * Helpers for DMA ops implementations. These generally rely on the fact that | |
4 | * the allocated memory contains normal pages in the direct kernel mapping. | |
5 | */ | |
efa70f2f | 6 | #include <linux/dma-contiguous.h> |
0a0f0d8b | 7 | #include <linux/dma-map-ops.h> |
545d2927 CH |
8 | #include <linux/dma-noncoherent.h> |
9 | ||
10 | /* | |
11 | * Create scatter-list for the already allocated DMA buffer. | |
12 | */ | |
13 | int dma_common_get_sgtable(struct device *dev, struct sg_table *sgt, | |
14 | void *cpu_addr, dma_addr_t dma_addr, size_t size, | |
15 | unsigned long attrs) | |
16 | { | |
17 | struct page *page = virt_to_page(cpu_addr); | |
18 | int ret; | |
19 | ||
20 | ret = sg_alloc_table(sgt, 1, GFP_KERNEL); | |
21 | if (!ret) | |
22 | sg_set_page(sgt->sgl, page, PAGE_ALIGN(size), 0); | |
23 | return ret; | |
24 | } | |
25 | ||
26 | /* | |
27 | * Create userspace mapping for the DMA-coherent memory. | |
28 | */ | |
29 | int dma_common_mmap(struct device *dev, struct vm_area_struct *vma, | |
30 | void *cpu_addr, dma_addr_t dma_addr, size_t size, | |
31 | unsigned long attrs) | |
32 | { | |
33 | #ifdef CONFIG_MMU | |
34 | unsigned long user_count = vma_pages(vma); | |
35 | unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT; | |
36 | unsigned long off = vma->vm_pgoff; | |
37 | int ret = -ENXIO; | |
38 | ||
39 | vma->vm_page_prot = dma_pgprot(dev, vma->vm_page_prot, attrs); | |
40 | ||
41 | if (dma_mmap_from_dev_coherent(dev, vma, cpu_addr, size, &ret)) | |
42 | return ret; | |
43 | ||
44 | if (off >= count || user_count > count - off) | |
45 | return -ENXIO; | |
46 | ||
47 | return remap_pfn_range(vma, vma->vm_start, | |
48 | page_to_pfn(virt_to_page(cpu_addr)) + vma->vm_pgoff, | |
49 | user_count << PAGE_SHIFT, vma->vm_page_prot); | |
50 | #else | |
51 | return -ENXIO; | |
52 | #endif /* CONFIG_MMU */ | |
53 | } | |
efa70f2f CH |
54 | |
55 | struct page *dma_common_alloc_pages(struct device *dev, size_t size, | |
56 | dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp) | |
57 | { | |
58 | const struct dma_map_ops *ops = get_dma_ops(dev); | |
59 | struct page *page; | |
60 | ||
61 | page = dma_alloc_contiguous(dev, size, gfp); | |
62 | if (!page) | |
63 | page = alloc_pages_node(dev_to_node(dev), gfp, get_order(size)); | |
64 | if (!page) | |
65 | return NULL; | |
66 | ||
67 | *dma_handle = ops->map_page(dev, page, 0, size, dir, | |
68 | DMA_ATTR_SKIP_CPU_SYNC); | |
69 | if (*dma_handle == DMA_MAPPING_ERROR) { | |
70 | dma_free_contiguous(dev, page, size); | |
71 | return NULL; | |
72 | } | |
73 | ||
74 | memset(page_address(page), 0, size); | |
75 | return page; | |
76 | } | |
77 | ||
78 | void dma_common_free_pages(struct device *dev, size_t size, struct page *page, | |
79 | dma_addr_t dma_handle, enum dma_data_direction dir) | |
80 | { | |
81 | const struct dma_map_ops *ops = get_dma_ops(dev); | |
82 | ||
83 | if (ops->unmap_page) | |
84 | ops->unmap_page(dev, dma_handle, size, dir, | |
85 | DMA_ATTR_SKIP_CPU_SYNC); | |
86 | dma_free_contiguous(dev, page, size); | |
87 | } |