Commit | Line | Data |
---|---|---|
b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
a8463d4b | 2 | /* |
2e86a047 CH |
3 | * DMA operations that map physical memory directly without using an IOMMU or |
4 | * flushing caches. | |
a8463d4b CB |
5 | */ |
6 | #include <linux/export.h> | |
7 | #include <linux/mm.h> | |
2e86a047 | 8 | #include <linux/dma-direct.h> |
a8463d4b | 9 | #include <linux/scatterlist.h> |
080321d3 | 10 | #include <linux/dma-contiguous.h> |
25f1e188 | 11 | #include <linux/pfn.h> |
a8463d4b | 12 | |
27975969 CH |
13 | #define DIRECT_MAPPING_ERROR 0 |
14 | ||
c61e9637 CH |
15 | /* |
16 | * Most architectures use ZONE_DMA for the first 16 Megabytes, but | |
17 | * some use it for entirely different regions: | |
18 | */ | |
19 | #ifndef ARCH_ZONE_DMA_BITS | |
20 | #define ARCH_ZONE_DMA_BITS 24 | |
21 | #endif | |
22 | ||
27975969 CH |
23 | static bool |
24 | check_addr(struct device *dev, dma_addr_t dma_addr, size_t size, | |
25 | const char *caller) | |
26 | { | |
27 | if (unlikely(dev && !dma_capable(dev, dma_addr, size))) { | |
28 | if (*dev->dma_mask >= DMA_BIT_MASK(32)) { | |
29 | dev_err(dev, | |
30 | "%s: overflow %pad+%zu of device mask %llx\n", | |
31 | caller, &dma_addr, size, *dev->dma_mask); | |
32 | } | |
33 | return false; | |
34 | } | |
35 | return true; | |
36 | } | |
37 | ||
002e6745 CH |
38 | static void *dma_direct_alloc(struct device *dev, size_t size, |
39 | dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs) | |
a8463d4b | 40 | { |
080321d3 CH |
41 | unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT; |
42 | int page_order = get_order(size); | |
43 | struct page *page = NULL; | |
a8463d4b | 44 | |
c61e9637 CH |
45 | /* GFP_DMA32 and GFP_DMA are no ops without the corresponding zones: */ |
46 | if (dev->coherent_dma_mask <= DMA_BIT_MASK(ARCH_ZONE_DMA_BITS)) | |
47 | gfp |= GFP_DMA; | |
48 | if (dev->coherent_dma_mask <= DMA_BIT_MASK(32) && !(gfp & GFP_DMA)) | |
49 | gfp |= GFP_DMA32; | |
50 | ||
080321d3 CH |
51 | /* CMA can be used only in the context which permits sleeping */ |
52 | if (gfpflags_allow_blocking(gfp)) | |
53 | page = dma_alloc_from_contiguous(dev, count, page_order, gfp); | |
54 | if (!page) | |
21f237e4 | 55 | page = alloc_pages_node(dev_to_node(dev), gfp, page_order); |
080321d3 CH |
56 | if (!page) |
57 | return NULL; | |
25f1e188 | 58 | |
080321d3 CH |
59 | *dma_handle = phys_to_dma(dev, page_to_phys(page)); |
60 | memset(page_address(page), 0, size); | |
61 | return page_address(page); | |
a8463d4b CB |
62 | } |
63 | ||
002e6745 CH |
64 | static void dma_direct_free(struct device *dev, size_t size, void *cpu_addr, |
65 | dma_addr_t dma_addr, unsigned long attrs) | |
a8463d4b | 66 | { |
080321d3 CH |
67 | unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT; |
68 | ||
69 | if (!dma_release_from_contiguous(dev, virt_to_page(cpu_addr), count)) | |
70 | free_pages((unsigned long)cpu_addr, get_order(size)); | |
a8463d4b CB |
71 | } |
72 | ||
002e6745 CH |
73 | static dma_addr_t dma_direct_map_page(struct device *dev, struct page *page, |
74 | unsigned long offset, size_t size, enum dma_data_direction dir, | |
75 | unsigned long attrs) | |
a8463d4b | 76 | { |
27975969 CH |
77 | dma_addr_t dma_addr = phys_to_dma(dev, page_to_phys(page)) + offset; |
78 | ||
79 | if (!check_addr(dev, dma_addr, size, __func__)) | |
80 | return DIRECT_MAPPING_ERROR; | |
81 | return dma_addr; | |
a8463d4b CB |
82 | } |
83 | ||
002e6745 CH |
84 | static int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl, |
85 | int nents, enum dma_data_direction dir, unsigned long attrs) | |
a8463d4b CB |
86 | { |
87 | int i; | |
88 | struct scatterlist *sg; | |
89 | ||
90 | for_each_sg(sgl, sg, nents, i) { | |
a8463d4b | 91 | BUG_ON(!sg_page(sg)); |
2e86a047 CH |
92 | |
93 | sg_dma_address(sg) = phys_to_dma(dev, sg_phys(sg)); | |
27975969 CH |
94 | if (!check_addr(dev, sg_dma_address(sg), sg->length, __func__)) |
95 | return 0; | |
a8463d4b CB |
96 | sg_dma_len(sg) = sg->length; |
97 | } | |
98 | ||
99 | return nents; | |
100 | } | |
101 | ||
27975969 CH |
102 | static int dma_direct_mapping_error(struct device *dev, dma_addr_t dma_addr) |
103 | { | |
104 | return dma_addr == DIRECT_MAPPING_ERROR; | |
105 | } | |
106 | ||
002e6745 CH |
107 | const struct dma_map_ops dma_direct_ops = { |
108 | .alloc = dma_direct_alloc, | |
109 | .free = dma_direct_free, | |
110 | .map_page = dma_direct_map_page, | |
111 | .map_sg = dma_direct_map_sg, | |
27975969 | 112 | .mapping_error = dma_direct_mapping_error, |
a8463d4b | 113 | }; |
002e6745 | 114 | EXPORT_SYMBOL(dma_direct_ops); |