1 /*
2 * Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corporation
3 *
4 * Provide default implementations of the DMA mapping callbacks for
5 * busses using the iommu infrastructure
6 */
7
8 #include <linux/export.h>
9 #include <asm/iommu.h>
10
11 /*
12 * Generic iommu implementation
13 */
14
15 /* Allocates a contiguous real buffer and creates mappings over it.
16 * Returns the virtual address of the buffer and sets dma_handle
17 * to the dma address (mapping) of the first page.
18 */
dma_iommu_alloc_coherent(struct device * dev,size_t size,dma_addr_t * dma_handle,gfp_t flag,struct dma_attrs * attrs)19 static void *dma_iommu_alloc_coherent(struct device *dev, size_t size,
20 dma_addr_t *dma_handle, gfp_t flag,
21 struct dma_attrs *attrs)
22 {
23 return iommu_alloc_coherent(dev, get_iommu_table_base(dev), size,
24 dma_handle, dev->coherent_dma_mask, flag,
25 dev_to_node(dev));
26 }
27
dma_iommu_free_coherent(struct device * dev,size_t size,void * vaddr,dma_addr_t dma_handle,struct dma_attrs * attrs)28 static void dma_iommu_free_coherent(struct device *dev, size_t size,
29 void *vaddr, dma_addr_t dma_handle,
30 struct dma_attrs *attrs)
31 {
32 iommu_free_coherent(get_iommu_table_base(dev), size, vaddr, dma_handle);
33 }
34
35 /* Creates TCEs for a user provided buffer. The user buffer must be
36 * contiguous real kernel storage (not vmalloc). The address passed here
37 * comprises a page address and offset into that page. The dma_addr_t
38 * returned will point to the same byte within the page as was passed in.
39 */
dma_iommu_map_page(struct device * dev,struct page * page,unsigned long offset,size_t size,enum dma_data_direction direction,struct dma_attrs * attrs)40 static dma_addr_t dma_iommu_map_page(struct device *dev, struct page *page,
41 unsigned long offset, size_t size,
42 enum dma_data_direction direction,
43 struct dma_attrs *attrs)
44 {
45 return iommu_map_page(dev, get_iommu_table_base(dev), page, offset,
46 size, device_to_mask(dev), direction, attrs);
47 }
48
49
dma_iommu_unmap_page(struct device * dev,dma_addr_t dma_handle,size_t size,enum dma_data_direction direction,struct dma_attrs * attrs)50 static void dma_iommu_unmap_page(struct device *dev, dma_addr_t dma_handle,
51 size_t size, enum dma_data_direction direction,
52 struct dma_attrs *attrs)
53 {
54 iommu_unmap_page(get_iommu_table_base(dev), dma_handle, size, direction,
55 attrs);
56 }
57
58
dma_iommu_map_sg(struct device * dev,struct scatterlist * sglist,int nelems,enum dma_data_direction direction,struct dma_attrs * attrs)59 static int dma_iommu_map_sg(struct device *dev, struct scatterlist *sglist,
60 int nelems, enum dma_data_direction direction,
61 struct dma_attrs *attrs)
62 {
63 return iommu_map_sg(dev, get_iommu_table_base(dev), sglist, nelems,
64 device_to_mask(dev), direction, attrs);
65 }
66
dma_iommu_unmap_sg(struct device * dev,struct scatterlist * sglist,int nelems,enum dma_data_direction direction,struct dma_attrs * attrs)67 static void dma_iommu_unmap_sg(struct device *dev, struct scatterlist *sglist,
68 int nelems, enum dma_data_direction direction,
69 struct dma_attrs *attrs)
70 {
71 iommu_unmap_sg(get_iommu_table_base(dev), sglist, nelems, direction,
72 attrs);
73 }
74
75 /* We support DMA to/from any memory page via the iommu */
dma_iommu_dma_supported(struct device * dev,u64 mask)76 static int dma_iommu_dma_supported(struct device *dev, u64 mask)
77 {
78 struct iommu_table *tbl = get_iommu_table_base(dev);
79
80 if (!tbl) {
81 dev_info(dev, "Warning: IOMMU dma not supported: mask 0x%08llx"
82 ", table unavailable\n", mask);
83 return 0;
84 }
85
86 if ((tbl->it_offset + tbl->it_size) > (mask >> IOMMU_PAGE_SHIFT)) {
87 dev_info(dev, "Warning: IOMMU window too big for device mask\n");
88 dev_info(dev, "mask: 0x%08llx, table end: 0x%08lx\n",
89 mask, (tbl->it_offset + tbl->it_size) <<
90 IOMMU_PAGE_SHIFT);
91 return 0;
92 } else
93 return 1;
94 }
95
dma_iommu_get_required_mask(struct device * dev)96 static u64 dma_iommu_get_required_mask(struct device *dev)
97 {
98 struct iommu_table *tbl = get_iommu_table_base(dev);
99 u64 mask;
100 if (!tbl)
101 return 0;
102
103 mask = 1ULL < (fls_long(tbl->it_offset + tbl->it_size) - 1);
104 mask += mask - 1;
105
106 return mask;
107 }
108
109 struct dma_map_ops dma_iommu_ops = {
110 .alloc = dma_iommu_alloc_coherent,
111 .free = dma_iommu_free_coherent,
112 .map_sg = dma_iommu_map_sg,
113 .unmap_sg = dma_iommu_unmap_sg,
114 .dma_supported = dma_iommu_dma_supported,
115 .map_page = dma_iommu_map_page,
116 .unmap_page = dma_iommu_unmap_page,
117 .get_required_mask = dma_iommu_get_required_mask,
118 };
119 EXPORT_SYMBOL(dma_iommu_ops);
120