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