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