1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corporation 4 * 5 * Provide default implementations of the DMA mapping callbacks for 6 * busses using the iommu infrastructure 7 */ 8 9 #include <linux/export.h> 10 #include <asm/iommu.h> 11 12 /* 13 * Generic iommu implementation 14 */ 15 16 /* Allocates a contiguous real buffer and creates mappings over it. 17 * Returns the virtual address of the buffer and sets dma_handle 18 * to the dma address (mapping) of the first page. 19 */ 20 static void *dma_iommu_alloc_coherent(struct device *dev, size_t size, 21 dma_addr_t *dma_handle, gfp_t flag, 22 unsigned long attrs) 23 { 24 return iommu_alloc_coherent(dev, get_iommu_table_base(dev), size, 25 dma_handle, dev->coherent_dma_mask, flag, 26 dev_to_node(dev)); 27 } 28 29 static void dma_iommu_free_coherent(struct device *dev, size_t size, 30 void *vaddr, dma_addr_t dma_handle, 31 unsigned long attrs) 32 { 33 iommu_free_coherent(get_iommu_table_base(dev), size, vaddr, dma_handle); 34 } 35 36 /* Creates TCEs for a user provided buffer. The user buffer must be 37 * contiguous real kernel storage (not vmalloc). The address passed here 38 * comprises a page address and offset into that page. The dma_addr_t 39 * returned will point to the same byte within the page as was passed in. 40 */ 41 static dma_addr_t dma_iommu_map_page(struct device *dev, struct page *page, 42 unsigned long offset, size_t size, 43 enum dma_data_direction direction, 44 unsigned long attrs) 45 { 46 return iommu_map_page(dev, get_iommu_table_base(dev), page, offset, 47 size, device_to_mask(dev), direction, attrs); 48 } 49 50 51 static void dma_iommu_unmap_page(struct device *dev, dma_addr_t dma_handle, 52 size_t size, enum dma_data_direction direction, 53 unsigned long attrs) 54 { 55 iommu_unmap_page(get_iommu_table_base(dev), dma_handle, size, direction, 56 attrs); 57 } 58 59 60 static int dma_iommu_map_sg(struct device *dev, struct scatterlist *sglist, 61 int nelems, enum dma_data_direction direction, 62 unsigned long attrs) 63 { 64 return ppc_iommu_map_sg(dev, get_iommu_table_base(dev), sglist, nelems, 65 device_to_mask(dev), direction, attrs); 66 } 67 68 static void dma_iommu_unmap_sg(struct device *dev, struct scatterlist *sglist, 69 int nelems, enum dma_data_direction direction, 70 unsigned long attrs) 71 { 72 ppc_iommu_unmap_sg(get_iommu_table_base(dev), sglist, nelems, 73 direction, attrs); 74 } 75 76 /* We support DMA to/from any memory page via the iommu */ 77 int dma_iommu_dma_supported(struct device *dev, u64 mask) 78 { 79 struct iommu_table *tbl = get_iommu_table_base(dev); 80 81 if (!tbl) { 82 dev_info(dev, "Warning: IOMMU dma not supported: mask 0x%08llx" 83 ", table unavailable\n", mask); 84 return 0; 85 } 86 87 if (tbl->it_offset > (mask >> tbl->it_page_shift)) { 88 dev_info(dev, "Warning: IOMMU offset too big for device mask\n"); 89 dev_info(dev, "mask: 0x%08llx, table offset: 0x%08lx\n", 90 mask, tbl->it_offset << tbl->it_page_shift); 91 return 0; 92 } else 93 return 1; 94 } 95 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 int dma_iommu_mapping_error(struct device *dev, dma_addr_t dma_addr) 110 { 111 return dma_addr == IOMMU_MAPPING_ERROR; 112 } 113 114 struct dma_map_ops dma_iommu_ops = { 115 .alloc = dma_iommu_alloc_coherent, 116 .free = dma_iommu_free_coherent, 117 .mmap = dma_nommu_mmap_coherent, 118 .map_sg = dma_iommu_map_sg, 119 .unmap_sg = dma_iommu_unmap_sg, 120 .dma_supported = dma_iommu_dma_supported, 121 .map_page = dma_iommu_map_page, 122 .unmap_page = dma_iommu_unmap_page, 123 .get_required_mask = dma_iommu_get_required_mask, 124 .mapping_error = dma_iommu_mapping_error, 125 }; 126 EXPORT_SYMBOL(dma_iommu_ops); 127