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/dma-direct.h> 10 #include <linux/pci.h> 11 #include <asm/iommu.h> 12 13 /* 14 * Generic iommu implementation 15 */ 16 17 /* Allocates a contiguous real buffer and creates mappings over it. 18 * Returns the virtual address of the buffer and sets dma_handle 19 * to the dma address (mapping) of the first page. 20 */ 21 static void *dma_iommu_alloc_coherent(struct device *dev, size_t size, 22 dma_addr_t *dma_handle, gfp_t flag, 23 unsigned long attrs) 24 { 25 return iommu_alloc_coherent(dev, get_iommu_table_base(dev), size, 26 dma_handle, dev->coherent_dma_mask, flag, 27 dev_to_node(dev)); 28 } 29 30 static void dma_iommu_free_coherent(struct device *dev, size_t size, 31 void *vaddr, dma_addr_t dma_handle, 32 unsigned long attrs) 33 { 34 iommu_free_coherent(get_iommu_table_base(dev), size, vaddr, dma_handle); 35 } 36 37 /* Creates TCEs for a user provided buffer. The user buffer must be 38 * contiguous real kernel storage (not vmalloc). The address passed here 39 * comprises a page address and offset into that page. The dma_addr_t 40 * returned will point to the same byte within the page as was passed in. 41 */ 42 static dma_addr_t dma_iommu_map_page(struct device *dev, struct page *page, 43 unsigned long offset, size_t size, 44 enum dma_data_direction direction, 45 unsigned long attrs) 46 { 47 return iommu_map_page(dev, get_iommu_table_base(dev), page, offset, 48 size, dma_get_mask(dev), direction, attrs); 49 } 50 51 52 static void dma_iommu_unmap_page(struct device *dev, dma_addr_t dma_handle, 53 size_t size, enum dma_data_direction direction, 54 unsigned long attrs) 55 { 56 iommu_unmap_page(get_iommu_table_base(dev), dma_handle, size, direction, 57 attrs); 58 } 59 60 61 static int dma_iommu_map_sg(struct device *dev, struct scatterlist *sglist, 62 int nelems, enum dma_data_direction direction, 63 unsigned long attrs) 64 { 65 return ppc_iommu_map_sg(dev, get_iommu_table_base(dev), sglist, nelems, 66 dma_get_mask(dev), direction, attrs); 67 } 68 69 static void dma_iommu_unmap_sg(struct device *dev, struct scatterlist *sglist, 70 int nelems, enum dma_data_direction direction, 71 unsigned long attrs) 72 { 73 ppc_iommu_unmap_sg(get_iommu_table_base(dev), sglist, nelems, 74 direction, attrs); 75 } 76 77 static bool dma_iommu_bypass_supported(struct device *dev, u64 mask) 78 { 79 struct pci_dev *pdev = to_pci_dev(dev); 80 struct pci_controller *phb = pci_bus_to_host(pdev->bus); 81 82 if (iommu_fixed_is_weak || !phb->controller_ops.iommu_bypass_supported) 83 return false; 84 return phb->controller_ops.iommu_bypass_supported(pdev, mask); 85 } 86 87 /* We support DMA to/from any memory page via the iommu */ 88 int dma_iommu_dma_supported(struct device *dev, u64 mask) 89 { 90 struct iommu_table *tbl = get_iommu_table_base(dev); 91 92 if (dev_is_pci(dev) && dma_iommu_bypass_supported(dev, mask)) { 93 dev->dma_ops_bypass = true; 94 dev_dbg(dev, "iommu: 64-bit OK, using fixed ops\n"); 95 return 1; 96 } 97 98 if (!tbl) { 99 dev_err(dev, "Warning: IOMMU dma not supported: mask 0x%08llx, table unavailable\n", mask); 100 return 0; 101 } 102 103 if (tbl->it_offset > (mask >> tbl->it_page_shift)) { 104 dev_info(dev, "Warning: IOMMU offset too big for device mask\n"); 105 dev_info(dev, "mask: 0x%08llx, table offset: 0x%08lx\n", 106 mask, tbl->it_offset << tbl->it_page_shift); 107 return 0; 108 } 109 110 dev_dbg(dev, "iommu: not 64-bit, using default ops\n"); 111 dev->dma_ops_bypass = false; 112 return 1; 113 } 114 115 u64 dma_iommu_get_required_mask(struct device *dev) 116 { 117 struct iommu_table *tbl = get_iommu_table_base(dev); 118 u64 mask; 119 120 if (!tbl) 121 return 0; 122 123 mask = 1ULL < (fls_long(tbl->it_offset + tbl->it_size) - 1); 124 mask += mask - 1; 125 126 return mask; 127 } 128 129 const struct dma_map_ops dma_iommu_ops = { 130 .alloc = dma_iommu_alloc_coherent, 131 .free = dma_iommu_free_coherent, 132 .map_sg = dma_iommu_map_sg, 133 .unmap_sg = dma_iommu_unmap_sg, 134 .dma_supported = dma_iommu_dma_supported, 135 .map_page = dma_iommu_map_page, 136 .unmap_page = dma_iommu_unmap_page, 137 .get_required_mask = dma_iommu_get_required_mask, 138 .mmap = dma_common_mmap, 139 .get_sgtable = dma_common_get_sgtable, 140 }; 141