1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corporation
5 * Provide default implementations of the DMA mapping callbacks for
6 * busses using the iommu infrastructure
9 #include <linux/export.h>
10 #include <asm/iommu.h>
13 * Generic iommu implementation
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.
20 static void *dma_iommu_alloc_coherent(struct device *dev, size_t size,
21 dma_addr_t *dma_handle, gfp_t flag,
24 return iommu_alloc_coherent(dev, get_iommu_table_base(dev), size,
25 dma_handle, dev->coherent_dma_mask, flag,
29 static void dma_iommu_free_coherent(struct device *dev, size_t size,
30 void *vaddr, dma_addr_t dma_handle,
33 iommu_free_coherent(get_iommu_table_base(dev), size, vaddr, dma_handle);
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.
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,
46 return iommu_map_page(dev, get_iommu_table_base(dev), page, offset,
47 size, device_to_mask(dev), direction, attrs);
51 static void dma_iommu_unmap_page(struct device *dev, dma_addr_t dma_handle,
52 size_t size, enum dma_data_direction direction,
55 iommu_unmap_page(get_iommu_table_base(dev), dma_handle, size, direction,
60 static int dma_iommu_map_sg(struct device *dev, struct scatterlist *sglist,
61 int nelems, enum dma_data_direction direction,
64 return ppc_iommu_map_sg(dev, get_iommu_table_base(dev), sglist, nelems,
65 device_to_mask(dev), direction, attrs);
68 static void dma_iommu_unmap_sg(struct device *dev, struct scatterlist *sglist,
69 int nelems, enum dma_data_direction direction,
72 ppc_iommu_unmap_sg(get_iommu_table_base(dev), sglist, nelems,
76 /* We support DMA to/from any memory page via the iommu */
77 int dma_iommu_dma_supported(struct device *dev, u64 mask)
79 struct iommu_table *tbl = get_iommu_table_base(dev);
82 dev_info(dev, "Warning: IOMMU dma not supported: mask 0x%08llx"
83 ", table unavailable\n", mask);
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);
96 static u64 dma_iommu_get_required_mask(struct device *dev)
98 struct iommu_table *tbl = get_iommu_table_base(dev);
103 mask = 1ULL << (fls_long(tbl->it_offset + tbl->it_size) +
104 tbl->it_page_shift - 1);
110 int dma_iommu_mapping_error(struct device *dev, dma_addr_t dma_addr)
112 return dma_addr == IOMMU_MAPPING_ERROR;
115 struct dma_map_ops dma_iommu_ops = {
116 .alloc = dma_iommu_alloc_coherent,
117 .free = dma_iommu_free_coherent,
118 .mmap = dma_nommu_mmap_coherent,
119 .map_sg = dma_iommu_map_sg,
120 .unmap_sg = dma_iommu_unmap_sg,
121 .dma_supported = dma_iommu_dma_supported,
122 .map_page = dma_iommu_map_page,
123 .unmap_page = dma_iommu_unmap_page,
124 .get_required_mask = dma_iommu_get_required_mask,
125 .mapping_error = dma_iommu_mapping_error,
127 EXPORT_SYMBOL(dma_iommu_ops);