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 */
dma_iommu_alloc_coherent(struct device * dev,size_t size,dma_addr_t * dma_handle,gfp_t flag,unsigned long attrs)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
dma_iommu_free_coherent(struct device * dev,size_t size,void * vaddr,dma_addr_t dma_handle,unsigned long attrs)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 */
dma_iommu_map_page(struct device * dev,struct page * page,unsigned long offset,size_t size,enum dma_data_direction direction,unsigned long attrs)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
dma_iommu_unmap_page(struct device * dev,dma_addr_t dma_handle,size_t size,enum dma_data_direction direction,unsigned long 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,
53 unsigned long attrs)
54 {
55 iommu_unmap_page(get_iommu_table_base(dev), dma_handle, size, direction,
56 attrs);
57 }
58
59
dma_iommu_map_sg(struct device * dev,struct scatterlist * sglist,int nelems,enum dma_data_direction direction,unsigned long attrs)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
dma_iommu_unmap_sg(struct device * dev,struct scatterlist * sglist,int nelems,enum dma_data_direction direction,unsigned long attrs)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 */
dma_iommu_dma_supported(struct device * dev,u64 mask)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
dma_iommu_get_required_mask(struct device * dev)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
dma_iommu_mapping_error(struct device * dev,dma_addr_t dma_addr)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
