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/dma-direct.h>
10 #include <linux/pci.h>
11 #include <asm/iommu.h>
14 * Generic iommu implementation
18 * The coherent mask may be smaller than the real mask, check if we can
19 * really use a direct window.
21 static inline bool dma_iommu_alloc_bypass(struct device *dev)
23 return dev->archdata.iommu_bypass && !iommu_fixed_is_weak &&
24 dma_direct_supported(dev, dev->coherent_dma_mask);
27 static inline bool dma_iommu_map_bypass(struct device *dev,
30 return dev->archdata.iommu_bypass &&
31 (!iommu_fixed_is_weak || (attrs & DMA_ATTR_WEAK_ORDERING));
34 /* Allocates a contiguous real buffer and creates mappings over it.
35 * Returns the virtual address of the buffer and sets dma_handle
36 * to the dma address (mapping) of the first page.
38 static void *dma_iommu_alloc_coherent(struct device *dev, size_t size,
39 dma_addr_t *dma_handle, gfp_t flag,
42 if (dma_iommu_alloc_bypass(dev))
43 return dma_direct_alloc(dev, size, dma_handle, flag, attrs);
44 return iommu_alloc_coherent(dev, get_iommu_table_base(dev), size,
45 dma_handle, dev->coherent_dma_mask, flag,
49 static void dma_iommu_free_coherent(struct device *dev, size_t size,
50 void *vaddr, dma_addr_t dma_handle,
53 if (dma_iommu_alloc_bypass(dev))
54 dma_direct_free(dev, size, vaddr, dma_handle, attrs);
56 iommu_free_coherent(get_iommu_table_base(dev), size, vaddr,
60 /* Creates TCEs for a user provided buffer. The user buffer must be
61 * contiguous real kernel storage (not vmalloc). The address passed here
62 * comprises a page address and offset into that page. The dma_addr_t
63 * returned will point to the same byte within the page as was passed in.
65 static dma_addr_t dma_iommu_map_page(struct device *dev, struct page *page,
66 unsigned long offset, size_t size,
67 enum dma_data_direction direction,
70 if (dma_iommu_map_bypass(dev, attrs))
71 return dma_direct_map_page(dev, page, offset, size, direction,
73 return iommu_map_page(dev, get_iommu_table_base(dev), page, offset,
74 size, dma_get_mask(dev), direction, attrs);
78 static void dma_iommu_unmap_page(struct device *dev, dma_addr_t dma_handle,
79 size_t size, enum dma_data_direction direction,
82 if (!dma_iommu_map_bypass(dev, attrs))
83 iommu_unmap_page(get_iommu_table_base(dev), dma_handle, size,
86 dma_direct_unmap_page(dev, dma_handle, size, direction, attrs);
90 static int dma_iommu_map_sg(struct device *dev, struct scatterlist *sglist,
91 int nelems, enum dma_data_direction direction,
94 if (dma_iommu_map_bypass(dev, attrs))
95 return dma_direct_map_sg(dev, sglist, nelems, direction, attrs);
96 return ppc_iommu_map_sg(dev, get_iommu_table_base(dev), sglist, nelems,
97 dma_get_mask(dev), direction, attrs);
100 static void dma_iommu_unmap_sg(struct device *dev, struct scatterlist *sglist,
101 int nelems, enum dma_data_direction direction,
104 if (!dma_iommu_map_bypass(dev, attrs))
105 ppc_iommu_unmap_sg(get_iommu_table_base(dev), sglist, nelems,
108 dma_direct_unmap_sg(dev, sglist, nelems, direction, attrs);
111 static bool dma_iommu_bypass_supported(struct device *dev, u64 mask)
113 struct pci_dev *pdev = to_pci_dev(dev);
114 struct pci_controller *phb = pci_bus_to_host(pdev->bus);
116 return phb->controller_ops.iommu_bypass_supported &&
117 phb->controller_ops.iommu_bypass_supported(pdev, mask);
120 /* We support DMA to/from any memory page via the iommu */
121 int dma_iommu_dma_supported(struct device *dev, u64 mask)
123 struct iommu_table *tbl = get_iommu_table_base(dev);
125 if (dev_is_pci(dev) && dma_iommu_bypass_supported(dev, mask)) {
126 dev->archdata.iommu_bypass = true;
127 dev_dbg(dev, "iommu: 64-bit OK, using fixed ops\n");
132 dev_err(dev, "Warning: IOMMU dma not supported: mask 0x%08llx, table unavailable\n", mask);
136 if (tbl->it_offset > (mask >> tbl->it_page_shift)) {
137 dev_info(dev, "Warning: IOMMU offset too big for device mask\n");
138 dev_info(dev, "mask: 0x%08llx, table offset: 0x%08lx\n",
139 mask, tbl->it_offset << tbl->it_page_shift);
143 dev_dbg(dev, "iommu: not 64-bit, using default ops\n");
144 dev->archdata.iommu_bypass = false;
148 u64 dma_iommu_get_required_mask(struct device *dev)
150 struct iommu_table *tbl = get_iommu_table_base(dev);
156 if (dev_is_pci(dev)) {
157 u64 bypass_mask = dma_direct_get_required_mask(dev);
159 if (dma_iommu_bypass_supported(dev, bypass_mask))
163 mask = 1ULL << (fls_long(tbl->it_offset + tbl->it_size) +
164 tbl->it_page_shift - 1);
170 static void dma_iommu_sync_for_cpu(struct device *dev, dma_addr_t addr,
171 size_t size, enum dma_data_direction dir)
173 if (dma_iommu_alloc_bypass(dev))
174 dma_direct_sync_single_for_cpu(dev, addr, size, dir);
177 static void dma_iommu_sync_for_device(struct device *dev, dma_addr_t addr,
178 size_t sz, enum dma_data_direction dir)
180 if (dma_iommu_alloc_bypass(dev))
181 dma_direct_sync_single_for_device(dev, addr, sz, dir);
184 extern void dma_iommu_sync_sg_for_cpu(struct device *dev,
185 struct scatterlist *sgl, int nents, enum dma_data_direction dir)
187 if (dma_iommu_alloc_bypass(dev))
188 dma_direct_sync_sg_for_cpu(dev, sgl, nents, dir);
191 extern void dma_iommu_sync_sg_for_device(struct device *dev,
192 struct scatterlist *sgl, int nents, enum dma_data_direction dir)
194 if (dma_iommu_alloc_bypass(dev))
195 dma_direct_sync_sg_for_device(dev, sgl, nents, dir);
198 const struct dma_map_ops dma_iommu_ops = {
199 .alloc = dma_iommu_alloc_coherent,
200 .free = dma_iommu_free_coherent,
201 .map_sg = dma_iommu_map_sg,
202 .unmap_sg = dma_iommu_unmap_sg,
203 .dma_supported = dma_iommu_dma_supported,
204 .map_page = dma_iommu_map_page,
205 .unmap_page = dma_iommu_unmap_page,
206 .get_required_mask = dma_iommu_get_required_mask,
207 .sync_single_for_cpu = dma_iommu_sync_for_cpu,
208 .sync_single_for_device = dma_iommu_sync_for_device,
209 .sync_sg_for_cpu = dma_iommu_sync_sg_for_cpu,
210 .sync_sg_for_device = dma_iommu_sync_sg_for_device,
211 .mmap = dma_common_mmap,
212 .get_sgtable = dma_common_get_sgtable,