1/*
2 * Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corporation
3 *
4 * Provide default implementations of the DMA mapping callbacks for
5 * busses using the iommu infrastructure
6 */
7
8#include <linux/export.h>
9#include <asm/iommu.h>
10
11/*
12 * Generic iommu implementation
13 */
14
15/* Allocates a contiguous real buffer and creates mappings over it.
16 * Returns the virtual address of the buffer and sets dma_handle
17 * to the dma address (mapping) of the first page.
18 */
19static void *dma_iommu_alloc_coherent(struct device *dev, size_t size,
20				      dma_addr_t *dma_handle, gfp_t flag,
21				      struct dma_attrs *attrs)
22{
23	return iommu_alloc_coherent(dev, get_iommu_table_base(dev), size,
24				    dma_handle, dev->coherent_dma_mask, flag,
25				    dev_to_node(dev));
26}
27
28static void dma_iommu_free_coherent(struct device *dev, size_t size,
29				    void *vaddr, dma_addr_t dma_handle,
30				    struct dma_attrs *attrs)
31{
32	iommu_free_coherent(get_iommu_table_base(dev), size, vaddr, dma_handle);
33}
34
35/* Creates TCEs for a user provided buffer.  The user buffer must be
36 * contiguous real kernel storage (not vmalloc).  The address passed here
37 * comprises a page address and offset into that page. The dma_addr_t
38 * returned will point to the same byte within the page as was passed in.
39 */
40static dma_addr_t dma_iommu_map_page(struct device *dev, struct page *page,
41				     unsigned long offset, size_t size,
42				     enum dma_data_direction direction,
43				     struct dma_attrs *attrs)
44{
45	return iommu_map_page(dev, get_iommu_table_base(dev), page, offset,
46			      size, device_to_mask(dev), direction, attrs);
47}
48
49
50static void dma_iommu_unmap_page(struct device *dev, dma_addr_t dma_handle,
51				 size_t size, enum dma_data_direction direction,
52				 struct dma_attrs *attrs)
53{
54	iommu_unmap_page(get_iommu_table_base(dev), dma_handle, size, direction,
55			 attrs);
56}
57
58
59static int dma_iommu_map_sg(struct device *dev, struct scatterlist *sglist,
60			    int nelems, enum dma_data_direction direction,
61			    struct dma_attrs *attrs)
62{
63	return iommu_map_sg(dev, get_iommu_table_base(dev), sglist, nelems,
64			    device_to_mask(dev), direction, attrs);
65}
66
67static void dma_iommu_unmap_sg(struct device *dev, struct scatterlist *sglist,
68		int nelems, enum dma_data_direction direction,
69		struct dma_attrs *attrs)
70{
71	iommu_unmap_sg(get_iommu_table_base(dev), sglist, nelems, direction,
72		       attrs);
73}
74
75/* We support DMA to/from any memory page via the iommu */
76static int dma_iommu_dma_supported(struct device *dev, u64 mask)
77{
78	struct iommu_table *tbl = get_iommu_table_base(dev);
79
80	if (!tbl) {
81		dev_info(dev, "Warning: IOMMU dma not supported: mask 0x%08llx"
82			", table unavailable\n", mask);
83		return 0;
84	}
85
86	if ((tbl->it_offset + tbl->it_size) > (mask >> IOMMU_PAGE_SHIFT)) {
87		dev_info(dev, "Warning: IOMMU window too big for device mask\n");
88		dev_info(dev, "mask: 0x%08llx, table end: 0x%08lx\n",
89				mask, (tbl->it_offset + tbl->it_size) <<
90				IOMMU_PAGE_SHIFT);
91		return 0;
92	} else
93		return 1;
94}
95
96static 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
109struct dma_map_ops dma_iommu_ops = {
110	.alloc			= dma_iommu_alloc_coherent,
111	.free			= dma_iommu_free_coherent,
112	.map_sg			= dma_iommu_map_sg,
113	.unmap_sg		= dma_iommu_unmap_sg,
114	.dma_supported		= dma_iommu_dma_supported,
115	.map_page		= dma_iommu_map_page,
116	.unmap_page		= dma_iommu_unmap_page,
117	.get_required_mask	= dma_iommu_get_required_mask,
118};
119EXPORT_SYMBOL(dma_iommu_ops);
120