1 /* Fallback functions when the main IOMMU code is not compiled in. This
2 code is roughly equivalent to i386. */
3 #include <linux/dma-mapping.h>
4 #include <linux/scatterlist.h>
5 #include <linux/string.h>
6 #include <linux/gfp.h>
7 #include <linux/pci.h>
8 #include <linux/mm.h>
9
10 #include <asm/processor.h>
11 #include <asm/iommu.h>
12 #include <asm/dma.h>
13
14 static int
check_addr(char * name,struct device * hwdev,dma_addr_t bus,size_t size)15 check_addr(char *name, struct device *hwdev, dma_addr_t bus, size_t size)
16 {
17 if (hwdev && !dma_capable(hwdev, bus, size)) {
18 if (*hwdev->dma_mask >= DMA_BIT_MASK(32))
19 printk(KERN_ERR
20 "nommu_%s: overflow %Lx+%zu of device mask %Lx\n",
21 name, (long long)bus, size,
22 (long long)*hwdev->dma_mask);
23 return 0;
24 }
25 return 1;
26 }
27
nommu_map_page(struct device * dev,struct page * page,unsigned long offset,size_t size,enum dma_data_direction dir,unsigned long attrs)28 static dma_addr_t nommu_map_page(struct device *dev, struct page *page,
29 unsigned long offset, size_t size,
30 enum dma_data_direction dir,
31 unsigned long attrs)
32 {
33 dma_addr_t bus = page_to_phys(page) + offset;
34 WARN_ON(size == 0);
35 if (!check_addr("map_single", dev, bus, size))
36 return DMA_ERROR_CODE;
37 flush_write_buffers();
38 return bus;
39 }
40
41 /* Map a set of buffers described by scatterlist in streaming
42 * mode for DMA. This is the scatter-gather version of the
43 * above pci_map_single interface. Here the scatter gather list
44 * elements are each tagged with the appropriate dma address
45 * and length. They are obtained via sg_dma_{address,length}(SG).
46 *
47 * NOTE: An implementation may be able to use a smaller number of
48 * DMA address/length pairs than there are SG table elements.
49 * (for example via virtual mapping capabilities)
50 * The routine returns the number of addr/length pairs actually
51 * used, at most nents.
52 *
53 * Device ownership issues as mentioned above for pci_map_single are
54 * the same here.
55 */
nommu_map_sg(struct device * hwdev,struct scatterlist * sg,int nents,enum dma_data_direction dir,unsigned long attrs)56 static int nommu_map_sg(struct device *hwdev, struct scatterlist *sg,
57 int nents, enum dma_data_direction dir,
58 unsigned long attrs)
59 {
60 struct scatterlist *s;
61 int i;
62
63 WARN_ON(nents == 0 || sg[0].length == 0);
64
65 for_each_sg(sg, s, nents, i) {
66 BUG_ON(!sg_page(s));
67 s->dma_address = sg_phys(s);
68 if (!check_addr("map_sg", hwdev, s->dma_address, s->length))
69 return 0;
70 s->dma_length = s->length;
71 }
72 flush_write_buffers();
73 return nents;
74 }
75
nommu_sync_single_for_device(struct device * dev,dma_addr_t addr,size_t size,enum dma_data_direction dir)76 static void nommu_sync_single_for_device(struct device *dev,
77 dma_addr_t addr, size_t size,
78 enum dma_data_direction dir)
79 {
80 flush_write_buffers();
81 }
82
83
nommu_sync_sg_for_device(struct device * dev,struct scatterlist * sg,int nelems,enum dma_data_direction dir)84 static void nommu_sync_sg_for_device(struct device *dev,
85 struct scatterlist *sg, int nelems,
86 enum dma_data_direction dir)
87 {
88 flush_write_buffers();
89 }
90
91 struct dma_map_ops nommu_dma_ops = {
92 .alloc = dma_generic_alloc_coherent,
93 .free = dma_generic_free_coherent,
94 .map_sg = nommu_map_sg,
95 .map_page = nommu_map_page,
96 .sync_single_for_device = nommu_sync_single_for_device,
97 .sync_sg_for_device = nommu_sync_sg_for_device,
98 .is_phys = 1,
99 };
100