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/init.h>
7 #include <linux/gfp.h>
8 #include <linux/pci.h>
9 #include <linux/mm.h>
10
11 #include <asm/processor.h>
12 #include <asm/iommu.h>
13 #include <asm/dma.h>
14
15 static int
check_addr(char * name,struct device * hwdev,dma_addr_t bus,size_t size)16 check_addr(char *name, struct device *hwdev, dma_addr_t bus, size_t size)
17 {
18 if (hwdev && !dma_capable(hwdev, bus, size)) {
19 if (*hwdev->dma_mask >= DMA_BIT_MASK(32))
20 printk(KERN_ERR
21 "nommu_%s: overflow %Lx+%zu of device mask %Lx\n",
22 name, (long long)bus, size,
23 (long long)*hwdev->dma_mask);
24 return 0;
25 }
26 return 1;
27 }
28
nommu_map_page(struct device * dev,struct page * page,unsigned long offset,size_t size,enum dma_data_direction dir,struct dma_attrs * attrs)29 static dma_addr_t nommu_map_page(struct device *dev, struct page *page,
30 unsigned long offset, size_t size,
31 enum dma_data_direction dir,
32 struct dma_attrs *attrs)
33 {
34 dma_addr_t bus = page_to_phys(page) + offset;
35 WARN_ON(size == 0);
36 if (!check_addr("map_single", dev, bus, size))
37 return DMA_ERROR_CODE;
38 flush_write_buffers();
39 return bus;
40 }
41
42 /* Map a set of buffers described by scatterlist in streaming
43 * mode for DMA. This is the scatter-gather version of the
44 * above pci_map_single interface. Here the scatter gather list
45 * elements are each tagged with the appropriate dma address
46 * and length. They are obtained via sg_dma_{address,length}(SG).
47 *
48 * NOTE: An implementation may be able to use a smaller number of
49 * DMA address/length pairs than there are SG table elements.
50 * (for example via virtual mapping capabilities)
51 * The routine returns the number of addr/length pairs actually
52 * used, at most nents.
53 *
54 * Device ownership issues as mentioned above for pci_map_single are
55 * the same here.
56 */
nommu_map_sg(struct device * hwdev,struct scatterlist * sg,int nents,enum dma_data_direction dir,struct dma_attrs * attrs)57 static int nommu_map_sg(struct device *hwdev, struct scatterlist *sg,
58 int nents, enum dma_data_direction dir,
59 struct dma_attrs *attrs)
60 {
61 struct scatterlist *s;
62 int i;
63
64 WARN_ON(nents == 0 || sg[0].length == 0);
65
66 for_each_sg(sg, s, nents, i) {
67 BUG_ON(!sg_page(s));
68 s->dma_address = sg_phys(s);
69 if (!check_addr("map_sg", hwdev, s->dma_address, s->length))
70 return 0;
71 s->dma_length = s->length;
72 }
73 flush_write_buffers();
74 return nents;
75 }
76
nommu_free_coherent(struct device * dev,size_t size,void * vaddr,dma_addr_t dma_addr,struct dma_attrs * attrs)77 static void nommu_free_coherent(struct device *dev, size_t size, void *vaddr,
78 dma_addr_t dma_addr, struct dma_attrs *attrs)
79 {
80 free_pages((unsigned long)vaddr, get_order(size));
81 }
82
nommu_sync_single_for_device(struct device * dev,dma_addr_t addr,size_t size,enum dma_data_direction dir)83 static void nommu_sync_single_for_device(struct device *dev,
84 dma_addr_t addr, size_t size,
85 enum dma_data_direction dir)
86 {
87 flush_write_buffers();
88 }
89
90
nommu_sync_sg_for_device(struct device * dev,struct scatterlist * sg,int nelems,enum dma_data_direction dir)91 static void nommu_sync_sg_for_device(struct device *dev,
92 struct scatterlist *sg, int nelems,
93 enum dma_data_direction dir)
94 {
95 flush_write_buffers();
96 }
97
98 struct dma_map_ops nommu_dma_ops = {
99 .alloc = dma_generic_alloc_coherent,
100 .free = nommu_free_coherent,
101 .map_sg = nommu_map_sg,
102 .map_page = nommu_map_page,
103 .sync_single_for_device = nommu_sync_single_for_device,
104 .sync_sg_for_device = nommu_sync_sg_for_device,
105 .is_phys = 1,
106 };
107