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>
10 #include <asm/processor.h>
11 #include <asm/iommu.h>
14 #define NOMMU_MAPPING_ERROR 0
17 check_addr(char *name
, struct device
*hwdev
, dma_addr_t bus
, size_t size
)
19 if (hwdev
&& !dma_capable(hwdev
, bus
, size
)) {
20 if (*hwdev
->dma_mask
>= DMA_BIT_MASK(32))
22 "nommu_%s: overflow %Lx+%zu of device mask %Lx\n",
23 name
, (long long)bus
, size
,
24 (long long)*hwdev
->dma_mask
);
30 static dma_addr_t
nommu_map_page(struct device
*dev
, struct page
*page
,
31 unsigned long offset
, size_t size
,
32 enum dma_data_direction dir
,
35 dma_addr_t bus
= page_to_phys(page
) + offset
;
37 if (!check_addr("map_single", dev
, bus
, size
))
38 return NOMMU_MAPPING_ERROR
;
39 flush_write_buffers();
43 /* Map a set of buffers described by scatterlist in streaming
44 * mode for DMA. This is the scatter-gather version of the
45 * above pci_map_single interface. Here the scatter gather list
46 * elements are each tagged with the appropriate dma address
47 * and length. They are obtained via sg_dma_{address,length}(SG).
49 * NOTE: An implementation may be able to use a smaller number of
50 * DMA address/length pairs than there are SG table elements.
51 * (for example via virtual mapping capabilities)
52 * The routine returns the number of addr/length pairs actually
53 * used, at most nents.
55 * Device ownership issues as mentioned above for pci_map_single are
58 static int nommu_map_sg(struct device
*hwdev
, struct scatterlist
*sg
,
59 int nents
, enum dma_data_direction dir
,
62 struct scatterlist
*s
;
65 WARN_ON(nents
== 0 || sg
[0].length
== 0);
67 for_each_sg(sg
, s
, nents
, i
) {
69 s
->dma_address
= sg_phys(s
);
70 if (!check_addr("map_sg", hwdev
, s
->dma_address
, s
->length
))
72 s
->dma_length
= s
->length
;
74 flush_write_buffers();
78 static void nommu_sync_single_for_device(struct device
*dev
,
79 dma_addr_t addr
, size_t size
,
80 enum dma_data_direction dir
)
82 flush_write_buffers();
86 static void nommu_sync_sg_for_device(struct device
*dev
,
87 struct scatterlist
*sg
, int nelems
,
88 enum dma_data_direction dir
)
90 flush_write_buffers();
93 static int nommu_mapping_error(struct device
*dev
, dma_addr_t dma_addr
)
95 return dma_addr
== NOMMU_MAPPING_ERROR
;
98 const struct dma_map_ops nommu_dma_ops
= {
99 .alloc
= dma_generic_alloc_coherent
,
100 .free
= dma_generic_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
,
106 .mapping_error
= nommu_mapping_error
,
107 .dma_supported
= x86_dma_supported
,