1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
|
/* Fallback functions when the main IOMMU code is not compiled in. This
code is roughly equivalent to i386. */
#include <linux/mm.h>
#include <linux/init.h>
#include <linux/pci.h>
#include <linux/string.h>
#include <asm/proto.h>
#include <asm/processor.h>
#include <asm/dma.h>
static int
check_addr(char *name, struct device *hwdev, dma_addr_t bus, size_t size)
{
if (hwdev && bus + size > *hwdev->dma_mask) {
printk(KERN_ERR
"nommu_%s: overflow %Lx+%lu of device mask %Lx\n",
name, (long long)bus, size, (long long)*hwdev->dma_mask);
return 0;
}
return 1;
}
static dma_addr_t
nommu_map_single(struct device *hwdev, void *ptr, size_t size,
int direction)
{
dma_addr_t bus = virt_to_bus(ptr);
if (!check_addr("map_single", hwdev, bus, size))
return bad_dma_address;
return bus;
}
void nommu_unmap_single(struct device *dev, dma_addr_t addr,size_t size,
int direction)
{
}
/* Map a set of buffers described by scatterlist in streaming
* mode for DMA. This is the scatter-gather version of the
* above pci_map_single interface. Here the scatter gather list
* elements are each tagged with the appropriate dma address
* and length. They are obtained via sg_dma_{address,length}(SG).
*
* NOTE: An implementation may be able to use a smaller number of
* DMA address/length pairs than there are SG table elements.
* (for example via virtual mapping capabilities)
* The routine returns the number of addr/length pairs actually
* used, at most nents.
*
* Device ownership issues as mentioned above for pci_map_single are
* the same here.
*/
int nommu_map_sg(struct device *hwdev, struct scatterlist *sg,
int nents, int direction)
{
int i;
BUG_ON(direction == DMA_NONE);
for (i = 0; i < nents; i++ ) {
struct scatterlist *s = &sg[i];
BUG_ON(!s->page);
s->dma_address = virt_to_bus(page_address(s->page) +s->offset);
if (!check_addr("map_sg", hwdev, s->dma_address, s->length))
return 0;
s->dma_length = s->length;
}
return nents;
}
/* Unmap a set of streaming mode DMA translations.
* Again, cpu read rules concerning calls here are the same as for
* pci_unmap_single() above.
*/
void nommu_unmap_sg(struct device *dev, struct scatterlist *sg,
int nents, int dir)
{
}
struct dma_mapping_ops nommu_dma_ops = {
.map_single = nommu_map_single,
.unmap_single = nommu_unmap_single,
.map_sg = nommu_map_sg,
.unmap_sg = nommu_unmap_sg,
.is_phys = 1,
};
void __init no_iommu_init(void)
{
if (dma_ops)
return;
dma_ops = &nommu_dma_ops;
}
|
