]>
git.proxmox.com Git - mirror_ubuntu-jammy-kernel.git/blob - arch/x86_64/kernel/pci-dma.c
2 * Dynamic DMA mapping support.
5 #include <linux/types.h>
7 #include <linux/string.h>
9 #include <linux/module.h>
12 /* Map a set of buffers described by scatterlist in streaming
13 * mode for DMA. This is the scatter-gather version of the
14 * above pci_map_single interface. Here the scatter gather list
15 * elements are each tagged with the appropriate dma address
16 * and length. They are obtained via sg_dma_{address,length}(SG).
18 * NOTE: An implementation may be able to use a smaller number of
19 * DMA address/length pairs than there are SG table elements.
20 * (for example via virtual mapping capabilities)
21 * The routine returns the number of addr/length pairs actually
22 * used, at most nents.
24 * Device ownership issues as mentioned above for pci_map_single are
27 int dma_map_sg(struct device
*hwdev
, struct scatterlist
*sg
,
28 int nents
, int direction
)
32 BUG_ON(direction
== DMA_NONE
);
33 for (i
= 0; i
< nents
; i
++ ) {
34 struct scatterlist
*s
= &sg
[i
];
36 s
->dma_address
= virt_to_bus(page_address(s
->page
) +s
->offset
);
37 s
->dma_length
= s
->length
;
42 EXPORT_SYMBOL(dma_map_sg
);
44 /* Unmap a set of streaming mode DMA translations.
45 * Again, cpu read rules concerning calls here are the same as for
46 * pci_unmap_single() above.
48 void dma_unmap_sg(struct device
*dev
, struct scatterlist
*sg
,
52 for (i
= 0; i
< nents
; i
++) {
53 struct scatterlist
*s
= &sg
[i
];
54 BUG_ON(s
->page
== NULL
);
55 BUG_ON(s
->dma_address
== 0);
56 dma_unmap_single(dev
, s
->dma_address
, s
->dma_length
, dir
);
60 EXPORT_SYMBOL(dma_unmap_sg
);