int
dma_map_sg(struct device *hwdev, struct scatterlist *sg, int nents,
enum dma_data_direction direction)
{
int i, rc;
if (direction == DMA_NONE)
BUG();
WARN_ON(nents == 0 || sg[0].length == 0);
if (swiotlb) {
rc = swiotlb_map_sg(hwdev, sg, nents, direction);
} else {
for (i = 0; i < nents; i++ ) {
sg[i].dma_address =
page_to_bus(sg[i].page) + sg[i].offset;
sg[i].dma_length = sg[i].length;
BUG_ON(!sg[i].page);
IOMMU_BUG_ON(address_needs_mapping(
hwdev, sg[i].dma_address));
}
rc = nents;
}
flush_write_buffers();
return rc;
}
dma_addr_t
dma_map_page(struct device *dev, struct page *page, unsigned long offset,
size_t size, enum dma_data_direction direction)
{
dma_addr_t dma_addr;
BUG_ON(direction == DMA_NONE);
if (swiotlb) {
dma_addr = swiotlb_map_page(
dev, page, offset, size, direction);
} else {
dma_addr = page_to_bus(page) + offset;
IOMMU_BUG_ON(address_needs_mapping(dev, dma_addr));
}
return dma_addr;
}
static int xen_map_sg(struct device *hwdev, struct scatterlist *sg,
int nents,
enum dma_data_direction direction,
struct dma_attrs *attrs)
{
struct scatterlist *s;
struct page *page;
int i, rc;
BUG_ON(direction == DMA_NONE);
WARN_ON(nents == 0 || sg[0].length == 0);
for_each_sg(sg, s, nents, i) {
BUG_ON(!sg_page(s));
page = sg_page(s);
s->dma_address = xen_dma_map_page(page) + s->offset;
s->dma_length = s->length;
IOMMU_BUG_ON(range_straddles_page_boundary(
page_to_phys(page), s->length));
}