dma_addr_t sn_pci_map_single (struct pci_dev * hwdev, void * ptr, size_t size, int direction);
Map the region pointed to by ptr for DMA and return the DMA address. Also known as platform_pci_map_single by the IA64 machvec code.
We map this to the one step pcibr_dmamap_trans interface rather than the two step pciio_dmamap_alloc/pciio_dmamap_addr because we have no way of saving the dmamap handle from the alloc to later free (which is pretty much unacceptable).
simplify our interface; get rid of dev_desc and vhdl (seems redundant given a pci_dev); figure out how to save dmamap handle so can use two step.