PHB_DMA_OFFSET
nentries = howmany(PHB_DMA_OFFSET + physmax, tce_page_size);
offset = PHB_DMA_OFFSET >> tce_page_shift;
map->dm_segs[seg].ds_addr += PHB_DMA_OFFSET;
map->dm_segs[seg].ds_addr += PHB_DMA_OFFSET;