ATA_BM_PRDT_ADDRESS
channel->bm_prdt_address = (volatile uint32 *)(controller->mmio_addr + kControllerChannelData[channelIndex].bmdma + ATA_BM_PRDT_ADDRESS);
pci->write_io_32(device, channel->bus_master_base + ATA_BM_PRDT_ADDRESS,
(pci->read_io_32(device, channel->bus_master_base + ATA_BM_PRDT_ADDRESS) & 3)