PIIX_SMB_BASE
base = pci_conf_read(pa->pa_pc, pa->pa_tag, PIIX_SMB_BASE) & 0xffff;
base = pci_conf_read(sc->sc_pc, sc->sc_pcitag, PIIX_SMB_BASE);
pci_conf_write(sc->sc_pc, sc->sc_pcitag, PIIX_SMB_BASE, base);