T_SATA0_AHCI_HBA_CAP_BKDR
val = SATA_RD4(sc, SCFG_OFFSET + T_SATA0_AHCI_HBA_CAP_BKDR);
SATA_WR4(sc, SCFG_OFFSET + T_SATA0_AHCI_HBA_CAP_BKDR, val);