AHCI_PREG_CMD_ST
r |= AHCI_PREG_CMD_ST;
if (r & AHCI_PREG_CMD_ST) {
r &= ~AHCI_PREG_CMD_ST;
(cmd & AHCI_PREG_CMD_ST) == 0) {
if ((cmd & (AHCI_PREG_CMD_ST | AHCI_PREG_CMD_CR |
if ((ahci_pread(ap, AHCI_PREG_CMD) & AHCI_PREG_CMD_ST) &&