MBOX_CMD_NAK
*resp_cmd = rv == 0 ? MBOX_CMD_ACK: MBOX_CMD_NAK;
*resp_cmd = rv == 0 ? MBOX_CMD_ACK: MBOX_CMD_NAK;
*resp_cmd = MBOX_CMD_NAK;
*resp_cmd = MBOX_CMD_NAK;
*resp_cmd = MBOX_CMD_NAK;