BT_HOST2BMC_ATN
#define BT_READY (BT_HOST_BUSY|BT_HOST2BMC_ATN|BT_BMC2HOST_ATN)
bt_write(sc, _BT_CTRL_REG, BT_HOST2BMC_ATN);
a.mask = BT_HOST2BMC_ATN | BT_BMC_BUSY;
rv |= BT_CLR_WR_PTR|BT_CLR_RD_PTR|BT_BMC2HOST_ATN|BT_HOST2BMC_ATN;
printf(" H2B : %2x\n", v & BT_HOST2BMC_ATN);