BT_CTRL_B_BUSY
if (bt_inb(bt_bmc, BT_CTRL) & BT_CTRL_B_BUSY)
bt_outb(bt_bmc, BT_CTRL_B_BUSY, BT_CTRL);
if (!(bt_inb(bt_bmc, BT_CTRL) & BT_CTRL_B_BUSY))