CT_BLT_CONTROL
while ((chipsfb_read32(sc, CT_BLT_CONTROL) & BLT_IS_BUSY) != 0) {
chipsfb_write32(sc, CT_BLT_CONTROL, cmd);
chipsfb_write32(sc, CT_BLT_CONTROL, cmd);
chipsfb_write32(sc, CT_BLT_CONTROL,
chipsfb_write32(sc, CT_BLT_CONTROL, cmd);