ARCMSR_HBEMU_DOORBELL_SYNC
CHIP_REG_WRITE32(HBE_MessageUnit, 0, iobound_doorbell, ARCMSR_HBEMU_DOORBELL_SYNC); /* synchronize doorbell to 0 */
CHIP_REG_WRITE32(HBF_MessageUnit, 0, iobound_doorbell, ARCMSR_HBEMU_DOORBELL_SYNC); /* synchronize doorbell to 0 */