regCP_RB_DOORBELL_CONTROL
tmp = RREG32_SOC15(GC, 0, regCP_RB_DOORBELL_CONTROL);
WREG32_SOC15(GC, 0, regCP_RB_DOORBELL_CONTROL, tmp);
tmp = RREG32_SOC15(GC, 0, regCP_RB_DOORBELL_CONTROL);
WREG32_SOC15(GC, 0, regCP_RB_DOORBELL_CONTROL, tmp);