mmCP_RB0_RPTR_ADDR
WREG32_SOC15(GC, 0, mmCP_RB0_RPTR_ADDR, lower_32_bits(rptr_addr));
WREG32(mmCP_RB0_RPTR_ADDR, lower_32_bits(rptr_addr));
WREG32(mmCP_RB0_RPTR_ADDR, lower_32_bits(rptr_addr));
WREG32(mmCP_RB0_RPTR_ADDR, lower_32_bits(rptr_addr));
WREG32_SOC15(GC, 0, mmCP_RB0_RPTR_ADDR, lower_32_bits(rptr_addr));