AXI_DMAC_REG_SG_ADDRESS
axi_dmac_write(dmac, AXI_DMAC_REG_SG_ADDRESS, 0xffffffff);
if (axi_dmac_read(dmac, AXI_DMAC_REG_SG_ADDRESS))
axi_dmac_write(dmac, AXI_DMAC_REG_SG_ADDRESS, (u32)sg->hw_phys);
case AXI_DMAC_REG_SG_ADDRESS: