AXI_DMAC_REG_SRC_ADDRESS_HIGH
axi_dmac_write(dmac, AXI_DMAC_REG_SRC_ADDRESS_HIGH, 0xffffffff);
mask = axi_dmac_read(dmac, AXI_DMAC_REG_SRC_ADDRESS_HIGH);
axi_dmac_write(dmac, AXI_DMAC_REG_SRC_ADDRESS_HIGH, sg->hw->src_addr >> 32);