AXI_DMAC_REG_Y_LENGTH
axi_dmac_write(dmac, AXI_DMAC_REG_Y_LENGTH, 1);
if (axi_dmac_read(dmac, AXI_DMAC_REG_Y_LENGTH) == 1)
axi_dmac_write(dmac, AXI_DMAC_REG_Y_LENGTH, sg->hw->y_len);
case AXI_DMAC_REG_Y_LENGTH: