Hardware Design¶

The hardware design includes a static region and a dynamic region. The static region includes common logic shared for different designs such as DMA and reset logic. The static region is not re-programmed when loading partial bitstreams. The dynamic region includes different designs and various IP instantiations that are specific for a certain design. The dynamic region is re-programmed when loading partial bitstreams. Note that when loading a full bitstream will re-program the whole FPGA.

Individual steps for genearting bitstreams¶

The scripts go through the following steps to generate the bitstreams.

Design checkpoints are generated for various components.
- IPs: the scripts for generating IPs can be found in hardware/ip.
- Block design: we use block designs to specify the static region where the scripts can be found under hardware/bd
- Reconfigurable modules: reconfigurable modules are SystemVerilog wrappers that instantiates IP blocks and SystemC modules in reconfigurable partitions. SystemC modules are generated by systemc-clang from C++. The modules are located in hardware/rtl.
The top design combines various components to form a synthesized top design checkpoints.
The synthesized design checkpoints are then pushed through implmentation steps producing routed design checkpoints.
The dynamic region in the routed design checkpoints are replaced with other possible modules for partial reconfiguration. Routed design checkpoints are produced for each possible partial reconfiguration.
The full bitstreams as well as partial bitstreams are generated from the routed design checkpoints.

Static region and block design¶

We implement the static region with a block deisng located in hardware/bd/bd_ultra96v2.tcl. The static region includes reset logic, multi-channel DMA engine and AXI interconnects. The following image shows the components in the static region.

When generating the bitstream, a design checkpoint will be generated for the block design under hardware/bd, which will be used to compose the top design.

Partial reconfiguration¶

A reconfigurable partition is specified in hardware/rtl/top_mcdma.sv as the reconf_part_0 module, in which its logic can be dynamically swapped without changing the static region. The module is a black-box and defines the ports to the static region.

module reconf_part_0(
  // ...
);
  // ...
endmodule

SystemC designs are wrapped in wrapper modules with necessary IPs. For example, the wrapper for zhw_encode can be found at hardware/rtl/z3wrapper.sv and we show the high level structure of the file as follows. Note that the wrapper is named reconf_part_0. When generating the bitstream, the wrapper will be synthesized to design checkpoints under hardware/rtl/RM_reconf_z3 folder.

module reconf_part_0(
  // port declaration
);
  // signal declaration
  axis_dwidth_32_64 in_traffic_32_64 (
    // port connection
  );
  axis_dwidth_64_32 out_traffic_64_32 (
    // port connection
  );
  mymodule_sc_module_0 dut ();
endmodule

The top design at hardware/rtl/top_mcdma.sv combines both the static region and the dynamic region.