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Minimal Example

To get you started quickly, here is a complete configuration file for a common use case: a 4x4 Mesh topology using XY routing.

In this system, we have a 2D array of "clusters" (endpoints), where each cluster acts as both a manager (initiating requests) and a subordinate (responding to requests).

The Configuration File

Save the following content as axi_mesh.yaml:

name: axi_mesh
description: "AXI mesh with XY routing"
network_type: "axi"

# 1. Routing Configuration
routing:
  route_algo: "XY"
  use_id_table: true

# 2. Protocol Definitions
protocols:
  - name: "axi_in"
    protocol: "AXI4"
    data_width: 64
    addr_width: 48
    id_width: 4
    user_width: 1
  - name: "axi_out"
    protocol: "AXI4"
    data_width: 64
    addr_width: 48
    id_width: 2
    user_width: 1

# 3. Endpoint Definitions
endpoints:
  - name: "cluster"
    array: [4, 4]
    addr_range:
      base: 0x0000_0000_0000
      size: 0x0000_0001_0000
    mgr_port_protocol:
      - "axi_in"
    sbr_port_protocol:
      - "axi_out"

# 4. Router Definitions
routers:
  - name: "router"
    array: [4, 4]
    degree: 5

# 5. Connectivity
connections:
  - src: "cluster"
    dst: "router"
    src_range:
      - [0, 3]
      - [0, 3]
    dst_range:
      - [0, 3]
      - [0, 3]
    dst_dir: "Eject"

Breakdown

Here is what is happening in each section of the configuration:

  1. System & Routing: We define the global System Configuration (name, description) and select XY as the Routing algorithm. use_id_table: true tells FlooGen to generate a lookup table for address translation, which simplifies the address map logic.

  2. Protocols: We define two AXI4 Protocols: axi_in (for incoming requests to the NoC) and axi_out (for outgoing requests from the NoC). Note that they have different ID widths to account for ID bits consumed by the routing logic.

  3. Endpoints: We instantiate a 4x4 array of Endpoints named cluster.

    • Addressing: Each cluster is assigned a chunk of the global address map starting at base with a stride of size.
    • Interfaces: Each cluster has a manager port (using axi_in) and a subordinate port (using axi_out).

  4. Routers: We instantiate a corresponding 4x4 array of Routers. The degree: 5 indicates 5 ports (North, East, South, West, and Local/Eject).

  5. Connections: The Connections section wires the endpoints to the routers.

    • We connect the cluster array to the router array 1-to-1.
    • dst_dir: "Eject" specifies that the clusters are connected to the "Local" (or Eject) port of the routers.
    • Note: The inter-router connections (North, East, South, West) are automatically inferred by FlooGen because we are using a Mesh topology with XY routing.

Run It

1. Visualize the Topology Before generating code, verify the graph looks correct:

floogen visualize -c axi_mesh.yaml

2. Generate the RTL Generate the SystemVerilog package and top-level module:

floogen rtl -c axi_mesh.yaml -o out/

You will find the generated files floo_axi_mesh_noc.sv and floo_axi_mesh_noc_pkg.sv in the out/ directory.