Wishbone Bus Generator

Generate a WISHBONE bus interconnect for a list of master(s) and slave(s) interfaces.

Dependencies

You should be able to build and run this code with any scala build tool, but it's setup to build and run with sbt.

You will also need Verilator. It's required by Chisel to run simulations of the circuits.

Build and run

Usage (with sbt):

sbt "run [options] <XML_description_file_path>"
    
By default, the bus is generated and every tests are run. If one or more 
of the options to generate or run tests is specified, only the specified 
generation and/or tests will be run. 

Options:

    --help, -h 
    Display this message.

    --bus, -b 
    Generate a Wishbone bus.

    --generic-test, -g
    Run a generic test on the bus.

    --test, -t
    Run test for the bus.

    --output-path, -o <path>
    Change the output path for all generated files.
    
    --split-output, -s
    Split the generated verilog files by modules.

The output Verilog file will have the same name as your description file.

You can find an example of an XML description in the examples/or1420RoundRobin_1_1_1_1.xml file.

Using custom signals

In your description, you can add custom signals to your bus architecture. For more information on these custom signals including tag types, refer to the Wishbone specification, notably section 3.1.6.

The custom signals are matched together by their <name> elements and to avoid most errors the following properties are verified when parsing the description:

• All signals that have the same name must have the same width.
• If two components with the same role (both masters or both slaves) use a custom signal with the same name, their tags also have to be the same.
• If two components with opposite roles (one master, one slave) use a custom signal with the same name, their tags have to correspond. E.g., TGA_O on master and TGA_I on the slave.
• If a custom signal is present in a master component, it needs to be present in at least one slave component and vice versa.

Add a new type of bus

You can add a new type of bus as follows:

• Create a new class for your bus in the bus folder, it should extend the BusModule type
• Also create a test class for your bus in the test folder
• Add a new BusType at the top of the Description.scala file and map it to a string in the Description constructor
• In the Generators class, add a matching between your BusType and your bus class in the generateBus method
• Also add a matching to your test class in the executeTest method

Add a new type of Arbiter

You can add a new type of arbiter as follows:

• Create a new class for your arbiter in the bus/arbiter folder, it should extend the BaseArbiterModule type
• Also create a test class for your new bus and arbiter pair in the test folder
• Add a new ArbiterType at the top of the Description.scala file and map it to a string in the Description constructor
• In the SharedBus class (or your new bus type), add a matching between your ArbiterType and your arbiter class when assigning the arbiter value
• In the Generators class, adapt the matching for your test class in the executeTest method