uvm-python 0.3.0

uvm-python UVM implementation in Python on top of cocotb

UVM library for Python

This is a port of SystemVerilog (SV) Universal Verification Methodology (UVM) 1.2 to Python and cocotb. Icarus Verilog (iverilog) and Verilator have been used for testing the code so far.

See documentation for more details:

• uvm-python Documentation.
• uvm-python User's Guide

SystemVerilog UVM is not currently supported by any open source/free tools. cocotb offers excellent solution to interact with any simulator (free/proprietary), so testbenches can be written in Python as well. uvm-python tries to offer an API similar to the original SV-UVM version. This means that many UVM verificaton skills and API knowledge are transferable from SV to Python very easily.

If you want to port a larger bulk of SV code to use uvm-python, you can try the script bin/sv2py.pl as the first step. It's a regex-based solution, and code will still require lots of manual edits to work.

Documentation

The documentation is available on readthedocs.io in uvm-python HTML documentation.

Installation

You can install uvm-python as a normal Python package. It is recommended to use venv to create a virtual environment for Python prior to installation.

Install from PyPi using pip:

python -m pip install uvm-python

or directly from source files (for the latest development version):

git clone https://github.com/tpoikela/uvm-python.git
cd uvm-python
python -m pip install . # If venv is used
# Or without venv, and no sudo:
python -m pip install --user .  # Omit --user for global installation

See Makefile for working examples. You can also use Makefiles in test/examples/simple as a template for your project.

Running the examples and development

See test/examples/simple/Makefile for working examples. More features/examples will be added incrementally.

To run all tests:

    SIM=icarus make test  # Use iverilog as a simulator

To run unit tests only:

    make test-unit  # Does not require simulator

Minimal working example

uvm-python must be installed prior to running the example. Alternatively, you can create a symlink to the uvm source folder:

cd test/examples/minimal
ln -s ../../../src/uvm uvm
SIM=icarus make

You can find the source code for this example here. This example creates a test component, registers it with the UVM factory, and starts the test.

You can execute the example by running SIM=icarus make. Alternatively, you can run it with SIM=verilator make.

# File: Makefile
TOPLEVEL_LANG ?= verilog
VERILOG_SOURCES ?= new_dut.sv
TOPLEVEL := new_dut
MODULE   ?= new_test
include $(shell cocotb-config --makefiles)/Makefile.sim

The top-level module must match TOPLEVEL in Makefile:

// File: new_dut.sv
module new_dut(input clk, input rst, output[7:0] byte_out);
    assign byte_out = 8'hAB;
endmodule: new_dut

The Python test file name must match MODULE in Makefile:

# File: new_test.py
import cocotb
from cocotb.triggers import Timer
from uvm import *

@uvm_component_utils
class NewTest(UVMTest):

    async def run_phase(self, phase: UVMPhase):
        phase.raise_objection(self)
        await Timer(100, "NS")
        uvm_info("NEW_TEST", "Test passed, all OK", UVM_MEDIUM)
        phase.drop_objection(self)


@cocotb.test()
async def test_dut(dut):
    await run_test('NewTest')

Current status

Testbenches can already be written with all the typical UVM components. UVM Phasing is in place, and working. Stimulus can be generated using (even hierarchical) sequences. Register layer supports already read/write to registers (via frontdoor), and to memories (frontdoor and backdoor). TLM 1.0 is implemented, put/get/analysis interfaces are done, and master/slave interfaces work. Initial implementation of TLM2.0 has also been added. The table below summarizes the status:

Feature	Status
TLM1.0	Done
TLM2.0	Done
Components	Done
Phases	Done
Objections	Test and env-level objections work
Sequences	Partially done, hier sequences work
Registers	Reg/mem access working, built-in sequences partially done

Please try it out, and let me know if something you require should be added, or even better, add it yourself, test it and create a pull request!

HDL Simulators

Tested with Icarus Verilog (iverilog v13.0 (devel)) and verilator (v5.008). The exact commit for iverilog can be found from ci/install_iverilog.sh.

Icarus Verilog and verilator are free simulators, which can be used with cocotb. uvm-python uses cocotb to interface with these simulators. Memory backdoor access has issues with packed multi-dimensional arrays in verilator. Also, some other examples are not working with verilator yet.

Proprietary simulators that work with cocotb should work with uvm-python as well, but haven't been tested.

Related projects

• cocotb cosimulation library for writing testbenches in Python
• uvm-python-verification-lib UVM Python Verification Agents Library