Overview

LM RISC-V DV is a verification environment which integrates SweRV EH-1 Core from Western Digital and a random assembly test generator from RISCV-DV which is a SV/UVM based instructions generator. This is a work in progress. At present it supports:

• RTL Compilation
• Random Assembly Test Generation
• Test Compilation (Random, Directed)
• RTL Simulation
• Spike ISS Simulation
• Post-simulation Comparison with ISS (Spike)
• Code Coverage Report Generation
• Extraction of Functional Coverage

You can watch the Youtube playlist about an Introduction to LM RISC-V DV and its Detailed Environment Demo.

Directory Structure

├── cores/
├── docs/
├── google_riscv_dv/
├── integrated_cores/
├── integration_files/
│   └── SweRV_EH1/
│       ├── directed_tests/
│       ├── google_riscv_dv/
│       ├── riscv_dv_extension/
│       ├── snapshots/
│       ├── testbench/
│       ├── yaml/
│       ├── cover.cfg
│       ├── Makefile
│       ├── sim.py
│       ├── SweRV_EH1_flist.f
│       └── waves.tcl
└── scripts/
    ├── core_integrate.sh
    └── toolchain_paths.sh

cores/

This directory is a place holder which will contain the cores in their original source forms cloned from their sites. Currently, LM RISC-V DV has been set up and tested for SweRV EH-1 core. When the cores are cloned, they will be checked out to the most recent versions which have been tested in this environment.

docs/

This directory is dedicated to all the documentation related to directory structure and environment flow. It also contains documentation for tests which are generated for a specific core.

google_riscv_dv/

RISCV-DV is cloned into this repository. It contains the source for random assembly test generator written in SystemVerilog/UVM.

integrated_cores/

After the cores and RISCV-DV are cloned into their respective directories, the verification environment for the cores will be set up here with each core in its separate directory.

integration files/

This directory contains files which will be used in setting up the verification environment. It contains:

• Makefiles, python scripts, YAML files, linker files, and core configuration files
• Modified RISCV-DV files specific for cores
• Modified RTL and Testbench files related to cores

scripts/

All the scripts for setting up the repository and core integration will be placed in this directory. At present, it contains two scripts.

• core_integrate.sh
• toolchain_paths.sh

Pre-Requisites

Following are the requirements for running the test generator and environment.

• RISC-V GNU Toolchain
• Instruction Set Simulator ISS (Spike)
• Python 3
• SV and UVM 1.2 Simulator

For manually building the RISC-V GNU Toolchain, visit the riscv-gnu-toolchain repository on Github. Pre-built toolchains can be downloaded from SiFive Software Page. We are using Spike ISS for LM RISC-V DV. It can be manually built from the source which can be obtained from riscv-isa-sim repository. Python 3.7 or above is recommended for the python scripts to work properly for test generation, compilation and simulation. According to RISCV-DV Documentation, a number of simulators has been verified with the test generator including Synopsys VCS, Cadence Incisive/Xcelium, Mentor Questa, and Aldec Riviera-PRO.

Setup

After the RISC-V GNU toolchain and Spike (or any other RISC-V ISS) are installed, their installation paths should be added to the ~/.bashrc file in RISCV_PATH and SPIKE_PATH (or path variable corresponding to installed ISS) variables respectively. Following is the sample of paths to be added on a ubuntu OS.

export RISCV_PATH = <path to>/riscv64-unknown-elf-gcc-8.3.0-2019.08.0-x86_64-linux-ubuntu14
export SPIKE_PATH = <path to directory containing spike executable>

Their is a toolchain_paths.sh script in scripts/ directory. You need to source it after exporting the above paths in the ~/.bashrc file as

source <path to toolchain_paths.sh>

Integration of Core with RISCV-DV

core_integrate.sh is a bash script placed in scripts/. You just simply need to run the script through terminal for setting up the environment for the core.

./core_integrate.sh

When the script is run, it:

• clones the cores (SweRV EH-1 for now) and RISCV-DV into their respective folders
• checkouts the sources to the lastest tested commit versions
• takes the required RTL and Testbench sources from cores and integration files, and set up the environment in integrated_cores

Currently, only SweRV EH-1 has been integrated. It will thus set up the environment for the SweRV EH-1 core only.

Contribution

This is a work in progress. We'd like to accept your contributions to this project.

Acknowledgement

• RISCV-DV
• SweRV EH-1 Core (Western Digital)
• Ibex core (lowRISC)

Contact

If you have any queries, feel free to contact us at [email protected] or contact page on our site Lampro Mellon.