ALS-FPGA

An F4PGA-based flow for Xilinx 7-Series FPGAs (xc7) with an approximate-LUT synthesis integrated into the Yosys flow.

Repository layout

als-fpga/
├── tools/
│   ├── f4pga/           # Modified F4PGA 
│   ├── vtr/             
│   └── f4pga-examples/  # Base toolchain installer
├── setup/
│   └── activate.sh      # Sourceable environment activation script
└── README.md

Prerequisites

• Linux x86-64.
• git, wget, xz-utils.
• ~10–15 GB of free disk for the toolchain environment.
• Miniconda is downloaded during installation.

Clone with submodules

The submodules are declared with SSH URLs, so make sure your SSH key is set up with GitHub before cloning.

git clone [email protected]:ECASLab/als-fpga.git
cd als-fpga
 
git submodule update --init --recursive

Install the base toolchain

Go to the f4pga-examples directory:

cd tools/f4pga-examples

Dowload Miniconda installer:

wget https://repo.continuum.io/miniconda/Miniconda3-latest-Linux-x86_64.sh -O conda_installer.sh

Declare dedicated path and family installation:

export F4PGA_INSTALL_DIR=~/opt/f4pga-als
export FPGA_FAM=xc7

Install conda in the path and create the environment:

bash conda_installer.sh -u -b -p $F4PGA_INSTALL_DIR/$FPGA_FAM/conda
source "$F4PGA_INSTALL_DIR/$FPGA_FAM/conda/etc/profile.d/conda.sh"
conda env create -f $FPGA_FAM/environment.yml   

Download architecture definitions and part files:

export F4PGA_PACKAGES='install-xc7 xc7a50t_test xc7a100t_test xc7a200t_test xc7z010_test'
mkdir -p $F4PGA_INSTALL_DIR/$FPGA_FAM
F4PGA_TIMESTAMP='20220920-124259'
F4PGA_HASH='007d1c1'
for PKG in $F4PGA_PACKAGES; do
  wget -qO- https://storage.googleapis.com/symbiflow-arch-defs/artifacts/prod/foss-fpga-tools/symbiflow-arch-defs/continuous/install/${F4PGA_TIMESTAMP}/symbiflow-arch-defs-${PKG}-${F4PGA_HASH}.tar.xz | tar -xJC $F4PGA_INSTALL_DIR/${FPGA_FAM}
done

Override with the modified F4PGA

With the environment active, uninstall the upstream f4pga and install this repo's version in editable mode:

conda activate xc7
pip uninstall -y f4pga
pip install -e tools/f4pga/f4pga    # adjust the path depending on where you are

You should see it uninstall f4pga 0.0.0+e1cd038f0 (upstream) and install f4pga 0.0.0+8bfab9dc.

Install VTR

Go to the VTR directory:

cd tools/vtr

Install system dependencies:

sudo ./install_apt_packages.sh

Install VTR:

make -j"$(nproc)"

ACE's binary lands at tools/vtr/build/ace2/ace. Create a symlink under a different name on the local binary directory:

mkdir -p ~/.local/bin
ln -sf "$PWD/build/ace2/ace" ~/.local/bin/vtr-ace

Then invoke it as vtr-ace wherever you need power estimation: To check it is working use:

vtr-ace --help

Environment SETUP

For daily work, this repo includes setup/activate.sh, which activates the conda environment, checks that the modified f4pga is the one in use, and makes sure vtr-ace is on PATH, all in one command, with a readable summary.

It must be sourced, not executed, since it needs to change PATH and activate conda in your current shell:

source setup/activate.sh