Now Maintained by @waviousllc

For the forseeable future, all development will take place on the waviousllc fork of this repo. S-Link was used on several projects at Wavious, so it made sense to fork it under the Wavious account. This repo will be monitored, however any issues or code updates should be done at the wav-slink-hw repo. https://github.com/waviousllc/wav-slink-hw

S-Link

S-Link is a simple, scalable, and flexible link controller protocol geared towards chiplets and chip-to-chip communication. S-Link defines the link layer, and gives freedom for various application and physical layers. The ultimate goal of S-Link is to provide a simple alternative for chiplet communication compared to other protocols.

S-Link supports the following features:

• Mult-lane support (provisions for upto 128+ lanes with asymmetric lane support, up to 8lanes currently supported)
• 128b/130b encoding
• Parameterizable Applicaiton Data Widths
• Configurable Attributes for fine tuning link controls and/or active link managemnet
• Low Power (P states) for power savings
• ECC/CRC for error checking of packet headers and payload data
• Parameterizable pipeline stages to optimze for frequency and/or power

Documentation

S-Link Documentation is hosted on ReadTheDocs.

Tools Required

Iverilog and Gtkwave are the main tools you would need to try out some simulations. Those can be installed using the following steps (or just visit their repos/websites for more info).

iverilog

sudo apt-get install bison flex gperf autoconf g++ zlib1g-dev  (zlib for saving in lx2 format)

git clone git://github.com/steveicarus/iverilog.git
cd iverilog
sh autoconf.sh (if compiling from git)
./configure
make
sudo make install

which iverilog

gtkwave

sudo apt-get install -y tcl-dev tk-dev libbz2-dev liblzma-dev
sudo apt-get install gtk2.0   # you may or may not want this

git clone https://github.com/gtkwave/gtkwave.git
cd gtkwave/gtkwave3 # pick your version

./configure
sudo make install

which gtkwave

Note

Verilator may be supported later, but due to serdes models it is unlikely.

Additional

This is primarily for building docs with ReadTheDocs. It is not required to run sims.

sudo apt-get install -y python3-pip python3-testresouces
cd S-Link
pip3 install -r requirements.txt

Run your first sim

Ensure that iverilog and gtkwave are installed.

cd verif/slink/run
./simulate.sh

This will run sanity_test which just sends a few packets from one side of S-Link to the other.

Synthesis/PnR

I had started using the experimental OpenROAD Flow for synthesis. Unfortunately as of Aug 1st 2020, the OpenROAD-flow repo has gone MIA so it appears I need to setup this flow manually. Stay tuned for more information and some scripts to run S-Link with the OpenROAD tools.

S-Link has been synthesized with Yosys, and prior to the OpenROAD-flow going missing, had been ran through OpenRoad to GDS (no optimizations, just flushing the flow out).

An initial 4TX/4RX 8bit PHY version of S-Link was tested on a Zedboard using Vivado 2019.2. This was tested using a simple AXI application layer and allowed the built in ARM core to communicate with an on-chip BRAM via AXI.

Using S-Link

Want to use S-Link? Download and integrate! You are free to use in commercial projects. If you do choose to use S-Link, I do ask that you let me know with some (minor) details about the use case just so I can see how it's being used. Also, please star the repo if you don't mind.

Want to Support S-Link?

Try it out! Offer suggestions for improvement! I have tried to create S-Link using only open source tools, and would like to continue support for those. That being said, it would be nice to have a commercial simulator and synthesis/PnR tools in order to check compatibility. Larger FPGAs and accompanying licenses would also be nice to have to try out various PHY types. If you or your oranization wish to help in any of these regards, please contact me.