6.2. Integrating Custom Chisel Projects into the Generator Build System
This section assumes integration of custom Chisel through git submodules. While it is possible to directly commit custom Chisel into the Chipyard framework, we heavily recommend managing custom code through git submodules. Using submodules decouples development of custom features from development on the Chipyard framework.
While developing, you want to include Chisel code in a submodule so that it can be shared by different projects. To add a submodule to the Chipyard framework, make sure that your project is organized as follows.
yourproject/ build.sbt src/main/scala/ YourFile.scala
Put this in a git repository and make it accessible.
Then add it as a submodule to under the following directory hierarchy:
build.sbt is a minimal file which describes metadata for a Chisel project.
For a simple project, the
build.sbt can even be empty, but below we provide an example
organization := "edu.berkeley.cs" version := "1.0" name := "yourproject" scalaVersion := "2.12.4"
cd generators/ git submodule add https://git-repository.com/yourproject.git
yourproject to the Chipyard top-level build.sbt file.
lazy val yourproject = (project in file("generators/yourproject")).settings(commonSettings).dependsOn(rocketchip)
You can then import the classes defined in the submodule in a new project if
you add it as a dependency. For instance, if you want to use this code in
chipyard project, change the final line in build.sbt to the following.
lazy val chipyard = (project in file(".")).settings(commonSettings).dependsOn(testchipip, yourproject)