The Trusted Firmware-A project provides a reference implementation of secure world software for Armv7-A and Armv8-A class processors.
The Projects page provides access to all facilities hosted including source code, documentation, Gerrit review for submitting changes, a wiki, the issue/task workboard/tracker as well as showing recent activity in the project.
Contribution guidelines can be found in the documentation and a getting started guide with Gerrit can be found on the wiki.
A project email list can be subscribed to to participate in development discussions.
A bi-weekly Technical Forum call is held to discuss technical subjects.