This four minute demonstration from Mellanox is really well done. It provides a simple and direct demonstration of the OCP Platform Control system.
I note the simplicity of the linux commands to drive the configuration of the switch. Especially, if you use Ansible/Puppet etc, you will appreciate how easy it is to configure and monitor network hardware.
You can find more information on Open Compute SW Interface on the OpenCompute Networking Specs Wiki and the PDF file linked there is good description of the complete specification.
I can’t find any links to more details on the specification. Let me know in the comments if you can help out.