Free/Open Source Software Hardware Requirements?

Bender asks: "Most on Slashdot seem to be concerned with getting Free/Open Source software to be compatible with hardware (firmware, register sets, etc). My question is from the other side of the table: I'm in the hardware business and I'm wondering if there are any central guidelines to better guarantee compatibility with Linux/*BSD. As an example, to guarantee that our hardware runs Microsoft Windows, we have to conform to the Windows Logo Program Requirements. These requirements dictate (among other things) firmware interfaces, debug ports, and DRM. Some of these requirements, if not implemented carefully, could trigger incompatibilities with non-Microsoft operating systems. Is there a Linux/*BSD equivalent to the Microsoft requirements to allow hardware designers to build OS agnostic systems?"