Strikes me it's probably impossible. Cisco is presumably bound by all kinds of tech cross-licensing deals, and can't just open up schematics, source etc.
If it was law, everyone, not just Cisco, would negotiate cross-licensing deals as such. As a result, there would be no way for people to license IP unless they allowed for open use after the fact.
Beyond that, as an example, open apis (for drivers re:hardwwre) are not the same as giving full chip scematics.
But! If the, for example, SoC stopped updating binary blobs, and things stopped working with newer kernels, as an example, then they'd have to 100% open up and provide sources.
People get all rah-rah about the environment, but I throw away pounds and pounds of highly polluting electronics, just so someone can sell me another.
So that any user could install anything they wanted and use it as they wish. Including replace components with similars and/or make modifications.