I've been writing DSP code using openly available documentation for the past 3 years or so. Some aspects are not currently available (mainly existing code - e.g. the EAP headers to allow direct audio output from the DSP, but if someone spends a bit of time with IDAPro I'm sure they could work out how to set up a link to that driver).

The information about getting started doing this programming is all there in the wiki (Programming the DSP) and the mailing list, or just ask me (or see my presentation at the Summit). I've recently restarted work on the dsp-tremor project (https://garage.maemo.org/projects/dsp-tremor/), so if you're interested please take a look.

Sorry for the canned advert, but as I don't use OGG Vorbis, it would be motivational if other people were also contributing, otherwise I'll get bored again and go do something else...