There are Opal specs, and UEFI/TPMv2 specs in public review, amongst a few others:
http://www.trustedcomputinggroup.org/resources/specifications_in_public_review
Also see some TCG talks at the Flash Summit, proceedings are now available (free, but email required). There are hundreds of PDFs, a few security and firmware related, in addition to TCG stuff.
http://www.flashmemorysummit.com/cgi-bin/start.cgi/HTMLOS_Pages/Entrance_Proceedings.html