In order to better support open source developers, Silicon Image has been kind enough to give me permission to publicly post the hardware documentation for some of their older SATA chipsets on my docs site, namely the 3112 in this case:
http://gkernel.sourceforge.net/specs/sii/3112A_SiI-DS-0095-B2.pdf.bz2
This documentation will assist developers in maintaining the siimage/sata_sil SATA drivers in the Linux kernel.
So now the 311x joins the ranks of "open hardware". Thanks, SiI!
Jeff