You might have trouble locating an unencumbered (opensource) version or for that matter re-engineering one avoiding their NDAs etc...
i found one: http://uzebox.org/forums/viewtopic.php?f=3&t=290
What would be more useful is a XMOS LINK implementation on the ARM (pandaboard) side. especially if this could be more generic to work with other boards like Beagleboard, BeagleBone etc.. Then interfacing could be trivial using services/channels or such on the XS1 side.
that would require writing a driver for the DMA controller on the pandaboard. the level of complexity is exponential compared to what i'm doing.