Going on for months has been a Linux driver to support Thunderbolt on Apple MacBook systems. A special driver is needed for supporting Thunderbolt on Apple hardware since Apple implemented Thunderbolt holt-plug support within their OS X driver rather than at the firmware level, which is where it's implemented by other Thunderbolt devices.
The Apple Thunderbolt driver is now up to its third code revision and has been tested with the 2013 MacBook Pro, MacBook Air 2013, and will run on all other Apple hardware with the "Cactus Ridge" Chip with MacBook Air/Pro hardware between mid-2012 and early 2014. This driver though by Andreas Noever does not support Thunderbolt chaining, no Apple Thunderbolt Display support, there is no device handoff support, and hibernate support can be tricky. the latest patches the Thunderbolt driver weighs in at 4,000 lines of code. Andreas Noever is trying to get this Thunderbolt driver added to the Linux 3.16 kernel.