Amlogic is being supported in the mainline kernel, see the work going on for the Odroid C2 for example, which uses an Amlogic S905. See this[1] site for more information and the incoming patches page[2] for a more up-to-date view on what's being worked on.
[1]: http://linux-meson.com/doku.php [2]: https://patchwork.kernel.org/project/linux-amlogic/list/