Rockchip now offers the support for Debian, a various of packages now adding support to build as Debian package. The rootfs is based on Linaro Releases. Add the support of low level graphics and video acceleration. It include libmali, xserver, gstreamer-rockchip etc.
Please refer rockchip-linux for more help.
If you want to get the latest rootfs, you can use rootfs-build-script to build.
Download Rootfs Image
Notes: Download the latest linaro-*-*-*-*-*.tar.
Develop in this rootfs
The support for debian from RockChip would work with Cross Build at Debian. Please read the Debian Cross_Compile for more information.
Here is the guide from Debian to support RK3288 based Chromebook: