Hi Tintin,
Actually GPU will be open-sourced in the future by Imagination. However the release time is not predictable so I assume it may take long time. We will upstream our JH7110 (chip in VisionFive 2) to Linux Kernel and open source our SDK, toolchain, datasheet and other related documentation. The part we might not be able to fully open source is our hardware design (part of TRM for example).