Hi Jonathan
one can look at Graphics recipes p.4 attached document
L3.10.53_1.1.0_iMX6QDLS_Bundle
: i.MX 6Quad, i.MX 6Dual, i.MX 6DualLite, i.MX 6Solo
Linux Binary Demo Files and Linux BSP Documentation
Regarding "open-source the GPU code", note this is third party IP
(Vivante).
Best regards
igor