Alas, the Vivante GC2000 cannot do bitcoin mining (not that you'd want to, anyway). The GPU can indeed do do OpenCL, but the maximum kernel size is limited whereas double-SHA1 requires quite a lot of operations.

It's more aimed at computer vision applications such as image filters for robotics.

FYI, I did some OpenCL tests and benchmarks on the GC2000 some time ago and reported about it here: https://blog.visucore.com/2013/3/12/opencl-on-i-mx6 . I'm also working on a reverse engineered open source driver for Vivante GPUs such as that in the i.mx6 (https://github.com/laanwj/etna_viv).