PowerVR is a GPU family designed by Imagination Technologies Group plc which isused on a lot of single board computers, tablets, smartphones and top-set boxes.
Imagination does manufacture any PowerVR graphics chips themselves. They are a design company, much like ARM, who license their designs to hardware manufacturers. The American fruit company Apple Inc is the biggest hardware manufacturer using PowerVR GPU designs.
There is zero free software support for PowerVR graphics chips. The Free Software Foundation considers free drivers for PowerVR graphics chips to be a "high priority" project . There are some efforts to create free PowerVR drivers but they have not amounted to much.
Imagination Technologies Group plc has published a dual-licensed (MIT and GNU GPL v2) driver for their binary blob microkernel. This makes it possible to get their PowerVR GPUs going under Linux but you will have to submit to their binary blob.