While I was browsing through the u-boot sources and kernel drivers for ls1028ardb board I stumbled upon the term "QIXIS", also in the reference manual there is a chapter called "QIXIS programming model". The problem is that it's extremely difficult to find anything about it.
Correct me if I'm wrong - but is this just a defined set of register offsets shared across multiple NXP's boards equipped with FPGA so that they can just use a single driver to control FPGA available on e.g. ls1028 and e.g. ls21**? https://kodi.software/ https://dltutuapp.com/tutuapp-download/