Mixing OpenCL kernel with VHDL Netlists

If I understood correctly what you need to do it hand off data from the accelerator to the HPS while the accelerator is still operating? Before I end up sending in the wrong direction I'll need to know more about the data flow of this system. For example if you wanted to send small amounts of information to the HPS while the kernel is still operating you could put a FIFO in your design that the kernel accesses as a channel that the HPS could pop the information out of. Typically circular buffers are how OpenCL developers manage this sort of thing because it allows you to overlap operations if you use the appropriate runtime calls to keep everything synchronized. By the sounds of it you are looking for a way to funnel information back to the HPS outside of the runtime managed portion which can be tricky if you allow the runtime to queue up operations. For example lets say you queue up the kernel to run twice in a row on different buffers but you have a backdoor way for the kernels to communicate with the HPS, now you need some sort of way to ensure the data sent through the alternative means has some sort of context so that you can tell the data apart.