How to expose FPGA memory as devdax

[AneeshS]

I have a PCIe FPGA card on which I have some amount of memory that I have exposed as a MMIO bar. I am using a 5.3 kernel 

My Linux driver already maps this memory and my user application can access this memory via mmap() interface.

My question is :- I would like to expose the memory via a /dev/dax character interface. The memory does have some persistent characteristics so I would like to expose the memory (about 1GB) as a devdax device.

I am trying to figure out how to modify my driver so I can expose this memory in /dev/dax.

For example, ndctl should be showing this memory. 

Thanks in advance for any pointers,

RK