Making a device driver for a custom hardware component

hi. i have made a simple 2s complement calculator with which perfomrs simple basic opertations like (* , / , + , -). It has an avalon slave interface, clk interface, interrupt interface and reset interface. It has 3 32 bit wide registers which are addressed by 2 bit address input. 2 registers for input and one for output results.

Simulating in model SIM shows that hte hardware works fine. I have then made a QSYS compionent for it, integrated it in a NIOS II QSYS system and generated VHDL output, .sopcinfo file, all successful.

I have then started to write some firmware code for this system, and I can access all my pheirpherals, except for my custom made 2's complement calculator, I may have designed the register interfaces wrong?

I have started to think about maybe i need to write a custom driver firmware code, basing my assumptation on that my hwardware implementation is correct.

I have read through a lot of NIOS II firmware documentation , but they are to comphrehensive and from my hardware almost only background its too much to digest, hundreds of pages on howe the firmware and HAL and driver layers are built up.

Is there an easy, small apllication note with example showing on how to make a custom made, 3x32bit registers QSYS component , with HAL API driver to work with NIOS II envirtonment.?

BR

Øystein