I am trying to troubleshoot my hps2fpga problem. I created a simple project that will toggle my LEDs whenever the FPGA receives any value change from the HPS2FPGA bridge. If I enable the bridge within U-boot, can I read and write to and from it? If I write a value in U-boot to the memory mapped location 0xC0000000 using mw, should my LED toggle? Currently, I have tried to do this, but I cannot get the LED to toggle at all. I can write using mw and read the same value back using md, but my LED does not toggle. Is writing values or reading values in U-boot equivalent to writing or reading values in a Linux environment or can I not read/write in U-boot to memory mapped locations?
One more thing that I noticed is that my /sys/class/fpga_bridge directory is empty and when I try to write/read from within Linux, the LED does not toggle either. I want to figure which part of my system is causing the bridge to not work.
I answered my own question when I looked over my FPGA project again. I found that part of my code was wrong and that was the reason the LEDs did not toggle when a value was written to the address. It is possible to write to the memory address and read from it in U-boot to test the function after enabling the bridges. …however, my /sys/class/fpga_bridge directory is still empty
I am not a sw developer, however, since you are still in uboot, would not you expect this to be the case? Drivers are Linux kernel programs, so if you are looking for a driver entry surely it will appear after the kernel has loaded.