HPS-to-FPGA read failure

I am using the Arrow SoCKit board with the Cyclone V SoC. I am unable to successfully read a 32-bit value from the FPGA using the lwhps2fpga bridge. The following are the pertinent characteristics of my system:

  • Linux version 4.14.130-ltsi-altera
  • Boot message: [1.077037] altera_hps2fpga_bridge ff400000.fpga_bridge: fpga bridge [lwhps2f pga] registered
  • root@arrow-sockit:~# ls /sys/class/fpga_bridge
    br0 br1
  • root@arrow-sockit:/sys/class/fpga_bridge/br0# cat name
  • root@arrow-sockit:~# cat /sys/class/fpga_bridge/br0/state
  • Base address of lwhps2fpga slave: 0xFF200000

When I run the program written to read the 32-bit value, I receive the following printf output: 01

All settings and configurations in Platform Designer are correct.

It appears that others have had problems with bridging from the HPS to the FPGA using later versions of Linux, but I cannot understand how this is a problem in my case since everything appears to be correctly configured.

Please advise. Thank you!