Cyclone5 U-Boot: reading Reset Manager's Status register return 0x0

I have Terasic’s Cyclone5 deveopment kit running Linux 4.19 and U-Boot 2017.11.
For debugging purposes; I’m adding some code in U-Boot to read Reset Manager’s status register. On warm reboot; it returns me valid value (SWWARM). But for Power on Resets, it returns 0x0 (instead of POR, of course).
It is simply reading a register. What am I doing wrong?