[U-Boot] P2020 L1 stack flickering

[Fabian Cenedese]

Hi

I'm trying to adjust u-boot to our board which is using a P2020.
I'm having strange effects with the stack in the L1 data cache,
during the NAND phase as well as in the SPL main u-boot.

Sometimes when a value is written to the cache this value itself
shows up correctly. However it's possible that other values in
the same cache line may change as well. When these values
are read back (e.g. LR) anything can go wrong. I don't attribute
this to u-boot itself but maybe somebody has an idea what could
be wrong to get these strange effects. It's also possible that the
JTAG debugger has an influence, but even without the booting
is unreliable. Sometimes it comes up without a problem,
sometimes it hangs even in the middle of outputting a string
on the SIO. As we have two boards with the same behaviour
I don't suspect a hardware defect but a problem in either
system (layout, power supply) or "hard-software" (FPGA).

Thanks and sorry for the off topic mail. If somebody has an
idea we can continue this in private mail.

bye  Fabi