[U-Boot] i.MX8MM mapped register access causes crashes

[Schrempf Frieder]

Hi Peng,

I'm still trying to get my i.MX8MM board running with mainline U-Boot. 
I'm using your patches and added some modifications, so I'm now able to 
run SPL and U-Boot proper.

One problem I have is, that accessing some regions in the memory map for 
peripheral register access, U-Boot crashes or hangs.

Example:

=> md 0x302d0000
302d0000: 00000743 0000e031 00000000 00000000    C...1...........
302d0010: ffffffff ffffffff ffffffff 00000000    ................
302d0020: 00000000 001012ec"Synchronous Abort" handler, esr 0x96000210
elr: 0000000040251b84 lr : 0000000040251ba0 (reloc)
elr: 00000000bffa3b84 lr : 00000000bffa3ba0
x0 : 00000000bffb9000 x1 : 00000000308800b4
x2 : 00000000bff6e9b4 x3 : 00000000302d0028
x4 : 0000000000000000 x5 : 00000000bffb96a2
x6 : 0000000000000004 x7 : 00000000bbf3c330
x8 : 00000000bbf3c2f0 x9 : 000000000000000c
x10: 00000000ffffffd8 x11: 0000000000000006
x12: 000000000001869f x13: 0000000000004238
x14: 00000000bbf3c59c x15: 0000000000000008
x16: 000000000000b900 x17: 000000000000ae80
x18: 00000000bbf41d70 x19: 0000000000000038
x20: 00000000302d0020 x21: 00000000302d0020
x22: 00000000bffb8e5f x23: 0000000000000008
x24: 0000000000000004 x25: 0000000000000004
x26: 0000000000000004 x27: 00000000bbf3c3b8
x28: 0000000000000002 x29: 00000000bbf3c330

Do you have any idea what might be wrong or how I could debug this issue?

Thanks,
Frieder