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

[Peng Fan]

> Subject: i.MX8MM mapped register access causes crashes
> 
> 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

You need to pass an arg after `md 0x302d0000`. Default it will dump
a lot registers, might 40 registers. It surely will crash, because there
are only a few registers in GPT1 which is the address you are dumping.

Regards,
Peng

> 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