[REGRESSION] imx8mm_evk: FSPI build broken by 37e50627e

[Alexander Koch]

I think I have narrowed down the cause for the broken SPL blob but I don't fully
understand it.

Comparing hexdumps of the last working SPL+DDR blob and the first broken one we
can see three chunks of difference:

1) two bytes near the IVT
2) U-Boot version string and compile timestamp
3) four bytes around offset 0x18b50 (striped at 16 bytes)

Let's ignore number 2) as that is expected and focus on 1) and 3).

For the first difference we have at offset 0x20 in spl.bin (0x1020 in
flash.bin):

  good: 0000 0020:  C0 0F 7E 00 00 DC 02 00
   bad: 0000 0020:  C0 1B 7E 00 00 D0 02 00

I first thought it could be the boot data pointer not reflecting the FSPI config
blob offset but if I read `struct ivt` correctly this is actually _after_ the
IVT itself.

So I patched these two bytes in the broken 'flash.bin' and that made the SPL run
(while console output still stopped before ATF).

The second chunk of interest is at offset 0x18b50 in spl.bin (0x19b50 in
flash.bin):

good:
  0001 8B50:  B8 C4 80 00 00 00 00 00
  0001 8B60:  F8 69 80 00 00 00 00 00
  0001 8B70:  74 63 80 00 00 00 00 00
  0001 8B80:  80 E5 7F 00 00 00 00 00

bad:
  0001 8B50:  B8 D4 80 00 00 00 00 00
  0001 8B60:  F8 79 80 00 00 00 00 00
  0001 8B70:  74 73 80 00 00 00 00 00
  0001 8B80:  80 F5 7F 00 00 00 00 00

After patching those 4 bytes I got ATF and U-Boot proper running so I'd consider
that flash.bin fixed.

Can anybody tell me what we have in those two locations?


Best regards

Alex