U-Boot is broken on real N900 HW (Was: Re: [PATCH 00/11] Fixes for Nokia RX-51)

[Pali Rohár]

On Wednesday 01 April 2020 00:35:07 Pali Rohár wrote:
> This patch series contain fixes for Nokia RX-51 board (aka N900).
> After these changes it is possible to run U-Boot in qemu emulator again.
> And U-Boot can boot kernel image from RAM, eMMC or OneNAND memory without
> problem.

But on real Nokia N900 device is U-Boot crashing in reboot loop.

I do not have serial console for Nokia N900 to debug this issue, but
seems that it is related to OMAP I2C and OMAP HS MMC code. Problem is
that there is no crash and even no error in qemu emulator so I cannot
debug this issue.

First problem is around /* reset lp5523 led */ code in rx51.c. On real
N900 device it generates repeating messages:

  Check if pads/pull-ups of bus are properly configured
  Timed out in wait_for_event: status=0000

When I commented that few lines all these messages disappeared. So
problem is with OMAP I2C.

Second problem happen after misc_init_r() function finishes. U-Boot just
prints on N900 screen message "data abort" and reboots. As I do not have
serial console it is hard to debug. but I figured out that problem is in
mmc_set_ios() function in mmc.c file. In function mmc_set_clock() I put
debug info prior to mmc_set_ios() call and after it, and debug info
prior was printed, not after.

I remember that somebody had serial jig for Nokia N900, could somebody
look at this reboot loop problem?

And any idea how should be OMAP I2C configured in U-Boot to correctly
work?

Maybe I will try to find some time to git bisect which change broke
U-Boot on real N900 hardware.