early stage debugging on a real product

[Simon Glass]

Hi Andy,

On Mon, 23 Nov 2020 at 07:04, Andy Shevchenko <andy.shevchenko at gmail.com> wrote:
>
> Hi!
>
> I have been debugging U-Boot on a product (Android-based) device (*)
> which is not yet supported by U-Boot. It's x86 based.
>
> I have stumbled over the couple of things:
> 1/ it required me to enable TIMER_EARLY and by code analysing I can
> tell that DM loop fails by some reason
> 2/ it hangs
>    reserve_uboot,
>    reserve_malloc,
>    reserve_board,
>    ...here...
>
> My suspicion that fastboot does bad things to it (overwritten memory)
> or something I have missed. Any ideas what to try / where to look into
> besides the above which I'm on?

#define DEBUG at the top of board_f.c - you might need DEBUG_UART

Make sure that start.S puts the top of memory in a sensible place. If
something has set up RAM already then you probably want it to be the
top of RAM, below 2GB.

>
> (*) Only I can get is just an approximate place where the code is
> stuck / hangs. And it's time consuming...
>

Use a Dediprog SPI emulator and an Intel debugger.

Regards,
Simon