Reset on Beaglebone Black has become unreliable/broken

[Ahmad Fatoum]

On 03.12.24 22:45, Konstantin Kletschke wrote:
> On Tue, Dec 03, 2024 at 09:28:39PM +0100, Ahmad Fatoum wrote:
>> See the patch I just Cc'd you on.
> 
> Worked like a charm!

Nice, you can reply with a

  Tested-by: Konstantin Kletschke <konstantin.kletschke at inside-m2m.de> # BBB

on the other patch, so it's picked up when the patch is applied.

> With vanilla code (one ">" in lowlevel.c) I get
> the LL output, the warm reset behaviour (stuck at S1, watchdog, reset
> cmd, linux reboot) is the same. As expected since its only debugging
> dealt with here.
> 
> Being the playful idiot child I am I was so happy this now working I wanted to
> see something more and added this in lowlevel.c:
> 
> @@ -135,6 +140,9 @@ static noinline int beaglebone_sram_init(void)
>         am33xx_enable_uart0_pin_mux();
>         omap_debug_ll_init();
>         putc_ll('>');
> +       putc_ll('6');
> +       putc_ll('6');
> +       putc_ll('6');
> 
> Aka added three 6 to be put out, which they are!
> 
> The side effect of my additional 3 6 chars is:
> 
> reset cmd, S1, wd 3, mw 0x44e00f00 0x1  and linux reboot are working fine now!
> Additional LL debug output is there, console notification message, >, my sixes,
> and it comes reliably up!

Very interesting. You can now try to move the 4 putc_ll`s to a later point in the
startup code and then see which line of barebox code needed the delay in front of
it.

Note that it's not safe to use puts_ll("string") before relocate_to_current_adr()
and setup_c() are called.

Cheers,
Ahmad


> 
> Kind Regards
> Konstantin
> 
> 


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