[Letux-kernel] LX20 prototype is booting

[H. Nikolaus Schaller]

> Am 29.04.2025 um 08:48 schrieb H. Nikolaus Schaller <hns at goldelico.com>:
> 
> 
> 
>> Am 29.04.2025 um 07:48 schrieb H. Nikolaus Schaller <hns at goldelico.com>:
>> 
>> 
>> 
>>> Am 28.04.2025 um 22:18 schrieb H. Nikolaus Schaller <hns at goldelico.com>:
>>> 
>>> So there is something wrong with passing or processing the command line...
>>> Maybe kernel gets stuck in some loop.
>>> Shouldn't be very difficult to analyse.
>> 
>> Ok, it turns out to be stuck in this panic (which can not be printed before standard printk is set up):
>> 
>> https://elixir.bootlin.com/linux/v6.1.28/source/drivers/of/fdt.c#L1265
>> 
>> So I have to analyse why memblock_alloc() fails. AFAIR we had a similar issue with the X1600.
> 
> Ok, it appears that there is no mem= entry in the command line... Hence there is no early
> memory which can be allocated and
> 
> https://elixir.bootlin.com/linux/v6.1.28/source/mm/memblock.c#L295
> 
> fails to set the end (which is 0 by default) to a reasonable value.
> 
> This is consistent with that our 6.15 kernel and the sudomaker 6.1 kernel show the same
> failure.
> 
> So we have to find the fix in our U-Boot and not the kernel. And it is likely something
> very simple...

Indeed, manually adding mem=128M at 0x0 to the bootargs makes the kernel boot up to calibrate_delay_converge().

So adding a proper mem= parameter in U-Boot is broken here, while it works on the LX16.

And the calibrate_delay_converge hints at some clock issue in the kernel.

BR,
Nikolaus