[Letux-kernel] MIPS-Generic Kernel on CI20

[H. Nikolaus Schaller]

Hi all,

> Am 23.05.2025 um 20:00 schrieb H. Nikolaus Schaller <hns at goldelico.com>:
> 
> 
> 
>> Am 23.05.2025 um 13:51 schrieb H. Nikolaus Schaller <hns at goldelico.com>:
>> 
>> But I only get this from SPL on the 115200 bps console...
>> 
>> b$@ᇤ夆ąFĤĄ䥧bb$@ᇤ夆̅FĬĄ䥧bʅdeĄB
>> 
> 
> Now I had the idea to look at the UART TX pin with oscilloscope.
> 
> Seems to be slightly slower than 250000 bps.
> 
> So the 115200 setting in code results in 250000.
> 
> Therefore I tried to reduce the "bit rate" in code to 115200/2 and now I get:
> 
> U-Boot SPL 2013.07-00034-g8f4c0881a8f-dirty (May 23 2025 - 19:54:33)
> HרUI다*T 2013.07-00034-g8f4c0881a8f-dirty (May 23 2025 - 19:54:33)
> get_ddr_type 227
> 
> Still a little strange, but a good starting point for further printf() debugging...

I have found that this approach is a dead end...

The x1600/x2000 tree seems to only support CI20 v1 while the ci20 branch
is for the CI20 v2a (which I have).

This became clear after I found that it defines CONFIG_SYS_DDR3_K4B2G0846Q

https://git.goldelico.com/?p=letux-uboot.git;a=blob;f=include/configs/ci20.h;h=885598183d4b5b285864e2b860ac1a70e5b294cb;hb=d17bb3a59582565a7080170d292ae27296577229#l38

while there is no K4B2G0846Q support at all in the x1600/x2000 branch.

And my CI20 v2a has such a Samsung K4B2G0846Q chip.

So we have no choice to extend https://git.goldelico.com/?p=letux-uboot.git;a=shortlog;h=refs/heads/ci20-v2013.10
to support FDT loading.

Good to know :)

BR,
Nikolaus