Re: Deprecate the ppc405 boards in QEMU?

[Thomas Huth]

On 06/10/2021 09.25, Thomas Huth wrote:
> On 05/10/2021 23.53, BALATON Zoltan wrote:
> [...]
> > Maybe these 405 boards in QEMU ran with modified firmware where the memory 
> > detection was patched out but it seems to detect the RAM so I wonder where 
> > it gets that from. Maybe by reading the SDRAM controller DCRs 
> > ppc4xx_sdram_init() sets up. Then I'm not sure what it needs the SPD for, 
> > I forgot how this worked on sam460ex. Maybe for the speed calibration, so 
> > could be it detects ram by reading DCRs then tries to get SPD data and 
> > that's where it stops as i2c is not emulated on taihu. This could be 
> > confirmed by checking what it pokes with -d guest_errors that shows 
> > accesses to missing devices but don't know where 405 has the i2c 
> > controller and if it's the same as newer SoCs. If so that could be reused 
> > and an i2c bus could be added with the SPD data like in sam460ex to make 
> > u-boot happy or you could skip this in u-boot.
>
> FWIW, I've just tried the latter (skipping the sdram init in u-boot), and 
> indeed, I can get to the u-boot prompt now.
[...]> I've also attached the patch with my modifications to u-boot.

FYI, the changes can now be found on this branch here:

 https://gitlab.com/huth/u-boot/-/commits/taihu

I also added a gitlab-CI file, so you can now download the u-boot.bin as an 
artifact from the corresponding pipeline, e.g.:

 https://gitlab.com/huth/u-boot/-/jobs/1667201028

 Thomas