[RFC] Dedicated command to make a target bootable with Barebox

[Jean-Christophe PLAGNIOL-VILLARD]

On 12:32 Mon 03 Sep     , Juergen Beisert wrote:
> Hi all,
> 
> currently I'm working on the difficult process to make an i.MX35 SoC boot from 
> an externally connected NAND device.
> 
> Nothing special with it, only the NAND flash controller in the i.MX35 (also in 
> i.MX25, i.MX27 and i.MX31) is braindamaged broken. This controller loses the 
> factory bad block markers when used without a workaround and losing these 
> markers is a _really_ bad idea.
> 
> But to use the workaround on these SoCs it needs a complicated preparation of 
> the NAND. Doing it manually is very error prone. And this kind of preparation 
> has to be kept when the system should be updated and so on. Not easy to 
> explain and so much more chances for the user to brick the system while the 
> update process.
> 
> This makes me think about a dedicated command which is responsible to make the 
> target bootable and does all the (more or less complicated) steps to ensure 
> the next time it gets powered it's able to boot again.
> 
> There are more architectures which needs a complicated setup to be able to 
> boot it from some kind of externally connected devices like NAND or eMMCs for 
> example. Some needs special NAND checksums only for the bootloader, others 
> needs to keep the partition table even if the bootloader gets updated and so 
> on.
> 
> Would it be possible to share one command (or one group of commands) by all 
> architectures? And each architecture adds its special code to the command? 
> 
> What kind of setup procedures we must cover with such a command?
> 
> My examples:
> 
> - for the Freescale i.MX SoCs with the broken NFC we must write the bootloader
>   in a different way than all the remaining data into the NAND device
> - for the Samsung S36410 we must save the factory bad block markers first to
>   support booting from NAND as its internal ROM expects the checksums at a
>   strange offset in the OOB area
On some ST SoC it's the same I think we do not need any command we just need
to specify it as mtd level for a specific mtd part

Best Regards,
J.