[U-Boot] DFU and UBIFS Volume upgrade

[Loic Poulain]

Thanks Heiko,

On Wed, 4 Sep 2019 at 07:24, Heiko Schocher <hs at denx.de> wrote:

> Hello Loic,
>
> added Lukasz as he is the DFU custodian.
>
> Am 03.09.2019 um 09:59 schrieb Loic Poulain:
> > Hi,
> >
> > AFAIU, today it's possible to update a UBI partition via DFU with a new
> UBI
> > blob using 'partubi'.
>
> Yes.
>
> > However, this causes two issues/limitations:
> > - It erases the partition, causing PEB erase counters amnesia (contrary
> to
> > Linux ubiformat)
>
> Yes, patches which fixes this are welcome :-P
>
> > - It's no possible to have a volume-grained upgrade (per UBIFS volume)
>
> I am not to deep in the DFU topic involved, but I think the problem
> is that ubi is not an interface like "nand" or "mmc" it is more something
> like a partition type ...
>
> The big problem with writting an ubi image into nand is, that you
> need to store the image first in RAM and you may have not enough ...
> so may writting volume serverally it may help out here.
>
> On the other side, it is may possible to introduce an ubi interface for
> UBI volumes. But what if your board has not setup yet UBI, nor the UBI
> Volumes? Is there an interface in DFU for setting up something like
> "partitions" ? You need to pass several parameters to create a new
> UBI Volume ...
>

That's a good point. This makes things a bit complicated.


> May Lukasz can say here more ...
>
> I prefer nowadays to boot a linux and use swupdate, which can handle
> UBI Volumes ...
>

I agree, so let's keep that out of DFU.

So, the priority is maybe to preserve erase-counters to keep optimal wear
leveling.
This should be quite simple to fix, I'll look at the UBI spec and come back
with a patch.

Regards,
Loic