Re: [Letux-kernel] [PATCH 09/32] ARM: dts: omap3-gta04: make NAND partitions compatible with recent U-Boot

[Ladislav Michl <ladis@linux-mips.org>]

On Wed, Jul 25, 2018 at 06:27:45PM +0200, Andreas Kemnade wrote:
> On Wed, 25 Jul 2018 10:33:05 +0200
> Ladislav Michl <ladis@linux-mips.org> wrote:
> 
> > On Wed, Jul 25, 2018 at 10:18:28AM +0200, H. Nikolaus Schaller wrote:
> > >   
> > > > Am 25.07.2018 um 10:07 schrieb Ladislav Michl <ladis@linux-mips.org>:
> > > > 
> > > > On Wed, Jul 25, 2018 at 08:58:41AM +0200, H. Nikolaus Schaller wrote:  
> > > >> Vendor defined U-Boot has changed the partition scheme a while ago:
> > > >> 
> > > >> * kernel partition 6MB
> > > >> * file system partition uses the remainder up to end of the NAND
> > > >> * increased size of the environment partition (to get an OneNAND compatible base address)
> > > >> * shrink the U-Boot partition
> > > >> 
> > > >> Let's be compatible (e.g. Debian kernel built from upstream).  
> > > > 
> > > > That, in fact, is breaking compatibility.  
> > > 
> > > With what? Nobody is using the old u-boot partition scheme any more
> > > (it is >5 years old).
> > >   
> > > > So once you are touching this
> > > > what about relying on partitioning provided by bootloader just to prevent
> > > > something like this happening again?  
> > > 
> > > Well, we define what compatible means here (since we are the vendor).
> > > And people complain with us. We simply recommend them to upgrade the
> > > boot-loader.  
> > 
> > Fair enough. Suggestion was to remove partitioning scheme from DTB alltogether
> > and let U-Boot provide one. But you being vendor you decide, of course :)
> > (I'd use only two partitions: MLO and UBI, latter one with BCH8, and store
> > everything in UBI volumes. That's a bit more flexible approach)
> > 
> hmm, so using mtdparts kernel commandline parameter? Somehow it sounds
> to be sane to not have partition tables in kernel. What only is needed
> is to have a nice transition scheme for systems in the wild, can
> commandline mtdparts overwrite dtb? So dtb is a fallback?

That's beginning to be offtopic here...  Anyway, see U-Boot's
CONFIG_FDT_FIXUP_PARTITIONS. Probably better to start a thread on
U-Boot mailing list if needed.

> But I think all that is a future improvement?

Depends on vendor decision, it could be done in a few days :)

Best regards,
	ladis