[U-Boot] [linux-sunxi] [RFC 11/11] mtd/nand: Sunxi NAND boot partition definitions

[Boris Brezillon]

Roy, Yassin,

On Mon, 08 Jun 2015 13:35:04 +0200
Roy Spliet <r.spliet at ultimaker.com> wrote:

> Hello Yassin,
> 
> Op 08-06-15 om 12:48 schreef Yassin:
> > Hi Roy
> > Thank you for working on this, I would like to suggest if you could implement separate control commands to switch ECC and Randomisation modes per partitions. I know this is not the best approach but it will provide more controls.
> Thanks for the suggestion. However, for now I do not see the immediate 
> need for this in U-boot. U-boot should really only care about one thing: 
> load Linux. Therefore, the only partition it needs to be able to read is 
> whatever partition is used for storing boot data on. And if we only care 
> about one NAND partition, we don't need per-partition settings.
> I agree that it would be nice to have eventually, but I think this 
> problem first needs to be solved in Linux properly. Then in U-boot we 
> can sync MTD up with Linux and we get the support we need "for free". 
> I'd personally recommend to take this approach over now first hacking up 
> all sorts of new commands in U-boot, as the latter will create more 
> problems with syncing up MTD and doing the right thing on the longer run.

Actually, the more I think about the more I agree with Yassin's
suggestion. We currently don't have any standard way to attach a
specific setting to a partition (even in Linux, and I hope I'll be able
to work on this aspect soon).
So for now, I really think we should reuse the existing/standard way of
declaring partitions in u-boot (mtdparts + mtdids variables + the
mtdparts command) and a sunxi specific commands to configure the ECC
and Randomizer config.
Once we have settled on something in Linux, we will be able to port it
to u-boot and get rid of these sunxi specific command, but in the
meantime this will allow us to boot a linux kernel (and even flash an
SPL) from u-boot without introducing heavy changes in the u-boot MTD
layer.

Best Regards,

Boris

-- 
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com