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

[Hans de Goede]

Hi,

On 14-06-15 13:31, Boris Brezillon wrote:
> 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.

Ack, note we do not even need any sunxi specific commands, we will
have separate nand code for the SPL and uboot itself, since the SPL
needs a simple mini read-only implementation. So we can compile the
parameters for the boot block vs the rest into the spl resp. uboot
binary directly.

Regards,

Hans