[U-Boot] MIPS: 1Mb U-Boot?

[Stefan Roese]

Hi David,

On 09/07/2012 12:31 AM, Downey, David (c) wrote:
> I'm David Downey, a software engineer at MIPS Technologies.
> 
> Currently, our Malta and SEAD-3 dev boards use YAMON, MIPS' in-house
> open source PROM monitor, as a boot loader.  We are looking to migrate
> YAMON's functionality to U-Boot.

Welcome. :)

> YAMON contains many features beyond the scope of a boot loader (e.g.
> bi-endianess, a EJTAG/GDB interface, a disassembler, etc.) that we
> would still like to make available to our customers.  As you might
> expect, these features result in a large image size.  (YAMON is 1 Mb,
> which is significantly larger than U-Boot's stated design max. of 256 Kb.)
> 
> Would there be any objection (legal or otherwise) to offering a "lean"
> (> 256 Kb) version of U-Boot for Malta/SEAD-3 through denx.de and a
> "deluxe" (~1 Mb) version of U-Boot (open source, of course) through
> developer.mips.com?  If there are objections, do you have any suggestions
> on how we can still offer these features to our customers while not
> breaking U-Boot's 256 Kb design rule?

AFAIK, there is no 256KiB design rule in U-Boot. At least none that is
strict. I maintain many U-Boot board ports. Some of them are even bigger
than 512KiB (enabling features like USB, UBI, UBIFS are quite "expensive").

And I don't see a problem with supporting your "deluxe" features in the
mainline U-Boot git repository at denx.de. As far as the code is in good
shape (see [1] and [2]). But you are of course entitled to host your own
git repository, if this is the way you prefer to handle it. Even though
such out-of-tree ports/features are a maintenance nightmare.

Best regards,
Stefan

[1] http://www.denx.de/wiki/U-Boot/CodingStyle
[2] http://www.denx.de/wiki/view/U-Boot/Patches

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