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

David Downey davidd at mips.com
Tue Sep 11 01:39:17 CEST 2012

Hi Stefan,

Thank you for your quick and thorough reply!

On Fri, 2012-09-07 at 08:33 +0200, Stefan Roese wrote:
> 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. :)

Thanks! :-)

> > 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.

Agreed it would be a nightmare to keep the MIPS repo in sync with the
denx.de mainline.  And relieved to e-hear that there is no strict 256KiB
image size rule.  So yes, I plan to contribute all the "deluxe" features
(as build time options) to denx.de's git repo.  Thanks for helping me
keep it simple...

> Best regards,
> Stefan
> [1] http://www.denx.de/wiki/U-Boot/CodingStyle
> [2] http://www.denx.de/wiki/view/U-Boot/Patches
> --
> DENX Software Engineering GmbH,      MD: Wolfgang Denk & Detlev Zundel
> HRB 165235 Munich,  Office: Kirchenstr.5, D-82194 Groebenzell, Germany
> Phone: (+49)-8142-66989-0 Fax: (+49)-8142-66989-80 Email: office at denx.de

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