[U-Boot] Multiple binaries built through u-boot source

[Stefan Roese]

Hi Aneesh,

On Tuesday 14 September 2010 15:33:53 V, Aneesh wrote:
> > >> I wanted to know if there is a generic way to create two
> > >> binaries from the u-boot source both compiled for different
> > >> address ranges. The first initializes the RAM (may be
> > >> something else as well) and the second is the u-boot binary
> > >> responsible for loading OS etc.
> 
> It's sheer coincidence that I also wanted to post a very similar query
> today. We have a similar requirement for OMAP platforms.
> 
> Presently, we are maintaining a mini bootloader(called x-loader, based
> on u-boot)separately. We want to integrate x-loader with u-boot and
> up-stream the source code.

That's definitely a good idea.
 
> > > Take a look at the NAND_SPL infrastructure (nand_spl/*). It was
> > > created for
> > > platforms booting from NAND with tight restrictions (e.g. 4k image
> > > size for
> > > inital setup, mostly DDR). General idea here is that 2 images are
> > > created:
> > > a) Very small SPL (secondary program loader) image with only basic
> > >    setup, like DDR and NAND
> > > 
> > > b) RAM based U-Boot image
> > >
> > > Both images are combined in the build process creating a single
> > > image that can be flashed into NAND.
> > > 
> > > doc/README.nand-boot-ppc440 might be interesting to get some more
> > > infos about this, some of it PPC4xx specific though.
> 
> This looks promising. However, our SPL has to load u-boot from MMC. Is
> it OK to keep it under nand_spl directory or should we create
> something like 'mmc_spl'?

Not sure. Perhaps we should now really think about a more generic approach and 
merge all this IPL/SPL stuff into a single directory. Perhaps something like 
this:

spl/
spl/nand
spl/onenand
spl/mmc
spl/board
...

Comments welcome.

Cheers,
Stefan

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