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

[Stefan Roese]

Hi Vipin,

On Tuesday 14 September 2010 07:22:10 Vipin Kumar wrote:
> This is about a generic problem which may also be faced
> by other developers. Our SoC has a masked bootrom area
> which copies an image from NOR/NAND memories to an internal
> embedded SRAM. The size of this SRAM is only 8K. This
> binary initializes the DDR for larger binaries (u-boot/OS)
> to be placed in RAM and executed from there.
> 
> 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.

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.

Cheers,
Stefan

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