[U-Boot] how to load u-boot environment from nand while spl is loading

[Scott Wood <scottwood@freescale.com>]

On Wed, 2015-11-11 at 16:38 +0100, Marek Vasut wrote:
> On Wednesday, November 11, 2015 at 04:29:34 PM, Francesco Lucconi wrote:
> 
> Hi,
> 
> > I'm working with imx28evk reference board with u-boot 2011.12 and for my
> > specific purposes I have to load u-boot nand environment during spl
> > binary is loading. I'm working with a static environment but this is not
> > so useful because I need to initialize some drivers (such as serial
> > console) with the current values stored within nand flash environment
> > (such as baudrate variable).
> > Comparing my u-boot version with more recent ones (u-boot 2015.10) I've
> > found out that the enviroment loading has been applied during ram
> > bootstrapping...can't we do this operation before u-boot.bin has been
> > loaded in ddr memory?
> > Could you send me any tips to solve this issue?
> 
> I think that the latest mainline already configures the serial console from
> the environment or at least it sets up the environment to be complete enough
> for getenv() to work. I'd suggest you give that a spin.

getenv() will work but that doesn't answer the question of which environment
it's accessing.  Typically in NAND SPL it will access a hard-coded default
environment, with the on-flash environment only being accessed from the main U
-Boot.

If CONFIG_NAND_ENV_DST is used, the SPL can load the real environment, but
there are no longer any boards that use CONFIG_NAND_ENV_DST (smdk6400 did but
it was removed due to lack of maintenance).

-Scott