[U-Boot] [PATCH v1 8/9] sunxi: non-FEL SPL boot support for sun7i

[Ian Campbell]

On Mon, 2014-03-17 at 15:33 -0400, Tom Rini wrote:
> > So, I'm confused about what to do here ;-)
> 
> And I've not made things clearer with a mis-recollection of things.  I
> don't know why I keep saying "bootm_low" when I mean "bootm_size" like
> I've done in later patches (and thankfully, when poking people on G+).

Ah, making that substitution makes things make a lot more sense!

> There's three ways to say "Please ensure that the FDT and if passed initrd
> do not relocate above a certain location".
> 1) In the environment, set bootm_size to kernel lowmem.  This means that
> boot_start_lmb restricts the pool used by both fdt and initrd to that
> value at the top.
> 2) In the environment, set fdt_high (and if using initrd, initrd_high)
> to the top of lowmem.  This means that we'll make sure they don't get
> relocated above that value.
> 3) In the environment set initrd_high to top of lowmem and set
> bootm_mapsize to lowmem.

Looking at http://patchwork.ozlabs.org/patch/329210/ it seems that you
went for #1 on TI stuff -- so I am going to follow suite.

> In all of the above, lowmem can be replaced with any valid size that's
> also smaller than lowmem, such as 256MB.

256MB sounds like a good value to be starting with.

>   Another option, in the
> environment, is to set initrd_high and fdt_high to 0xffffffff and then
> relocation is disabled.  I would _not_ recommend this in the general
> case as one of the points of relocation is to ensure we don't get
> overwritten by the kernel BSS.

Sure.

Thanks,
Ian.