a question about falcon mode

[Abder]

Hi Alex,

Just a quick remarque that intrigued me:

Le jeu. 25 nov. 2021 à 15:57, Alex G. <mr.nuke.me at gmail.com> a écrit :
>
> On 11/25/21 1:07 AM, Chan Kim wrote:
> > Hello all,
> >
> > I'm trying to implement falcon mode for our board. Then should I first
> > implement the normal mode(spl + proper)?
> >
> > It looks like so while I'm reading doc/README.falcon. (It says, after
> > loading kernel, DT etc. I should give 'spl export' command).
> >
>
> Falcon mode is a bit board dependent.  There are a couple of ways you
> could go about this.
>
> The first is to have an "fdtargs" partition. This is where "spl export"
> comes in. Once you run "spl export", it will give a modified dtb at
> "$fdtargsaddr". It's that DTB that you need to write to your ftdargs
> partition. For example:
>
>      > spl export fdt $loadaddr - $fdt_addr_r
>      > mmc write $fdtargsaddr 0x9800 0x8000
>
> In this example the ftdargs partition starts at sector 0x9800, and is
> 0x800 sectors long.
>
>
> The second option is to forget about "spl export" and "fdtargs", and
> package your kernel, devicetree, and overlays in a FIT container. You'd
> make sure to enable SPL_LOAD_FIT_APPLY_OVERLAY. There isn't much more to
> this other than the usual gotcha's with FIT and overlays.
>

Do you mean by this that the SPL has the capability to generate the
"fdtargs" by it self (if we provide it with the dtb in the fitImage) ?

Form my last experience with the falcon mode, I had a - not sure -
conclusion that the only way to generate the "fdtargs" is by using the
"spl export" command from uboot cmdline !
because the reality of the fdtargs blob, as its name indicates, is not
just the fdt but it has also the bootargs (inside the chosen node )
that are required by the kernel. So if you give only the DTB to the
SPL it will not work - to my knowledge -, cuz the data that will be
passed to the kernel needs to contain also the bootargs !

Can you please confirm to me if this capability is implemented on the
SPL and that we can actually forget about the "spl export" command ?

Thanks
And apologies Chan for jumping on your thread,


Best regards,
--
Abder