[PATCH v1 2/3] fdtdec: Introduce fdtdec_setup_mem_ram_top() to determine end of topmost DRAM bank

[Ilias Apalodimas]

Hi Marek,

On Thu, 26 Mar 2026 at 22:40, Marek Vasut <marek.vasut at mailbox.org> wrote:
>
> On 3/26/26 12:51 PM, Ilias Apalodimas wrote:
>
> [...]
>
> > +/**
> > + * fdtdec_setup_mem_ram_top() - decode and setup gd->ram_top to highest address
> > + * available in any memory bank
> > + *
> > + * Decode the /memory 'reg' property to determine the highest end of the memory
> > + * bank and populate the global data ram_top with it.
> > + *
> > + * This function should be called from a boards board_get_usable_ram_top().
> > + * This helper function allows for boards to query the device tree for topmost
> > + * DRAM address.
> > + *
> > + * Return: 0 if OK, -EINVAL if the /memory node or reg property is missing or
> > + * invalid
> > + */
> > +int fdtdec_setup_mem_ram_top(void);
> > +
> >   /**
> >    * fdtdec_setup_memory_banksize() - decode and populate gd->bd->bi_dram
> >    *
> > diff --git a/lib/fdtdec.c b/lib/fdtdec.c
> > index d820f75b031d..c5ee2ecb3a49 100644
> > --- a/lib/fdtdec.c
> > +++ b/lib/fdtdec.c
> > @@ -1162,6 +1162,26 @@ int fdtdec_setup_mem_size_base_lowest(void)
> >       return fdtdec_setup_mem_for_each_bank(fdtdec_setup_mem_size_base_lowest_bankfn);
> >   }
> >
> > +static void fdtdec_setup_mem_ram_top_bankfn(struct resource *res, int bank)
> > +{
> > +     if ((res->end + 1) > gd->ram_top) {
> > +             gd->ram_top = res->end + 1;
> > +             gd->ram_size += res->end - res->start;
> Since this is called fdtdec_setup_mem_ram_top(), it likely shouldn't be
> manipulating with gd->ram_size ?

Sure. I don;t mind either way. We either rename the function to
something more readable or just add a new callback that updates the
sizes.
I'll just move this to a new callback.

Cheers
/Ilias