[PATCH v2 4/4] common: Allow relocations on the top of the last bank

[Ilias Apalodimas]

Hi Jonas

[...]

> >  #if defined(CFG_SYS_SDRAM_BASE) && CFG_SYS_SDRAM_BASE > 0
> >       /*
> >        * Detect whether we have so much RAM that it goes past the end of our
> > @@ -321,6 +323,19 @@ __weak phys_addr_t board_get_usable_ram_top(phys_size_t total_size)
> >                */
> >               return 0;
> >  #endif
> > +     if (IS_ENABLED(CONFIG_RELOCATE_LAST_BANK)) {
> > +             phys_addr_t old_top = gd->ram_top;
> > +
> > +             ret = fdtdec_setup_mem_ram_top();
>
> This seem to make assumption that memory is already fully described in
> FDT? Maybe this should instead be based on gd->bd->bi_dram, however that
> is possible initialized at a later initcall.

It is. That was my first approach in fixing it, but the
gd->bd->bi_dram contained garbage at that point.

>
> If I got the call chain correct board_get_usable_ram_top() is normally
> called from INITCALL(setup_dest_addr), and gd->bd->bi_dram banks are
> typically initialized in INITCALL(dram_init_banksize), a later initcall.

Yes

>
> On e.g. Rockchip there is no memory bank information in FDT at that
> stage and memory banks is populated to gd->bd->bi_dram based on
> information from dram init and only later possible added to the FDT for
> booting OS.

And that happens after u-boot has relocated or before?

>
> Rockchip does have a platform board_get_usable_ram_top() so this will
> not be an issue, but the new generic Kconfig option added here seem to
> have a dependency on FDT containing memory bank information, if I am not
> mistaken. Maybe something worth mentioning in help and commit message?

I can amend the Kconfig option. However, people using that default
function are already aware of this.

Thanks
/Ilias
>
> Regards,
> Jonas
>
> > +             if (ret)
> > +                     debug("failed to relocate to ram top");
> > +             ret = fdtdec_setup_ram_size();
> > +             if (ret) {
> > +                     debug("failed to calculate RAM size");
> > +                     gd->ram_top = old_top;
> > +             }
> > +     }
> > +
> >       return gd->ram_top;
> >  }
> >
>