[U-Boot] U-Boot memory allocation problems with ast2500

[Maxim Sloyko]

On Fri, Sep 9, 2016 at 4:18 PM, Simon Glass <sjg at chromium.org> wrote:

> Hi Maxim,
>
> On 9 September 2016 at 15:53, Maxim Sloyko <maxims at google.com> wrote:
> >
> > Hi all,
> >
> > First, disclaimer: this is the first time I'm doing something with
> U-Boot or the part (ast2500), so any claim I make below can be false or
> just plain nonsense.
>
> Welcome!
>
> >
> > I'm working on expanding support of Aspeed ast2500 part in U-Boot.
> >
> > I ran into some problems, when I tried to use Linux Kernel device tree
> for this part in U-Boot. Looking at diagnostic messages (
> http://pastebin.ca/3713876) I figured out that the problem is that U-Boot
> continues to use malloc_simple, even after it has been relocated to RAM. As
> a result, it fails to allocate 130k needed for environment, because it is
> larger than the configured size of a memory chunk for simple malloc.
>
> The test for this is in dlmalloc.c - the GD_FLG_FULL_MALLOC_INIT flag.
> The flag is set in initr_reloc() after relocation.
>
> I wonder if your global_data (the 'gd' pointer) is not set up
> correctly, so it cannot write to the flag.
>

OK, so you are right, this flag turned out to be a problem. Global data was
setup normally, but then for some reason in board_init there was a line

 gd->flags = 0;

I removed it and everything works now.

Thanks for your help!


>
> What version of U-Boot is it? Is the tree available somewhere?
>
> >
> > I suspect that this has something to do with memory configuration, do
> you know what I may be missing? Also, it looks like lowlevel_init has been
> called twice, i.e. again after relocation -- is this expected? This might
> be what is causing the problem, because lowlevel_init does a lot of RAM
> related configuration, but I don't know what to do about it.
>
> I would expect lowlevel_init() to be called only once (or perhaps once
> in SPL and once in U-Boot proper).
>
> >
> > There is some very basic support for this part in U-Boot, provided by
> manufacturer, but it is basically a single platform.S assembly file that
> does everything, like RAM configuration and some other peripherals support
> in lowlevel_init procedure.
> >
> > So, if I want to add proper support for this part, i.e. with device tree
> and all, is there a way to make this a gradual process? I mean, is it
> possible to leave existing RAM initialization procedure in lowlevel_init
> and just add new drivers for something I'm interested in or  is this all or
> nothing kind of thing?
>
> Yes you can do things gradually. If you have a sane early memory
> environment then you shouldn't have much trouble.
>
> >
> > Thank you.
> >
> > --
> > Maxim Sloyko
>
> Regards,
> Simon
>



-- 
*M*axim *S*loyko