Hi,
thank you for the answer, meanwhile I also found the bootinfo
details in the ~5000 pages am335x datasheet.
Starting the second stage bootloader (barebox.bin file on the mmc)
from the MLO also works ('out of the box' actually).
giorgio
> On February 16, 2018 at 8:51 AM Sascha Hauer <s.hauer@xxxxxxxxxxxxxx> wrote:
>
>
> Hi Giorgio,
>
> On Tue, Feb 13, 2018 at 11:12:54PM +0100, Giorgio Dal Molin wrote:
> > Hi all,
> >
> > I'm trying to add board code for an am335x based HW project.
> > I had a look at similar boards like 'boards/phytec-som-am335x'
> > or 'boards/beaglebone'.
> > I understand that I need two images: the (little) MLO and the
> > (bigger) barebox.
> >
> > What it's not really clear is how the MLO loads and starts the
> > barebox.
>
> See arch/arm/mach-omap/xload.c. It is compiled when no shell is enabled
> (I think at least for clarity there should be a separate Kconfig
> symbol). In this file omap_xload() detects where the SoC has booted from
> and loads the full barebox from the same source.
>
> >
> > Moreover I saw there's always a call to:
> >
> > am33xx_save_bootinfo((void *)bootinfo);
> >
> > in the MLO lowlevel entry function; I suspect the argument
> > 'bootinfo' is the register r0 left by the function __barebox_arm_head()
> > but I cannot really understand the logic behind it.
>
> When the am335x ROM passes control to the bootloader then it passes in
> R0 a pointer to the bootinfo. This is a three word structure which has
> informations where the SoC has booted from. In am33xx_save_bootinfo() we
> copy the information to a known place where we can pick it up later, see
> am33xx_bootsource().
>
> Sascha
>
>
> --
> Pengutronix e.K. | |
> Industrial Linux Solutions | http://www.pengutronix.de/ |
> Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
> Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
_______________________________________________
barebox mailing list
barebox@xxxxxxxxxxxxxxxxxxx
http://lists.infradead.org/mailman/listinfo/barebox
