[U-Boot] Default LAWBAR mapping at reset for mpc85xx?

Schneider, Kolja Kolja.Schneider at men.de
Thu May 3 10:46:55 CEST 2012


> > If you mean the BDI is trying to initialize things rather than leave the
> > system in its default state, don't do that.
> 
> Yes, trying to get there.
> 

Easily done, just throw out everything in the [init] section. Or is this really just
about BDI presence, as Scott suggested?

> >
> > > We have 64 MB NOR flash and have based out design on the P1020RDB
> and we boot from NOR.
> > > Using the emulator but with minimal config we cannot get past the
> switch_as part in start.S
> > > if we define a LAWBAR for our flash space in the emulator, u-boot will
> boot correctly.

Have you checked your board's law.c and the corresponding flash-related 
#defines, i.e. CONFIG_SYS_FLASH_BASE_PHYS, and the LAW size?

> Ahh, so we have 0xff80_0000 to 0xffff_ffff to begin with.
> This space will probably be too small for us as we want to relocate the
> main part of the boot to beginning of flash(once the bringup is complete).
> This raises another question, not the is just one u-boot.bin img with
> bot the bootpg and the rest of the uboot. This img pads the space between
> normal u-boot
> and bootpg.
> Ideally one show have the option to build 2 images, one bootpg and another
> img
> for normal u-boot so one can burn these at different locations without
> padding.
> I cannot see any support for this but i might be missing something?

Do you really need this? Why not just use the last 512k for u-boot?

> > > 2) RDB has its CCSRBAR defined to 0xffe00000 which is not the default
> ccsrbar(0xff700000)
> > >    this looks like a typo,
> >
> > It's not a typo.  We do this on all the 85xx boards.  At this point
> > you'll probably need a time machine to find out why (probably just fit
> > into software's intended memory map better), but we're not going to
> > change it now.
> 
> I see, I think you got this value from the reference manual because it is
> misprinted
> in there and corrected in the errata.
> 
> >
> > > and if it is, does u-boot work on RDB boards if changed
> > >    to the default?
> >
> > I would not expect U-Boot to break if you change the CCSRBAR setting
> > (but of course I can't guarantee that), but you will need to update the
> > device tree to match, and other OSes may have this hardcoded.
> >

I changed it to 0xff70000 again due to some special board-specific 
black magic hack we had to perform around here, works fine on P1022.

:-) Kolja



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