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Date:      Tue, 17 Mar 2015 12:34:19 -0600
From:      Ian Lepore <ian@freebsd.org>
To:        Paul Mather <paul@gromit.dlib.vt.edu>
Cc:        Tim Kientzle <tim@kientzle.com>, freebsd-arm <freebsd-arm@freebsd.org>
Subject:   Re: How to use u-boot-beaglebone port?
Message-ID:  <1426617259.62241.3.camel@freebsd.org>
In-Reply-To: <F7EAB879-E70D-4ED5-8C5B-3B21FBED123A@gromit.dlib.vt.edu>
References:  <17B779D7-2962-4455-9062-51411F316648@gromit.dlib.vt.edu> <986F5E5D-C784-4BEF-81E3-49A9F27C0E8F@kientzle.com> <1426534773.95554.15.camel@freebsd.org> <F016BFCC-8CAA-4AE6-8142-40A9B69BD707@gromit.dlib.vt.edu> <1426607993.25614.9.camel@freebsd.org> <F7EAB879-E70D-4ED5-8C5B-3B21FBED123A@gromit.dlib.vt.edu>

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On Tue, 2015-03-17 at 14:21 -0400, Paul Mather wrote:
> On Mar 17, 2015, at 11:59 AM, Ian Lepore <ian@freebsd.org> wrote:
> 
> > On Tue, 2015-03-17 at 09:55 -0400, Paul Mather wrote:
> >> On Mar 16, 2015, at 3:39 PM, Ian Lepore <ian@FreeBSD.org> wrote:
> >> 
> >>> On Sun, 2015-03-15 at 19:57 -0700, Tim Kientzle wrote:
> >>>>> On Mar 12, 2015, at 5:59 PM, Paul Mather <paul@gromit.dlib.vt.edu> wrote:
> >>>>> 
> >>>>> Has anyone successfully used the sysutils/u-boot-beaglebone port?
> >>>>> 
> >>>>> I managed to build [1] and install it today.  I tried to install it to the SD card FAT partition, as per the README, and the result was an unbootable system.
> >>>>> 
> >>>>> When I copied the u-boot.img file as u-boot.img (rather than the bb-uboot.img as suggested in the README), I got it to start up to the "U-Boot#" prompt.
> >>>> 
> >>>> 
> >>>> Apparently, no one ever patched the port to use bb-uboot.img and bb-ubldr
> >>>> as the name.
> >>>> 
> >>>> I did this in Crochet when I was experimenting with having multiple
> >>>> U-Boots on a single SD card image.  That experiment was to try
> >>>> to see what would be required to build single images that booted on
> >>>> multiple different devices.
> >>>> 
> >>> 
> >>> When I created the u-boot-beaglebone port I specifically removed that
> >>> bb- prefix stuff, because there will never be a unified image that runs
> >>> on both rpi and beaglebone [*].  I had hoped someone would update
> >>> crochet to use the new ports and this is one of the minor changes that
> >>> would be needed on the crochet side.
> >>> 
> >>> -- Ian
> >>> 
> >>> [*] Because armv6 != armv7 in this case.  While armv6 is synonymous with
> >>> armv7 for most purposes in freebsd, the rpi is the exception to that in
> >>> that it really IS armv6, and that leads to the kernel being built with
> >>> different cache maintenance routines that don't work on armv7.
> >> 
> >> 
> >> Does the sysutils/u-boot-beaglebone boot the BeagleBone Black for you?  As I reported earlier in the start to this thread, I can't get it to boot the system for me.
> >> 
> >> I've copied MLO, u-boot.img, and /boot/ubldr to the FAT partition, but I just get to where U-Boot loads ubldr and then pauses before starting over again in a loop.
> >> 
> >> Are there some other files that need to be copied to the FAT partition, or are those three files, plus the defaults compiled into u-boot.img sufficient to boot the BeagleBone Black from SD card?
> >> 
> >> Cheers,
> >> 
> >> Paul.
> > 
> > Yep, it works for me on BBW and BBB.  The only time I've seen a totally
> > silent lockup like that is when the loadaddr variable in the uboot env
> > didn't match the UBLDR_LOADADDR value when ubldr was compiled.  For BB,
> > those values are usually 0x88000000, iirc.  If you do a "readelf -a
> > ubldr" on your build system you should see a line like
> > 
> >  Entry point address:               0x88000074
> > 
> > and whatever it is should be your uboot loadaddr + 0x74.
> 
> My current /boot/ubldr entry point address appears to be 0x1000074, which seems to be derived from the default set in /usr/src/sys/boot/arm/uboot/Makefile.
> 
> What would I need to put in uEnv.txt to get such a ubldr to boot via the sysutils/u-boot-beaglebone port files?  Would I just need to have the single line "loadaddr=1000000" in uEnv.txt, or would I have to reproduce the whole environment embedded into u-boot.img?  (Do the settings in uEnv.txt replace entirely those in u-boot.img?)
> 
> > You should only need MLO, u-boot.img, and ubldr on the fat partition.
> > (There is an optional uEnv.txt that can be there, but it's not required
> > to boot.)
> 
> It looks like your supposition above is correct and a mis-matching loadaddr variable is likely to blame.
> 
> Is a loadaddr of 0x1000000 correct for a BBB?
> 
> Cheers,
> 
> Paul.

The address is a physical ram address, so you can't just make up any
number -- there has to be actual ram at that address on the board, and
the address must not conflict with where u-boot itself is loaded and
where the kernel will be loaded.

I think the BB ram starts at 0x80000000, so 0x10000000 won't work.  The
right fix would be to recompile ubldr with UBLDR_LOADADDR set to
0x88000000.

-- Ian





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