V2 RC10 via OE cross compile to OMAP3

[Freeman P. Pascal IV]

On Sat, 2009-12-12 at 12:54 +0100, Sascha Hauer wrote:
> On Thu, Dec 10, 2009 at 10:50:49PM -0700, Freeman P. Pascal IV wrote:
> > Hello,
> >         
> >         I'm trying to build RC10 for use on an Archos 7 internet media
> >         tablet.  The idea is to load u-boot V2 during the stage 3 boot
> >         instead of the original modified initramfs image from flash.
> >         I could then select which kernel and root file-system I use to
> >         boot the rest of the way.
> >         
> >         On top of this, I am trying to use an OpenEmbedded overlay
> >         that is based on the SDE (Special Developer Edition) release
> >         provided by Archos.  I want to use the cross compiler
> >         generated by the OE image in preparation for generating a
> >         recipe for doing the same when building my release images.
> >         
> >         With a bit tweaking, I have been able to generate binaries for
> >         RC10 for my Archos 7 and my BeagleBoard.  Both using the their
> >         own cross compiler tools generated by their separate OE
> >         projects.  This is using the patches for the OMAP3 found on
> >         this list. 
> >         
> >         From what I have read, I should be able to copy the
> >         executable
> >         ELF binary (not the .bin file) on to my respective devices and
> >         run it to test if it works.  When I do this, I get an "Illegal
> >         instruction" error.
> >         
> >         Could I get someone to confirm or deny my assumption about
> >         being able to test the elf binary on my devices?  Should I be
> >         compiling the sandbox version for my devices instead of the
> >         platform/board specific versions?
> 
> You cannot run the ELF file on your devices, you have to use the bin
> file for this. The ELF file is only usable for the sandbox target in
> which case you run it on the machine you compiled it on.
> 
> Sascha
> 

Using the elf executable was really only a test to see if I had the
compiler settings correct.  If it started up and got to a prompt I was
going to be satisfied.  If it ran I could have some confidence it would
do so once I moved into flash where my existing boot-load could execute
it.

The problem is that the Archos 5 and Archos 7 are consumer devices with
no exposed JTAG and no obvious serial port.  There is a recovery chain,
but it requires that the original stage 0 boot-loader, stage 1
boot-loader, and recovery flash image are all functional.  I want to
preserve the original boot-loader, but use V2 to intercept loading the
normal kernel and allow for pre-boot operations (such as selecting an
alternate kernel, rootfs, or kernel arguments).  The whole idea is to
try avoid bricking the device while still allowing some pre-boot
flexibility.

Does anyone have any suggestions how to test and possibly debug without
GDB support within the restrictions I listed above?  Qemu-omap3 could be
an alternative, but I would have to emulate enough of the Archos
hardware to make it possible.


-Freeman