Re: [PATCH] omap: use 512k barebox partition

[Juergen Beisert <jbe@pengutronix.de>]

Sascha Hauer wrote:
> On Mon, Jul 30, 2012 at 10:11:32AM +0200, Juergen Beisert wrote:
> > Hi Sascha,
> >
> > Sascha Hauer wrote:
> > > On Fri, Jul 27, 2012 at 06:54:16PM +0200, Juergen Beisert wrote:
> > > > Sascha Hauer wrote:
> > > > > On Fri, Jul 27, 2012 at 01:09:07PM +0200, Jan Weitzel wrote:
> > > > > > Use 512k NAND Partion for barebox. Problem is we don't know the
> > > > > > size of the barebox inside xload. Set it also to 512k
> > > > > > Fix enviroment for boards with size in config
> > > > >
> > > > > The barebox binary has the size encoded into it at offset 0x2c. We
> > > > > could use this to transfer the correct size.
> > > >
> > > > Will this be a reliable "API" to the outerworld? Also in future
> > > > versions of Barebox?
> > >
> > > Yes, definitely.
> > >
> > > That said, it is not a feature you can generally rely upon, because
> > > some SoCs may require some special image layout conflicting with this.
> >
> > This would require a "movable marker" inside the binary image.
> >
> > > If your SoC can support this header, barebox will support it in the
> > > future aswell.
> >
> > Okay.
> >
> > > The header is in arch/arm/include/asm/barebox-arm-head.h. As you can
> > > see it also contains the ascii string 'barebox' which means that you
> > > can test for it, and if you find it, the next word will contain the
> > > address this binary should be copied to (only used to skip copying the
> > > binary to the correct place, it's not mandatory to start the image
> > > there). The word after it will contain the image size.
> > >
> > > This means, what you can do is:
> > >
> > > - Test if the image contains 'barebox'
> >
> > This might be very dangerous, as this kind of string can be part of the
> > binary more than one times, if it is used as part of an output string for
> > example ("Hi, barebox here").
>
> Should have said: 'contains the string 'barebox' at offset 0x20'

Okay. This would mean: There might be a marker at 0x20, else nowhere in the 
image.

jbe

-- 
Pengutronix e.K.                              | Juergen Beisert             |
Linux Solutions for Science and Industry      | http://www.pengutronix.de/  |

_______________________________________________
barebox mailing list
barebox@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/barebox