[LinuxBIOS] New LAR access functions

Jordan Crouse jordan.crouse at amd.com
Thu Jul 12 17:27:49 CEST 2007

On 12/07/07 03:05 +0200, Peter Stuge wrote:
> On Thu, Jul 12, 2007 at 02:16:21AM +0200, Segher Boessenkool wrote:
> > > 1 means combining flashrom and lar somehow.. Thoughts?
> > 
> > I think the boot block should be outside of the LAR completely.
> Hmm. Interesting!
> > A normal LinuxBIOS upgrade shouldn't touch the bootblock;
> I agree. That's why lar should know about flash chip sector sizes.

This is probably best - lar is best suited for doing the math and
making sure that the blobs are written out in the right format. Somewhat
safer then making flashrom rearrange the bits later.

I'm thinking that we could probably get away with someting simple like
a -S <sector size> option, and LAR would would arrange the archive
correctly, and then write the sector size along with the total ROM size
in the "bootblock header".

> And/or flashrom about larballs.

flashrom should at the very least know how to read a lar and make sure
it is sane.  If we include the sector size from above, then flashrom 
could do some very basic sanity checking before starting.
> > that way, recovery code in there can help the user load a working
> > image into flash after some screw-up, over a serial port or
> > whatever.
> > 
> > This also handily solves the current problem :-)
> But it creates another quite real problem for the first upgrade to LB
> where we need to distribute the bootblock separately. I think that's
> a _really_ undesirable scenario. :\ Especially since it will be the
> common case for some time still.
> One file is no file, two files are two files too many. ;)

I completely agree.  Its always best to only have a single deliverable.


Jordan Crouse
Systems Software Development Engineer 
Advanced Micro Devices, Inc.

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