[LinuxBIOS] New LAR access functions

[Stefan Reinauer]

* Peter Stuge <peter at stuge.se> [070712 19:25]:
> Re these files, I desperately want a fallback so that something
> intelligent can be done also without any flash description files.

This could just be assume a block size of 4, 8 or 16k for the archive.
Currently blocks are aligned to 16 bytes. Smallest sector size I have
seen was 256 bytes I think.

> Again single/many deliverables/components. Copying those small files
> around can be a huge hassle. I would love to compile the latest list
> available into the binary at build time, and allow a newer text file
> to override it at run time. (Maybe even replace in the binary with
> ELF tricks? :)

objcopy is your friend here. Hey, we could pack the descriptions into a
lar file and link that into the binary ;)
 
> Hard to say. Sharing of single flash chips between multiple readers
> on a single board supports having varying sector sizes, but lower
> cost probably supports uniform sector sizes. OTOH flash may be so
> cheap anyway that the little extra cost for varying sector sizes win.

What does SPI do? Just like DIP, PLCC will probably go away in some ys.
(By the time we have large flash chips ;-)

> I like the varying sector sizes a lot because it means we can use the
> flash as NV storage in more ways, and I think we need the space.

Indeed.

> > But 90% of flashrom's flash chip drivers dont know how to do that,
> > and it would be quite some redesign to change it.
> 
> At least they know about sectors and page sizes already.
 
Do they? ;) Not for the non-uniform sizes at least...

Usually flashing works like this:

erase all of the chip with jedec
rewrite it with whatever function is defined to do so

> > It should be viable to flash "everything but the bootblock" in lar.
> 
> Good idea! It should even be the default. If flashrom detects that
> the boot block sector already has an LB bootblock it doesn't
> erase/flash it unless explicitly told to do so.

yes. 

> Note this means the bootblock eats up 64kb of SST49LF080A chips.
> Plenty of room for serial recovery yay. :)
 
:-) On the 080A we can almost say we have that space. Our bootblock is
already pretty large (16k).. I wonder whether we can shrink it. (Before
we make it big again.. :)
 

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