[coreboot] Conventions for describing flash memory layouts

Patrick 'P. J.' McDermott pj at pehjota.net
Sat Mar 18 23:47:35 CET 2017

On 2017-03-18 at 18:00, Sam Kuper wrote:
> The page https://www.coreboot.org/index.php?title=Board:lenovo/x201&oldid=24709#Flashing
> says:
> > The flash memory in the X201 is divided into roughly 4 parts:
> >
> > - Descriptor (12K)
> > - ME firmware (5M-12K)
> > - Rewriteable flash (3M-96K)
> > - Locked bootblock (96K)
> I guess that "K" refers to kibibytes and that "M" refers to mebibytes.


> I also guess that the values in parentheses refer to the sizes of the
> corresponding occupants of the flash memory, with the "-" symbol
> representing "minus". This was not my first guess, but is the one that
> seems to make the most sense.

I'm not familiar with Ibex Peak's standard flash layout, but this sounds
correct.  The 12-KiB "Descriptor" should contain both the Intel Flash
Descriptor and the Gigabit Ethernet Region.  And the region sizes by
that math add up to 8 MiB, which sounds right.

Patrick "P. J." McDermott:  http://www.pehjota.net/
Lead Developer, ProteanOS:  http://www.proteanos.com/
Founder and CEO, Libiquity: http://www.libiquity.com/

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