sandybridge: Make build possible without descriptor.bin

On newer Intel systems, the flash ROM is shared between the host
processor (BIOS), it's Management Engine (ME) and an integrated ethernet
controller (GbE). The layout of the flash ROM (and other information) is
kept in the so called Intel Firmware Descriptor (IFD). If we only want
to build coreboot to update the BIOS section, all we need is the flash
layout.

This patch adds the option to specify the flash layout in the
mainboard's Kconfig, and thus, to build without the real IFD. However,
with such a build, one has to make sure that the IFD section on the
flash ROM won't be written over (nor any other section that hasn't been
included by coreboot). A patch to write selected sections of a flash ROM
with IFD has been sent to the flashrom mailing list [1].

[1] http://www.flashrom.org/pipermail/flashrom/2013-June/011083.html

Change-Id: Ia23e439a00a197fb54852263f8e206f16c3e8851
Signed-off-by: Nico Huber <nico.huber@secunet.com>
Reviewed-on: http://review.coreboot.org/3524
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
3 files changed