When updating firmware, it is very often that we may want to preserve
few sections, for example vital product data (VPD) including serial
number, calibration data and cache. A firmware updater has to hard-code
the section names that need to be preserved and is hard to maintain.
A better approach is to specify that in FMAP area flags (the `area_flag`
field) using FMAP_AREA_PRESERVE. With this patchset, a FMD parser flag
"PRESERVE" is introduced and will be converted to FMAP_AREA_PRESERVE
when generating FMAP data (by fmap_from_fmd.c).
For example, The FMD statement:
  RO_VPD(PRESERVE)@0x0 16k
will generate an FMAP firmware section that:
  area_name = "RO_VPD"
  area_offset = 0
  area_size = 16384
  area_flags = FMAP_AREA_PRESERVE
BUG=chromium:936768
TEST=make; boots on x86 "google/eve" and arm "google/kukui" devices
     Manually added 'PRESERVE' to some FMD files, and verify (by running
     fmap.py) the output coreboot.rom has FMAP_AREA_PRESERVE set
Change-Id: I51e7d31029b98868a1cab0d26bf04a14db01b1c0
Signed-off-by: Hung-Te Lin <hungte@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/31707
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
		
	
		
			
				
	
	
	
		
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