[S] Change in coreboot[master]: cbfstool: Expand the max size of image to 32M

[Julius Werner (Code Review)]

Attention is currently required from: Bao Zheng, Zheng Bao.

Julius Werner has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/68389 )

Change subject: cbfstool: Expand the max size of image to 32M
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Patch Set 1: Code-Review-1

(1 comment)

Patchset:

PS1: 
This is not what you think it is, and it would break existing boards. 32M images are already possible and being used (see e.g. google/volteer/chromeos.fmd). The problem is that on Intel chipsets, for flash sizes >16MB the flash is no longer memory-mapped in one contiguous block. Instead, the top 16MB are mapped at 0xff000000-0xffffffff, and the rest is mapped at a separate, chipset-specific "extended window" location. You have to supply the --ext-win-base and --ext-win-size options to cbfstool to specify that location (see CONFIG_EXT_BIOS_WIN_BASE and related options).