CBFS: Correct ROM_SIZE for ARM boards, use CBFS_SIZE for cbfstool

Some projects (like ChromeOS) put more content than described by CBFS
onto their image. For top-aligned images (read: x86), this has
traditionally been achieved with a CBFS_SIZE Kconfig (which denotes the
area actually managed by CBFS, as opposed to ROM_SIZE) that is used to
calculate the CBFS entry start offset. On bottom-aligned boards, many
define a fake (smaller) ROM_SIZE for only the CBFS part, which is not
consistently done and can be an issue because ROM_SIZE is expected to be
a power of two.

This patch changes all non-x86 boards to describe their actual
(physical) ROM size via one of the BOARD_ROMSIZE_KB_xxx options as a
mainboard Kconfig select (which is the correct place to declare
unchangeable physical properties of the board). It also changes the
cbfstool create invocation to use CBFS_SIZE as the -s parameter for
those architectures, which defaults to ROM_SIZE but gets overridden for
special use cases like ChromeOS. This has the advantage that cbfstool
has a consistent idea of where the area it is responsible for ends,
which offers better bounds-checking and is needed for a subsequent fix.

Also change the FMAP offset to default to right behind the (now
consistently known) CBFS region for non-x86 boards, which has emerged as
a de-facto standard on those architectures and allows us to reduce the
amount of custom configuration. In the future, the nightmare that is
ChromeOS's image build system could be redesigned to enforce this
automatically, and also confirm that it doesn't overwrite any space used
by CBFS (which is now consistently defined as the file size of
coreboot.rom on non-x86).

CQ-DEPEND=CL:231576,CL:231475
BRANCH=None
BUG=chromium:422501
TEST=Built and booted on Veyron_Pinky.

Change-Id: I89aa5b30e25679e074d4cb5eee4c08178892ada6
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: e707c67c69599274b890d0686522880aa2e16d71
Original-Change-Id: I4fce5a56a8d72f4c4dd3a08c129025f1565351cc
Original-Signed-off-by: Julius Werner <jwerner@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/229974
Original-Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/9619
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

1 files changed, 7 insertions, 1 deletions

diff --git a/src/Kconfig b/src/Kconfig
index 377f7cfa1b..8a5d905a07 100644
--- a/src/Kconfig
+++ b/src/Kconfig
@@ -413,8 +413,14 @@ config IOAPIC
 	default n
 
 config CBFS_SIZE
-	hex
+	hex "Size of CBFS filesystem in ROM"
 	default ROM_SIZE
+	help
+	  This is the part of the ROM actually managed by CBFS, located at the
+	  end of the ROM (passed through cbfstool -o) on x86 and at at the start
+	  of the ROM (passed through cbfstool -s) everywhere else. Defaults to
+	  span the whole ROM but can be overwritten to make coreboot live
+	  alongside other components (like ChromeOS's vboot/FMAP).
 
 config CACHE_ROM_SIZE_OVERRIDE
 	hex