ARM: Put the ROM stage into the image before other bits.

On ARM, there's frequently some firmware built into the SOC which runs
first and which loads other firmware like Coreboot from some other
media. To prevent the bootblock from having to know how to find and load
the ROM stage from what may be a complicated source (sd card,
netbooting, etc.), we can put the ROM stage immediately after the
bootblock and ensure that they're both loaded at the same time.

This change adjusts the Makefile.inc for ARM so that the ROM stage is put
into the image before any other files so that we know it comes first.
This changes the behavior of the CONFIG_UPDATE_IMAGE config option used
by abuild, although it's not entirely clear whether that's still used.

Change-Id: I832386243788156db5f5abbc9760a4e2026cf2cd
Signed-off-by: Gabe Black <gabeblack@chromium.org>
Reviewed-on: http://review.coreboot.org/3420
Reviewed-by: Patrick Georgi <patrick@georgi-clan.de>
Tested-by: build bot (Jenkins)

src/arch/armv7/Makefile.inc

@@ -46,16 +46,20 @@ prebuild-files = \
 prebuilt-files = $(foreach file,$(cbfs-files), $(call extract_nth,1,$(file)))
 
 # TODO Change -b to Kconfig variable.
-$(obj)/coreboot.pre1: $(objcbfs)/bootblock.bin $$(prebuilt-files) $(CBFSTOOL)
+$(obj)/coreboot.pre: $(objcbfs)/bootblock.bin $(objcbfs)/romstage.elf $$(prebuilt-files) $(CBFSTOOL)
 	$(CBFSTOOL) $@.tmp create -m armv7 -s $(CONFIG_COREBOOT_ROMSIZE_KB)K \
 		-B $(objcbfs)/bootblock.bin -a 64 -b 0x0000 \
 		-H $(CONFIG_CBFS_HEADER_ROM_OFFSET) \
 		-o $(CONFIG_CBFS_ROM_OFFSET)
+	@printf "    CBFS       $(subst $(obj)/,,$(@))\n"
+	$(CBFSTOOL) $@.tmp add-stage \
+		-f $(objcbfs)/romstage.elf -b 0 \
+		-n $(CONFIG_CBFS_PREFIX)/romstage -c none
 	$(prebuild-files) true
 	mv $@.tmp $@
 else
-.PHONY: $(obj)/coreboot.pre1
-$(obj)/coreboot.pre1: $(CBFSTOOL)
+.PHONY: $(obj)/coreboot.pre
+$(obj)/coreboot.pre: $(CBFSTOOL)
 	mv $(obj)/coreboot.rom $@
 endif
 
@@ -183,17 +187,6 @@ ifeq ($(CONFIG_HAVE_BUS_CONFIG),y)
 ramstage-srcs += src/mainboard/$(MAINBOARDDIR)/get_bus_conf.c
 endif
 
-################################################################################
-# Build the final rom image
-
-$(obj)/coreboot.pre: $(objcbfs)/romstage.elf $(obj)/coreboot.pre1 $(CBFSTOOL)
-	@printf "    CBFS       $(subst $(obj)/,,$(@))\n"
-	cp $(obj)/coreboot.pre1 $@.tmp
-	$(CBFSTOOL) $@.tmp add-stage \
-		-f $(objcbfs)/romstage.elf \
-		-n $(CONFIG_CBFS_PREFIX)/romstage -c none
-	mv $@.tmp $@
-
 ################################################################################
 # Build the bootblock