amd/soc/common: Use relative offset for AMDFW

The amdfw.rom is mostly in region COREBOOT. Calculate the relative
address as the CBFS module address. That is for future 32M flash size
support.

TEST=binary identical test on amd/birman amd/majolica amd/gardenia
  amd/mayan amd/bilby amd/mandolin amd/chausie amd/pademelon
  pcengines/apu2
  google/skyrim google/guybrush google/zork google/kahlee google/myst

This commit is part of a series of patches to support 32/64M flash.
BUG=b:255374782

Change-Id: I2add8e4e6755e582b3be6a150cf83d1468f2f1be
Signed-off-by: Zheng Bao <fishbaozi@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/72961
Reviewed-by: Fred Reitberger <reitbergerfred@gmail.com>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/amd/common/Makefile.inc

@@ -41,13 +41,19 @@ DEP_FILES = $(patsubst %,$(FIRMWARE_LOCATION)/%, $(AMDFW_CFG_IN_FW_LOC)) \
 amd_microcode_bins += $(wildcard ${FIRMWARE_LOCATION}/*UcodePatch_*.bin)
 
 ifeq ($(CONFIG_RESET_VECTOR_IN_RAM),y)
-$(objcbfs)/bootblock.bin: $(obj)/amdfw.rom
+$(objcbfs)/bootblock.bin: $(obj)/amdfw.rom $(obj)/fmap_config.h
 	cp $< $@
 
+amdfw_region_start=$(subst $(spc),,FMAP_SECTION_$(call regions-for-file,apu/amdfw)_START)
+amdfw_offset=$(call int-subtract, \
+	$(CONFIG_AMD_FWM_POSITION) \
+	$(call int-subtract, \
+	$(call get_fmap_value,$(amdfw_region_start)) \
+	$(call get_fmap_value,FMAP_SECTION_FLASH_START)))
+
 add_bootblock = \
 	$(CBFSTOOL) $(1) add -f $(2) -n apu/amdfw -t amdfw \
-	-b $(call int-add, \
-	$(call int-subtract, 0xffffffff $(CONFIG_ROM_SIZE)) 1 $(CONFIG_AMD_FWM_POSITION))
+        -b $(amdfw_offset) -r $(call regions-for-file,apu/amdfw)
 
 endif # ifeq ($(CONFIG_RESET_VECTOR_IN_RAM),y)