x86: Build a .rom file which can be flashed to an x86 machine

On x86 machines U-Boot needs to be added to a large ROM image which is
then flashed onto the target board. The ROM has a particular format so it
makes sense for U-Boot to build this image automatically. Unfortunately
it relies on binary blobs so we cannot require this for the default
build as yet.

Create a u-boot.rom output file for this purpose.

Signed-off-by: Simon Glass <sjg@chromium.org>

Makefile

@@ -749,6 +749,9 @@ ALL-$(CONFIG_SPL) += $(CONFIG_SPL_TARGET:"%"=%)
 endif
 ALL-$(CONFIG_REMAKE_ELF) += u-boot.elf
 
+# We can't do this yet due to the need for binary blobs
+# ALL-$(CONFIG_X86_RESET_VECTOR) += u-boot.rom
+
 # enable combined SPL/u-boot/dtb rules for tegra
 ifneq ($(CONFIG_TEGRA),)
 ifeq ($(CONFIG_SPL),y)
@@ -817,7 +820,8 @@ OBJCOPYFLAGS_u-boot.srec := -O srec
 u-boot.hex u-boot.srec: u-boot FORCE
 	$(call if_changed,objcopy)
 
-OBJCOPYFLAGS_u-boot.bin := -O binary
+OBJCOPYFLAGS_u-boot.bin := -O binary \
+		$(if $(CONFIG_X86_RESET_VECTOR),-R .start16 -R .resetvec)
 
 binary_size_check: u-boot.bin FORCE
 	@file_size=$(shell wc -c u-boot.bin | awk '{print $$1}') ; \
@@ -956,6 +960,36 @@ u-boot-nand.gph: u-boot.bin FORCE
 	$(call if_changed,mkimage)
 	@dd if=/dev/zero bs=8 count=1 2>/dev/null >> $@
 
+# x86 uses a large ROM. We fill it with 0xff, put the 16-bit stuff (including
+# reset vector) at the top, Intel ME descriptor at the bottom, and U-Boot in
+# the middle.
+ifneq ($(CONFIG_X86_RESET_VECTOR),)
+rom: u-boot.rom FORCE
+
+u-boot.rom: u-boot-x86-16bit.bin u-boot-dtb.bin \
+		$(srctree)/board/$(BOARDDIR)/mrc.bin
+	$(objtree)/tools/ifdtool -c -r $(CONFIG_ROM_SIZE) u-boot.tmp
+	if [ -n "$(CONFIG_HAVE_INTEL_ME)" ]; then \
+		$(objtree)/tools/ifdtool -D \
+			$(srctree)/board/$(BOARDDIR)/descriptor.bin u-boot.tmp; \
+		$(objtree)/tools/ifdtool \
+			-i ME:$(srctree)/board/$(BOARDDIR)/me.bin u-boot.tmp; \
+	fi
+	$(objtree)/tools/ifdtool -w \
+		$(CONFIG_SYS_TEXT_BASE):$(objtree)/u-boot-dtb.bin u-boot.tmp
+	$(objtree)/tools/ifdtool -w \
+		$(CONFIG_X86_MRC_START):$(srctree)/board/$(BOARDDIR)/mrc.bin \
+		u-boot.tmp
+	$(objtree)/tools/ifdtool -w \
+		$(CONFIG_SYS_X86_START16):$(objtree)/u-boot-x86-16bit.bin \
+		u-boot.tmp
+	mv u-boot.tmp $@
+
+OBJCOPYFLAGS_u-boot-x86-16bit.bin := -O binary -j .start16 -j .resetvec
+u-boot-x86-16bit.bin: u-boot FORCE
+	$(call if_changed,objcopy)
+endif
+
 ifneq ($(CONFIG_SUNXI),)
 OBJCOPYFLAGS_u-boot-sunxi-with-spl.bin = -I binary -O binary \
 				   --pad-to=$(CONFIG_SPL_PAD_TO) --gap-fill=0xff

arch/x86/Kconfig

@@ -34,6 +34,19 @@ config TARGET_CHROMEBOOK_LINK
 
 endchoice
 
+config ROM_SIZE
+	hex
+	default 0x800000
+
+config HAVE_INTEL_ME
+	bool "Platform requires Intel Management Engine"
+	help
+	  Newer higher-end devices have an Intel Management Engine (ME)
+	  which is a very large binary blob (typically 1.5MB) which is
+	  required for the platform to work. This enforces a particular
+	  SPI flash format. You will need to supply the me.bin file in
+	  your board directory.
+
 source "arch/x86/cpu/ivybridge/Kconfig"
 
 source "board/chromebook-x86/coreboot/Kconfig"

include/configs/chromebook_link.h

@@ -18,8 +18,10 @@
 #define CONFIG_SYS_CAR_ADDR			0xff7e0000
 #define CONFIG_SYS_CAR_SIZE			(128 * 1024)
 #define CONFIG_SYS_MONITOR_LEN			(1 << 20)
+#define CONFIG_SYS_X86_START16			0xfffff800
 #define CONFIG_BOARD_EARLY_INIT_R
 
+#define CONFIG_X86_RESET_VECTOR
 #define CONFIG_NR_DRAM_BANKS			8
 
 #define CONFIG_COREBOOT_SERIAL