spl: Add a way to specify a list of device trees to include

When building a FIT, more than one device tree can be included. The board
can select (at run-time) the one that it wants.

Add a Kconfig option to allow the list of devices trees (supported by the
board) to be specified.

When using SPL_LOAD_FIT, build u-boot.img in FIT format instead of the
legacy image format. Include all the listed device tree files in this FIT.

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

Makefile

@@ -893,9 +893,16 @@ quiet_cmd_cpp_cfg = CFG     $@
 cmd_cpp_cfg = $(CPP) -Wp,-MD,$(depfile) $(cpp_flags) $(LDPPFLAGS) -ansi \
 	-DDO_DEPS_ONLY -D__ASSEMBLY__ -x assembler-with-cpp -P -dM -E -o $@ $<
 
+ifdef CONFIG_SPL_LOAD_FIT
+MKIMAGEFLAGS_u-boot.img = -f auto -A $(ARCH) -T firmware -C none -O u-boot \
+	-a $(CONFIG_SYS_TEXT_BASE) -e $(CONFIG_SYS_UBOOT_START) \
+	-n "U-Boot $(UBOOTRELEASE) for $(BOARD) board" -E \
+	-b $(patsubst %,arch/$(ARCH)/dts/%.dtb,$(subst ",,$(CONFIG_OF_LIST)))
+else
 MKIMAGEFLAGS_u-boot.img = -A $(ARCH) -T firmware -C none -O u-boot \
 	-a $(CONFIG_SYS_TEXT_BASE) -e $(CONFIG_SYS_UBOOT_START) \
 	-n "U-Boot $(UBOOTRELEASE) for $(BOARD) board"
+endif
 
 MKIMAGEFLAGS_u-boot-dtb.img = $(MKIMAGEFLAGS_u-boot.img)
 
@@ -908,7 +915,8 @@ MKIMAGEFLAGS_u-boot-spl.kwb = -n $(srctree)/$(CONFIG_SYS_KWD_CONFIG:"%"=%) \
 MKIMAGEFLAGS_u-boot.pbl = -n $(srctree)/$(CONFIG_SYS_FSL_PBL_RCW:"%"=%) \
 		-R $(srctree)/$(CONFIG_SYS_FSL_PBL_PBI:"%"=%) -T pblimage
 
-u-boot-dtb.img u-boot.img u-boot.kwb u-boot.pbl: u-boot.bin FORCE
+u-boot-dtb.img u-boot.img u-boot.kwb u-boot.pbl: \
+		$(if $(CONFIG_SPL_LOAD_FIT),u-boot-nodtb.bin dts/dt.dtb,u-boot.bin) FORCE
 	$(call if_changed,mkimage)
 
 u-boot-spl.kwb: u-boot.img spl/u-boot-spl.bin FORCE

dts/Kconfig

@@ -59,6 +59,16 @@ config DEFAULT_DEVICE_TREE
 	  It can be overridden from the command line:
 	  $ make DEVICE_TREE=<device-tree-name>
 
+config OF_LIST
+	string "List of device tree files to include for DT control"
+	depends on SPL_LOAD_FIT
+	help
+	  This option specifies a list of device tree files to use for DT
+	  control. These will be packaged into a FIT. At run-time, SPL will
+	  select the correct DT to use by examining the hardware (e.g.
+	  reading a board ID value). This is a list of device tree files
+	  (without the directory or .dtb suffix) separated by <space>.
+
 config OF_SPL_REMOVE_PROPS
 	string "List of device tree properties to drop for SPL"
 	depends on SPL_OF_CONTROL