spl: make CONFIG_OF_EMBED pass dts through fdtgrep

Building spl with CONFIG_OF_EMBED enabled results in an error message
on my board: "SPL image too big". This is because the fdtgrep build
step is only executed for CONFIG_OF_SEPARATE.

Fix this by moving the fdtgrep build step ('cmd_fdtgreo') from
scripts/Makefile.spl to dts/Makefile so that the reduced dtb is
available for all kinds of spl builds.

The resulting variable name for the embedded device tree blob changes,
too, which is why common.h and fdtdec.c have tiny changes.

Signed-off-by: Simon Goldschmidt <sgoldschmidt@de.pepperl-fuchs.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

dts/Makefile

@@ -22,10 +22,29 @@ DTB := $(ARCH_PATH)/$(DEVICE_TREE).dtb
 dtb_depends += $(DTB:.dtb=.dts)
 endif
 
+# Pass the original device tree file through fdtgrep twice. The first pass
+# removes any unwanted nodes (i.e. those which don't have the
+# 'u-boot,dm-pre-reloc' property and thus are not needed by SPL. The second
+# pass removes various unused properties from the remaining nodes.
+# The output is typically a much smaller device tree file.
+ifeq ($(CONFIG_TPL_BUILD),y)
+fdtgrep_props := -b u-boot,dm-pre-reloc -b u-boot,dm-tpl
+else
+fdtgrep_props := -b u-boot,dm-pre-reloc -b u-boot,dm-spl
+endif
+quiet_cmd_fdtgrep = FDTGREP $@
+      cmd_fdtgrep = $(objtree)/tools/fdtgrep $(fdtgrep_props) -RT $< \
+		-n /chosen -n /config -O dtb | \
+	$(objtree)/tools/fdtgrep -r -O dtb - -o $@ \
+		$(addprefix -P ,$(subst $\",,$(CONFIG_OF_SPL_REMOVE_PROPS)))
+
+$(obj)/dt-spl.dtb: $(DTB) $(objtree)/tools/fdtgrep FORCE
+	$(call if_changed,fdtgrep)
+
 $(obj)/dt.dtb: $(DTB) FORCE
 	$(call if_changed,shipped)
 
-targets += dt.dtb
+targets += dt.dtb dt-spl.dtb
 
 $(DTB): $(dtb_depends)
 ifeq ($(EXT_DTB),)
@@ -42,14 +61,22 @@ endif
 arch-dtbs:
 	$(Q)$(MAKE) $(build)=$(ARCH_PATH) dtbs
 
-.SECONDARY: $(obj)/dt.dtb.S
+.SECONDARY: $(obj)/dt.dtb.S $(obj)/dt-spl.dtb.S
 
+
+ifeq ($(CONFIG_SPL_BUILD),y)
+obj-$(CONFIG_OF_EMBED) := dt-spl.dtb.o
+# support "out-of-tree" build for dtb-spl
+$(obj)/dt-spl.dtb.o: $(obj)/dt-spl.dtb.S FORCE
+	$(call if_changed_dep,as_o_S)
+else
 obj-$(CONFIG_OF_EMBED) := dt.dtb.o
+endif
 
-dtbs: $(obj)/dt.dtb
+dtbs: $(obj)/dt.dtb $(obj)/dt-spl.dtb
 	@:
 
-clean-files := dt.dtb.S
+clean-files := dt.dtb.S dt-spl.dtb.S
 
 # Let clean descend into dts directories
 subdir- += ../arch/arm/dts ../arch/microblaze/dts ../arch/mips/dts ../arch/sandbox/dts ../arch/x86/dts

include/common.h

@@ -201,6 +201,7 @@ int last_stage_init(void);
 extern ulong monitor_flash_len;
 int mac_read_from_eeprom(void);
 extern u8 __dtb_dt_begin[];	/* embedded device tree blob */
+extern u8 __dtb_dt_spl_begin[];	/* embedded device tree blob for SPL/TPL */
 int set_cpu_clk_info(void);
 int mdm_init(void);
 int print_cpuinfo(void);

lib/fdtdec.c

@@ -1268,7 +1268,11 @@ int fdtdec_setup(void)
 # endif
 # ifdef CONFIG_OF_EMBED
 	/* Get a pointer to the FDT */
+#  ifdef CONFIG_SPL_BUILD
+	gd->fdt_blob = __dtb_dt_spl_begin;
+#  else
 	gd->fdt_blob = __dtb_dt_begin;
+#  endif
 # elif defined CONFIG_OF_SEPARATE
 #  ifdef CONFIG_SPL_BUILD
 	/* FDT is at end of BSS unless it is in a different memory region */

scripts/Makefile.spl

@@ -239,24 +239,8 @@ $(obj)/$(SPL_BIN)-pad.bin: $(obj)/$(SPL_BIN)
 	@bss_size_str=$(shell $(NM) $< | awk 'BEGIN {size = 0} /__bss_size/ {size = $$1} END {print "ibase=16; " toupper(size)}' | bc); \
 	dd if=/dev/zero of=$@ bs=1 count=$${bss_size_str} 2>/dev/null;
 
-# Pass the original device tree file through fdtgrep twice. The first pass
+$(obj)/$(SPL_BIN).dtb: dts/dt-spl.dtb FORCE
-# removes any unwanted nodes (i.e. those which don't have the
+	$(call if_changed,copy)
-# 'u-boot,dm-pre-reloc' property and thus are not needed by SPL. The second
-# pass removes various unused properties from the remaining nodes.
-# The output is typically a much smaller device tree file.
-ifeq ($(CONFIG_TPL_BUILD),y)
-fdtgrep_props := -b u-boot,dm-pre-reloc -b u-boot,dm-tpl
-else
-fdtgrep_props := -b u-boot,dm-pre-reloc -b u-boot,dm-spl
-endif
-quiet_cmd_fdtgrep = FDTGREP $@
-      cmd_fdtgrep = $(objtree)/tools/fdtgrep $(fdtgrep_props) -RT $< \
-		-n /chosen -n /config -O dtb | \
-	$(objtree)/tools/fdtgrep -r -O dtb - -o $@ \
-		$(addprefix -P ,$(subst $\",,$(CONFIG_OF_SPL_REMOVE_PROPS)))
-
-$(obj)/$(SPL_BIN).dtb: dts/dt.dtb $(objtree)/tools/fdtgrep FORCE
-	$(call if_changed,fdtgrep)
 
 pythonpath = PYTHONPATH=scripts/dtc/pylibfdt