The SPL device tree size must be minimised to save memory. Only include
properties that are needed by SPL - this is determined by the presence
of the "u-boot,dm-pre-reloc" property. Also remove a predefined list of
unused properties from the nodes that remain.
Signed-off-by: Simon Glass <s...@chromium.org>
---
Changes in v3:
- Convert hex number to upper case to keep bc happy
Changes in v2:
- Add new patch to reduce SPL device tree size with fdtgrep
Makefile | 2 +-
arch/arm/cpu/u-boot-spl.lds | 2 +-
dts/Kconfig | 12 ++++++++++++
scripts/Makefile.spl | 28 ++++++++++++++++++++++++++++
4 files changed, 42 insertions(+), 2 deletions(-)
diff --git a/Makefile b/Makefile
index 0a674bf..4276f13 100644
--- a/Makefile
+++ b/Makefile
@@ -1258,7 +1258,7 @@ u-boot.lds: $(LDSCRIPT) prepare FORCE
spl/u-boot-spl.bin: spl/u-boot-spl
@:
-spl/u-boot-spl: tools prepare
+spl/u-boot-spl: tools prepare $(if $(CONFIG_OF_SEPARATE),dts/dt.dtb)
$(Q)$(MAKE) obj=spl -f $(srctree)/scripts/Makefile.spl all
spl/sunxi-spl.bin: spl/u-boot-spl
diff --git a/arch/arm/cpu/u-boot-spl.lds b/arch/arm/cpu/u-boot-spl.lds
index a8be204..4b6e0f6 100644
--- a/arch/arm/cpu/u-boot-spl.lds
+++ b/arch/arm/cpu/u-boot-spl.lds
@@ -66,7 +66,7 @@ SECTIONS
. = ALIGN(4);
__bss_end = .;
}
-
+ __bss_size = __bss_end - __bss_start;
.dynsym _image_binary_end : { *(.dynsym) }
.dynbss : { *(.dynbss) }
.dynstr : { *(.dynstr*) }
diff --git a/dts/Kconfig b/dts/Kconfig
index 957f5c7..09cfefb 100644
--- a/dts/Kconfig
+++ b/dts/Kconfig
@@ -56,4 +56,16 @@ config DEFAULT_DEVICE_TREE
It can be overridden from the command line:
$ make DEVICE_TREE=<device-tree-name>
+config OF_SPL_REMOVE_PROPS
+ string "List of device tree properties to drop for SPL"
+ depends on OF_CONTROL && SPL
+ default "pinctrl-0 pinctrl-names clocks clock-names interrupt-parent"
+ help
+ Since SPL normally runs in a reduced memory space, the device tree
+ is cut down to only what is needed to load and start U-Boot. Only
+ nodes marked with the property "u-boot,dm-pre-reloc" will be
+ included. In addition, some properties are not used by U-Boot and
+ can be discarded. This option defines the list of properties to
+ discard.
+
endmenu
diff --git a/scripts/Makefile.spl b/scripts/Makefile.spl
index fd572f4..bcc7ca2 100644
--- a/scripts/Makefile.spl
+++ b/scripts/Makefile.spl
@@ -151,6 +151,8 @@ boot.bin: $(obj)/u-boot-spl.bin
ALL-y += $(obj)/$(SPL_BIN).bin $(obj)/$(SPL_BIN).cfg
+ALL-$(CONFIG_OF_SEPARATE) += $(obj)/$(SPL_BIN)-pad.bin
$(obj)/$(SPL_BIN)-dtb.bin
+
ifdef CONFIG_SAMSUNG
ALL-y += $(obj)/$(BOARD)-spl.bin
endif
@@ -165,6 +167,32 @@ endif
all: $(ALL-y)
+quiet_cmd_cat = CAT $@
+cmd_cat = cat $(filter-out $(PHONY), $^) > $@
+
+$(obj)/$(SPL_BIN)-dtb.bin: $(obj)/$(SPL_BIN).bin $(obj)/$(SPL_BIN)-pad.bin \
+ $(obj)/$(SPL_BIN).dtb FORCE
+ $(call if_changed,cat)
+
+# Create a file that pads from the end of u-boot-spl.bin to bss_end
+$(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
+# 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.
+quiet_cmd_fdtgrep = FDTGREP $@
+ cmd_fdtgrep = $(objtree)/tools/fdtgrep -b u-boot,dm-pre-reloc -RT $< \
+ -n /chosen -O dtb | \
+ $(objtree)/tools/fdtgrep -r -O dtb - -o $@ \
+ $(addprefix -P ,$(subst $\",,$(CONFIG_OF_SPL_REMOVE_PROPS)))
+
+$(obj)/$(SPL_BIN).dtb: dts/dt.dtb
+ $(call cmd,fdtgrep)
+
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 $@ $<
--
2.4.3.573.g4eafbef
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