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https://github.com/u-boot/u-boot.git
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c16b137e49
Based on the following Linux commits:
- 54a702f70589 ("kbuild: mark $(targets) as .SECONDARY and remove
.PRECIOUS markers")
- 8e9b61b293d9 ("kbuild: move .SECONDARY special target to
Kbuild.include")
GNU Make automatically deletes intermediate files that are updated
in a chain of pattern rules.
Example 1) %.dtb.o <- %.dtb.S <- %.dtb <- %.dts
Example 2) %.o <- %.c <- %.c_shipped
A couple of makefiles mark such targets as .PRECIOUS to prevent Make
from deleting them, but the correct way is to use .SECONDARY.
.SECONDARY
Prerequisites of this special target are treated as intermediate
files but are never automatically deleted.
.PRECIOUS
When make is interrupted during execution, it may delete the target
file it is updating if the file was modified since make started.
If you mark the file as precious, make will never delete the file
if interrupted.
Both can avoid deletion of intermediate files, but the difference is
the behavior when Make is interrupted; .SECONDARY deletes the target,
but .PRECIOUS does not.
The use of .PRECIOUS is relatively rare since we do not want to keep
partially constructed (possibly corrupted) targets.
.SECONDARY with no prerequisites causes all targets to be treated as
secondary. This agrees the policy of Kbuild.
scripts/Kbuild.include seems a suitable place to add it because it is
included from almost all sub-makes.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
62 lines
1.5 KiB
Makefile
62 lines
1.5 KiB
Makefile
# SPDX-License-Identifier: GPL-2.0+
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#
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# Copyright (c) 2011 The Chromium OS Authors.
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# This Makefile builds the internal U-Boot fdt if CONFIG_OF_CONTROL is
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# enabled. See doc/README.fdt-control for more details.
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DEVICE_TREE ?= $(CONFIG_DEFAULT_DEVICE_TREE:"%"=%)
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ifeq ($(DEVICE_TREE),)
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DEVICE_TREE := unset
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endif
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ARCH_PATH := arch/$(ARCH)/dts
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dtb_depends := arch-dtbs
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ifneq ($(EXT_DTB),)
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DTB := $(EXT_DTB)
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else
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DTB := $(ARCH_PATH)/$(DEVICE_TREE).dtb
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dtb_depends += $(DTB:.dtb=.dts)
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endif
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$(obj)/dt-spl.dtb: $(DTB) $(objtree)/tools/fdtgrep FORCE
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$(call if_changed,fdtgrep)
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$(obj)/dt.dtb: $(DTB) FORCE
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$(call if_changed,shipped)
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targets += dt.dtb dt-spl.dtb
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$(DTB): $(dtb_depends)
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ifeq ($(EXT_DTB),)
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$(Q)$(MAKE) $(build)=$(ARCH_PATH) $@
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endif
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$(Q)test -e $@ || ( \
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echo >&2; \
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echo >&2 "Device Tree Source is not correctly specified."; \
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echo >&2 "Please define 'CONFIG_DEFAULT_DEVICE_TREE'"; \
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echo >&2 "or build with 'DEVICE_TREE=<device_tree>' argument"; \
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echo >&2; \
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/bin/false)
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arch-dtbs:
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$(Q)$(MAKE) $(build)=$(ARCH_PATH) dtbs
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ifeq ($(CONFIG_SPL_BUILD),y)
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obj-$(CONFIG_OF_EMBED) := dt-spl.dtb.o
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# support "out-of-tree" build for dtb-spl
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$(obj)/dt-spl.dtb.o: $(obj)/dt-spl.dtb.S FORCE
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$(call if_changed_dep,as_o_S)
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else
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obj-$(CONFIG_OF_EMBED) := dt.dtb.o
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endif
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dtbs: $(obj)/dt.dtb $(obj)/dt-spl.dtb
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@:
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clean-files := dt.dtb.S dt-spl.dtb.S
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# Let clean descend into dts directories
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subdir- += ../arch/arm/dts ../arch/microblaze/dts ../arch/mips/dts ../arch/sandbox/dts ../arch/x86/dts ../arch/powerpc/dts ../arch/riscv/dts
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