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ARM: supply a DTB file to be appended

Message ID 1315476884-28470-1-git-send-email-linus.walleij@stericsson.com (mailing list archive)
State New, archived
Headers show

Commit Message

Linus Walleij Sept. 8, 2011, 10:14 a.m. UTC
From: Linus Walleij <linus.walleij@linaro.org>

This adds a Kconfig string where you can specify a
file to be appended to the zImage on build, then
auto-appends it. The idea is to mimic how we supply
an initramfs image by a similar parameter.

This makes it easy to script the kernel build with
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different device trees, and it also vastly simplifies
building uImages since "make uImage" will now pick
up the devcie tree and include it in the final image
as part of the build process.

Cc: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: David Brown <davidb@codeaurora.org>
Cc: Niklas Hernaeus <niklas.hernaeus@linaro.org>
Cc: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This builds on top of Nicos pending appended device tree
patches. Nico, if this gains some liking, please include
it in your series.
 arch/arm/Kconfig       |   10 ++++++++++
 arch/arm/boot/Makefile |    8 +++++++-
 2 files changed, 17 insertions(+), 1 deletions(-)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 4ea9974..cb8ee68 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1789,6 +1789,16 @@  config ARM_APPENDED_DTB
 	  (dtb) appended to zImage
 	  (e.g. cat zImage <filename>.dtb > zImage_w_dtb).
+	string "DTB file"
+	depends on ARM_APPENDED_DTB
+	default ""
+	help
+	  This gives the name of file from the build directory to append
+	  to the zImage after it has been built.
+	  If you are not sure, leave it blank.
 	bool "Supplement the appended DTB with traditional ATAG information"
 	depends on ARM_APPENDED_DTB
diff --git a/arch/arm/boot/Makefile b/arch/arm/boot/Makefile
index a1edfd5..5ab6abf 100644
--- a/arch/arm/boot/Makefile
+++ b/arch/arm/boot/Makefile
@@ -53,8 +53,14 @@  $(obj)/Image: vmlinux FORCE
 $(obj)/compressed/vmlinux: $(obj)/Image FORCE
 	$(Q)$(MAKE) $(build)=$(obj)/compressed $@
-$(obj)/zImage:	$(obj)/compressed/vmlinux FORCE
+# Rule to optionally append a DTB
+dtbfile := $(shell echo $(CONFIG_ARM_APPENDED_DTB_FILE))
+quiet_cmd_append = CAT     $@
+      cmd_append = (cat /dev/null $(dtbfile) >> $@)
+$(obj)/zImage:	$(obj)/compressed/vmlinux $(dtbfile) FORCE
 	$(call if_changed,objcopy)
+	$(call if_changed,append)
 	@echo '  Kernel: $@ is ready'