ARM: zImage: Allow the appending of a device tree binary
This patch provides the ability to boot using a device tree that is appended
to the raw binary zImage (e.g. cat zImage <filename>.dtb > zImage_w_dtb).
Signed-off-by: John Bonesio <bones@secretlab.ca>
[nico: ported to latest zImage changes plus additional cleanups/improvements]
Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Tony Lindgren <tony@atomide.com>
Tested-by: Shawn Guo <shawn.guo@linaro.org>
Tested-by: Dave Martin <dave.martin@linaro.org>
Tested-by: Thomas Abraham <thomas.abraham@linaro.org>
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 5ebc5d9..c66e080 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1781,6 +1781,26 @@
endchoice
+config ARM_APPENDED_DTB
+ bool "Use appended device tree blob to zImage (EXPERIMENTAL)"
+ depends on OF && !ZBOOT_ROM && EXPERIMENTAL
+ help
+ With this option, the boot code will look for a device tree binary
+ (DTB) appended to zImage
+ (e.g. cat zImage <filename>.dtb > zImage_w_dtb).
+
+ This is meant as a backward compatibility convenience for those
+ systems with a bootloader that can't be upgraded to accommodate
+ the documented boot protocol using a device tree.
+
+ Beware that there is very little in terms of protection against
+ this option being confused by leftover garbage in memory that might
+ look like a DTB header after a reboot if no actual DTB is appended
+ to zImage. Do not leave this option active in a production kernel
+ if you don't intend to always append a DTB. Proper passing of the
+ location into r2 of a bootloader provided DTB is always preferable
+ to this option.
+
config CMDLINE
string "Default kernel command string"
default ""