1 files changed, 32 insertions, 0 deletions

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 3269576dbfa8..5a3a78633177 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1793,6 +1793,38 @@ config ZBOOT_ROM_SH_MOBILE_SDHI
 
 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 ARM_ATAG_DTB_COMPAT
+        bool "Supplement the appended DTB with traditional ATAG information"
+        depends on ARM_APPENDED_DTB
+        help
+          Some old bootloaders can't be updated to a DTB capable one, yet
+          they provide ATAGs with memory configuration, the ramdisk address,
+          the kernel cmdline string, etc.  Such information is dynamically
+          provided by the bootloader and can't always be stored in a static
+          DTB.  To allow a device tree enabled kernel to be used with such
+          bootloaders, this option allows zImage to extract the information
+          from the ATAG list and store it at run time into the appended DTB.
+
 config CMDLINE
         string "Default kernel command string"
         default ""