Merge branch 'devel-stable' into for-next

[karo-tx-linux.git] / arch / arm / Kconfig

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index c932ae3bdfbd7fd509c7f2ff0ab2904e791d870b..1e9413b60d174035d4a3dd9e5c25f33c09179d2b 100644 (file)
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1819,6 +1819,38 @@ 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 ""