Makefile: add rules to generate SPL FIT images

Some platforms require more complex U-Boot images than we can easily
generate via the mkimage command line, for instance to load additional
image files.
Introduce a CONFIG_SPL_FIT_SOURCE and CONFIG_SPL_FIT_GENERATOR symbol,
which can either hold an .its source file describing the image layout,
or, in the second case, a generator tool (script) to create such
a source file. This script gets passed the list of device tree files
from the CONFIG_OF_LIST variable.
A platform or board can define either of those in their defconfig file
to allow an easy building of such an image.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Jagan Teki <jagan@openedev.com>
(cherry picked from commit 1a12fdc461421b5a385ab5d7926e5425d429d48e)

1 files changed, 17 insertions, 0 deletions

diff --git a/Kconfig b/Kconfig
index 139599ba0e..02f954d64e 100644
--- a/Kconfig
+++ b/Kconfig
@@ -240,6 +240,23 @@ config SPL_FIT_IMAGE_POST_PROCESS
 	  injected into the FIT creation (i.e. the blobs would have been pre-
 	  processed before being added to the FIT image).
 
+config SPL_FIT_SOURCE
+	string ".its source file for U-Boot FIT image"
+	depends on SPL_FIT
+	help
+	  Specifies a (platform specific) FIT source file to generate the
+	  U-Boot FIT image. This could specify further image to load and/or
+	  execute.
+
+config SPL_FIT_GENERATOR
+	string ".its file generator script for U-Boot FIT image"
+	depends on SPL_FIT
+	help
+	  Specifies a (platform specific) script file to generate the FIT
+	  source file used to build the U-Boot FIT image file. This gets
+	  passed a list of supported device tree file stub names to
+	  include in the generated image.
+
 endif # FIT
 
 config OF_BOARD_SETUP