[PATCH 3/4] u-boot-script: add support to use builtin dt

[Felix Moessbauer <felix.moessbauer@siemens.com>]

This patch adds support to use the u-boot builtin device tree instead of
the one from the rootfs / linux. This enables the use of dt overlays
even if the corresponding device tree in the kernel is not compiled with
symbol support (uboot builtin DTBs always have symbol information).

To use the builtin dt, add the WKS sourceparam "builtin_dt=yes" to the
rootfs-u-boot sourcer.

Co-developed-by: Florian Bezdeka <florian.bezdeka@siemens.com>
Signed-off-by: Felix Moessbauer <felix.moessbauer@siemens.com>
---
 .../u-boot-script/files/u-boot-script            |  3 +++
 .../u-boot-script/files/update-u-boot-script     | 16 ++++++++++++----
 .../lib/wic/plugins/source/rootfs-u-boot.py      |  3 +++
 3 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/meta/recipes-bsp/u-boot-script/files/u-boot-script b/meta/recipes-bsp/u-boot-script/files/u-boot-script
index d053d721..a11212c0 100644
--- a/meta/recipes-bsp/u-boot-script/files/u-boot-script
+++ b/meta/recipes-bsp/u-boot-script/files/u-boot-script
@@ -15,3 +15,6 @@ NO_INITRD=""
 
 # U-boot commands to prepend to boot script
 SCRIPT_PREPEND=""
+
+# use u-boot builtin device tree
+BUILTIN_DT="no"
diff --git a/meta/recipes-bsp/u-boot-script/files/update-u-boot-script b/meta/recipes-bsp/u-boot-script/files/update-u-boot-script
index 14a81563..f4e36ed2 100755
--- a/meta/recipes-bsp/u-boot-script/files/update-u-boot-script
+++ b/meta/recipes-bsp/u-boot-script/files/update-u-boot-script
@@ -33,10 +33,18 @@ echo "${SCRIPT_PREPEND}" >> ${BOOT_CMD}
 
 echo "setenv bootargs ${KERNEL_ARGS}" >> ${BOOT_CMD}
 
-echo "echo Loading /usr/lib/linux-image-${KERNEL_VERSION}/\${fdtfile}..." \
-     >> ${BOOT_CMD}
-echo "load \${devtype} \${devnum}:${ROOT_PARTITION} \${fdt_addr_r}" \
-     "/usr/lib/linux-image-${KERNEL_VERSION}/\${fdtfile}" >> ${BOOT_CMD}
+if [ "${BUILTIN_DT}" = "yes" ]; then
+	echo "echo Loading builtin device tree..." \
+	     >> ${BOOT_CMD}
+	echo "fdt addr \${fdtcontroladdr}" >> ${BOOT_CMD}
+	echo "fdt move \${fdtcontroladdr} \${fdt_addr_r}" >> ${BOOT_CMD}
+else
+	echo "echo Loading /usr/lib/linux-image-${KERNEL_VERSION}/\${fdtfile}..." \
+	     >> ${BOOT_CMD}
+	echo "load \${devtype} \${devnum}:${ROOT_PARTITION} \${fdt_addr_r}" \
+	     "/usr/lib/linux-image-${KERNEL_VERSION}/\${fdtfile}" >> ${BOOT_CMD}
+fi
+
 echo "echo Loading /boot/${KERNEL_FILE}-${KERNEL_VERSION}..." >> ${BOOT_CMD}
 echo "load \${devtype} \${devnum}:\${distro_bootpart} \${kernel_addr_r}" \
      "/boot/${KERNEL_FILE}-${KERNEL_VERSION}" >> ${BOOT_CMD}
diff --git a/meta/scripts/lib/wic/plugins/source/rootfs-u-boot.py b/meta/scripts/lib/wic/plugins/source/rootfs-u-boot.py
index 0b4f9eec..93600dc2 100644
--- a/meta/scripts/lib/wic/plugins/source/rootfs-u-boot.py
+++ b/meta/scripts/lib/wic/plugins/source/rootfs-u-boot.py
@@ -10,6 +10,7 @@
 # Recognized sourceparams:
 #  - no_initrd=yes          (disables initrd loading)
 #  - overlays=file.dtbo ... (overlay files)
+#  - builtin_dt=no          (use DT from uboot instead of kernel)
 #  - script_prepend=cmd;... (prepends U-Boot command)
 
 import glob
@@ -82,6 +83,8 @@ class RootfsUBootPlugin(RootfsPlugin):
             cfg.write('NO_INITRD="%s"\n' % no_initrd)
             overlays = source_params.get('overlays') or ''
             cfg.write('OVERLAYS="%s"\n' % overlays)
+            builtin_dt = source_params.get('builtin_dt') or ''
+            cfg.write('BUILTIN_DT="%s"\n' % builtin_dt)
             script_prepend = source_params.get('script_prepend') or ''
             # remove escapes from $\{var\} that are needed to avoid expansion by wic
             script_prepend = re.sub(r'\$\\{([^\\]+)\\}', r'${\1}', script_prepend)
-- 
2.34.1