[ImageBuilder] Make DEVICE_TREE optional parameter

[Ayan Kumar Halder <ayan.kumar.halder@xxxxxxx>]

There are systems where device tree binary is passed by the U-Boot as
$fdtcontroladdr. In such cases, no external device tree binary is provided
during uboot script generation.

This is an enhancement on top of the following commit:-
uboot-script-gen: Dynamically compute addr and size when loading bina…

When DEVICE_TREE is not present, $CALC is set as the addresses and sizes should
be computed dynamically from U-Boot.

Signed-off-by: Ayan Kumar Halder <ayan.kumar.halder@xxxxxxx>
---
 README.md                |  3 ++-
 scripts/uboot-script-gen | 26 +++++++++++++++++++-------
 2 files changed, 21 insertions(+), 8 deletions(-)

diff --git a/README.md b/README.md
index 4be6efb..d80bdc9 100644
--- a/README.md
+++ b/README.md
@@ -90,7 +90,8 @@ Where:
   DTB are stored in 'host_kernel_addr' and 'host_fdt_addr' u-boot
   env variables respectively, to be used manually when booting.
 
-- DEVICE_TREE specifies the DTB file to load.
+- DEVICE_TREE specifies the DTB file to load. If not set, then $fdtcontroladdr
+  is used as the address of the DTB loaded by u-boot.
 
 - XEN specifies the Xen hypervisor binary to load. Note that it has to
   be a regular Xen binary, not a u-boot binary.
diff --git a/scripts/uboot-script-gen b/scripts/uboot-script-gen
index fed53aa..9fe4a55 100755
--- a/scripts/uboot-script-gen
+++ b/scripts/uboot-script-gen
@@ -560,7 +560,7 @@ function device_tree_editing()
     if test $UBOOT_SOURCE
     then
         if test "$CALC"; then
-            echo "fdt addr \${host_fdt_addr}" >> $UBOOT_SOURCE
+            echo "fdt addr \${fdtcontroladdr}" >> $UBOOT_SOURCE
         else
             echo "fdt addr $device_tree_addr" >> $UBOOT_SOURCE
         fi
@@ -591,7 +591,7 @@ function device_tree_editing()
 
 function fill_reserved_spaces_from_dtb()
 {
-    if [ ! -f $DEVICE_TREE ]
+    if test ! -f $DEVICE_TREE || test -z ${DEVICE_TREE+x}
     then
         if test "$CALC"; then
             return
@@ -1502,6 +1502,11 @@ check_depends
 declare -A DOMU_VCPU_HARD_AFFINITY
 source "$cfg_file"
 
+if test -z ${DEVICE_TREE+x}
+then
+    CALC=y
+fi
+
 SCRIPT_PATH=$(dirname "$0")
 source "$SCRIPT_PATH/common"
 source "$SCRIPT_PATH/xen_dt_domu"
@@ -1703,9 +1708,13 @@ then
     done
 fi
 
-check_file_type $DEVICE_TREE "Device Tree Blob"
-device_tree_addr=$memaddr
-load_file $DEVICE_TREE "host_fdt" "$XEN_LOAD"
+if test ${DEVICE_TREE+x}
+then
+    check_file_type $DEVICE_TREE "Device Tree Blob"
+    device_tree_addr=$memaddr
+    load_file $DEVICE_TREE "host_fdt" "$XEN_LOAD"
+fi
+
 bitstream_load_and_config  # bitstream is loaded last but used first
 device_tree_editing $device_tree_addr
 
@@ -1727,14 +1736,17 @@ fi
 if [ "$BOOT_CMD" != "none" ]
 then
     if test "$CALC"; then
-        echo "$BOOT_CMD \${host_kernel_addr} $([ "$BOOT_CMD" = "bootefi" ] || 
echo '-') \${host_fdt_addr}" >> $UBOOT_SOURCE
+        echo "$BOOT_CMD \${host_kernel_addr} $([ "$BOOT_CMD" = "bootefi" ] || 
echo '-') \${fdtcontroladdr}" >> $UBOOT_SOURCE
     else
         echo "$BOOT_CMD $kernel_addr $([ "$BOOT_CMD" = "bootefi" ] || echo 
'-') $device_tree_addr" >> $UBOOT_SOURCE
     fi
 else
     # skip boot command but store load addresses to be used later
     echo "setenv host_kernel_addr $kernel_addr" >> $UBOOT_SOURCE
-    echo "setenv host_fdt_addr $device_tree_addr" >> $UBOOT_SOURCE
+    if test ${DEVICE_TREE+x}
+    then
+        echo "setenv host_fdt_addr $device_tree_addr" >> $UBOOT_SOURCE
+    fi
 fi
 
 if test "$FIT"
-- 
2.25.1