Add android's DTB/DTBO partitions format

Documentation: https://source.android.com/devices/architecture/dto/partitions
Reference implementation: https://android.googlesource.com/platform/system/libufdt/+/refs/heads/master/utils/

Signed-off-by: Denis Efremov <efremov@linux.com>

archive/android_dto.ksy

@@ -0,0 +1,79 @@
+meta:
+  id: android_dto
+  title: Android DTB/DTBO Partition
+  license: CC0-1.0
+  file-extension: img
+  endian: be
+
+doc: |
+  Format for Android DTB/DTBO partitions. It's kind of archive with
+  dtb/dtbo files. Used only when there is a separate unique partition
+  (dtb, dtbo) on an android device to organize device tree files.
+  The format consists of a header with info about size and number
+  of device tree entries and the entries themselves. This format
+  description could be used to extract device tree entries from a
+  partition images and decompile them with dtc (device tree compiler).
+
+doc-ref:
+  - https://source.android.com/devices/architecture/dto/partitions
+  - https://android.googlesource.com/platform/system/libufdt/+/refs/tags/android-10.0.0_r47
+
+seq:
+  - id: header
+    type: dt_table_header
+  - id: entries
+    type: dt_table_entry
+    repeat: expr
+    repeat-expr: header.dt_entry_count
+
+types:
+  dt_table_header:
+    seq:
+    - id: magic
+      contents: [ 0xd7, 0xb7, 0xab, 0x1e ]
+    - id: total_size
+      type: u4
+      doc: includes dt_table_header + all dt_table_entry and all dtb/dtbo
+    - id: header_size
+      type: u4
+      doc: sizeof(dt_table_header)
+    - id: dt_entry_size
+      type: u4
+      doc: sizeof(dt_table_entry)
+    - id: dt_entry_count
+      type: u4
+      doc: number of dt_table_entry
+    - id: dt_entries_offset
+      type: u4
+      doc: offset to the first dt_table_entry from head of dt_table_header
+    - id: page_size
+      type: u4
+      doc: flash page size
+    - id: version
+      type: u4
+      doc: DTBO image version
+  dt_table_entry:
+    seq:
+    - id: dt_size
+      type: u4
+      doc: size of this entry
+    - id: dt_offset
+      type: u4
+      doc: offset from head of dt_table_header
+    - id: id
+      type: u4
+      doc: optional, must be zero if unused
+    - id: rev
+      type: u4
+      doc: optional, must be zero if unused
+    - id: custom
+      type: u4
+      repeat: expr
+      repeat-expr: 4
+      doc: optional, must be zero if unused
+    instances:
+      body:
+        io: _root._io
+        pos: dt_offset
+        size: dt_size
+        doc: DTB/DTBO file