patching: introduce add-only mode for DT Makefile AutoPatcher

- Autopatcher was commiting atrocities to the upstream DTs that are so
  carefully hand-crafted, by simply rewriting everything, or trying to be
  smart and failing at it (`incremental: true`)
- Instead, add `add-only: true` mode, where we simply only ever add to the
  end of the Makefile, adding each new .dts and optionally the `subdir-y`
  for overlays

lib/tools/common/dt_makefile_patcher.py

@@ -65,7 +65,8 @@ class AutomaticPatchDescription:
 		return f"Armbian Autopatcher: {self.description}"
 
 
-def auto_patch_dt_makefile(git_work_dir: str, dt_rel_dir: str, config_var: str, dt_files_to_add: list[str], incremental: bool) -> dict[str, str]:
+def auto_patch_dt_makefile(git_work_dir: str, dt_rel_dir: str, config_var: str, dt_files_to_add: list[str], incremental: bool, add_only: bool) -> \
+	dict[str, str]:
 	ret: dict[str, str] = {}
 	dt_path = os.path.join(git_work_dir, dt_rel_dir)
 	# Bomb if it does not exist or is not a directory
@@ -83,6 +84,23 @@ def auto_patch_dt_makefile(git_work_dir: str, dt_rel_dir: str, config_var: str,
 		makefile_contents = f.read()
 	log.info(f"Read {len(makefile_contents)} bytes from {makefile_path}")
 	log.debug(f"Contents:\n{makefile_contents}")
+
+	if add_only:
+		# much simpler. just add individual -y lines for each dt file to add directly to the end of the Makefile and hope for the best
+		log.info(f"Add-only mode: will just add {len(dt_files_to_add)} dt files to the end of the Makefile")
+		with open(makefile_path, "a") as f:
+			f.write("\n\n# Added by Armbian autopatcher in add-only:true mode\n")
+			for one_dt_file in dt_files_to_add:
+				f.write(f"\ndtb-$({config_var}) += {one_dt_file[:-4]}.dtb\n")  # replace .dts suffix with .dtb
+			overlay_lines = []
+			add_overlay_lines(dt_path, incremental, overlay_lines, ret)
+			if len(overlay_lines) > 0:
+				f.write("\n")
+				f.write("\n".join(overlay_lines))
+		log.info(f"Wrote add-only entries to {makefile_path}")
+		ret["extra_desc"] = "add-only mode"
+		return ret
+
 	# Parse it into a list of lines
 	makefile_lines = makefile_contents.splitlines()
 	log.info(f"Read {len(makefile_lines)} lines from {makefile_path}")
@@ -166,17 +184,7 @@ def auto_patch_dt_makefile(git_work_dir: str, dt_rel_dir: str, config_var: str,
 
 	# Late to the game: if DT_DIR/overlay/Makefile exists, add it.
 	overlay_lines = []
-	DT_OVERLAY_PATH = os.path.join(dt_path, "overlay")
+	add_overlay_lines(dt_path, incremental, overlay_lines, ret)
-	DT_OVERLAY_MAKEFILE_PATH = os.path.join(DT_OVERLAY_PATH, "Makefile")
-	overlay_lines.append("")
-	if os.path.isfile(DT_OVERLAY_MAKEFILE_PATH):
-		if incremental:
-			overlay_lines.append("# Armbian: Incremental: assuming overlay targets are already in the Makefile")
-		else:
-			ret["DT_OVERLAY_MAKEFILE_PATH"] = DT_OVERLAY_MAKEFILE_PATH
-			ret["DT_OVERLAY_PATH"] = DT_OVERLAY_PATH
-			overlay_lines.append("# Added by Armbian autopatcher for DT overlay")
-			overlay_lines.append("subdir-y       := $(dts-dirs) overlay")
 
 	# Now join the preambles, midamble, postamble and overlay stuff into a single list
 	new_makefile_lines = preamble_lines + midamble_lines + postamble_lines + overlay_lines
@@ -191,6 +199,20 @@ def auto_patch_dt_makefile(git_work_dir: str, dt_rel_dir: str, config_var: str,
 	return ret
 
 
+def add_overlay_lines(dt_path: str, incremental: bool, overlay_lines: list[str], ret: dict[str, str]):
+	DT_OVERLAY_PATH = os.path.join(dt_path, "overlay")
+	DT_OVERLAY_MAKEFILE_PATH = os.path.join(DT_OVERLAY_PATH, "Makefile")
+	overlay_lines.append("")
+	if os.path.isfile(DT_OVERLAY_MAKEFILE_PATH):
+		if incremental:
+			overlay_lines.append("# Armbian: Incremental: assuming overlay targets are already in the Makefile")
+		else:
+			ret["DT_OVERLAY_MAKEFILE_PATH"] = DT_OVERLAY_MAKEFILE_PATH
+			ret["DT_OVERLAY_PATH"] = DT_OVERLAY_PATH
+			overlay_lines.append("# Added by Armbian autopatcher for DT overlay")
+			overlay_lines.append("subdir-y       := $(dts-dirs) overlay")
+
+
 def copy_bare_files(autopatcher_params: AutoPatcherParams, type: str) -> list[AutomaticPatchDescription]:
 	ret_desc_list: list[AutomaticPatchDescription] = []
 
@@ -284,7 +306,7 @@ def auto_patch_all_dt_makefiles(autopatcher_params: AutoPatcherParams) -> list[A
 		log.warning(f"Autopatching DT Makefile in {one_autopatch_config.directory} with config '{one_autopatch_config.config_var}'...")
 		autopatch_makefile_info = auto_patch_dt_makefile(
 			autopatcher_params.git_work_dir, one_autopatch_config.directory, one_autopatch_config.config_var,
-			autopatcher_params.all_dt_files_copied, one_autopatch_config.incremental
+			autopatcher_params.all_dt_files_copied, one_autopatch_config.incremental, one_autopatch_config.add_only
 		)
 
 		desc = AutomaticPatchDescription()

lib/tools/common/patching_config.py

@@ -17,6 +17,7 @@ class PatchingAutoPatchMakefileDTConfig:
 		self.config_var: str = data.get("config-var", None)
 		self.directory: str = data.get("directory", None)
 		self.incremental: bool = not not data.get("incremental", False)
+		self.add_only: bool = not not data.get("add-only", True)
 
 	def __str__(self):
 		return f"PatchingAutoPatchMakefileDTConfig(config-var={self.config_var}, directory={self.directory}, incremental={self.incremental})"