gen_defines: emit output for all nodes in dependency order

This makes the results easier to read, since node output appears in
the same order as the top level comment summarizing the tree.

Reorganize how flash partitions are emitted so they also appear in
dependency order, allowing us to extend the comment at the top of the
file to say that nodes are emitted in that order, along with other
useful information.

Print comments even for nodes that are disabled or have no binding,
to make it clearer that the script considered them and decided not to
output anything for them.

Signed-off-by: Martí Bolívar <marti.bolivar@nordicsemi.no>

scripts/dts/gen_defines.py

@@ -29,6 +29,7 @@ import edtlib
 def main():
     global conf_file
     global header_file
+    global flash_area_num
 
     args = parse_args()
 
@@ -43,17 +44,21 @@ def main():
 
     conf_file = open(args.conf_out, "w", encoding="utf-8")
     header_file = open(args.header_out, "w", encoding="utf-8")
+    flash_area_num = 0
 
     write_top_comment(edt)
 
-    for node in edt.nodes:
-        if node.enabled and node.matching_compat:
-            # Skip 'fixed-partitions' devices since they are handled by
-            # write_flash() and would generate extra spurious #defines
-            if node.matching_compat == "fixed-partitions":
-                continue
+    for node in sorted(edt.nodes, key=lambda node: node.dep_ordinal):
+        write_node_comment(node)
 
-            write_node_comment(node)
+        # Flash partition nodes are handled as a special case. It
+        # would be nicer if we had bindings that would let us
+        # avoid that, but this will do for now.
+        if node.name.startswith("partition@"):
+            write_flash_partition(node, flash_area_num)
+            flash_area_num += 1
+
+        if node.enabled and node.matching_compat:
             write_regs(node)
             write_irqs(node)
             write_props(node)
@@ -67,11 +72,10 @@ def main():
         #define DT_COMPAT_<COMPAT> 1
         out(f"COMPAT_{str2ident(compat)}", 1)
 
-    # Derived from /chosen
+    # Definitions derived from /chosen nodes
     write_addr_size(edt, "zephyr,ccm", "CCM")
     write_addr_size(edt, "zephyr,dtcm", "DTCM")
     write_addr_size(edt, "zephyr,ipc_shm", "IPC_SHM")
-
     write_flash(edt)
 
     conf_file.close()
@@ -121,6 +125,12 @@ Nodes in dependency order (ordinal and path):
                 + ", ".join(node.path for node in scc))
         s += f"  {scc[0].dep_ordinal:<3} {scc[0].path}\n"
 
+    s += """
+Definitions derived from these nodes in dependency order are next,
+followed by tree-wide information (active compatibles, chosen nodes,
+etc.).
+"""
+
     out_comment(s, blank_before=False)
 
 
@@ -130,12 +140,16 @@ def write_node_comment(node):
     s = f"""\
 Devicetree node:
   {node.path}
-
+"""
+    if node.matching_compat:
+        s += f"""
 Binding (compatible = {node.matching_compat}):
   {relativize(node.binding_path)}
-
-Dependency Ordinal: {node.dep_ordinal}
 """
+    else:
+        s += "\nNo matching binding.\n"
+
+    s += f"\nDependency Ordinal: {node.dep_ordinal}\n"
 
     if node.depends_on:
         s += "\nRequires:\n"
@@ -147,9 +161,15 @@ Dependency Ordinal: {node.dep_ordinal}
         for req in node.required_by:
             s += f"  {req.dep_ordinal:<3} {req.path}\n"
 
-    # Indent description by two spaces
-    s += "\nDescription:\n" + \
-         "\n".join("  " + line for line in node.description.splitlines())
+    if node.description:
+        # Indent description by two spaces
+        s += "\nDescription:\n" + \
+            "\n".join("  " + line for line in
+                      node.description.splitlines()) + \
+            "\n"
+
+    if not node.enabled:
+        s += "\nNode is disabled.\n"
 
     out_comment(s)
 
@@ -367,20 +387,14 @@ def write_addr_size(edt, prop_name, prefix):
 
 
 def write_flash(edt):
-    # Writes flash-related output
+    # Writes chosen and tree-wide flash-related output
 
     write_flash_node(edt)
     write_code_partition(edt)
 
-    flash_index = 0
-    for node in edt.nodes:
-        if node.name.startswith("partition@"):
-            write_flash_partition(node, flash_index)
-            flash_index += 1
-
-    if flash_index != 0:
+    if flash_area_num != 0:
         out_comment("Number of flash partitions")
-        out("FLASH_AREA_NUM", flash_index)
+        out("FLASH_AREA_NUM", flash_area_num)
 
 
 def write_flash_node(edt):
@@ -439,8 +453,6 @@ def write_code_partition(edt):
 
 
 def write_flash_partition(partition_node, index):
-    out_comment("Flash partition at " + partition_node.path)
-
     if partition_node.label is None:
         err(f"missing 'label' property on {partition_node!r}")