[RFC] DT: emit ordinals

dts/binding-template.yaml

@@ -7,6 +7,13 @@ description: |
 # Used to map nodes to bindings
 compatible: "manufacturer,device"
 
+# Set this to a truthy value if this binding is describing a node that
+# has a struct device representation within the Zephyr device
+# hierarchy.
+#
+# (This is used to track dependencies between such devices.)
+is-device: true
+
 # The 'compatible' above would match this node:
 #
 #     device {

scripts/dts/edtlib.py

@@ -484,9 +484,9 @@ def _check_binding(self, binding, binding_path):
                 _err("malformed or empty '{}' in {}"
                      .format(prop, binding_path))
 
-        ok_top = {"title", "description", "compatible", "properties", "#cells",
-                  "bus", "on-bus", "parent-bus", "child-bus", "parent", "child",
-                  "child-binding", "sub-node"}
+        ok_top = {"title", "description", "compatible", "is-device",
+                  "properties", "#cells", "bus", "on-bus", "parent-bus",
+                  "child-bus", "parent", "child", "child-binding", "sub-node"}
 
         for prop in binding:
             if prop not in ok_top and not prop.endswith("-cells"):
@@ -645,6 +645,10 @@ class Node:
     name:
       The name of the node
 
+    is_device:
+      True if the node's binding signals that it corresponds to a Zephyr
+      device model struct device. False otherwise.
+
     unit_addr:
       An integer with the ...@<unit-address> portion of the node name,
       translated through any 'ranges' properties on parent nodes, or None if
@@ -755,6 +759,11 @@ def name(self):
         "See the class docstring"
         return self._node.name
 
+    @property
+    def is_device(self):
+        "See the class docstring"
+        return self._binding and self._binding.get('is-device', False)
+
     @property
     def unit_addr(self):
         "See the class docstring"

scripts/dts/gen_defines.py

@@ -52,6 +52,7 @@ def main():
                 continue
 
             write_node_comment(node)
+            write_deps(node)
             write_regs(node)
             write_irqs(node)
             write_props(node)
@@ -166,6 +167,21 @@ def relativize(path):
         return path
 
 
+def write_deps(node):
+    # Writes dependency ordinal information for the node.
+
+    def dep_ords(nodes):
+        return [node.dep_ordinal for node in nodes]
+
+    out_node(node, 'ORDINAL', node.dep_ordinal)
+    out_node_init(node, 'REQUIRES_NODES', dep_ords(node.depends_on))
+    out_node_init(node, 'REQUIRES_DEVS',
+                  dep_ords([n for n in node.depends_on if n.is_device]))
+    out_node_init(node, 'SUPPORTS_NODES', dep_ords(node.required_by))
+    out_node_init(node, 'SUPPORTS_DEVS',
+                  dep_ords([n for n in node.required_by if n.is_device]))
+
+
 def write_regs(node):
     # Writes address/size output for the registers in the node's 'reg' property