edtlib: add hash attribute to nodes

include/zephyr/devicetree.h

@@ -242,6 +242,16 @@
  */
 #define DT_HAS_ALIAS(alias_name) DT_NODE_EXISTS(DT_ALIAS(alias_name))
 
+/**
+ * @brief Get the hash associated with a DT node
+ *
+ * Get the hash for the specified node_id. The hash is calculated on the
+ * full devicetree path of the node.
+ * @param node_id node identifier
+ * @return hash value as a preprocessor token
+ */
+#define DT_HASH(node_id) DT_CAT(node_id, _HASH)
+
 /**
  * @brief Get a node identifier for an instance of a compatible
  *

scripts/dts/gen_defines.py

@@ -720,6 +720,9 @@ def fmt_dep_list(dep_list):
         else:
             return "/* nothing */"
 
+    out_comment("Node's hash:")
+    out_dt_define(f"{node.z_path_id}_HASH", node.hash)
+
     out_comment("Node's dependency ordinal:")
     out_dt_define(f"{node.z_path_id}_ORD", node.dep_ordinal)
     out_dt_define(f"{node.z_path_id}_ORD_STR_SORTABLE", f"{node.dep_ordinal:0>5}")

scripts/dts/python-devicetree/src/devicetree/edtlib.py

@@ -72,6 +72,8 @@
 from dataclasses import dataclass
 from typing import (Any, Callable, Iterable, NoReturn,
                     Optional, TYPE_CHECKING, Union)
+import base64
+import hashlib
 import logging
 import os
 import re
@@ -90,6 +92,14 @@
 from devicetree.grutils import Graph
 from devicetree._private import _slice_helper
 
+def _compute_hash(path: str) -> str:
+    # Calculates the hash associated with the node's full path.
+    hasher = hashlib.sha256()
+    hasher.update(path.encode())
+    hash = base64.b64encode(hasher.digest()).decode()
+    # replace invalid chars and drop padding
+    return hash.translate(hash.maketrans("+/", "__", "="))
+
 #
 # Public classes
 #
@@ -912,6 +922,11 @@ class Node:
       The ordinal is defined for all Nodes, and is unique among nodes in its
       EDT 'nodes' list.
 
+    hash:
+      A hashed value of the devicetree path of the node. This is defined for
+      all Nodes, and is checked for uniqueness among nodes in its EDT 'nodes'
+      list.
+
     required_by:
       A list with the nodes that directly depend on the node
 
@@ -1027,6 +1042,7 @@ def __init__(
         self.interrupts: list[ControllerAndData] = []
         self.pinctrls: list[PinCtrl] = []
         self.bus_node = self._bus_node(support_fixed_partitions_on_any_bus)
+        self.hash: str = _compute_hash(dt_node.path)
 
         self._init_binding()
         self._init_regs()
@@ -2270,10 +2286,18 @@ def _init_nodes(self) -> None:
         # Creates a list of edtlib.Node objects from the dtlib.Node objects, in
         # self.nodes
 
+        hash2node: dict[str, Node] = {}
+
         for dt_node in self._dt.node_iter():
             # Warning: We depend on parent Nodes being created before their
             # children. This is guaranteed by node_iter().
             node = Node(dt_node, self, self._fixed_partitions_no_bus)
+
+            if node.hash in hash2node:
+                _err(f"hash collision between '{node.path}' and "
+                     f"'{hash2node[node.hash].path}'")
+            hash2node[node.hash] = node
+
             self.nodes.append(node)
             self._node2enode[dt_node] = node
 

scripts/dts/python-devicetree/tests/test_edtlib.py

@@ -241,6 +241,16 @@ def test_hierarchy():
 
     assert edt.get_node("/parent/child-1").children == {}
 
+def test_hashes():
+    '''Test Node.hash on hierarchy nodes'''
+    with from_here():
+        edt = edtlib.EDT("test.dts", ["test-bindings"])
+
+    assert edt.get_node("/").hash == "il7asoJjJEMhngUeSt4tHVu8Zxx4EFG_FDeJfL3_oPE"
+    assert edt.get_node("/parent").hash == "38lte65vn2I4YtFxqM921ZudsWz2sWGcCxAYf5EsKEQ"
+    assert edt.get_node("/parent/child-1").hash == "sv1LnIlXN4B1lRFuZL4WHWu9yfzRUhmY_kwWqkKr1Og"
+    assert edt.get_node("/parent/child-2").hash == "ayvZczwhPy5g_cnGHKwwWICJ7uD0gMOHAU06nNILOsI"
+
 def test_child_index():
     '''Test Node.child_index.'''
     with from_here():