[Skiboot] [PATCH V2 1/3] core/device: Add function to return child node using name at substring "@"

[Athira Rajeev]

Add a function dt_find_by_name_substr() that returns the child node if
it matches till first occurence at "@" of a given name, otherwise NULL.
This is helpful for cases with node name like: "name at addr". In
scenarios where nodes are added with "name at addr" format and if the
value of "addr" is not known, that node can't be matched with node
name or addr. Hence matching with substring as node name will return
the expected result. Patch adds dt_find_by_name_substr() function
and testcase for the same in core/test/run-device.c

Signed-off-by: Athira Rajeev <atrajeev at linux.vnet.ibm.com>
---
Changelog:
v1 -> v2:
- Addressed review comment from Dan to update
  the utility funtion to search and compare
  upto "@". Renamed it as dt_find_by_name_substr.
  
 core/device.c          | 18 ++++++++++++++++++
 core/test/run-device.c | 11 +++++++++++
 include/device.h       |  3 +++
 3 files changed, 32 insertions(+)

diff --git a/core/device.c b/core/device.c
index 2de37c74..df3a5775 100644
--- a/core/device.c
+++ b/core/device.c
@@ -395,6 +395,24 @@ struct dt_node *dt_find_by_name(struct dt_node *root, const char *name)
 }
 
 
+struct dt_node *dt_find_by_name_substr(struct dt_node *root, const char *name)
+{
+	struct dt_node *child, *match;
+	char *pos;
+
+	list_for_each(&root->children, child, list) {
+		pos = strchr(child->name, '@');
+		if (!strncmp(child->name, name, pos - child->name))
+			return child;
+
+		match = dt_find_by_name_substr(child, name);
+		if (match)
+			return match;
+	}
+
+	return NULL;
+}
+
 struct dt_node *dt_new_check(struct dt_node *parent, const char *name)
 {
 	struct dt_node *node = dt_find_by_name(parent, name);
diff --git a/core/test/run-device.c b/core/test/run-device.c
index 4a12382b..0e463e58 100644
--- a/core/test/run-device.c
+++ b/core/test/run-device.c
@@ -466,6 +466,17 @@ int main(void)
 	new_prop_ph = dt_prop_get_u32(ut2, "something");
 	assert(!(new_prop_ph == ev1_ph));
 	dt_free(subtree);
+
+	/* Test dt_find_by_name_substr */
+	root = dt_new_root("");
+	addr1 = dt_new_addr(root, "node", 0x1);
+	addr2 = dt_new_addr(root, "node0_1", 0x2);
+	assert(dt_find_by_name(root, "node at 1") == addr1);
+	assert(dt_find_by_name(root, "node0_1 at 2") == addr2);
+	assert(dt_find_by_name_substr(root, "node at 1") == addr1);
+	assert(dt_find_by_name_substr(root, "node0_1 at 2") == addr2);
+	dt_free(root);
+
 	return 0;
 }
 
diff --git a/include/device.h b/include/device.h
index 93fb90ff..b6a1a813 100644
--- a/include/device.h
+++ b/include/device.h
@@ -184,6 +184,9 @@ struct dt_node *dt_find_by_path(struct dt_node *root, const char *path);
 /* Find a child node by name */
 struct dt_node *dt_find_by_name(struct dt_node *root, const char *name);
 
+/* Find a child node by name and substring */
+struct dt_node *dt_find_by_name_substr(struct dt_node *root, const char *name);
+
 /* Find a node by phandle */
 struct dt_node *dt_find_by_phandle(struct dt_node *root, u32 phandle);
 
-- 
2.27.0