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From c22e650e66b862babe9c00bebb20b8029c7b0362 Mon Sep 17 00:00:00 2001
From: Grant Likely <grant.likely@linaro.org>
Date: Fri, 14 Mar 2014 17:07:12 +0000
Subject: [PATCH] of: Make of_find_node_by_path() handle /aliases
Make of_find_node_by_path() handle aliases as prefixes. To make this
work the name search is refactored to search by path component instead
of by full string. This should be a more efficient search, and it makes
it possible to start a search at a subnode of a tree.
Signed-off-by: David Daney <david.daney@cavium.com>
Signed-off-by: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
[grant.likely: Rework to not require allocating at runtime]
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Grant Likely <grant.likely@linaro.org>
---
drivers/of/base.c | 67 ++++++++++++++++++++++++++++++++++++++++++++++++++-----
1 file changed, 61 insertions(+), 6 deletions(-)
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -633,23 +633,78 @@ struct device_node *of_get_child_by_name
}
EXPORT_SYMBOL(of_get_child_by_name);
+static struct device_node *__of_find_node_by_path(struct device_node *parent,
+ const char *path)
+{
+ struct device_node *child;
+ int len = strchrnul(path, '/') - path;
+
+ if (!len)
+ return NULL;
+
+ __for_each_child_of_node(parent, child) {
+ const char *name = strrchr(child->full_name, '/');
+ if (WARN(!name, "malformed device_node %s\n", child->full_name))
+ continue;
+ name++;
+ if (strncmp(path, name, len) == 0 && (strlen(name) == len))
+ return child;
+ }
+ return NULL;
+}
+
/**
* of_find_node_by_path - Find a node matching a full OF path
- * @path: The full path to match
+ * @path: Either the full path to match, or if the path does not
+ * start with '/', the name of a property of the /aliases
+ * node (an alias). In the case of an alias, the node
+ * matching the alias' value will be returned.
+ *
+ * Valid paths:
+ * /foo/bar Full path
+ * foo Valid alias
+ * foo/bar Valid alias + relative path
*
* Returns a node pointer with refcount incremented, use
* of_node_put() on it when done.
*/
struct device_node *of_find_node_by_path(const char *path)
{
- struct device_node *np = of_allnodes;
+ struct device_node *np = NULL;
+ struct property *pp;
unsigned long flags;
+ if (strcmp(path, "/") == 0)
+ return of_node_get(of_allnodes);
+
+ /* The path could begin with an alias */
+ if (*path != '/') {
+ char *p = strchrnul(path, '/');
+ int len = p - path;
+
+ /* of_aliases must not be NULL */
+ if (!of_aliases)
+ return NULL;
+
+ for_each_property_of_node(of_aliases, pp) {
+ if (strlen(pp->name) == len && !strncmp(pp->name, path, len)) {
+ np = of_find_node_by_path(pp->value);
+ break;
+ }
+ }
+ if (!np)
+ return NULL;
+ path = p;
+ }
+
+ /* Step down the tree matching path components */
raw_spin_lock_irqsave(&devtree_lock, flags);
- for (; np; np = np->allnext) {
- if (np->full_name && (of_node_cmp(np->full_name, path) == 0)
- && of_node_get(np))
- break;
+ if (!np)
+ np = of_node_get(of_allnodes);
+ while (np && *path == '/') {
+ path++; /* Increment past '/' delimiter */
+ np = __of_find_node_by_path(np, path);
+ path = strchrnul(path, '/');
}
raw_spin_unlock_irqrestore(&devtree_lock, flags);
return np;
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