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Commit c22e650e authored by Grant Likely's avatar Grant Likely
Browse files

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: default avatarDavid Daney <david.daney@cavium.com>
Signed-off-by: default avatarPantelis Antoniou <pantelis.antoniou@konsulko.com>
[grant.likely: Rework to not require allocating at runtime]
Acked-by: default avatarRob Herring <robh@kernel.org>
Signed-off-by: default avatarGrant Likely <grant.likely@linaro.org>
parent 0d0e02d6

drivers/of/base.c

+61 −6
Original line number Diff line number Diff line
@@ -783,24 +783,79 @@ struct device_node *of_get_child_by_name(const struct device_node *node, 
}

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;



	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))

	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);

	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;

}