[RFC PATCH v2 03/12] of: Make of_find_node_by_path() traverse /aliases for relative paths.
From: David Daney <hidden>
Date: 2011-03-04 19:45:18
Also in:
linux-mips, lkml
Subsystem:
open firmware and flattened device tree, the rest · Maintainers:
Rob Herring, Saravana Kannan, Linus Torvalds
Currently all paths passed to of_find_node_by_path() must begin with a '/', indicating a full path to the desired node. Augment the look-up code so that if a path does *not* begin with '/', the path is used as the name of an /aliases property. The value of this alias is then used as the full node path to be found. Signed-off-by: David Daney <redacted> --- This patch is unchanged from the previous version I send separately. I have not forgotten about Grant's feedback, just deferred it to the next version. drivers/of/base.c | 24 +++++++++++++++++++++++- 1 files changed, 23 insertions(+), 1 deletions(-)
diff --git a/drivers/of/base.c b/drivers/of/base.c
index 710b53b..e63da9c 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c@@ -340,7 +340,10 @@ EXPORT_SYMBOL(of_get_next_child); /** * 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. * * Returns a node pointer with refcount incremented, use * of_node_put() on it when done.
@@ -348,13 +351,32 @@ EXPORT_SYMBOL(of_get_next_child); struct device_node *of_find_node_by_path(const char *path) { struct device_node *np = allnodes; + struct device_node *aliases = NULL; read_lock(&devtree_lock); + + if (path[0] != '/') { + aliases = of_find_node_by_path("/aliases"); + if (!aliases) + goto out; + path = of_get_property(aliases, path, NULL); + /* + * The alias must begin with '/', otherwise we could + * get stuck in an endless loop and blow out the + * stack. + */ + if (!path || path[0] != '/') + goto out; + } + for (; np; np = np->allnext) { if (np->full_name && (of_node_cmp(np->full_name, path) == 0) && of_node_get(np)) break; } +out: + if (aliases) + of_node_put(aliases); read_unlock(&devtree_lock); return np; }
--
1.7.2.3