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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>
This commit is contained in:
Grant Likely 2014-03-14 17:07:12 +00:00
parent 0d0e02d605
commit c22e650e66
1 changed files with 61 additions and 6 deletions
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67
drivers/of/base.c
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@ -783,23 +783,78 @@ 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;
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;