Subject: [PATCH v3 2/3] of: add optional options parameter to of_find_node_by_path()

From: [email-masked] (Peter Hurley)
Date: Wed, 04 Mar 2015 10:45:02 -0500

Hi Leif,

On 11/27/2014 12:56 PM, Leif Lindholm wrote:
> Update of_find_node_by_path():
> 1) Rename function to of_find_node_opts_by_path(), adding an optional
>    pointer argument. Provide a static inline wrapper version of
>    of_find_node_by_path() which calls the new function with NULL as
>    the optional argument.
> 2) Ignore any part of the path beyond and including the ':' separator.
> 3) Set the new provided pointer argument to the beginning of the string
>    following the ':' separator.
> 4: Add tests.
> 
> Signed-off-by: Leif Lindholm <[email-masked]>
> ---
>  drivers/of/base.c     |   21 +++++++++++++++++----
>  drivers/of/selftest.c |   12 ++++++++++++
>  include/linux/of.h    |   14 +++++++++++++-
>  3 files changed, 42 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/of/base.c b/drivers/of/base.c
> index 3823edf..7f0e5f7 100644
> --- a/drivers/of/base.c
> +++ b/drivers/of/base.c
> @@ -699,10 +699,15 @@ static struct device_node *__of_find_node_by_path(struct device_node *parent,
>  {
>  	struct device_node *child;
>  	int len = strchrnul(path, '/') - path;
> +	int term;
>  
>  	if (!len)
>  		return NULL;
>  
> +	term = strchrnul(path, ':') - path;
> +	if (term < len)
> +		len = term;
> +
>  	__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))
> @@ -715,11 +720,14 @@ static struct device_node *__of_find_node_by_path(struct device_node *parent,
>  }
>  
>  /**
> - *	of_find_node_by_path - Find a node matching a full OF path
> + *	of_find_node_opts_by_path - Find a node matching a full OF path
>   *	@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.
> + *	@opts: Address of a pointer into which to store the start of
> + *	       an options string appended to the end of the path with
> + *	       a ':' separator.
>   *
>   *	Valid paths:
>   *		/foo/bar	Full path
> @@ -729,19 +737,24 @@ static struct device_node *__of_find_node_by_path(struct device_node *parent,
>   *	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 *of_find_node_opts_by_path(const char *path, const char **opts)
>  {
>  	struct device_node *np = NULL;
>  	struct property *pp;
>  	unsigned long flags;
> +	char *separator;
>  
>  	if (strcmp(path, "/") == 0)
>  		return of_node_get(of_allnodes);
>  
> +	separator = strchr(path, ':');
> +	if (separator && opts)
> +		*opts = separator + 1;
> +
>  	/* The path could begin with an alias */
>  	if (*path != '/') {
>  		char *p = strchrnul(path, '/');
> -		int len = p - path;
> +		int len = separator ? separator - path : p - path;
>  
>  		/* of_aliases must not be NULL */
>  		if (!of_aliases)
> @@ -770,7 +783,7 @@ struct device_node *of_find_node_by_path(const char *path)
>  	raw_spin_unlock_irqrestore(&devtree_lock, flags);
>  	return np;
>  }
> -EXPORT_SYMBOL(of_find_node_by_path);
> +EXPORT_SYMBOL(of_find_node_opts_by_path);
>  
>  /**
>   *	of_find_node_by_name - Find a node by its "name" property
> diff --git a/drivers/of/selftest.c b/drivers/of/selftest.c
> index e2d79af..c298065 100644
> --- a/drivers/of/selftest.c
> +++ b/drivers/of/selftest.c
> @@ -43,6 +43,7 @@ static bool selftest_live_tree;
>  static void __init of_selftest_find_node_by_name(void)
>  {
>  	struct device_node *np;
> +	const char *options;
>  
>  	np = of_find_node_by_path("/testcase-data");
>  	selftest(np && !strcmp("/testcase-data", np->full_name),
> @@ -83,6 +84,17 @@ static void __init of_selftest_find_node_by_name(void)
>  	np = of_find_node_by_path("testcase-alias/missing-path");
>  	selftest(!np, "non-existent alias with relative path returned node %s\n", np->full_name);
>  	of_node_put(np);
> +
> +	np = of_find_node_opts_by_path("/testcase-data:testoption", &options);
> +	selftest(np && !strcmp("testoption", options),
> +		 "option path test failed\n");
> +	of_node_put(np);
> +
> +	np = of_find_node_opts_by_path("testcase-alias:testaliasoption",
> +				       &options);
> +	selftest(np && !strcmp("testaliasoption", options),
> +		 "option alias path test failed\n");
> +	of_node_put(np);
>  }

The path parsing gets lost if the string after ':' contains '/'.

The selftests below fail with:
[    1.365528] ### dt-test ### FAIL of_selftest_find_node_by_name():99 option path test failed
[    1.365610] ### dt-test ### FAIL of_selftest_find_node_by_name():115 option alias path test failed

Regards,
Peter Hurley

--- >% ---
diff --git a/drivers/of/unittest.c b/drivers/of/unittest.c
index 41a4a13..07ba5aa 100644
--- a/drivers/of/unittest.c
+++ b/drivers/of/unittest.c
@@ -94,6 +94,11 @@ static void __init of_selftest_find_node_by_name(void)
 		 "option path test failed\n");
 	of_node_put(np);
 
+	np = of_find_node_opts_by_path("/testcase-data:test/option", &options);
+	selftest(np && !strcmp("test/option", options),
+		 "option path test failed\n");
+	of_node_put(np);
+
 	np = of_find_node_opts_by_path("/testcase-data:testoption", NULL);
 	selftest(np, "NULL option path test failed\n");
 	of_node_put(np);
@@ -104,6 +109,12 @@ static void __init of_selftest_find_node_by_name(void)
 		 "option alias path test failed\n");
 	of_node_put(np);
 
+	np = of_find_node_opts_by_path("testcase-alias:test/alias/option",
+				       &options);
+	selftest(np && !strcmp("test/alias/option", options),
+		 "option alias path test failed\n");
+	of_node_put(np);
+
 	np = of_find_node_opts_by_path("testcase-alias:testaliasoption", NULL);
 	selftest(np, "NULL option alias path test failed\n");
 	of_node_put(np);

>  static void __init of_selftest_dynamic(void)
> diff --git a/include/linux/of.h b/include/linux/of.h
> index 29f0adc..a36be70 100644
> --- a/include/linux/of.h
> +++ b/include/linux/of.h
> @@ -228,7 +228,13 @@ extern struct device_node *of_find_matching_node_and_match(
>  	const struct of_device_id *matches,
>  	const struct of_device_id **match);
>  
> -extern struct device_node *of_find_node_by_path(const char *path);
> +extern struct device_node *of_find_node_opts_by_path(const char *path,
> +	const char **opts);
> +static inline struct device_node *of_find_node_by_path(const char *path)
> +{
> +	return of_find_node_opts_by_path(path, NULL);
> +}
> +
>  extern struct device_node *of_find_node_by_phandle(phandle handle);
>  extern struct device_node *of_get_parent(const struct device_node *node);
>  extern struct device_node *of_get_next_parent(struct device_node *node);
> @@ -385,6 +391,12 @@ static inline struct device_node *of_find_node_by_path(const char *path)
>  	return NULL;
>  }
>  
> +static inline struct device_node *of_find_node_opts_by_path(const char *path,
> +	const char **opts)
> +{
> +	return NULL;
> +}
> +
>  static inline struct device_node *of_get_parent(const struct device_node *node)
>  {
>  	return NULL;
>