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Commit 69843396 authored by Pantelis Antoniou's avatar Pantelis Antoniou Committed by Grant Likely
Browse files

OF: Utility helper functions for dynamic nodes 



Introduce helper functions for working with the live DT tree,
all of them related to dynamically adding/removing nodes and
properties.

__of_prop_dup() copies a property dynamically
__of_node_alloc() creates an empty node

Bug fix about prop->len == 0 by Ionut Nicu <ioan.nicu.ext@nsn.com>

Signed-off-by: default avatarPantelis Antoniou <pantelis.antoniou@konsulko.com>
[glikely: Added unittest for of_copy_property and dropped fine-grained allocations]
[glikely: removed name, type and phandle arguments from __of_node_alloc]
Signed-off-by: default avatarGrant Likely <grant.likely@linaro.org>
parent 6afc0dc3

drivers/of/dynamic.c

+77 −0
Original line number Diff line number Diff line
@@ -214,3 +214,80 @@ void of_node_release(struct kobject *kobj) 
	kfree(node->data);

	kfree(node);

}



/**

 * __of_prop_dup - Copy a property dynamically.

 * @prop:	Property to copy

 * @allocflags:	Allocation flags (typically pass GFP_KERNEL)

 *

 * Copy a property by dynamically allocating the memory of both the

 * property stucture and the property name & contents. The property's

 * flags have the OF_DYNAMIC bit set so that we can differentiate between

 * dynamically allocated properties and not.

 * Returns the newly allocated property or NULL on out of memory error.

 */

struct property *__of_prop_dup(const struct property *prop, gfp_t allocflags)

{

	struct property *new;



	new = kzalloc(sizeof(*new), allocflags);

	if (!new)

		return NULL;



	/*

	 * NOTE: There is no check for zero length value.

	 * In case of a boolean property This will allocate a value

	 * of zero bytes. We do this to work around the use

	 * of of_get_property() calls on boolean values.

	 */

	new->name = kstrdup(prop->name, allocflags);

	new->value = kmemdup(prop->value, prop->length, allocflags);

	new->length = prop->length;

	if (!new->name || !new->value)

		goto err_free;



	/* mark the property as dynamic */

	of_property_set_flag(new, OF_DYNAMIC);



	return new;



 err_free:

	kfree(new->name);

	kfree(new->value);

	kfree(new);

	return NULL;

}



/**

 * __of_node_alloc() - Create an empty device node dynamically.

 * @full_name:	Full name of the new device node

 * @allocflags:	Allocation flags (typically pass GFP_KERNEL)

 *

 * Create an empty device tree node, suitable for further modification.

 * The node data are dynamically allocated and all the node flags

 * have the OF_DYNAMIC & OF_DETACHED bits set.

 * Returns the newly allocated node or NULL on out of memory error.

 */

struct device_node *__of_node_alloc(const char *full_name, gfp_t allocflags)

{

	struct device_node *node;



	node = kzalloc(sizeof(*node), allocflags);

	if (!node)

		return NULL;



	node->full_name = kstrdup(full_name, allocflags);

	of_node_set_flag(node, OF_DYNAMIC);

	of_node_set_flag(node, OF_DETACHED);

	if (!node->full_name)

		goto err_free;



	of_node_init(node);



	return node;



 err_free:

	kfree(node->full_name);

	kfree(node);

	return NULL;

}

drivers/of/of_private.h

+10 −0
Original line number Diff line number Diff line
@@ -51,4 +51,14 @@ static inline int of_property_notify(int action, struct device_node *np, 
}

#endif /* CONFIG_OF_DYNAMIC */



/**

 * General utilities for working with live trees.

 *

 * All functions with two leading underscores operate

 * without taking node references, so you either have to

 * own the devtree lock or work on detached trees only.

 */

struct property *__of_prop_dup(const struct property *prop, gfp_t allocflags);

struct device_node *__of_node_alloc(const char *full_name, gfp_t allocflags);



#endif /* _LINUX_OF_PRIVATE_H */

drivers/of/selftest.c

+28 −0
Original line number Diff line number Diff line
@@ -16,6 +16,8 @@ 
#include <linux/slab.h>

#include <linux/device.h>



#include "of_private.h"



static struct selftest_results {

	int passed;

	int failed;
@@ -266,6 +268,31 @@ static void __init of_selftest_property_match_string(void) 
	selftest(rc == -EILSEQ, "unterminated string; rc=%i", rc);

}



#define propcmp(p1, p2) (((p1)->length == (p2)->length) && \

			(p1)->value && (p2)->value && \

			!memcmp((p1)->value, (p2)->value, (p1)->length) && \

			!strcmp((p1)->name, (p2)->name))

static void __init of_selftest_property_copy(void)

{

#ifdef CONFIG_OF_DYNAMIC

	struct property p1 = { .name = "p1", .length = 0, .value = "" };

	struct property p2 = { .name = "p2", .length = 5, .value = "abcd" };

	struct property *new;



	new = __of_prop_dup(&p1, GFP_KERNEL);

	selftest(new && propcmp(&p1, new), "empty property didn't copy correctly\n");

	kfree(new->value);

	kfree(new->name);

	kfree(new);



	new = __of_prop_dup(&p2, GFP_KERNEL);

	selftest(new && propcmp(&p2, new), "non-empty property didn't copy correctly\n");

	kfree(new->value);

	kfree(new->name);

	kfree(new);

#endif

}



static void __init of_selftest_parse_interrupts(void)

{

	struct device_node *np;
@@ -533,6 +560,7 @@ static int __init of_selftest(void) 
	of_selftest_dynamic();

	of_selftest_parse_phandle_with_args();

	of_selftest_property_match_string();

	of_selftest_property_copy();

	of_selftest_parse_interrupts();

	of_selftest_parse_interrupts_extended();

	of_selftest_match_node();