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Commit bd69f73f authored by Grant Likely's avatar Grant Likely
Browse files

of: Create function for counting number of phandles in a property 



This patch creates of_count_phandle_with_args(), a new function for
counting the number of phandle+argument tuples in a given property. This
is better than the existing method of parsing each phandle individually
until parsing fails which is a horribly slow way to do the count.

Tested on ARM using the selftest code.

v3: - Rebased on top of selftest code cleanup patch
v2: - fix bug where of_parse_phandle_with_args() could behave like _count_.
    - made of_gpio_named_count() into a static inline regardless of CONFIG_OF_GPIO

Tested-by: default avatarAndreas Larsson <andreas@gaisler.com>
Signed-off-by: default avatarGrant Likely <grant.likely@secretlab.ca>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Rob Herring <rob.herring@calxeda.com>
parent 23ce04c0

drivers/of/base.c

+37 −4
Original line number Diff line number Diff line
@@ -1091,7 +1091,8 @@ EXPORT_SYMBOL(of_parse_phandle); 
 * To get a device_node of the `node2' node you may call this:

 * of_parse_phandle_with_args(node3, "list", "#list-cells", 1, &args);

 */

int of_parse_phandle_with_args(const struct device_node *np, const char *list_name,

static int __of_parse_phandle_with_args(const struct device_node *np,

					const char *list_name,

					const char *cells_name, int index,

					struct of_phandle_args *out_args)

{
@@ -1183,15 +1184,47 @@ int of_parse_phandle_with_args(const struct device_node *np, const char *list_na 
	 * Unlock node before returning result; will be one of:

	 * -ENOENT : index is for empty phandle

	 * -EINVAL : parsing error on data

	 * [1..n]  : Number of phandle (count mode; when index = -1)

	 */

	rc = -ENOENT;

	rc = index < 0 ? cur_index : -ENOENT;

 err:

	if (node)

		of_node_put(node);

	return rc;

}



int of_parse_phandle_with_args(const struct device_node *np, const char *list_name,

				const char *cells_name, int index,

				struct of_phandle_args *out_args)

{

	if (index < 0)

		return -EINVAL;

	return __of_parse_phandle_with_args(np, list_name, cells_name, index, out_args);

}

EXPORT_SYMBOL(of_parse_phandle_with_args);



/**

 * of_count_phandle_with_args() - Find the number of phandles references in a property

 * @np:		pointer to a device tree node containing a list

 * @list_name:	property name that contains a list

 * @cells_name:	property name that specifies phandles' arguments count

 *

 * Returns the number of phandle + argument tuples within a property. It

 * is a typical pattern to encode a list of phandle and variable

 * arguments into a single property. The number of arguments is encoded

 * by a property in the phandle-target node. For example, a gpios

 * property would contain a list of GPIO specifies consisting of a

 * phandle and 1 or more arguments. The number of arguments are

 * determined by the #gpio-cells property in the node pointed to by the

 * phandle.

 */

int of_count_phandle_with_args(const struct device_node *np, const char *list_name,

				const char *cells_name)

{

	return __of_parse_phandle_with_args(np, list_name, cells_name, -1, NULL);

}

EXPORT_SYMBOL(of_count_phandle_with_args);



#if defined(CONFIG_OF_DYNAMIC)

static int of_property_notify(int action, struct device_node *np,

			      struct property *prop)

drivers/of/selftest.c

+15 −0
Original line number Diff line number Diff line
@@ -36,6 +36,9 @@ static void __init of_selftest_parse_phandle_with_args(void) 
		return;

	}



	rc = of_count_phandle_with_args(np, "phandle-list", "#phandle-cells");

	selftest(rc == 7, "of_count_phandle_with_args() returned %i, expected 7\n", rc);



	for (i = 0; i < 8; i++) {

		bool passed = true;

		rc = of_parse_phandle_with_args(np, "phandle-list",
@@ -94,21 +97,33 @@ static void __init of_selftest_parse_phandle_with_args(void) 
	rc = of_parse_phandle_with_args(np, "phandle-list-missing",

					"#phandle-cells", 0, &args);

	selftest(rc == -ENOENT, "expected:%i got:%i\n", -ENOENT, rc);

	rc = of_count_phandle_with_args(np, "phandle-list-missing",

					"#phandle-cells");

	selftest(rc == -ENOENT, "expected:%i got:%i\n", -ENOENT, rc);



	/* Check for missing cells property */

	rc = of_parse_phandle_with_args(np, "phandle-list",

					"#phandle-cells-missing", 0, &args);

	selftest(rc == -EINVAL, "expected:%i got:%i\n", -EINVAL, rc);

	rc = of_count_phandle_with_args(np, "phandle-list",

					"#phandle-cells-missing");

	selftest(rc == -EINVAL, "expected:%i got:%i\n", -EINVAL, rc);



	/* Check for bad phandle in list */

	rc = of_parse_phandle_with_args(np, "phandle-list-bad-phandle",

					"#phandle-cells", 0, &args);

	selftest(rc == -EINVAL, "expected:%i got:%i\n", -EINVAL, rc);

	rc = of_count_phandle_with_args(np, "phandle-list-bad-phandle",

					"#phandle-cells");

	selftest(rc == -EINVAL, "expected:%i got:%i\n", -EINVAL, rc);



	/* Check for incorrectly formed argument list */

	rc = of_parse_phandle_with_args(np, "phandle-list-bad-args",

					"#phandle-cells", 1, &args);

	selftest(rc == -EINVAL, "expected:%i got:%i\n", -EINVAL, rc);

	rc = of_count_phandle_with_args(np, "phandle-list-bad-args",

					"#phandle-cells");

	selftest(rc == -EINVAL, "expected:%i got:%i\n", -EINVAL, rc);

}



static void __init of_selftest_property_match_string(void)

include/linux/of.h

+9 −0
Original line number Diff line number Diff line
@@ -277,6 +277,8 @@ extern struct device_node *of_parse_phandle(const struct device_node *np, 
extern int of_parse_phandle_with_args(const struct device_node *np,

	const char *list_name, const char *cells_name, int index,

	struct of_phandle_args *out_args);

extern int of_count_phandle_with_args(const struct device_node *np,

	const char *list_name, const char *cells_name);



extern void of_alias_scan(void * (*dt_alloc)(u64 size, u64 align));

extern int of_alias_get_id(struct device_node *np, const char *stem);
@@ -467,6 +469,13 @@ static inline int of_parse_phandle_with_args(struct device_node *np, 
	return -ENOSYS;

}



static inline int of_count_phandle_with_args(struct device_node *np,

					     const char *list_name,

					     const char *cells_name)

{

	return -ENOSYS;

}



static inline int of_alias_get_id(struct device_node *np, const char *stem)

{

	return -ENOSYS;