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

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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: Andreas Larsson <andreas@gaisler.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Rob Herring <rob.herring@calxeda.com>
This commit is contained in:
Grant Likely 2013-02-10 22:57:21 +00:00
parent 23ce04c073
commit bd69f73f2c
3 changed files with 61 additions and 4 deletions
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41
drivers/of/base.c
View File

@ -1091,9 +1091,10 @@ 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,
const char *cells_name, int index,
struct of_phandle_args *out_args)
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)
{
const __be32 *list, *list_end;
int rc = 0, size, cur_index = 0;
@ -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)

15
drivers/of/selftest.c
View File

@ -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)

9
include/linux/of.h
View File

@ -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;