[PATCH V2 2/3] of: Create function for counting number of phandles in a property
Grant Likely
grant.likely at secretlab.ca
Wed Feb 13 04:59:40 EST 2013
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.
It also converts of_gpio_named_count() to use the new function instead
of using the above described horrible method.
This also requires the return value of of_gpio_count() &
of_gpio_named_count() from 'unsigned int' to 'int' so that it can return
an error code. All the users of that function are fixed up to correctly
handle a negative return value.
Tested on ARM using the selftest code.
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
Signed-off-by: Grant Likely <grant.likely at secretlab.ca>
Cc: Linus Walleij <linus.walleij at linaro.org>
Cc: Rob Herring <rob.herring at calxeda.com>
Cc: Andreas Larsson <andreas at gaisler.com>
---
drivers/of/base.c | 56 ++++++++++++++++++++++++++++++++++++++++++-------
drivers/of/selftest.c | 25 ++++++++++++++++++++--
include/linux/of.h | 9 ++++++++
3 files changed, 80 insertions(+), 10 deletions(-)
diff --git a/drivers/of/base.c b/drivers/of/base.c
index e2d44e0..adaa815 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -1082,12 +1082,13 @@ 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 size, cur_index = 0;
+ int rc = 0, size, cur_index = 0;
uint32_t count = 0;
struct device_node *node = NULL;
phandle phandle;
@@ -1116,12 +1117,14 @@ int of_parse_phandle_with_args(const struct device_node *np, const char *list_na
if (!node) {
pr_err("%s: could not find phandle\n",
np->full_name);
+ rc = -EINVAL;
break;
}
if (of_property_read_u32(node, cells_name, &count)) {
pr_err("%s: could not get %s for %s\n",
np->full_name, cells_name,
node->full_name);
+ rc = -EINVAL;
break;
}
@@ -1132,6 +1135,7 @@ int of_parse_phandle_with_args(const struct device_node *np, const char *list_na
if (list + count > list_end) {
pr_err("%s: arguments longer than property\n",
np->full_name);
+ rc = -EINVAL;
break;
}
}
@@ -1143,8 +1147,10 @@ int of_parse_phandle_with_args(const struct device_node *np, const char *list_na
* or return -ENOENT for an empty entry.
*/
if (cur_index == index) {
- if (!phandle)
- return -ENOENT;
+ if (!phandle) {
+ rc = -ENOENT;
+ break;
+ }
if (out_args) {
int i;
@@ -1155,22 +1161,56 @@ int of_parse_phandle_with_args(const struct device_node *np, const char *list_na
for (i = 0; i < count; i++)
out_args->args[i] = be32_to_cpup(list++);
}
- return 0;
+
+ rc = 0;
+ break;
}
of_node_put(node);
node = NULL;
list += count;
cur_index++;
+ rc = cur_index;
}
/* Loop exited without finding a valid entry; return an error */
if (node)
of_node_put(node);
- return -EINVAL;
+ return index < 0 ? rc : -ENOENT;
+}
+
+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)
diff --git a/drivers/of/selftest.c b/drivers/of/selftest.c
index 9f62eb5..9c44491 100644
--- a/drivers/of/selftest.c
+++ b/drivers/of/selftest.c
@@ -35,6 +35,11 @@ static void __init of_selftest_parse_phandle_with_args(void)
return;
}
+ rc = of_count_phandle_with_args(np, "phandle-list", "#phandle-cells");
+ if (rc != 7)
+ pr_err("of_count_phandle_with_args() returned %i, expected 7\n", rc);
+ passed_all &= (rc == 7);
+
for (i = 0; i < 8; i++) {
bool passed = true;
rc = of_parse_phandle_with_args(np, "phandle-list",
@@ -79,7 +84,7 @@ static void __init of_selftest_parse_phandle_with_args(void)
passed &= (args.args[0] == (i + 1));
break;
case 7:
- passed &= (rc == -EINVAL);
+ passed &= (rc == -ENOENT);
break;
default:
passed = false;
@@ -100,22 +105,38 @@ static void __init of_selftest_parse_phandle_with_args(void)
/* Check for missing list property */
rc = of_parse_phandle_with_args(np, "phandle-list-missing",
"#phandle-cells", 0, &args);
- passed_all &= (rc == -EINVAL);
+ passed_all &= (rc == -ENOENT);
+ rc = of_count_phandle_with_args(np, "phandle-list-missing",
+ "#phandle-cells");
+ passed_all &= (rc == -ENOENT);
+ pr_err("rc = %i\n", rc);
/* Check for missing cells property */
rc = of_parse_phandle_with_args(np, "phandle-list",
"#phandle-cells-missing", 0, &args);
passed_all &= (rc == -EINVAL);
+ rc = of_count_phandle_with_args(np, "phandle-list",
+ "#phandle-cells-missing");
+ passed_all &= (rc == -EINVAL);
+ pr_err("rc = %i\n", rc);
/* Check for bad phandle in list */
rc = of_parse_phandle_with_args(np, "phandle-list-bad-phandle",
"#phandle-cells", 0, &args);
passed_all &= (rc == -EINVAL);
+ rc = of_count_phandle_with_args(np, "phandle-list-bad-phandle",
+ "#phandle-cells");
+ passed_all &= (rc == -EINVAL);
+ pr_err("rc = %i\n", rc);
/* Check for incorrectly formed argument list */
rc = of_parse_phandle_with_args(np, "phandle-list-bad-args",
"#phandle-cells", 1, &args);
passed_all &= (rc == -EINVAL);
+ rc = of_count_phandle_with_args(np, "phandle-list-bad-args",
+ "#phandle-cells");
+ passed_all &= (rc == -EINVAL);
+ pr_err("rc = %i\n", rc);
pr_info("end - %s\n", passed_all ? "PASS" : "FAIL");
}
diff --git a/include/linux/of.h b/include/linux/of.h
index b9e1b91..f8a088c 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -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_parse_count_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;
--
1.7.10.4
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