Mailing List Archive

Based on tag Linux v5.14.2 commit bbdd3de144fc142f2f4b9834c9241cc4e7f3d3fc

Import the Linux helper of_property_read_variable_u32_array. This
function find and read an array of 32 bit integers from a property,
with bounds on the minimum and maximum array size.

Signed-off-by: Rahul Singh <rahul.singh@arm.com>
---
Change in v2: Patch introduced in v2
---
xen/common/device_tree.c | 61 +++++++++++++++++++++++++++++++++++
xen/include/xen/device_tree.h | 26 +++++++++++++++
2 files changed, 87 insertions(+)

diff --git a/xen/common/device_tree.c b/xen/common/device_tree.c
index 03d25a81ce..53160d61f8 100644
--- a/xen/common/device_tree.c
+++ b/xen/common/device_tree.c
@@ -208,6 +208,67 @@ int dt_property_read_string(const struct dt_device_node *np,
return 0;
}

+/**
+ * dt_find_property_value_of_size
+ *
+ * @np: device node from which the property value is to be read.
+ * @propname: name of the property to be searched.
+ * @min: minimum allowed length of property value
+ * @max: maximum allowed length of property value (0 means unlimited)
+ * @len: if !=NULL, actual length is written to here
+ *
+ * Search for a property in a device node and valid the requested size.
+ *
+ * Return: The property value on success, -EINVAL if the property does not
+ * exist, -ENODATA if property does not have a value, and -EOVERFLOW if the
+ * property data is too small or too large.
+ */
+static void *dt_find_property_value_of_size(const struct dt_device_node *np,
+ const char *propname, u32 min,
+ u32 max, size_t *len)
+{
+ const struct dt_property *prop = dt_find_property(np, propname, NULL);
+
+ if ( !prop )
+ return ERR_PTR(-EINVAL);
+ if ( !prop->value )
+ return ERR_PTR(-ENODATA);
+ if ( prop->length < min )
+ return ERR_PTR(-EOVERFLOW);
+ if ( max && prop->length > max )
+ return ERR_PTR(-EOVERFLOW);
+
+ if ( len )
+ *len = prop->length;
+
+ return prop->value;
+}
+
+int dt_property_read_variable_u32_array(const struct dt_device_node *np,
+ const char *propname, u32 *out_values,
+ size_t sz_min, size_t sz_max)
+{
+ size_t sz, count;
+ const __be32 *val = dt_find_property_value_of_size(np, propname,
+ (sz_min * sizeof(*out_values)),
+ (sz_max * sizeof(*out_values)),
+ &sz);
+
+ if ( IS_ERR(val) )
+ return PTR_ERR(val);
+
+ if ( !sz_max )
+ sz = sz_min;
+ else
+ sz /= sizeof(*out_values);
+
+ count = sz;
+ while ( count-- )
+ *out_values++ = be32_to_cpup(val++);
+
+ return sz;
+}
+
int dt_property_match_string(const struct dt_device_node *np,
const char *propname, const char *string)
{
diff --git a/xen/include/xen/device_tree.h b/xen/include/xen/device_tree.h
index b02696be94..1693fb8e8c 100644
--- a/xen/include/xen/device_tree.h
+++ b/xen/include/xen/device_tree.h
@@ -366,6 +366,32 @@ bool_t dt_property_read_u32(const struct dt_device_node *np,
bool_t dt_property_read_u64(const struct dt_device_node *np,
const char *name, u64 *out_value);

+
+/**
+ * dt_property_read_variable_u32_array - Find and read an array of 32 bit
+ * integers from a property, with bounds on the minimum and maximum array size.
+ *
+ * @np: device node from which the property value is to be read.
+ * @propname: name of the property to be searched.
+ * @out_values: pointer to return found values.
+ * @sz_min: minimum number of array elements to read
+ * @sz_max: maximum number of array elements to read, if zero there is no
+ * upper limit on the number of elements in the dts entry but only
+ * sz_min will be read.
+ *
+ * Search for a property in a device node and read 32-bit value(s) from
+ * it.
+ *
+ * Return: The number of elements read on success, -EINVAL if the property
+ * does not exist, -ENODATA if property does not have a value, and -EOVERFLOW
+ * if the property data is smaller than sz_min or longer than sz_max.
+ *
+ * The out_values is modified only if a valid u32 value can be decoded.
+ */
+int dt_property_read_variable_u32_array(const struct dt_device_node *np,
+ const char *propname, u32 *out_values,
+ size_t sz_min, size_t sz_max);
+
/**
* dt_property_read_bool - Check if a property exists
* @np: node to get the value
--
2.17.1