1 files changed, 68 insertions, 49 deletions

diff --git a/drivers/acpi/property.c b/drivers/acpi/property.c
index f2fd3fee588a..03f5ec11ab31 100644
--- a/drivers/acpi/property.c
+++ b/drivers/acpi/property.c
@@ -468,10 +468,11 @@ static int acpi_data_get_property_array(struct acpi_device_data *data,
 }
 
 /**
- * acpi_data_get_property_reference - returns handle to the referenced object
- * @data: ACPI device data object containing the property
+ * __acpi_node_get_property_reference - returns handle to the referenced object
+ * @fwnode: Firmware node to get the property from
  * @propname: Name of the property
  * @index: Index of the reference to return
+ * @num_args: Maximum number of arguments after each reference
  * @args: Location to store the returned reference with optional arguments
  *
  * Find property with @name, verifify that it is a package containing at least
@@ -482,17 +483,40 @@ static int acpi_data_get_property_array(struct acpi_device_data *data,
  * If there's more than one reference in the property value package, @index is
  * used to select the one to return.
  *
+ * It is possible to leave holes in the property value set like in the
+ * example below:
+ *
+ * Package () {
+ *     "cs-gpios",
+ *     Package () {
+ *        ^GPIO, 19, 0, 0,
+ *        ^GPIO, 20, 0, 0,
+ *        0,
+ *        ^GPIO, 21, 0, 0,
+ *     }
+ * }
+ *
+ * Calling this function with index %2 return %-ENOENT and with index %3
+ * returns the last entry. If the property does not contain any more values
+ * %-ENODATA is returned. The NULL entry must be single integer and
+ * preferably contain value %0.
+ *
  * Return: %0 on success, negative error code on failure.
  */
-static int acpi_data_get_property_reference(struct acpi_device_data *data,
-					    const char *propname, size_t index,
-					    struct acpi_reference_args *args)
+int __acpi_node_get_property_reference(struct fwnode_handle *fwnode,
+	const char *propname, size_t index, size_t num_args,
+	struct acpi_reference_args *args)
 {
 	const union acpi_object *element, *end;
 	const union acpi_object *obj;
+	struct acpi_device_data *data;
 	struct acpi_device *device;
 	int ret, idx = 0;
 
+	data = acpi_device_data_of_node(fwnode);
+	if (!data)
+		return -EINVAL;
+
 	ret = acpi_data_get_property(data, propname, ACPI_TYPE_ANY, &obj);
 	if (ret)
 		return ret;
@@ -532,59 +556,54 @@ static int acpi_data_get_property_reference(struct acpi_device_data *data,
 	while (element < end) {
 		u32 nargs, i;
 
-		if (element->type != ACPI_TYPE_LOCAL_REFERENCE)
-			return -EPROTO;
-
-		ret = acpi_bus_get_device(element->reference.handle, &device);
-		if (ret)
-			return -ENODEV;
-
-		element++;
-		nargs = 0;
-
-		/* assume following integer elements are all args */
-		for (i = 0; element + i < end; i++) {
-			int type = element[i].type;
+		if (element->type == ACPI_TYPE_LOCAL_REFERENCE) {
+			ret = acpi_bus_get_device(element->reference.handle,
+						  &device);
+			if (ret)
+				return -ENODEV;
+
+			nargs = 0;
+			element++;
+
+			/* assume following integer elements are all args */
+			for (i = 0; element + i < end && i < num_args; i++) {
+				int type = element[i].type;
+
+				if (type == ACPI_TYPE_INTEGER)
+					nargs++;
+				else if (type == ACPI_TYPE_LOCAL_REFERENCE)
+					break;
+				else
+					return -EPROTO;
+			}
 
-			if (type == ACPI_TYPE_INTEGER)
-				nargs++;
-			else if (type == ACPI_TYPE_LOCAL_REFERENCE)
-				break;
-			else
+			if (nargs > MAX_ACPI_REFERENCE_ARGS)
 				return -EPROTO;
-		}
 
-		if (idx++ == index) {
-			args->adev = device;
-			args->nargs = nargs;
-			for (i = 0; i < nargs; i++)
-				args->args[i] = element[i].integer.value;
+			if (idx == index) {
+				args->adev = device;
+				args->nargs = nargs;
+				for (i = 0; i < nargs; i++)
+					args->args[i] = element[i].integer.value;
 
-			return 0;
+				return 0;
+			}
+
+			element += nargs;
+		} else if (element->type == ACPI_TYPE_INTEGER) {
+			if (idx == index)
+				return -ENOENT;
+			element++;
+		} else {
+			return -EPROTO;
 		}
 
-		element += nargs;
+		idx++;
 	}
 
-	return -EPROTO;
-}
-
-/**
- * acpi_node_get_property_reference - get a handle to the referenced object.
- * @fwnode: Firmware node to get the property from.
- * @propname: Name of the property.
- * @index: Index of the reference to return.
- * @args: Location to store the returned reference with optional arguments.
- */
-int acpi_node_get_property_reference(struct fwnode_handle *fwnode,
-				     const char *name, size_t index,
-				     struct acpi_reference_args *args)
-{
-	struct acpi_device_data *data = acpi_device_data_of_node(fwnode);
-
-	return data ? acpi_data_get_property_reference(data, name, index, args) : -EINVAL;
+	return -ENODATA;
 }
-EXPORT_SYMBOL_GPL(acpi_node_get_property_reference);
+EXPORT_SYMBOL_GPL(__acpi_node_get_property_reference);
 
 static int acpi_data_prop_read_single(struct acpi_device_data *data,
 				      const char *propname,