+/* ACPI _DSD data subnodes UUID: dbb8e3e6-5886-4ba6-8795-1319f52a966b */
+static const u8 ads_uuid[16] = {
+ 0xe6, 0xe3, 0xb8, 0xdb, 0x86, 0x58, 0xa6, 0x4b,
+ 0x87, 0x95, 0x13, 0x19, 0xf5, 0x2a, 0x96, 0x6b
+};
+
+static bool acpi_enumerate_nondev_subnodes(acpi_handle scope,
+ const union acpi_object *desc,
+ struct acpi_device_data *data);
+static bool acpi_extract_properties(const union acpi_object *desc,
+ struct acpi_device_data *data);
+
+static bool acpi_nondev_subnode_ok(acpi_handle scope,
+ const union acpi_object *link,
+ struct list_head *list)
+{
+ struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER };
+ struct acpi_data_node *dn;
+ acpi_handle handle;
+ acpi_status status;
+
+ dn = kzalloc(sizeof(*dn), GFP_KERNEL);
+ if (!dn)
+ return false;
+
+ dn->name = link->package.elements[0].string.pointer;
+ dn->fwnode.type = FWNODE_ACPI_DATA;
+ INIT_LIST_HEAD(&dn->data.subnodes);
+
+ status = acpi_get_handle(scope, link->package.elements[1].string.pointer,
+ &handle);
+ if (ACPI_FAILURE(status))
+ goto fail;
+
+ status = acpi_evaluate_object_typed(handle, NULL, NULL, &buf,
+ ACPI_TYPE_PACKAGE);
+ if (ACPI_FAILURE(status))
+ goto fail;
+
+ if (acpi_extract_properties(buf.pointer, &dn->data))
+ dn->handle = handle;
+
+ /*
+ * The scope for the subnode object lookup is the one of the namespace
+ * node (device) containing the object that has returned the package.
+ * That is, it's the scope of that object's parent.
+ */
+ status = acpi_get_parent(handle, &scope);
+ if (ACPI_SUCCESS(status)
+ && acpi_enumerate_nondev_subnodes(scope, buf.pointer, &dn->data))
+ dn->handle = handle;
+
+ if (dn->handle) {
+ dn->data.pointer = buf.pointer;
+ list_add_tail(&dn->sibling, list);
+ return true;
+ }
+
+ acpi_handle_debug(handle, "Invalid properties/subnodes data, skipping\n");
+
+ fail:
+ ACPI_FREE(buf.pointer);
+ kfree(dn);
+ return false;
+}
+
+static int acpi_add_nondev_subnodes(acpi_handle scope,
+ const union acpi_object *links,
+ struct list_head *list)
+{
+ bool ret = false;
+ int i;
+
+ for (i = 0; i < links->package.count; i++) {
+ const union acpi_object *link;
+
+ link = &links->package.elements[i];
+ /* Only two elements allowed, both must be strings. */
+ if (link->package.count == 2
+ && link->package.elements[0].type == ACPI_TYPE_STRING
+ && link->package.elements[1].type == ACPI_TYPE_STRING
+ && acpi_nondev_subnode_ok(scope, link, list))
+ ret = true;
+ }
+
+ return ret;
+}
+
+static bool acpi_enumerate_nondev_subnodes(acpi_handle scope,
+ const union acpi_object *desc,
+ struct acpi_device_data *data)
+{
+ int i;
+
+ /* Look for the ACPI data subnodes UUID. */
+ for (i = 0; i < desc->package.count; i += 2) {
+ const union acpi_object *uuid, *links;
+
+ uuid = &desc->package.elements[i];
+ links = &desc->package.elements[i + 1];
+
+ /*
+ * The first element must be a UUID and the second one must be
+ * a package.
+ */
+ if (uuid->type != ACPI_TYPE_BUFFER || uuid->buffer.length != 16
+ || links->type != ACPI_TYPE_PACKAGE)
+ break;
+
+ if (memcmp(uuid->buffer.pointer, ads_uuid, sizeof(ads_uuid)))
+ continue;
+
+ return acpi_add_nondev_subnodes(scope, links, &data->subnodes);
+ }
+
+ return false;
+}