===================================================================
@@ -2,14 +2,17 @@
/*
* ACPI device specific properties support.
*
- * Copyright (C) 2014, Intel Corporation
+ * Copyright (C) 2014 - 2023, Intel Corporation
* All rights reserved.
*
* Authors: Mika Westerberg <mika.westerberg@linux.intel.com>
* Darren Hart <dvhart@linux.intel.com>
* Rafael J. Wysocki <rafael.j.wysocki@intel.com>
+ * Sakari Ailus <sakari.ailus@linux.intel.com>
*/
+#define pr_fmt(fmt) "ACPI: " fmt
+
#include <linux/acpi.h>
#include <linux/device.h>
#include <linux/export.h>
@@ -800,27 +803,15 @@ static int acpi_get_ref_args(struct fwno
u32 nargs = 0, i;
/*
- * Find the referred data extension node under the
- * referred device node.
- */
- for (; *element < end && (*element)->type == ACPI_TYPE_STRING;
- (*element)++) {
- const char *child_name = (*element)->string.pointer;
-
- ref_fwnode = acpi_fwnode_get_named_child_node(ref_fwnode, child_name);
- if (!ref_fwnode)
- return -EINVAL;
- }
-
- /*
* Assume the following integer elements are all args. Stop counting on
- * the first reference or end of the package arguments. In case of
- * neither reference, nor integer, return an error, we can't parse it.
+ * the first reference (possibly represented as a string) or end of the
+ * package arguments. In case of neither reference, nor integer, return
+ * an error, we can't parse it.
*/
for (i = 0; (*element) + i < end && i < num_args; i++) {
acpi_object_type type = (*element)[i].type;
- if (type == ACPI_TYPE_LOCAL_REFERENCE)
+ if (type == ACPI_TYPE_LOCAL_REFERENCE || type == ACPI_TYPE_STRING)
break;
if (type == ACPI_TYPE_INTEGER)
@@ -844,6 +835,44 @@ static int acpi_get_ref_args(struct fwno
return 0;
}
+static struct fwnode_handle *acpi_parse_string_ref(const struct fwnode_handle *fwnode,
+ const char *refstring)
+{
+ acpi_handle scope, handle;
+ struct acpi_data_node *dn;
+ struct acpi_device *device;
+ acpi_status status;
+
+ if (is_acpi_device_node(fwnode)) {
+ scope = to_acpi_device_node(fwnode)->handle;
+ } else if (is_acpi_data_node(fwnode)) {
+ scope = to_acpi_data_node(fwnode)->handle;
+ } else {
+ pr_debug("Bad node type for node %pfw\n", fwnode);
+ return NULL;
+ }
+
+ status = acpi_get_handle(scope, refstring, &handle);
+ if (ACPI_FAILURE(status)) {
+ acpi_handle_debug(scope, "Unable to get an ACPI handle for %s\n",
+ refstring);
+ return NULL;
+ }
+
+ device = acpi_fetch_acpi_dev(handle);
+ if (device)
+ return acpi_fwnode_handle(device);
+
+ status = acpi_get_data_full(handle, acpi_nondev_subnode_tag,
+ (void **)&dn, NULL);
+ if (ACPI_FAILURE(status) || !dn) {
+ acpi_handle_debug(handle, "Subnode not found\n");
+ return NULL;
+ }
+
+ return &dn->fwnode;
+}
+
/**
* __acpi_node_get_property_reference - returns handle to the referenced object
* @fwnode: Firmware node to get the property from
@@ -886,6 +915,7 @@ int __acpi_node_get_property_reference(c
const union acpi_object *element, *end;
const union acpi_object *obj;
const struct acpi_device_data *data;
+ struct fwnode_handle *ref_fwnode;
struct acpi_device *device;
int ret, idx = 0;
@@ -909,16 +939,30 @@ int __acpi_node_get_property_reference(c
args->fwnode = acpi_fwnode_handle(device);
args->nargs = 0;
+
+ return 0;
+ case ACPI_TYPE_STRING:
+ if (index)
+ return -ENOENT;
+
+ ref_fwnode = acpi_parse_string_ref(fwnode, obj->string.pointer);
+ if (!ref_fwnode)
+ return -EINVAL;
+
+ args->fwnode = ref_fwnode;
+ args->nargs = 0;
+
return 0;
case ACPI_TYPE_PACKAGE:
/*
* If it is not a single reference, then it is a package of
- * references followed by number of ints as follows:
+ * references, followed by number of ints as follows:
*
* Package () { REF, INT, REF, INT, INT }
*
- * The index argument is then used to determine which reference
- * the caller wants (along with the arguments).
+ * Here, REF may be either a local reference or a string. The
+ * index argument is then used to determine which reference the
+ * caller wants (along with the arguments).
*/
break;
default:
@@ -946,6 +990,24 @@ int __acpi_node_get_property_reference(c
if (ret < 0)
return ret;
+ if (idx == index)
+ return 0;
+
+ break;
+ case ACPI_TYPE_STRING:
+ ref_fwnode = acpi_parse_string_ref(fwnode,
+ element->string.pointer);
+ if (!ref_fwnode)
+ return -EINVAL;
+
+ element++;
+
+ ret = acpi_get_ref_args(idx == index ? args : NULL,
+ ref_fwnode, &element, end,
+ num_args);
+ if (ret < 0)
+ return ret;
+
if (idx == index)
return 0;