Merge patch series "software node: provide support for fw_devlink"

Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com> says:

Currently only devicetree systems have their devices' probe ordered
against their suppliers automatically by fw_devlink. Software nodes have
lately been used extensively treewide to describe references to resource
suppliers: most notably, the GPIO subsystem uses it in many places. Now
that the conversion of "dangling" GPIO chip software nodes to using real
links is almost done, it makes sense to ensure no needless probe
deferrals by implementing the add_links() callback from the fwnode
interface.

This series extends software node support to use fw_devlink and adds test
coverage for the new behaviour.

Caveats: a supplier software node must be registered before the consumer
device is added, If the swnode is registered after the consumer was added,
add_links() has already run and set FWNODE_FLAG_LINKS_ADDED, so the late
supplier is missed. Graph/remote- endpoint ordering is left out for now as
well as there are no known users.

Link: https://patch.msgid.link/20260713-swnode-fw-devlink-v4-0-d4f2dee27ad9@oss.qualcomm.com
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

8 files changed, 601 insertions, 0 deletions

diff --git a/MAINTAINERS b/MAINTAINERS
index 15011f5752a9..e30aa3b63eff 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -25101,10 +25101,12 @@ R:	Andy Shevchenko <andriy.shevchenko@linux.intel.com>
 R:	Daniel Scally <djrscally@gmail.com>
 R:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
 R:	Sakari Ailus <sakari.ailus@linux.intel.com>
+R:	Bartosz Golaszewski <brgl@kernel.org>
 L:	linux-acpi@vger.kernel.org
 S:	Maintained
 F:	drivers/base/property.c
 F:	drivers/base/swnode.c
+F:	drivers/base/test/swnode-devlink-test.c
 F:	include/linux/fwnode.h
 F:	include/linux/property.h
 
diff --git a/drivers/base/swnode.c b/drivers/base/swnode.c
index 869228a65cb3..1f2315858cc3 100644
--- a/drivers/base/swnode.c
+++ b/drivers/base/swnode.c
@@ -699,6 +699,62 @@ software_node_graph_parse_endpoint(const struct fwnode_handle *fwnode,
 	return 0;
 }
 
+static int software_node_add_links(struct fwnode_handle *fwnode)
+{
+	const struct software_node_ref_args *ref, *ref_array;
+	struct swnode *swnode = to_swnode(fwnode);
+	const struct property_entry *prop;
+	struct fwnode_handle *refnode;
+	unsigned int count;
+
+	if (!swnode || !swnode->node->properties)
+		return 0;
+
+	/*
+	 * Unlike Device Tree, where phandles appear in many non-supplier
+	 * contexts and a curated allowlist is required, a software node only
+	 * carries a DEV_PROP_REF property when the author explicitly describes
+	 * a reference to another node. Every such reference is therefore an
+	 * intentional supplier dependency, so we create fwnode links for all
+	 * of them.
+	 */
+	for (prop = swnode->node->properties; prop->name; prop++) {
+		if (prop->type != DEV_PROP_REF || prop->is_inline)
+			continue;
+
+		/*
+		 * TODO: Graph "remote-endpoint" references go both ways
+		 * between endpoint child nodes and would create endpoint
+		 * cycles. Let's leave it out for now until we have potential
+		 * users.
+		 */
+		if (!strcmp(prop->name, "remote-endpoint"))
+			continue;
+
+		ref_array = prop->pointer;
+		count = prop->length / sizeof(*ref_array);
+
+		for (unsigned int i = 0; i < count; i++) {
+			ref = &ref_array[i];
+
+			if (ref->swnode)
+				refnode = software_node_fwnode(ref->swnode);
+			else if (ref->fwnode)
+				refnode = ref->fwnode;
+			else
+				continue;
+
+			/* Supplier not registered yet, or self-reference. */
+			if (!refnode || refnode == &swnode->fwnode)
+				continue;
+
+			fwnode_link_add(&swnode->fwnode, refnode, 0);
+		}
+	}
+
+	return 0;
+}
+
 static const struct fwnode_operations software_node_ops = {
 	.get = software_node_get,
 	.put = software_node_put,
@@ -716,6 +772,7 @@ static const struct fwnode_operations software_node_ops = {
 	.graph_get_remote_endpoint = software_node_graph_get_remote_endpoint,
 	.graph_get_port_parent = software_node_graph_get_port_parent,
 	.graph_parse_endpoint = software_node_graph_parse_endpoint,
+	.add_links = software_node_add_links,
 };
 
 /* -------------------------------------------------------------------------- */
@@ -787,6 +844,8 @@ static void software_node_release(struct kobject *kobj)
 {
 	struct swnode *swnode = kobj_to_swnode(kobj);
 
+	fwnode_links_purge(&swnode->fwnode);
+
 	if (swnode->parent) {
 		ida_free(&swnode->parent->child_ids, swnode->id);
 		list_del(&swnode->entry);
@@ -1105,6 +1164,17 @@ void software_node_notify(struct device *dev)
 	if (!swnode)
 		return;
 
+	/*
+	 * When the software node is the device's secondary firmware node,
+	 * the core only records the owning device on the primary fwnode
+	 * (see device_add()). fw_devlink resolves a supplier device through
+	 * fwnode->dev, so without this a consumer referencing the software
+	 * node could never find the supplier device and would defer forever.
+	 * Make fwnode.dev point to its owner in that case.
+	 */
+	if (!device_match_fwnode(dev, &swnode->fwnode) && !swnode->fwnode.dev)
+		swnode->fwnode.dev = dev;
+
 	swnode_get(swnode);
 	ret = sysfs_create_link(&dev->kobj, &swnode->kobj, "software_node");
 	if (ret)
@@ -1127,6 +1197,15 @@ void software_node_notify_remove(struct device *dev)
 
 	sysfs_remove_link(&swnode->kobj, dev_name(dev));
 	sysfs_remove_link(&dev->kobj, "software_node");
+
+	/*
+	 * Drop the device pointer mirrored onto a secondary software node in
+	 * software_node_notify(). For a primary software node the core owns
+	 * fwnode->dev and clears it in device_del().
+	 */
+	if (!device_match_fwnode(dev, &swnode->fwnode) && swnode->fwnode.dev == dev)
+		swnode->fwnode.dev = NULL;
+
 	swnode_put(swnode);
 
 	if (swnode->managed) {
diff --git a/drivers/base/test/Kconfig b/drivers/base/test/Kconfig
index 2756870615cc..1ecf0791241a 100644
--- a/drivers/base/test/Kconfig
+++ b/drivers/base/test/Kconfig
@@ -18,3 +18,8 @@ config DRIVER_PE_KUNIT_TEST
 	tristate "KUnit Tests for property entry API" if !KUNIT_ALL_TESTS
 	depends on KUNIT
 	default KUNIT_ALL_TESTS
+
+config DRIVER_SWNODE_KUNIT_TEST
+	tristate "KUnit Tests for software node fw_devlink links" if !KUNIT_ALL_TESTS
+	depends on KUNIT
+	default KUNIT_ALL_TESTS
diff --git a/drivers/base/test/Makefile b/drivers/base/test/Makefile
index e321dfc7e922..9ced7bbd569f 100644
--- a/drivers/base/test/Makefile
+++ b/drivers/base/test/Makefile
@@ -6,3 +6,5 @@ obj-$(CONFIG_DM_KUNIT_TEST)	+= platform-device-test.o
 
 obj-$(CONFIG_DRIVER_PE_KUNIT_TEST) += property-entry-test.o
 CFLAGS_property-entry-test.o += $(DISABLE_STRUCTLEAK_PLUGIN)
+
+obj-$(CONFIG_DRIVER_SWNODE_KUNIT_TEST) += swnode-devlink-test.o
diff --git a/drivers/base/test/swnode-devlink-test.c b/drivers/base/test/swnode-devlink-test.c
new file mode 100644
index 000000000000..f53549e92611
--- /dev/null
+++ b/drivers/base/test/swnode-devlink-test.c
@@ -0,0 +1,337 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) Qualcomm Technologies, Inc. and/or its subsidiaries
+ */
+
+#include <linux/array_size.h>
+#include <linux/device.h>
+#include <linux/fwnode.h>
+#include <linux/list.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/time.h>
+#include <linux/types.h>
+#include <linux/wait.h>
+
+#include <kunit/fwnode.h>
+#include <kunit/platform_device.h>
+#include <kunit/test.h>
+
+static int swnode_count_suppliers(struct fwnode_handle *fwnode)
+{
+	struct fwnode_link *link;
+	unsigned int count = 0;
+
+	/*
+	 * The suppliers and consumers lists should typically only be accessed
+	 * with the fwnode_link_lock taken but it's private to the driver core.
+	 *
+	 * These are tests and at this point nobody should be modifying them so
+	 * let's just access the list.
+	 */
+	list_for_each_entry(link, &fwnode->suppliers, c_hook)
+		count++;
+
+	return count;
+}
+
+/* True if a supplier link con->sup exists, checked from both list ends. */
+static bool swnode_has_link(struct fwnode_handle *consumer,
+			    struct fwnode_handle *supplier)
+{
+	bool from_con = false, from_sup = false;
+	struct fwnode_link *link;
+
+	list_for_each_entry(link, &consumer->suppliers, c_hook) {
+		if (link->supplier == supplier && link->consumer == consumer)
+			from_con = true;
+	}
+
+	list_for_each_entry(link, &supplier->consumers, s_hook) {
+		if (link->supplier == supplier && link->consumer == consumer)
+			from_sup = true;
+	}
+
+	return from_con && from_sup;
+}
+
+/* A single reference creates exactly one supplier link, on both list ends. */
+static void swnode_devlink_test_single_ref(struct kunit *test)
+{
+	static const struct software_node supp_swnode = {
+		.name = "swnode-devlink-test-supplier",
+	};
+
+	struct fwnode_handle *cons_fwnode, *supp_fwnode;
+	int ret;
+
+	const struct property_entry props[] = {
+		PROPERTY_ENTRY_REF("supplier", &supp_swnode),
+		{ }
+	};
+
+	supp_fwnode = kunit_software_node_register(test, &supp_swnode);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, supp_fwnode);
+
+	cons_fwnode = kunit_fwnode_create_software_node(test, props, NULL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, cons_fwnode);
+
+	ret = fwnode_call_int_op(cons_fwnode, add_links);
+	KUNIT_EXPECT_EQ(test, ret, 0);
+
+	KUNIT_EXPECT_EQ(test, swnode_count_suppliers(cons_fwnode), 1);
+	KUNIT_EXPECT_TRUE(test, swnode_has_link(cons_fwnode, supp_fwnode));
+}
+
+/* Multiple distinct references create multiple supplier links. */
+static void swnode_devlink_test_multiple_refs(struct kunit *test)
+{
+	static const struct software_node supp1_swnode = {
+		.name = "swnode-devlink-test-supplier-1",
+	};
+	static const struct software_node supp2_swnode = {
+		.name = "swnode-devlink-test-supplier-2",
+	};
+	static const struct software_node *supp_nodes[] = {
+		&supp1_swnode, &supp2_swnode, NULL
+	};
+
+	const struct property_entry props[] = {
+		PROPERTY_ENTRY_REF("foo", &supp1_swnode),
+		PROPERTY_ENTRY_REF("bar", &supp2_swnode),
+		{ }
+	};
+
+	struct fwnode_handle *fwnode;
+	int ret;
+
+	ret = kunit_software_node_register_node_group(test, supp_nodes);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+
+	fwnode = kunit_fwnode_create_software_node(test, props, NULL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, fwnode);
+
+	ret = fwnode_call_int_op(fwnode, add_links);
+	KUNIT_EXPECT_EQ(test, ret, 0);
+
+	KUNIT_EXPECT_EQ(test, swnode_count_suppliers(fwnode), 2);
+	KUNIT_EXPECT_TRUE(test, swnode_has_link(fwnode, software_node_fwnode(&supp1_swnode)));
+	KUNIT_EXPECT_TRUE(test, swnode_has_link(fwnode, software_node_fwnode(&supp2_swnode)));
+}
+
+/* A reference to an unregistered node creates no link (graceful skip). */
+static void swnode_devlink_test_unregistered_ref(struct kunit *test)
+{
+	static const struct software_node supp_swnode = {
+		.name = "swnode-devlink-test-supplier",
+	};
+
+	const struct property_entry props[] = {
+		PROPERTY_ENTRY_REF("supplier", &supp_swnode),
+		{ }
+	};
+
+	struct fwnode_handle *fwnode;
+	int ret;
+
+	fwnode = kunit_fwnode_create_software_node(test, props, NULL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, fwnode);
+
+	ret = fwnode_call_int_op(fwnode, add_links);
+	KUNIT_EXPECT_EQ(test, ret, 0);
+	KUNIT_EXPECT_EQ(test, swnode_count_suppliers(fwnode), 0);
+}
+
+/* Graph "remote-endpoint" references are excluded. */
+static void swnode_devlink_test_remote_endpoint_excluded(struct kunit *test)
+{
+	static const struct software_node ep_swnode = {
+		.name = "swnode-devlink-test-end-point"
+	};
+
+	const struct property_entry props[] = {
+		PROPERTY_ENTRY_REF("remote-endpoint", &ep_swnode),
+		{ }
+	};
+
+	struct fwnode_handle *cons_fwnode, *supp_fwnode;
+	int ret;
+
+	supp_fwnode = kunit_software_node_register(test, &ep_swnode);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, supp_fwnode);
+
+	cons_fwnode = kunit_fwnode_create_software_node(test, props, NULL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, cons_fwnode);
+
+	ret = fwnode_call_int_op(cons_fwnode, add_links);
+	KUNIT_EXPECT_EQ(test, ret, 0);
+	KUNIT_EXPECT_EQ(test, swnode_count_suppliers(cons_fwnode), 0);
+}
+
+/* A reference array creates one link per registered element. */
+static void swnode_devlink_test_ref_array(struct kunit *test)
+{
+	static const struct software_node supp1_swnode = {
+		.name = "swnode-devlink-test-supplier-1",
+	};
+	static const struct software_node supp2_swnode = {
+		.name = "swnode-devlink-test-supplier-2",
+	};
+	static const struct software_node *supp_nodes[] = {
+		&supp1_swnode, &supp2_swnode, NULL
+	};
+	static const struct software_node_ref_args refs[] = {
+		SOFTWARE_NODE_REFERENCE(&supp1_swnode),
+		SOFTWARE_NODE_REFERENCE(&supp2_swnode, 4, 2),
+	};
+
+	const struct property_entry props[] = {
+		PROPERTY_ENTRY_REF_ARRAY("suppliers", refs),
+		{ }
+	};
+
+	struct fwnode_handle *fwnode;
+	int ret;
+
+	ret = kunit_software_node_register_node_group(test, supp_nodes);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+
+	fwnode = kunit_fwnode_create_software_node(test, props, NULL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, fwnode);
+
+	ret = fwnode_call_int_op(fwnode, add_links);
+	KUNIT_EXPECT_EQ(test, ret, 0);
+
+	KUNIT_EXPECT_EQ(test, swnode_count_suppliers(fwnode), 2);
+	KUNIT_EXPECT_TRUE(test, swnode_has_link(fwnode, software_node_fwnode(&supp1_swnode)));
+	KUNIT_EXPECT_TRUE(test, swnode_has_link(fwnode, software_node_fwnode(&supp2_swnode)));
+}
+
+/*
+ * End-to-end test: fw_devlink must defer a consumer's probe until its
+ * supplier has probed.
+ *
+ * The reference created by software_node_add_links() is only useful if the
+ * driver core promotes it to a real device_link and uses it to order probing.
+ * This test drives actual probing through the platform bus and asserts the
+ * supplier binds before the consumer.
+ */
+
+#define SWNODE_DEVLINK_TEST_SUPPLIER	"swnode-link-supplier"
+#define SWNODE_DEVLINK_TEST_CONSUMER	"swnode-link-consumer"
+#define SWNODE_DEVLINK_TEST_TIMEOUT_MS	(2 * MSEC_PER_SEC)
+
+struct swnode_test_probe_order {
+	/* Names in the order their drivers' .probe ran. */
+	const char *probed[2];
+	unsigned int count;
+	wait_queue_head_t wq;
+};
+
+static int swnode_test_record_probe(struct platform_device *pdev)
+{
+	struct swnode_test_probe_order *order = platform_get_drvdata(pdev);
+
+	if (order && order->count < ARRAY_SIZE(order->probed)) {
+		order->probed[order->count++] = dev_name(&pdev->dev);
+		wake_up_interruptible(&order->wq);
+	}
+
+	return 0;
+}
+
+static struct platform_driver swnode_test_supplier_driver = {
+	.probe = swnode_test_record_probe,
+	.driver = {
+		.name = SWNODE_DEVLINK_TEST_SUPPLIER,
+	},
+};
+
+static struct platform_driver swnode_test_consumer_driver = {
+	.probe = swnode_test_record_probe,
+	.driver = {
+		.name = SWNODE_DEVLINK_TEST_CONSUMER,
+	},
+};
+
+static void swnode_devlink_test_probe_order(struct kunit *test)
+{
+	static const struct software_node supplier_swnode = {
+		.name = "swnode-devlink-test-supplier",
+	};
+
+	const struct property_entry consumer_props[] = {
+		PROPERTY_ENTRY_REF("supplier-ref", &supplier_swnode),
+		{ }
+	};
+
+	struct platform_device *supplier, *consumer;
+	struct swnode_test_probe_order *order;
+	struct fwnode_handle *fwnode;
+	int ret;
+
+	order = kunit_kzalloc(test, sizeof(*order), GFP_KERNEL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, order);
+	init_waitqueue_head(&order->wq);
+
+	fwnode = kunit_software_node_register(test, &supplier_swnode);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, fwnode);
+
+	ret = kunit_platform_driver_register(test, &swnode_test_supplier_driver);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+	ret = kunit_platform_driver_register(test, &swnode_test_consumer_driver);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+
+	supplier = kunit_platform_device_alloc(test, SWNODE_DEVLINK_TEST_SUPPLIER,
+					       PLATFORM_DEVID_NONE);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, supplier);
+	consumer = kunit_platform_device_alloc(test, SWNODE_DEVLINK_TEST_CONSUMER,
+					       PLATFORM_DEVID_NONE);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, consumer);
+
+	platform_set_drvdata(supplier, order);
+	platform_set_drvdata(consumer, order);
+
+	ret = kunit_device_add_software_node(test, &supplier->dev, &supplier_swnode);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+	ret = device_create_managed_software_node(&consumer->dev,
+						  consumer_props, NULL);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+
+	ret = kunit_platform_device_add(test, consumer);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+	ret = kunit_platform_device_add(test, supplier);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+
+	ret = wait_event_interruptible_timeout(order->wq,
+					       order->count == 2,
+					       msecs_to_jiffies(SWNODE_DEVLINK_TEST_TIMEOUT_MS));
+	KUNIT_ASSERT_GT(test, ret, 0);
+
+	KUNIT_EXPECT_STREQ(test, order->probed[0], SWNODE_DEVLINK_TEST_SUPPLIER);
+	KUNIT_EXPECT_STREQ(test, order->probed[1], SWNODE_DEVLINK_TEST_CONSUMER);
+
+	/* Tear down the consumer (and its device link) before the supplier. */
+	kunit_platform_device_unregister(test, consumer);
+}
+
+static struct kunit_case swnode_test_cases[] = {
+	KUNIT_CASE(swnode_devlink_test_single_ref),
+	KUNIT_CASE(swnode_devlink_test_multiple_refs),
+	KUNIT_CASE(swnode_devlink_test_unregistered_ref),
+	KUNIT_CASE(swnode_devlink_test_remote_endpoint_excluded),
+	KUNIT_CASE(swnode_devlink_test_ref_array),
+	KUNIT_CASE(swnode_devlink_test_probe_order),
+	{ }
+};
+
+static struct kunit_suite swnode_test_suite = {
+	.name = "software-node-links",
+	.test_cases = swnode_test_cases,
+};
+
+kunit_test_suite(swnode_test_suite);
+
+MODULE_DESCRIPTION("Test module for software node fw_devlink support");
+MODULE_AUTHOR("Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>");
+MODULE_LICENSE("GPL");
diff --git a/include/kunit/fwnode.h b/include/kunit/fwnode.h
new file mode 100644
index 000000000000..e250bb87e144
--- /dev/null
+++ b/include/kunit/fwnode.h
@@ -0,0 +1,29 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * KUnit resource management helpers for firmware nodes.
+ *
+ * Copyright (C) Qualcomm Technologies, Inc. and/or its subsidiaries
+ */
+
+#ifndef _KUNIT_FWNODE_H
+#define _KUNIT_FWNODE_H
+
+struct device;
+struct fwnode_handle;
+struct kunit;
+struct property_entry;
+struct software_node;
+
+struct fwnode_handle *
+kunit_fwnode_create_software_node(struct kunit *test,
+				  const struct property_entry *properties,
+				  const struct fwnode_handle *parent);
+struct fwnode_handle *
+kunit_software_node_register(struct kunit *test,
+			     const struct software_node *node);
+int kunit_software_node_register_node_group(struct kunit *test,
+					    const struct software_node *const *nodes);
+int kunit_device_add_software_node(struct kunit *test, struct device *dev,
+				   const struct software_node *node);
+
+#endif /* _KUNIT_FWNODE_H */
diff --git a/lib/kunit/Makefile b/lib/kunit/Makefile
index 2e8a6b71a2ab..204e02b10eba 100644
--- a/lib/kunit/Makefile
+++ b/lib/kunit/Makefile
@@ -11,6 +11,7 @@ kunit-objs +=				test.o \
 					attributes.o \
 					device.o \
 					platform.o \
+					fwnode.o \
 					bug.o
 
 ifeq ($(CONFIG_KUNIT_DEBUGFS),y)
diff --git a/lib/kunit/fwnode.c b/lib/kunit/fwnode.c
new file mode 100644
index 000000000000..a58ce0984d76
--- /dev/null
+++ b/lib/kunit/fwnode.c
@@ -0,0 +1,146 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) Qualcomm Technologies, Inc. and/or its subsidiaries
+ */
+
+#include <kunit/fwnode.h>
+#include <kunit/test.h>
+
+#include <linux/fwnode.h>
+#include <linux/property.h>
+
+KUNIT_DEFINE_ACTION_WRAPPER(fwnode_remove_software_node_wrapper,
+			    fwnode_remove_software_node,
+			    struct fwnode_handle *);
+
+/**
+ * kunit_fwnode_create_software_node() - Create a kunit-managed software node
+ * @test: Test context
+ * @properties: Properties to use to create the new software node
+ * @parent: Parent of this software node
+ *
+ * Create a test-managed software node and return its firmware node handle.
+ * The software node is removed after the test case completes.
+ *
+ * Returns:
+ * Firmware node handle of the newly created software node or IS_ERR() on
+ * failure.
+ */
+struct fwnode_handle *
+kunit_fwnode_create_software_node(struct kunit *test,
+				  const struct property_entry *properties,
+				  const struct fwnode_handle *parent)
+{
+	struct fwnode_handle *fwnode;
+	int ret;
+
+	fwnode = fwnode_create_software_node(properties, parent);
+	if (IS_ERR(fwnode))
+		return fwnode;
+
+	ret = kunit_add_action_or_reset(test, fwnode_remove_software_node_wrapper,
+					fwnode);
+	if (ret)
+		return ERR_PTR(ret);
+
+	return fwnode;
+}
+EXPORT_SYMBOL_GPL(kunit_fwnode_create_software_node);
+
+KUNIT_DEFINE_ACTION_WRAPPER(software_node_unregister_wrapper,
+			    software_node_unregister,
+			    const struct software_node *);
+
+/**
+ * kunit_software_node_register() - Register a kunit-managed software node
+ * @test: Test context
+ * @swnode: Software node to register
+ *
+ * Register a test-managed software node and return its firmware node handle.
+ * The software node is unregistered after the test case completes.
+ *
+ * Returns:
+ * Firmware node handle of the registered software node or IS_ERR() on failure.
+ */
+struct fwnode_handle *
+kunit_software_node_register(struct kunit *test,
+			     const struct software_node *swnode)
+{
+	struct fwnode_handle *fwnode;
+	int ret;
+
+	ret = software_node_register(swnode);
+	if (ret)
+		return ERR_PTR(ret);
+
+	fwnode = software_node_fwnode(swnode);
+	if (WARN_ON(!fwnode))
+		return ERR_PTR(-ENOENT);
+
+	ret = kunit_add_action_or_reset(test, software_node_unregister_wrapper,
+					(void *)swnode);
+	if (ret)
+		return ERR_PTR(ret);
+
+	return fwnode;
+}
+EXPORT_SYMBOL_GPL(kunit_software_node_register);
+
+KUNIT_DEFINE_ACTION_WRAPPER(software_node_unregister_node_group_wrapper,
+			    software_node_unregister_node_group,
+			    const struct software_node *const *);
+
+/**
+ * kunit_software_node_register_node_group() - Register a kunit-managed software node group
+ * @test: Test context
+ * @nodes: Software node group to register
+ *
+ * Register a test-managed software node group. The nodes are unregistered
+ * after the test case completes.
+ *
+ * Returns:
+ * 0 on success, negative error number on failure.
+ */
+int kunit_software_node_register_node_group(struct kunit *test,
+					    const struct software_node *const *nodes)
+{
+	int ret;
+
+	ret = software_node_register_node_group(nodes);
+	if (ret)
+		return ret;
+
+	return kunit_add_action_or_reset(test, software_node_unregister_node_group_wrapper,
+					 (void *)nodes);
+}
+EXPORT_SYMBOL_GPL(kunit_software_node_register_node_group);
+
+KUNIT_DEFINE_ACTION_WRAPPER(device_remove_software_node_wrapper,
+			    device_remove_software_node,
+			    struct device *);
+
+/**
+ * kunit_device_add_software_node() - Assign a kunit-managed software node to a device
+ * @test: Test context
+ * @dev: Device to assign the software node for
+ * @node: The software node to assign
+ *
+ * Make @node the secondary firmware node of @dev. If @dev has no primary
+ * firmware node, @node will become the primary node. The software node will
+ * be automatically removed from @dev when the test case completes.
+ *
+ * Returns:
+ * 0 on success, negative error number on failure.
+ */
+int kunit_device_add_software_node(struct kunit *test, struct device *dev,
+				   const struct software_node *node)
+{
+	int ret;
+
+	ret = device_add_software_node(dev, node);
+	if (ret)
+		return ret;
+
+	return kunit_add_action_or_reset(test, device_remove_software_node_wrapper, dev);
+}
+EXPORT_SYMBOL_GPL(kunit_device_add_software_node);