Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
interconnect: Add kunit tests for core functionality
The interconnect framework currently lacks in-tree unit tests to verify
the core logic in isolation. This makes it difficult to validate
regression stability when modifying the provider/consumer APIs or
aggregation logic.
Introduce a kunit test suite that verifies the fundamental behavior of
the subsystem. The tests cover:
- Provider API (node creation, linking, topology construction).
- Consumer API (path enabling/disabling, bandwidth requests).
- Standard aggregation logic (accumulating bandwidth across links).
- Bulk operations for setting bandwidth on multiple paths.
The suite simulates a simple SoC topology with multiple masters and a
shared bus to validate traffic aggregation behavior in a controlled
software environment, without requiring specific hardware or Device
Tree support.
Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Link: https://lore.kernel.org/r/20260110184309.906735-1-visitorckw@gmail.com
Signed-off-by: Georgi Djakov <djakov@kernel.org>
authored by
Kuan-Wei Chiu
and committed by
Georgi Djakov
06ebbe71
a3e2ea79
+340
+14
drivers/interconnect/Kconfig
+14
drivers/interconnect/Kconfig
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help
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Support for wrapping clocks into the interconnect nodes.
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config INTERCONNECT_KUNIT_TEST
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tristate "KUnit tests for Interconnect framework"
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depends on KUNIT
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default KUNIT_ALL_TESTS
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help
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This builds the KUnit test suite for the generic system interconnect
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framework.
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The tests cover the core functionality of the interconnect subsystem,
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including provider/consumer APIs, topology management, and bandwidth
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aggregation logic.
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If unsure, say N.
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endif
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drivers/interconnect/Makefile
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drivers/interconnect/Makefile
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drivers/interconnect/icc-kunit.c
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drivers/interconnect/icc-kunit.c
···
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// SPDX-License-Identifier: GPL-2.0
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/*
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* KUnit tests for the Interconnect framework.
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*
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* Copyright (c) 2025 Kuan-Wei Chiu <visitorckw@gmail.com>
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*
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* This suite verifies the behavior of the interconnect core, including
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* topology construction, bandwidth aggregation, and path lifecycle.
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*/
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#include <kunit/platform_device.h>
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#include <kunit/test.h>
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#include <linux/interconnect-provider.h>
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#include <linux/interconnect.h>
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#include <linux/list.h>
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#include <linux/module.h>
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#include <linux/overflow.h>
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#include <linux/platform_device.h>
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#include <linux/slab.h>
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#include "internal.h"
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enum {
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NODE_CPU,
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NODE_GPU,
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NODE_BUS,
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NODE_DDR,
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NODE_MAX
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};
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struct test_node_data {
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int id;
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const char *name;
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int num_links;
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int links[2];
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};
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/*
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* Static Topology:
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* CPU -\
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* -> BUS -> DDR
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* GPU -/
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*/
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static const struct test_node_data test_topology[] = {
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{ NODE_CPU, "cpu", 1, { NODE_BUS } },
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{ NODE_GPU, "gpu", 1, { NODE_BUS } },
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{ NODE_BUS, "bus", 1, { NODE_DDR } },
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{ NODE_DDR, "ddr", 0, { } },
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};
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struct icc_test_priv {
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struct icc_provider provider;
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struct platform_device *pdev;
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struct icc_node *nodes[NODE_MAX];
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};
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static struct icc_node *get_node(struct icc_test_priv *priv, int id)
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{
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int idx = id - NODE_CPU;
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if (idx < 0 || idx >= ARRAY_SIZE(test_topology))
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return NULL;
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return priv->nodes[idx];
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}
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static int icc_test_set(struct icc_node *src, struct icc_node *dst)
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{
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return 0;
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}
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static int icc_test_aggregate(struct icc_node *node, u32 tag, u32 avg_bw,
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u32 peak_bw, u32 *agg_avg, u32 *agg_peak)
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{
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return icc_std_aggregate(node, tag, avg_bw, peak_bw, agg_avg, agg_peak);
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}
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static struct icc_node *icc_test_xlate(const struct of_phandle_args *spec, void *data)
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{
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return NULL;
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}
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static int icc_test_get_bw(struct icc_node *node, u32 *avg, u32 *peak)
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{
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*avg = 0;
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*peak = 0;
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return 0;
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}
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static int icc_test_init(struct kunit *test)
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{
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struct icc_test_priv *priv;
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struct icc_node *node;
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int i, j, ret;
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priv = kunit_kzalloc(test, sizeof(*priv), GFP_KERNEL);
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KUNIT_ASSERT_NOT_ERR_OR_NULL(test, priv);
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test->priv = priv;
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priv->pdev = kunit_platform_device_alloc(test, "icc-test-dev", -1);
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KUNIT_ASSERT_NOT_ERR_OR_NULL(test, priv->pdev);
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KUNIT_ASSERT_EQ(test, kunit_platform_device_add(test, priv->pdev), 0);
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priv->provider.set = icc_test_set;
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priv->provider.aggregate = icc_test_aggregate;
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priv->provider.xlate = icc_test_xlate;
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priv->provider.get_bw = icc_test_get_bw;
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priv->provider.dev = &priv->pdev->dev;
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priv->provider.data = priv;
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INIT_LIST_HEAD(&priv->provider.nodes);
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ret = icc_provider_register(&priv->provider);
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KUNIT_ASSERT_EQ(test, ret, 0);
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for (i = 0; i < ARRAY_SIZE(test_topology); i++) {
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const struct test_node_data *data = &test_topology[i];
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node = icc_node_create(data->id);
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KUNIT_ASSERT_NOT_ERR_OR_NULL(test, node);
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node->name = data->name;
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icc_node_add(node, &priv->provider);
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priv->nodes[i] = node;
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}
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for (i = 0; i < ARRAY_SIZE(test_topology); i++) {
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const struct test_node_data *data = &test_topology[i];
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struct icc_node *src = get_node(priv, data->id);
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for (j = 0; j < data->num_links; j++) {
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ret = icc_link_create(src, data->links[j]);
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KUNIT_ASSERT_EQ_MSG(test, ret, 0, "Failed to link %s->%d",
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src->name, data->links[j]);
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}
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}
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icc_sync_state(&priv->pdev->dev);
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return 0;
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}
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static void icc_test_exit(struct kunit *test)
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{
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struct icc_test_priv *priv = test->priv;
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icc_nodes_remove(&priv->provider);
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icc_provider_deregister(&priv->provider);
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}
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/*
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* Helper to construct a mock path.
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*
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* Because we are bypassing icc_get(), we must manually link the requests
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* to the nodes' req_list so that icc_std_aggregate() can discover them.
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*/
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static struct icc_path *icc_test_create_path(struct kunit *test,
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struct icc_node **nodes, int num)
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{
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struct icc_path *path;
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int i;
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path = kunit_kzalloc(test, struct_size(path, reqs, num), GFP_KERNEL);
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KUNIT_ASSERT_NOT_ERR_OR_NULL(test, path);
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path->num_nodes = num;
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for (i = 0; i < num; i++) {
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path->reqs[i].node = nodes[i];
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hlist_add_head(&path->reqs[i].req_node, &nodes[i]->req_list);
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}
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path->name = "mock-path";
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return path;
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}
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static void icc_test_destroy_path(struct kunit *test, struct icc_path *path)
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{
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int i;
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for (i = 0; i < path->num_nodes; i++)
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hlist_del(&path->reqs[i].req_node);
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kunit_kfree(test, path);
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}
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static void icc_test_topology_integrity(struct kunit *test)
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{
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struct icc_test_priv *priv = test->priv;
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struct icc_node *cpu = get_node(priv, NODE_CPU);
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struct icc_node *bus = get_node(priv, NODE_BUS);
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KUNIT_EXPECT_EQ(test, cpu->num_links, 1);
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KUNIT_EXPECT_PTR_EQ(test, cpu->links[0], bus);
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KUNIT_EXPECT_PTR_EQ(test, cpu->provider, &priv->provider);
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}
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static void icc_test_set_bw(struct kunit *test)
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{
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struct icc_test_priv *priv = test->priv;
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struct icc_path *path;
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struct icc_node *path_nodes[3];
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int ret;
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/* Path: CPU -> BUS -> DDR */
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path_nodes[0] = get_node(priv, NODE_CPU);
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path_nodes[1] = get_node(priv, NODE_BUS);
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path_nodes[2] = get_node(priv, NODE_DDR);
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path = icc_test_create_path(test, path_nodes, 3);
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ret = icc_enable(path);
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KUNIT_ASSERT_EQ(test, ret, 0);
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ret = icc_set_bw(path, 1000, 2000);
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KUNIT_EXPECT_EQ(test, ret, 0);
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KUNIT_EXPECT_EQ(test, path_nodes[0]->avg_bw, 1000);
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KUNIT_EXPECT_EQ(test, path_nodes[0]->peak_bw, 2000);
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KUNIT_EXPECT_EQ(test, path_nodes[1]->avg_bw, 1000);
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KUNIT_EXPECT_EQ(test, path_nodes[1]->peak_bw, 2000);
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icc_set_tag(path, 0xABC);
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KUNIT_EXPECT_EQ(test, path->reqs[0].tag, 0xABC);
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icc_disable(path);
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KUNIT_EXPECT_EQ(test, path_nodes[0]->avg_bw, 0);
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icc_test_destroy_path(test, path);
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}
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static void icc_test_aggregation(struct kunit *test)
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{
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struct icc_test_priv *priv = test->priv;
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struct icc_path *path_cpu, *path_gpu;
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struct icc_node *nodes_cpu[3], *nodes_gpu[2];
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struct icc_node *bus = get_node(priv, NODE_BUS);
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int ret;
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nodes_cpu[0] = get_node(priv, NODE_CPU);
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nodes_cpu[1] = bus;
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nodes_cpu[2] = get_node(priv, NODE_DDR);
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path_cpu = icc_test_create_path(test, nodes_cpu, 3);
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nodes_gpu[0] = get_node(priv, NODE_GPU);
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nodes_gpu[1] = bus;
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path_gpu = icc_test_create_path(test, nodes_gpu, 2);
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icc_enable(path_cpu);
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icc_enable(path_gpu);
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ret = icc_set_bw(path_cpu, 1000, 1000);
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KUNIT_EXPECT_EQ(test, ret, 0);
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KUNIT_EXPECT_EQ(test, bus->avg_bw, 1000);
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ret = icc_set_bw(path_gpu, 2000, 2000);
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KUNIT_EXPECT_EQ(test, ret, 0);
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/* Bus aggregates: CPU(1000) + GPU(2000) */
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KUNIT_EXPECT_EQ(test, bus->avg_bw, 3000);
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/* Peak aggregates: max(CPU, GPU) */
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KUNIT_EXPECT_EQ(test, bus->peak_bw, 2000);
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icc_test_destroy_path(test, path_cpu);
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icc_test_destroy_path(test, path_gpu);
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}
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static void icc_test_bulk_ops(struct kunit *test)
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{
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struct icc_test_priv *priv = test->priv;
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struct icc_node *nodes_cpu[3], *nodes_gpu[2];
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struct icc_bulk_data bulk[2];
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int ret;
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nodes_cpu[0] = get_node(priv, NODE_CPU);
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nodes_cpu[1] = get_node(priv, NODE_BUS);
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nodes_cpu[2] = get_node(priv, NODE_DDR);
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nodes_gpu[0] = get_node(priv, NODE_GPU);
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nodes_gpu[1] = get_node(priv, NODE_BUS);
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bulk[0].path = icc_test_create_path(test, nodes_cpu, 3);
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bulk[0].avg_bw = 500;
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bulk[0].peak_bw = 500;
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bulk[1].path = icc_test_create_path(test, nodes_gpu, 2);
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bulk[1].avg_bw = 600;
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bulk[1].peak_bw = 600;
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ret = icc_bulk_set_bw(2, bulk);
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KUNIT_EXPECT_EQ(test, ret, 0);
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/* Paths disabled, bandwidth should be 0 */
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KUNIT_EXPECT_EQ(test, get_node(priv, NODE_BUS)->avg_bw, 0);
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ret = icc_bulk_enable(2, bulk);
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KUNIT_EXPECT_EQ(test, ret, 0);
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/* Paths enabled, aggregation applies */
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KUNIT_EXPECT_EQ(test, get_node(priv, NODE_BUS)->avg_bw, 1100);
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icc_bulk_disable(2, bulk);
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KUNIT_EXPECT_EQ(test, get_node(priv, NODE_BUS)->avg_bw, 0);
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icc_test_destroy_path(test, bulk[0].path);
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icc_test_destroy_path(test, bulk[1].path);
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}
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static struct kunit_case icc_test_cases[] = {
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KUNIT_CASE(icc_test_topology_integrity),
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KUNIT_CASE(icc_test_set_bw),
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KUNIT_CASE(icc_test_aggregation),
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KUNIT_CASE(icc_test_bulk_ops),
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{}
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};
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static struct kunit_suite icc_test_suite = {
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.name = "interconnect",
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.init = icc_test_init,
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.exit = icc_test_exit,
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.test_cases = icc_test_cases,
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};
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kunit_test_suite(icc_test_suite);
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MODULE_AUTHOR("Kuan-Wei Chiu <visitorckw@gmail.com>");
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MODULE_DESCRIPTION("KUnit tests for the Interconnect framework");
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MODULE_LICENSE("GPL");