clk: tests: Add some tests for orphan with multiple parents

Let's leverage the dummy mux with multiple parents we have to create a
mux whose default parent will never be registered, and thus will always
be orphan by default.

We can then create some tests to make sure that the clock API behaves
properly in such a case, and that the transition to a non-orphan clock
when we change the parent is done properly.

Tested-by: Alexander Stein <alexander.stein@ew.tq-group.com> # imx8mp
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com> # exynos4210, meson g12b
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20220816112530.1837489-12-maxime@cerno.tech
Tested-by: Linux Kernel Functional Testing <lkft@linaro.org>
Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

drivers/clk/clk_test.c

@@ -480,6 +480,242 @@ clk_multiple_parents_mux_test_suite = {
 	.test_cases = clk_multiple_parents_mux_test_cases,
 };
 
+static int
+clk_orphan_transparent_multiple_parent_mux_test_init(struct kunit *test)
+{
+	struct clk_multiple_parent_ctx *ctx;
+	const char *parents[2] = { "missing-parent", "proper-parent"};
+	int ret;
+
+	ctx = kunit_kzalloc(test, sizeof(*ctx), GFP_KERNEL);
+	if (!ctx)
+		return -ENOMEM;
+	test->priv = ctx;
+
+	ctx->parents_ctx[1].hw.init = CLK_HW_INIT_NO_PARENT("proper-parent",
+							    &clk_dummy_rate_ops,
+							    0);
+	ctx->parents_ctx[1].rate = DUMMY_CLOCK_INIT_RATE;
+	ret = clk_hw_register(NULL, &ctx->parents_ctx[1].hw);
+	if (ret)
+		return ret;
+
+	ctx->hw.init = CLK_HW_INIT_PARENTS("test-orphan-mux", parents,
+					   &clk_multiple_parents_mux_ops,
+					   CLK_SET_RATE_PARENT);
+	ret = clk_hw_register(NULL, &ctx->hw);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static void
+clk_orphan_transparent_multiple_parent_mux_test_exit(struct kunit *test)
+{
+	struct clk_multiple_parent_ctx *ctx = test->priv;
+
+	clk_hw_unregister(&ctx->hw);
+	clk_hw_unregister(&ctx->parents_ctx[1].hw);
+}
+
+/*
+ * Test that, for a mux whose current parent hasn't been registered yet and is
+ * thus orphan, clk_get_parent() will return NULL.
+ */
+static void
+clk_test_orphan_transparent_multiple_parent_mux_get_parent(struct kunit *test)
+{
+	struct clk_multiple_parent_ctx *ctx = test->priv;
+	struct clk_hw *hw = &ctx->hw;
+	struct clk *clk = clk_hw_get_clk(hw, NULL);
+
+	KUNIT_EXPECT_PTR_EQ(test, clk_get_parent(clk), NULL);
+
+	clk_put(clk);
+}
+
+/*
+ * Test that, for a mux whose current parent hasn't been registered yet,
+ * calling clk_set_parent() to a valid parent will properly update the
+ * mux parent and its orphan status.
+ */
+static void
+clk_test_orphan_transparent_multiple_parent_mux_set_parent(struct kunit *test)
+{
+	struct clk_multiple_parent_ctx *ctx = test->priv;
+	struct clk_hw *hw = &ctx->hw;
+	struct clk *clk = clk_hw_get_clk(hw, NULL);
+	struct clk *parent, *new_parent;
+	int ret;
+
+	parent = clk_hw_get_clk(&ctx->parents_ctx[1].hw, NULL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, parent);
+
+	ret = clk_set_parent(clk, parent);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+
+	new_parent = clk_get_parent(clk);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, parent);
+	KUNIT_EXPECT_TRUE(test, clk_is_match(parent, new_parent));
+
+	clk_put(parent);
+	clk_put(clk);
+}
+
+/*
+ * Test that, for a mux that started orphan but got switched to a valid
+ * parent, the rate of the mux and its new parent are consistent.
+ */
+static void
+clk_test_orphan_transparent_multiple_parent_mux_set_parent_get_rate(struct kunit *test)
+{
+	struct clk_multiple_parent_ctx *ctx = test->priv;
+	struct clk_hw *hw = &ctx->hw;
+	struct clk *clk = clk_hw_get_clk(hw, NULL);
+	struct clk *parent;
+	unsigned long parent_rate, rate;
+	int ret;
+
+	parent = clk_hw_get_clk(&ctx->parents_ctx[1].hw, NULL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, parent);
+
+	parent_rate = clk_get_rate(parent);
+	KUNIT_ASSERT_GT(test, parent_rate, 0);
+
+	ret = clk_set_parent(clk, parent);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+
+	rate = clk_get_rate(clk);
+	KUNIT_ASSERT_GT(test, rate, 0);
+	KUNIT_EXPECT_EQ(test, parent_rate, rate);
+
+	clk_put(parent);
+	clk_put(clk);
+}
+
+/*
+ * Test that, for a mux that started orphan but got switched to a valid
+ * parent, calling clk_set_rate_range() will affect the parent state if
+ * its rate is out of range.
+ */
+static void
+clk_test_orphan_transparent_multiple_parent_mux_set_parent_set_range_modified(struct kunit *test)
+{
+	struct clk_multiple_parent_ctx *ctx = test->priv;
+	struct clk_hw *hw = &ctx->hw;
+	struct clk *clk = clk_hw_get_clk(hw, NULL);
+	struct clk *parent;
+	unsigned long rate;
+	int ret;
+
+	parent = clk_hw_get_clk(&ctx->parents_ctx[1].hw, NULL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, parent);
+
+	ret = clk_set_parent(clk, parent);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+
+	ret = clk_set_rate_range(clk, DUMMY_CLOCK_RATE_1, DUMMY_CLOCK_RATE_2);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+
+	rate = clk_get_rate(clk);
+	KUNIT_ASSERT_GT(test, rate, 0);
+	KUNIT_EXPECT_GE(test, rate, DUMMY_CLOCK_RATE_1);
+	KUNIT_EXPECT_LE(test, rate, DUMMY_CLOCK_RATE_2);
+
+	clk_put(parent);
+	clk_put(clk);
+}
+
+/*
+ * Test that, for a mux whose current parent hasn't been registered yet,
+ * calling clk_set_rate_range() will succeed, and will be taken into
+ * account when rounding a rate.
+ */
+static void
+clk_test_orphan_transparent_multiple_parent_mux_set_range_round_rate(struct kunit *test)
+{
+	struct clk_multiple_parent_ctx *ctx = test->priv;
+	struct clk_hw *hw = &ctx->hw;
+	struct clk *clk = clk_hw_get_clk(hw, NULL);
+	unsigned long rate;
+	int ret;
+
+	ret = clk_set_rate_range(clk, DUMMY_CLOCK_RATE_1, DUMMY_CLOCK_RATE_2);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+
+	rate = clk_round_rate(clk, DUMMY_CLOCK_RATE_1 - 1000);
+	KUNIT_ASSERT_GT(test, rate, 0);
+	KUNIT_EXPECT_GE(test, rate, DUMMY_CLOCK_RATE_1);
+	KUNIT_EXPECT_LE(test, rate, DUMMY_CLOCK_RATE_2);
+
+	clk_put(clk);
+}
+
+/*
+ * Test that, for a mux that started orphan, was assigned and rate and
+ * then got switched to a valid parent, its rate is eventually within
+ * range.
+ *
+ * FIXME: Even though we update the rate as part of clk_set_parent(), we
+ * don't evaluate whether that new rate is within range and needs to be
+ * adjusted.
+ */
+static void
+clk_test_orphan_transparent_multiple_parent_mux_set_range_set_parent_get_rate(struct kunit *test)
+{
+	struct clk_multiple_parent_ctx *ctx = test->priv;
+	struct clk_hw *hw = &ctx->hw;
+	struct clk *clk = clk_hw_get_clk(hw, NULL);
+	struct clk *parent;
+	unsigned long rate;
+	int ret;
+
+	kunit_skip(test, "This needs to be fixed in the core.");
+
+	clk_hw_set_rate_range(hw, DUMMY_CLOCK_RATE_1, DUMMY_CLOCK_RATE_2);
+
+	parent = clk_hw_get_clk(&ctx->parents_ctx[1].hw, NULL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, parent);
+
+	ret = clk_set_parent(clk, parent);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+
+	rate = clk_get_rate(clk);
+	KUNIT_ASSERT_GT(test, rate, 0);
+	KUNIT_EXPECT_GE(test, rate, DUMMY_CLOCK_RATE_1);
+	KUNIT_EXPECT_LE(test, rate, DUMMY_CLOCK_RATE_2);
+
+	clk_put(parent);
+	clk_put(clk);
+}
+
+static struct kunit_case clk_orphan_transparent_multiple_parent_mux_test_cases[] = {
+	KUNIT_CASE(clk_test_orphan_transparent_multiple_parent_mux_get_parent),
+	KUNIT_CASE(clk_test_orphan_transparent_multiple_parent_mux_set_parent),
+	KUNIT_CASE(clk_test_orphan_transparent_multiple_parent_mux_set_parent_get_rate),
+	KUNIT_CASE(clk_test_orphan_transparent_multiple_parent_mux_set_parent_set_range_modified),
+	KUNIT_CASE(clk_test_orphan_transparent_multiple_parent_mux_set_range_round_rate),
+	KUNIT_CASE(clk_test_orphan_transparent_multiple_parent_mux_set_range_set_parent_get_rate),
+	{}
+};
+
+/*
+ * Test suite for a basic mux clock with two parents. The default parent
+ * isn't registered, only the second parent is. By default, the clock
+ * will thus be orphan.
+ *
+ * These tests exercise the behaviour of the consumer API when dealing
+ * with an orphan clock, and how we deal with the transition to a valid
+ * parent.
+ */
+static struct kunit_suite clk_orphan_transparent_multiple_parent_mux_test_suite = {
+	.name = "clk-orphan-transparent-multiple-parent-mux-test",
+	.init = clk_orphan_transparent_multiple_parent_mux_test_init,
+	.exit = clk_orphan_transparent_multiple_parent_mux_test_exit,
+	.test_cases = clk_orphan_transparent_multiple_parent_mux_test_cases,
+};
+
 struct clk_single_parent_ctx {
 	struct clk_dummy_context parent_ctx;
 	struct clk_hw hw;
@@ -1460,6 +1696,7 @@ static struct kunit_suite clk_range_minimize_test_suite = {
 kunit_test_suites(
 	&clk_test_suite,
 	&clk_multiple_parents_mux_test_suite,
+	&clk_orphan_transparent_multiple_parent_mux_test_suite,
 	&clk_orphan_transparent_single_parent_test_suite,
 	&clk_range_test_suite,
 	&clk_range_maximize_test_suite,