[PATCH RFC v4 04/12] clk: test: introduce test suite for sibling rate changes on a divider

[Brian Masney <bmasney@redhat.com>]

Introduce a test suite that creates a parent with two divider-only
children, and ensure that changing the rate of one child does not
affect the rate of the sibling. Some of the tests are disabled
until the underlying issue is fixed in the clk core.

Signed-off-by: Brian Masney <bmasney@redhat.com>
---
 drivers/clk/clk_test.c | 145 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 145 insertions(+)

diff --git a/drivers/clk/clk_test.c b/drivers/clk/clk_test.c
index e1f72fcede1df1d486744b171728231ec8fa8836..1aca266f9922beb7d81124c07d21b2a3d700dc5c 100644
--- a/drivers/clk/clk_test.c
+++ b/drivers/clk/clk_test.c
@@ -653,6 +653,150 @@ clk_multiple_parents_mux_test_suite = {
 	.test_cases = clk_multiple_parents_mux_test_cases,
 };
 
+struct clk_rate_change_sibling_div_div_context {
+	struct clk_dummy_context parent;
+	struct clk_dummy_div child1, child2;
+	struct clk *parent_clk, *child1_clk, *child2_clk;
+};
+
+static int clk_rate_change_sibling_div_div_test_init(struct kunit *test)
+{
+	struct clk_rate_change_sibling_div_div_context *ctx;
+	int ret;
+
+	ctx = kunit_kzalloc(test, sizeof(*ctx), GFP_KERNEL);
+	if (!ctx)
+		return -ENOMEM;
+	test->priv = ctx;
+
+	ctx->parent.hw.init = CLK_HW_INIT_NO_PARENT("parent", &clk_dummy_rate_ops, 0);
+	ctx->parent.rate = 24 * HZ_PER_MHZ;
+	ret = clk_hw_register_kunit(test, NULL, &ctx->parent.hw);
+	if (ret)
+		return ret;
+
+	ctx->child1.hw.init = CLK_HW_INIT_HW("child1", &ctx->parent.hw, &clk_dummy_div_ops,
+					     CLK_SET_RATE_PARENT);
+	ctx->child1.div = 1;
+	ret = clk_hw_register_kunit(test, NULL, &ctx->child1.hw);
+	if (ret)
+		return ret;
+
+	ctx->child2.hw.init = CLK_HW_INIT_HW("child2", &ctx->parent.hw, &clk_dummy_div_ops,
+					     CLK_SET_RATE_PARENT);
+	ctx->child2.div = 1;
+	ret = clk_hw_register_kunit(test, NULL, &ctx->child2.hw);
+	if (ret)
+		return ret;
+
+	ctx->parent_clk = clk_hw_get_clk(&ctx->parent.hw, NULL);
+	ctx->child1_clk = clk_hw_get_clk(&ctx->child1.hw, NULL);
+	ctx->child2_clk = clk_hw_get_clk(&ctx->child2.hw, NULL);
+
+	KUNIT_EXPECT_EQ(test, clk_get_rate(ctx->parent_clk), 24 * HZ_PER_MHZ);
+	KUNIT_EXPECT_EQ(test, clk_get_rate(ctx->child1_clk), 24 * HZ_PER_MHZ);
+	KUNIT_EXPECT_EQ(test, clk_get_rate(ctx->child2_clk), 24 * HZ_PER_MHZ);
+
+	return 0;
+}
+
+static void clk_rate_change_sibling_div_div_test_exit(struct kunit *test)
+{
+	struct clk_rate_change_sibling_div_div_context *ctx = test->priv;
+
+	clk_put(ctx->parent_clk);
+	clk_put(ctx->child1_clk);
+	clk_put(ctx->child2_clk);
+}
+
+/*
+ * Test that, for a parent with two divider-only children with CLK_SET_RATE_PARENT set
+ * and one requests a rate compatible with the existing parent rate, the parent and
+ * sibling rates are not affected.
+ */
+static void clk_test_rate_change_sibling_div_div_1(struct kunit *test)
+{
+	struct clk_rate_change_sibling_div_div_context *ctx = test->priv;
+	int ret;
+
+	ret = clk_set_rate(ctx->child1_clk, 6 * HZ_PER_MHZ);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+
+	KUNIT_EXPECT_EQ(test, clk_get_rate(ctx->parent_clk), 24 * HZ_PER_MHZ);
+	KUNIT_EXPECT_EQ(test, clk_get_rate(ctx->child1_clk), 6 * HZ_PER_MHZ);
+	KUNIT_EXPECT_EQ(test, ctx->child1.div, 4);
+	KUNIT_EXPECT_EQ(test, clk_get_rate(ctx->child2_clk), 24 * HZ_PER_MHZ);
+	KUNIT_EXPECT_EQ(test, ctx->child2.div, 1);
+}
+
+/*
+ * Test that, for a parent with two divider-only children with CLK_SET_RATE_PARENT
+ * set and one requests a rate incompatible with the existing parent rate, the
+ * sibling rate is not affected. The requested child rate picks a parent rate
+ * that's compatible with both children.
+ */
+static void clk_test_rate_change_sibling_div_div_2(struct kunit *test)
+{
+	struct clk_rate_change_sibling_div_div_context *ctx = test->priv;
+	int ret;
+
+	kunit_skip(test, "This needs to be fixed in the core.");
+
+	ret = clk_set_rate(ctx->child1_clk, 48 * HZ_PER_MHZ);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+
+	KUNIT_EXPECT_EQ(test, clk_get_rate(ctx->parent_clk), 48 * HZ_PER_MHZ);
+	KUNIT_EXPECT_EQ(test, clk_get_rate(ctx->child1_clk), 48 * HZ_PER_MHZ);
+	KUNIT_EXPECT_EQ(test, ctx->child1.div, 1);
+	KUNIT_EXPECT_EQ(test, clk_get_rate(ctx->child2_clk), 24 * HZ_PER_MHZ);
+	KUNIT_EXPECT_EQ(test, ctx->child2.div, 2);
+}
+
+/*
+ * Test that, for a parent with two divider-only children with CLK_SET_RATE_PARENT
+ * set and one requests a rate incompatible with the existing parent rate, the
+ * sibling rate is not affected. The requested child rates require a parent rate
+ * that neither child would initially pick.
+ */
+static void clk_test_rate_change_sibling_div_div_3(struct kunit *test)
+{
+	struct clk_rate_change_sibling_div_div_context *ctx = test->priv;
+	int ret;
+
+	kunit_skip(test, "This needs to be fixed in the core.");
+
+	ret = clk_set_rate(ctx->child1_clk, 32 * HZ_PER_MHZ);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+
+	ret = clk_set_rate(ctx->child2_clk, 48 * HZ_PER_MHZ);
+	KUNIT_ASSERT_EQ(test, ret, 0);
+
+	KUNIT_EXPECT_EQ(test, clk_get_rate(ctx->parent_clk), 96 * HZ_PER_MHZ);
+	KUNIT_EXPECT_EQ(test, clk_get_rate(ctx->child1_clk), 32 * HZ_PER_MHZ);
+	KUNIT_EXPECT_EQ(test, ctx->child1.div, 3);
+	KUNIT_EXPECT_EQ(test, clk_get_rate(ctx->child2_clk), 48 * HZ_PER_MHZ);
+	KUNIT_EXPECT_EQ(test, ctx->child2.div, 2);
+}
+
+static struct kunit_case clk_rate_change_sibling_div_div_cases[] = {
+	KUNIT_CASE(clk_test_rate_change_sibling_div_div_1),
+	KUNIT_CASE(clk_test_rate_change_sibling_div_div_2),
+	KUNIT_CASE(clk_test_rate_change_sibling_div_div_3),
+	{}
+};
+
+/*
+ * Test suite that creates a parent with two divider-only children, and
+ * ensures that changing the rate of one child does not affect the rate
+ * of the other child.
+ */
+static struct kunit_suite clk_rate_change_sibling_div_div_test_suite = {
+	.name = "clk-rate-change-sibling-div-div",
+	.init = clk_rate_change_sibling_div_div_test_init,
+	.exit = clk_rate_change_sibling_div_div_test_exit,
+	.test_cases = clk_rate_change_sibling_div_div_cases,
+};
+
 static int
 clk_orphan_transparent_multiple_parent_mux_test_init(struct kunit *test)
 {
@@ -3593,6 +3737,7 @@ kunit_test_suites(
 	&clk_leaf_mux_set_rate_parent_test_suite,
 	&clk_test_suite,
 	&clk_multiple_parents_mux_test_suite,
+	&clk_rate_change_sibling_div_div_test_suite,
 	&clk_mux_no_reparent_test_suite,
 	&clk_mux_notifier_test_suite,
 	&clk_orphan_transparent_multiple_parent_mux_test_suite,

-- 
2.51.0