[PATCH v6 16/28] clk: Set req_rate on reparenting

Maxime Ripard
2022-07-11T15:25:02Z

If a non-rate clock started by default with a parent that never
registered, core->req_rate will be 0. The expectation is that whenever
the parent will be registered, req_rate will be updated with the new
value that has just been computed.

However, if that clock is a mux, clk_set_parent() can also make that
clock no longer orphan. In this case however, we never update req_rate.
Let's make sure it's the case for the newly unorphan clock and all its
children.

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>
---
drivers/clk/clk.c | 18 ++++
drivers/clk/clk_test.c | 239 +++++++++++++++++++++++++++++++++++++++++
2 files changed, 257 insertions(+)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 53b28e63deae..6f5284f6cab5 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -1765,6 +1765,23 @@ static void clk_core_update_orphan_status(struct clk_core *core, bool is_orphan)
clk_core_update_orphan_status(child, is_orphan);
}

+/*
+ * Update the orphan rate and req_rate of @core and all its children.
+ */
+static void clk_core_update_orphan_child_rates(struct clk_core *core)
+{
+ struct clk_core *child;
+ unsigned long parent_rate = 0;
+
+ if (core->parent)
+ parent_rate = core->parent->rate;
+
+ core->rate = core->req_rate = clk_recalc(core, parent_rate);
+
+ hlist_for_each_entry(child, &core->children, child_node)
+ clk_core_update_orphan_child_rates(child);
+}
+
static void clk_reparent(struct clk_core *core, struct clk_core *new_parent)
{
bool was_orphan = core->orphan;
@@ -1789,6 +1806,7 @@ static void clk_reparent(struct clk_core *core, struct clk_core *new_parent)
}

core->parent = new_parent;
+ clk_core_update_orphan_child_rates(core);
}

static struct clk_core *__clk_set_parent_before(struct clk_core *core,
diff --git a/drivers/clk/clk_test.c b/drivers/clk/clk_test.c
index d3e121f21ae2..d1b1372f7aaa 100644
--- a/drivers/clk/clk_test.c
+++ b/drivers/clk/clk_test.c
@@ -594,6 +594,41 @@ clk_test_orphan_transparent_multiple_parent_mux_set_parent(struct kunit *test)
clk_put(clk);
}

+/*
+ * Test that, for a mux that started orphan but got switched to a valid
+ * parent, calling clk_drop_range() on the mux won't affect the parent
+ * rate.
+ */
+static void
+clk_test_orphan_transparent_multiple_parent_mux_set_parent_drop_range(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, new_parent_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);
+
+ ret = clk_drop_range(clk);
+ KUNIT_ASSERT_EQ(test, ret, 0);
+
+ new_parent_rate = clk_get_rate(clk);
+ KUNIT_ASSERT_GT(test, new_parent_rate, 0);
+ KUNIT_EXPECT_EQ(test, parent_rate, new_parent_rate);
+
+ 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.
@@ -625,6 +660,39 @@ clk_test_orphan_transparent_multiple_parent_mux_set_parent_get_rate(struct kunit
clk_put(clk);
}

+/*
+ * Test that, for a mux that started orphan but got switched to a valid
+ * parent, calling clk_put() on the mux won't affect the parent rate.
+ */
+static void
+clk_test_orphan_transparent_multiple_parent_mux_set_parent_put(struct kunit *test)
+{
+ struct clk_multiple_parent_ctx *ctx = test->priv;
+ struct clk *clk, *parent;
+ unsigned long parent_rate, new_parent_rate;
+ int ret;
+
+ parent = clk_hw_get_clk(&ctx->parents_ctx[1].hw, NULL);
+ KUNIT_ASSERT_NOT_ERR_OR_NULL(test, parent);
+
+ clk = clk_hw_get_clk(&ctx->hw, NULL);
+ KUNIT_ASSERT_NOT_ERR_OR_NULL(test, clk);
+
+ 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);
+
+ clk_put(clk);
+
+ new_parent_rate = clk_get_rate(parent);
+ KUNIT_ASSERT_GT(test, new_parent_rate, 0);
+ KUNIT_EXPECT_EQ(test, parent_rate, new_parent_rate);
+
+ clk_put(parent);
+}
+
/*
* 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
@@ -658,6 +726,43 @@ clk_test_orphan_transparent_multiple_parent_mux_set_parent_set_range_modified(st
clk_put(clk);
}

+/*
+ * Test that, for a mux that started orphan but got switched to a valid
+ * parent, calling clk_set_rate_range() won't affect the parent state if
+ * its rate is within range.
+ */
+static void
+clk_test_orphan_transparent_multiple_parent_mux_set_parent_set_range_untouched(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, new_parent_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);
+
+ ret = clk_set_rate_range(clk,
+ DUMMY_CLOCK_INIT_RATE - 1000,
+ DUMMY_CLOCK_INIT_RATE + 1000);
+ KUNIT_ASSERT_EQ(test, ret, 0);
+
+ new_parent_rate = clk_get_rate(parent);
+ KUNIT_ASSERT_GT(test, new_parent_rate, 0);
+ KUNIT_EXPECT_EQ(test, parent_rate, new_parent_rate);
+
+ 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
@@ -724,8 +829,11 @@ clk_test_orphan_transparent_multiple_parent_mux_set_range_set_parent_get_rate(st
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_drop_range),
KUNIT_CASE(clk_test_orphan_transparent_multiple_parent_mux_set_parent_get_rate),
+ KUNIT_CASE(clk_test_orphan_transparent_multiple_parent_mux_set_parent_put),
KUNIT_CASE(clk_test_orphan_transparent_multiple_parent_mux_set_parent_set_range_modified),
+ KUNIT_CASE(clk_test_orphan_transparent_multiple_parent_mux_set_parent_set_range_untouched),
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),
{}
@@ -1021,6 +1129,136 @@ static struct kunit_suite clk_orphan_transparent_single_parent_test_suite = {
.test_cases = clk_orphan_transparent_single_parent_mux_test_cases,
};

+struct clk_single_parent_two_lvl_ctx {
+ struct clk_dummy_context parent_parent_ctx;
+ struct clk_dummy_context parent_ctx;
+ struct clk_hw hw;
+};
+
+static int
+clk_orphan_two_level_root_last_test_init(struct kunit *test)
+{
+ struct clk_single_parent_two_lvl_ctx *ctx;
+ int ret;
+
+ ctx = kunit_kzalloc(test, sizeof(*ctx), GFP_KERNEL);
+ if (!ctx)
+ return -ENOMEM;
+ test->priv = ctx;
+
+ ctx->parent_ctx.hw.init =
+ CLK_HW_INIT("intermediate-parent",
+ "root-parent",
+ &clk_dummy_single_parent_ops,
+ CLK_SET_RATE_PARENT);
+ ret = clk_hw_register(NULL, &ctx->parent_ctx.hw);
+ if (ret)
+ return ret;
+
+ ctx->hw.init =
+ CLK_HW_INIT("test-clk", "intermediate-parent",
+ &clk_dummy_single_parent_ops,
+ CLK_SET_RATE_PARENT);
+ ret = clk_hw_register(NULL, &ctx->hw);
+ if (ret)
+ return ret;
+
+ ctx->parent_parent_ctx.rate = DUMMY_CLOCK_INIT_RATE;
+ ctx->parent_parent_ctx.hw.init =
+ CLK_HW_INIT_NO_PARENT("root-parent",
+ &clk_dummy_rate_ops,
+ 0);
+ ret = clk_hw_register(NULL, &ctx->parent_parent_ctx.hw);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+static void
+clk_orphan_two_level_root_last_test_exit(struct kunit *test)
+{
+ struct clk_single_parent_two_lvl_ctx *ctx = test->priv;
+
+ clk_hw_unregister(&ctx->hw);
+ clk_hw_unregister(&ctx->parent_ctx.hw);
+ clk_hw_unregister(&ctx->parent_parent_ctx.hw);
+}
+
+/*
+ * Test that, for a clock whose parent used to be orphan, clk_get_rate()
+ * will return the proper rate.
+ */
+static void
+clk_orphan_two_level_root_last_test_get_rate(struct kunit *test)
+{
+ struct clk_single_parent_two_lvl_ctx *ctx = test->priv;
+ struct clk_hw *hw = &ctx->hw;
+ struct clk *clk = clk_hw_get_clk(hw, NULL);
+ unsigned long rate;
+
+ rate = clk_get_rate(clk);
+ KUNIT_EXPECT_EQ(test, rate, DUMMY_CLOCK_INIT_RATE);
+
+ clk_put(clk);
+}
+
+/*
+ * Test that, for a clock whose parent used to be orphan,
+ * clk_set_rate_range() won't affect its rate if it is already within
+ * range.
+ *
+ * See (for Exynos 4210):
+ * https://lore.kernel.org/linux-clk/366a0232-bb4a-c357-6aa8-636e398e05eb@samsung.com/
+ */
+static void
+clk_orphan_two_level_root_last_test_set_range(struct kunit *test)
+{
+ struct clk_single_parent_two_lvl_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_INIT_RATE - 1000,
+ DUMMY_CLOCK_INIT_RATE + 1000);
+ KUNIT_ASSERT_EQ(test, ret, 0);
+
+ rate = clk_get_rate(clk);
+ KUNIT_ASSERT_GT(test, rate, 0);
+ KUNIT_EXPECT_EQ(test, rate, DUMMY_CLOCK_INIT_RATE);
+
+ clk_put(clk);
+}
+
+static struct kunit_case
+clk_orphan_two_level_root_last_test_cases[] = {
+ KUNIT_CASE(clk_orphan_two_level_root_last_test_get_rate),
+ KUNIT_CASE(clk_orphan_two_level_root_last_test_set_range),
+ {}
+};
+
+/*
+ * Test suite for a basic, transparent, clock with a parent that is also
+ * such a clock. The parent's parent is registered last, while the
+ * parent and its child are registered in that order. The intermediate
+ * and leaf clocks will thus be orphan when registered, but the leaf
+ * clock itself will always have its parent and will never be
+ * reparented. Indeed, it's only orphan because its parent is.
+ *
+ * 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_two_level_root_last_test_suite = {
+ .name = "clk-orphan-two-level-root-last-test",
+ .init = clk_orphan_two_level_root_last_test_init,
+ .exit = clk_orphan_two_level_root_last_test_exit,
+ .test_cases = clk_orphan_two_level_root_last_test_cases,
+};
+
/*
* Test that clk_set_rate_range won't return an error for a valid range
* and that it will make sure the rate of the clock is within the
@@ -1729,6 +1967,7 @@ kunit_test_suites(
&clk_multiple_parents_mux_test_suite,
&clk_orphan_transparent_multiple_parent_mux_test_suite,
&clk_orphan_transparent_single_parent_test_suite,
+ &clk_orphan_two_level_root_last_test_suite,
&clk_range_test_suite,
&clk_range_maximize_test_suite,
&clk_range_minimize_test_suite,
--
2.36.1