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From e22b0f50781bc8507c1e3b8f775ac69d406bd155 Mon Sep 17 00:00:00 2001
From: Maxime Ripard <maxime@cerno.tech>
Date: Fri, 25 Mar 2022 11:27:28 +0100
Subject: [PATCH] clk: test: Test clk_set_rate_range on orphan mux
A bug recently affected the Tegra30 where calling clk_set_rate_range()
on a clock would make it change its rate to the minimum.
This was due to the clock in question being a mux that was orphan at
registration, which lead to the clk_core req_rate being 0, and the
clk_set_rate_range() function then calling clk_set_rate() with req_rate,
effectively making that clock running at the minimum rate allowed, even
though the initial rate was within that range.
Make a test suite to create a mux initially orphan, and then make sure
that if our clock rate was initially within a given range, then
enforcing that range won't affect it.
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
---
drivers/clk/clk_test.c | 105 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 105 insertions(+)
--- a/drivers/clk/clk_test.c
+++ b/drivers/clk/clk_test.c
@@ -72,6 +72,19 @@ static int clk_dummy_set_rate(struct clk
return 0;
}
+static int clk_dummy_single_set_parent(struct clk_hw *hw, u8 index)
+{
+ if (index >= clk_hw_get_num_parents(hw))
+ return -EINVAL;
+
+ return 0;
+}
+
+static u8 clk_dummy_single_get_parent(struct clk_hw *hw)
+{
+ return 0;
+}
+
static const struct clk_ops clk_dummy_rate_ops = {
.recalc_rate = clk_dummy_recalc_rate,
.determine_rate = clk_dummy_determine_rate,
@@ -90,6 +103,11 @@ static const struct clk_ops clk_dummy_mi
.set_rate = clk_dummy_set_rate,
};
+static const struct clk_ops clk_dummy_single_parent_ops = {
+ .set_parent = clk_dummy_single_set_parent,
+ .get_parent = clk_dummy_single_get_parent,
+};
+
static int clk_test_init_with_ops(struct kunit *test, const struct clk_ops *ops)
{
struct clk_dummy_context *ctx;
@@ -239,6 +257,92 @@ static struct kunit_suite clk_test_suite
.test_cases = clk_test_cases,
};
+struct clk_single_parent_ctx {
+ struct clk_dummy_context parent_ctx;
+ struct clk_hw hw;
+};
+
+static int clk_orphan_transparent_single_parent_mux_test_init(struct kunit *test)
+{
+ struct clk_single_parent_ctx *ctx;
+ struct clk_init_data init = { };
+ const char *parents[] = { "orphan_parent" };
+ int ret;
+
+ ctx = kunit_kzalloc(test, sizeof(*ctx), GFP_KERNEL);
+ if (!ctx)
+ return -ENOMEM;
+ test->priv = ctx;
+
+ init.name = "test_orphan_dummy_parent";
+ init.ops = &clk_dummy_single_parent_ops;
+ init.parent_names = parents;
+ init.num_parents = ARRAY_SIZE(parents);
+ init.flags = CLK_SET_RATE_PARENT;
+ ctx->hw.init = &init;
+
+ ret = clk_hw_register(NULL, &ctx->hw);
+ if (ret)
+ return ret;
+
+ memset(&init, 0, sizeof(init));
+ init.name = "orphan_parent";
+ init.ops = &clk_dummy_rate_ops;
+ ctx->parent_ctx.hw.init = &init;
+ ctx->parent_ctx.rate = DUMMY_CLOCK_INIT_RATE;
+
+ ret = clk_hw_register(NULL, &ctx->parent_ctx.hw);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+static void clk_orphan_transparent_single_parent_mux_test_exit(struct kunit *test)
+{
+ struct clk_single_parent_ctx *ctx = test->priv;
+
+ clk_hw_unregister(&ctx->hw);
+ clk_hw_unregister(&ctx->parent_ctx.hw);
+}
+
+/*
+ * Test that a mux-only clock, with an initial rate within a range,
+ * will still have the same rate after the range has been enforced.
+ */
+static void clk_test_orphan_transparent_parent_mux_set_range(struct kunit *test)
+{
+ struct clk_single_parent_ctx *ctx = test->priv;
+ struct clk_hw *hw = &ctx->hw;
+ struct clk *clk = hw->clk;
+ unsigned long rate, new_rate;
+
+ rate = clk_get_rate(clk);
+ KUNIT_ASSERT_GT(test, rate, 0);
+
+ KUNIT_ASSERT_EQ(test,
+ clk_set_rate_range(clk,
+ ctx->parent_ctx.rate - 1000,
+ ctx->parent_ctx.rate + 1000),
+ 0);
+
+ new_rate = clk_get_rate(clk);
+ KUNIT_ASSERT_GT(test, new_rate, 0);
+ KUNIT_EXPECT_EQ(test, rate, new_rate);
+}
+
+static struct kunit_case clk_orphan_transparent_single_parent_mux_test_cases[] = {
+ KUNIT_CASE(clk_test_orphan_transparent_parent_mux_set_range),
+ {}
+};
+
+static struct kunit_suite clk_orphan_transparent_single_parent_test_suite = {
+ .name = "clk-orphan-transparent-single-parent-test",
+ .init = clk_orphan_transparent_single_parent_mux_test_init,
+ .exit = clk_orphan_transparent_single_parent_mux_test_exit,
+ .test_cases = clk_orphan_transparent_single_parent_mux_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
@@ -788,6 +892,7 @@ static struct kunit_suite clk_range_mini
kunit_test_suites(
&clk_test_suite,
+ &clk_orphan_transparent_single_parent_test_suite,
&clk_range_test_suite,
&clk_range_maximize_test_suite,
&clk_range_minimize_test_suite
|
