linux-kernel - Re: [PATCH v3 2/2] clk: tests: Add missing test cases for mux determine

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Date:   Tue, 02 May 2023 20:08:03 -0700
From:   Stephen Boyd <sboyd@...nel.org>
To:     Michael Turquette <mturquette@...libre.com>,
        Yang Xiwen via B4 Relay 
        <devnull+forbidden405.outlook.com@...nel.org>,
        forbidden405@...look.com
Cc:     linux-clk@...r.kernel.org, linux-kernel@...r.kernel.org,
        Yang Xiwen <forbidden405@...look.com>
Subject: Re: [PATCH v3 2/2] clk: tests: Add missing test cases for mux determine_rate

Quoting Yang Xiwen via B4 Relay (2023-04-26 12:34:17)
> diff --git a/drivers/clk/clk_test.c b/drivers/clk/clk_test.c
> index f9a5c2964c65d..4f7f9a964637a 100644
> --- a/drivers/clk/clk_test.c
> +++ b/drivers/clk/clk_test.c
> @@ -2194,7 +2194,47 @@ static void clk_leaf_mux_set_rate_parent_test_exit(struct kunit *test)
>   * parent, the rate request structure returned by __clk_determine_rate
>   * is sane and will be what we expect.
>   */
> -static void clk_leaf_mux_set_rate_parent_determine_rate(struct kunit *test)

Just leave this one alone and put the other test cases right after it.
Don't rename it and also move it lower down. It makes the diff hard to
read.

> +static void clk_leaf_mux_set_rate_parent_determine_rate_case1(struct kunit *test)

Please add a comment above each test case like there is for
clk_leaf_mux_set_rate_parent_determine_rate() that describes what is
being tested.

> +{
> +       struct clk_leaf_mux_ctx *ctx = test->priv;
> +       struct clk_hw *hw = &ctx->hw;
> +       struct clk *clk = clk_hw_get_clk(hw, NULL);
> +       struct clk_rate_request req;
> +       unsigned long rate;
> +       int ret;
> +
> +       rate = clk_get_rate(clk);
> +       KUNIT_ASSERT_EQ(test, rate, DUMMY_CLOCK_RATE_1);
> +
> +       clk_hw_init_rate_request(hw, &req, 0);
> +
> +       ret = __clk_determine_rate(hw, &req);
> +       KUNIT_ASSERT_EQ(test, ret, -EINVAL);
> +
> +       clk_put(clk);
> +}
> +
> +static void clk_leaf_mux_set_rate_parent_determine_rate_case2(struct kunit *test)
> +{
> +       struct clk_leaf_mux_ctx *ctx = test->priv;
> +       struct clk_hw *hw = &ctx->hw;
> +       struct clk *clk = clk_hw_get_clk(hw, NULL);
> +       struct clk_rate_request req;
> +       unsigned long rate;
> +       int ret;
> +
> +       rate = clk_get_rate(clk);
> +       KUNIT_ASSERT_EQ(test, rate, DUMMY_CLOCK_RATE_1);
> +
> +       clk_hw_init_rate_request(hw, &req, DUMMY_CLOCK_INIT_RATE);
> +
> +       ret = __clk_determine_rate(hw, &req);
> +       KUNIT_ASSERT_EQ(test, ret, -EINVAL);

There should be some KUNIT_EXPECT statement in each test.

> +
> +       clk_put(clk);
> +}
> +
> +static void clk_leaf_mux_set_rate_parent_determine_rate_case3(struct kunit *test)
>  {
>         struct clk_leaf_mux_ctx *ctx = test->priv;
>         struct clk_hw *hw = &ctx->hw;
> @@ -2218,8 +2258,95 @@ static void clk_leaf_mux_set_rate_parent_determine_rate(struct kunit *test)
>         clk_put(clk);
>  }
>  
> +static void clk_leaf_mux_set_rate_parent_determine_rate_case4(struct kunit *test)
> +{
> +       struct clk_leaf_mux_ctx *ctx = test->priv;
> +       struct clk_hw *hw = &ctx->hw;
> +       struct clk *clk = clk_hw_get_clk(hw, NULL);
> +       struct clk_rate_request req;
> +       unsigned long rate;
> +       int ret;
> +
> +       rate = clk_get_rate(clk);
> +       KUNIT_ASSERT_EQ(test, rate, DUMMY_CLOCK_RATE_1);
> +
> +       clk_hw_init_rate_request(hw, &req, (DUMMY_CLOCK_RATE_1 + DUMMY_CLOCK_RATE_2) / 2);
> +
> +       ret = __clk_determine_rate(hw, &req);
> +       KUNIT_ASSERT_EQ(test, ret, 0);
> +
> +       KUNIT_EXPECT_EQ(test, req.rate, DUMMY_CLOCK_RATE_1);
> +       KUNIT_EXPECT_EQ(test, req.best_parent_rate, DUMMY_CLOCK_RATE_1);
> +       KUNIT_EXPECT_PTR_EQ(test, req.best_parent_hw, &ctx->mux_ctx.hw);
> +
> +       clk_put(clk);
> +}
> +
> +static void clk_leaf_mux_set_rate_parent_determine_rate_case5(struct kunit *test)
> +{
> +       struct clk_leaf_mux_ctx *ctx = test->priv;
> +       struct clk_hw *hw = &ctx->hw;
> +       struct clk *clk = clk_hw_get_clk(hw, NULL);
> +       struct clk_rate_request req;
> +       unsigned long rate;
> +       int ret;
> +
> +       rate = clk_get_rate(clk);
> +       KUNIT_ASSERT_EQ(test, rate, DUMMY_CLOCK_RATE_1);
> +
> +       clk_hw_init_rate_request(hw, &req, DUMMY_CLOCK_RATE_2 + 100000);
> +
> +       ret = __clk_determine_rate(hw, &req);
> +       KUNIT_ASSERT_EQ(test, ret, 0);
> +
> +       KUNIT_EXPECT_EQ(test, req.rate, DUMMY_CLOCK_RATE_2);
> +       KUNIT_EXPECT_EQ(test, req.best_parent_rate, DUMMY_CLOCK_RATE_2);
> +       KUNIT_EXPECT_PTR_EQ(test, req.best_parent_hw, &ctx->mux_ctx.hw);
> +
> +       clk_put(clk);
> +}
> +
> +static void clk_leaf_mux_set_rate_parent_determine_rate_case6(struct kunit *test)
> +{
> +       struct clk_leaf_mux_ctx *ctx = test->priv;
> +       struct clk_hw *hw = &ctx->hw;
> +       struct clk *clk = clk_hw_get_clk(hw, NULL);
> +       struct clk_rate_request req;
> +       unsigned long rate;
> +       int ret;
> +
> +       rate = clk_get_rate(clk);
> +       KUNIT_ASSERT_EQ(test, rate, DUMMY_CLOCK_RATE_1);
> +
> +       clk_hw_init_rate_request(hw, &req, ULONG_MAX);
> +
> +       ret = __clk_determine_rate(hw, &req);
> +       KUNIT_ASSERT_EQ(test, ret, 0);
> +
> +       KUNIT_EXPECT_EQ(test, req.rate, DUMMY_CLOCK_RATE_2);
> +       KUNIT_EXPECT_EQ(test, req.best_parent_rate, DUMMY_CLOCK_RATE_2);
> +       KUNIT_EXPECT_PTR_EQ(test, req.best_parent_hw, &ctx->mux_ctx.hw);
> +
> +       clk_put(clk);
> +}
> +
> +/* We test 6 cases here:
> + * 1. The requested rate is 0;
> + * 2. The requested rate is not 0 but lower than any rate that parents could offer;
> + * 3. The requested rate is exactly one of the parents' clock rate;
> + * 4. The requested rate is between the lowest clock rate and the highest clock rate that the parents could offer;
> + * 5. The requested rate is larger than all rates that parents could offer;
> + * 6. The requested rate is ULONG_MAX.
> + *
> + * Hopefully they covered all cases.
> + */

Please remove this comment and name the cases better.

>  static struct kunit_case clk_leaf_mux_set_rate_parent_test_cases[] = {
> -       KUNIT_CASE(clk_leaf_mux_set_rate_parent_determine_rate),
> +       KUNIT_CASE(clk_leaf_mux_set_rate_parent_determine_rate_case1),

Maybe call it clk_leaf_mux_determine_rate_request_zero?

> +       KUNIT_CASE(clk_leaf_mux_set_rate_parent_determine_rate_case2),

clk_leaf_mux_determine_rate_lower_than_parents_fails

> +       KUNIT_CASE(clk_leaf_mux_set_rate_parent_determine_rate_case3),

clk_leaf_mux_determine_rate_exactly_parent1

> +       KUNIT_CASE(clk_leaf_mux_set_rate_parent_determine_rate_case4),

I'm not sure I understand what is being tested in this case. Are we
testing that __clk_determine_rate() with a rate between parent0 and
parent1 picks parent1?

> +       KUNIT_CASE(clk_leaf_mux_set_rate_parent_determine_rate_case5),

clk_leaf_mux_determine_rate_larger_than_parents

> +       KUNIT_CASE(clk_leaf_mux_set_rate_parent_determine_rate_case6),

clk_leaf_mux_determine_rate_ULONG_MAX_picks_parent1