linux-kernel - Re: [PATCH 2/2] clk: Introduce kunit wrapper around __clk_determine

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Message-ID: <a03ae5b7-9235-40a7-9e29-9033678ffea0@roeck-us.net>
Date:   Fri, 21 Jul 2023 09:15:09 -0700
From:   Guenter Roeck <linux@...ck-us.net>
To:     Maxime Ripard <mripard@...nel.org>
Cc:     Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>, linux-clk@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        kernel test robot <yujie.liu@...el.com>
Subject: Re: [PATCH 2/2] clk: Introduce kunit wrapper around
 __clk_determine_rate

On Fri, Jul 21, 2023 at 09:09:33AM +0200, Maxime Ripard wrote:
> Some kunit tests are meant to test the behaviour of providers but don't
> run those functions with the clk prepare_lock held which results in
> lockdep warning.
> 
> __clk_determine_rate is one of the functions being executed from a test
> which should have the lock held. Let's introduce a wrapper around it
> meant to be used only by kunit tests.
> 
> Reported-by: Guenter Roeck <linux@...ck-us.net>
> Link: https://lore.kernel.org/linux-clk/2b594e50-2bbf-4a2d-88e6-49fc39f3957a@roeck-us.net/
> Reported-by: kernel test robot <yujie.liu@...el.com>
> Link: https://lore.kernel.org/oe-lkp/202301310919.b9d56ee3-yujie.liu@intel.com
> Fixes: 262ca38f4b6e ("clk: Stop forwarding clk_rate_requests to the parent")
> Signed-off-by: Maxime Ripard <mripard@...nel.org>

Tested-by: Guenter Roeck <linux@...ck-us.net>

> ---
>  drivers/clk/clk.c            | 25 +++++++++++++++++++++++++
>  drivers/clk/clk_test.c       |  2 +-
>  include/linux/clk-provider.h | 10 ++++++++++
>  3 files changed, 36 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> index 8ee9bd02af76..8fdbfec6bd85 100644
> --- a/drivers/clk/clk.c
> +++ b/drivers/clk/clk.c
> @@ -1669,6 +1669,31 @@ int __clk_determine_rate(struct clk_hw *hw, struct clk_rate_request *req)
>  }
>  EXPORT_SYMBOL_GPL(__clk_determine_rate);
>  
> +#if IS_ENABLED(CONFIG_KUNIT)
> +/**
> + * __clk_kunit_determine_rate - get the closest rate actually supported by a clock
> + * @hw: determine the rate of this clock
> + * @req: target rate request
> + *
> + * Useful for clk_ops such as .set_rate and .determine_rate. Only usable
> + * in a kunit test context. Use __clk_determine_rate() otherwise.
> + */
> +int __clk_kunit_determine_rate(struct clk_hw *hw, struct clk_rate_request *req)
> +{
> +	int ret;
> +
> +	if (!kunit_get_current_test())
> +		return -EINVAL;
> +
> +	clk_prepare_lock();
> +	ret = __clk_determine_rate(hw, req);
> +	clk_prepare_unlock();
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(__clk_kunit_determine_rate);
> +#endif
> +
>  /**
>   * clk_hw_round_rate() - round the given rate for a hw clk
>   * @hw: the hw clk for which we are rounding a rate
> diff --git a/drivers/clk/clk_test.c b/drivers/clk/clk_test.c
> index a64f7036baa3..b835e08892b4 100644
> --- a/drivers/clk/clk_test.c
> +++ b/drivers/clk/clk_test.c
> @@ -2232,7 +2232,7 @@ static void clk_leaf_mux_set_rate_parent_determine_rate(struct kunit *test)
>  
>  	clk_kunit_init_rate_request(hw, &req, DUMMY_CLOCK_RATE_2);
>  
> -	ret = __clk_determine_rate(hw, &req);
> +	ret = __clk_kunit_determine_rate(hw, &req);
>  	KUNIT_ASSERT_EQ(test, ret, 0);
>  
>  	KUNIT_EXPECT_EQ(test, req.rate, DUMMY_CLOCK_RATE_2);
> diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
> index efdebfa3fce9..43049f2c1dd2 100644
> --- a/include/linux/clk-provider.h
> +++ b/include/linux/clk-provider.h
> @@ -1352,6 +1352,16 @@ void clk_hw_get_rate_range(struct clk_hw *hw, unsigned long *min_rate,
>  void clk_hw_set_rate_range(struct clk_hw *hw, unsigned long min_rate,
>  			   unsigned long max_rate);
>  
> +#if IS_ENABLED(CONFIG_KUNIT)
> +int __clk_kunit_determine_rate(struct clk_hw *hw, struct clk_rate_request *req);
> +#else
> +static inline int __clk_kunit_determine_rate(struct clk_hw *hw,
> +					     struct clk_rate_request *req)
> +{
> +	return -ENOENT;
> +}
> +#endif
> +
>  static inline void __clk_hw_set_clk(struct clk_hw *dst, struct clk_hw *src)
>  {
>  	dst->clk = src->clk;
> 
> -- 
> 2.41.0
>