linux-kernel - Re: [PATCH 1/2] clk: Introduce kunit wrapper around clk_hw_init_rate

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Message-ID: <24a22c85-d4f6-4598-a95f-a1f0503978a2@roeck-us.net>
Date:   Fri, 21 Jul 2023 09:14:58 -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 1/2] clk: Introduce kunit wrapper around
 clk_hw_init_rate_request

On Fri, Jul 21, 2023 at 09:09:32AM +0200, Maxime Ripard wrote:
> Some kunit tests are meant to test the behaviour of providers (and
> most notably __clk_determine_rate()), but don't run those functions with
> the clk prepare_lock held which results in lockdep warning.
> 
> clk_hw_init_rate_request 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            | 26 ++++++++++++++++++++++++++
>  drivers/clk/clk_test.c       |  2 +-
>  include/linux/clk-provider.h | 11 +++++++++++
>  3 files changed, 38 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> index c249f9791ae8..8ee9bd02af76 100644
> --- a/drivers/clk/clk.c
> +++ b/drivers/clk/clk.c
> @@ -6,6 +6,7 @@
>   * Standard functionality for the common clock API.  See Documentation/driver-api/clk.rst
>   */
>  
> +#include <kunit/test-bug.h>
>  #include <linux/clk.h>
>  #include <linux/clk-provider.h>
>  #include <linux/clk/clk-conf.h>
> @@ -1556,6 +1557,31 @@ void clk_hw_init_rate_request(const struct clk_hw *hw,
>  }
>  EXPORT_SYMBOL_GPL(clk_hw_init_rate_request);
>  
> +#if IS_ENABLED(CONFIG_KUNIT)
> +/**
> + * clk_kunit_init_rate_request - Initializes a clk_rate_request
> + * @hw: the clk for which we want to submit a rate request
> + * @req: the clk_rate_request structure we want to initialise
> + * @rate: the rate which is to be requested
> + *
> + * Initializes a clk_rate_request structure to submit to
> + * __clk_determine_rate() or similar functions. Only usable in kunit
> + * test contexts, use clk_hw_init_rate_request() otherwise.
> + */
> +void clk_kunit_init_rate_request(const struct clk_hw *hw,
> +				 struct clk_rate_request *req,
> +				 unsigned long rate)
> +{
> +	if (!kunit_get_current_test())
> +		return;
> +
> +	clk_prepare_lock();
> +	clk_hw_init_rate_request(hw, req, rate);
> +	clk_prepare_unlock();
> +}
> +EXPORT_SYMBOL_GPL(clk_kunit_init_rate_request);
> +#endif
> +
>  /**
>   * clk_hw_forward_rate_request - Forwards a clk_rate_request to a clock's parent
>   * @hw: the original clock that got the rate request
> diff --git a/drivers/clk/clk_test.c b/drivers/clk/clk_test.c
> index a154ec9d0111..a64f7036baa3 100644
> --- a/drivers/clk/clk_test.c
> +++ b/drivers/clk/clk_test.c
> @@ -2230,7 +2230,7 @@ static void clk_leaf_mux_set_rate_parent_determine_rate(struct kunit *test)
>  	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);
> +	clk_kunit_init_rate_request(hw, &req, DUMMY_CLOCK_RATE_2);
>  
>  	ret = __clk_determine_rate(hw, &req);
>  	KUNIT_ASSERT_EQ(test, ret, 0);
> diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
> index 0f0cd01906b4..efdebfa3fce9 100644
> --- a/include/linux/clk-provider.h
> +++ b/include/linux/clk-provider.h
> @@ -67,6 +67,17 @@ struct clk_rate_request {
>  void clk_hw_init_rate_request(const struct clk_hw *hw,
>  			      struct clk_rate_request *req,
>  			      unsigned long rate);
> +#if IS_ENABLED(CONFIG_KUNIT)
> +void clk_kunit_init_rate_request(const struct clk_hw *hw,
> +				 struct clk_rate_request *req,
> +				 unsigned long rate);
> +#else
> +static inline void clk_kunit_init_rate_request(const struct clk_hw *hw,
> +					       struct clk_rate_request *req,
> +					       unsigned long rate)
> +{
> +}
> +#endif
>  void clk_hw_forward_rate_request(const struct clk_hw *core,
>  				 const struct clk_rate_request *old_req,
>  				 const struct clk_hw *parent,
> 
> -- 
> 2.41.0
>