linux-kernel - Re: [PATCH] clk: Warn and add workaround on misuse of .parent

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Message-ID: <63814a60.df0a0220.22f38.b1a4@mx.google.com>
Date:   Sat, 26 Nov 2022 00:06:07 +0100
From:   Christian Marangi <ansuelsmth@...il.com>
To:     Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>, linux-clk@...r.kernel.org,
        linux-kernel@...r.kernel.org, Robert Marko <robimarko@...il.com>
Subject: Re: [PATCH] clk: Warn and add workaround on misuse of .parent_data
 with .name only

On Tue, Nov 08, 2022 at 09:49:18PM +0100, Christian Marangi wrote:
> By a simple mistake in a .parent_names to .parent_data conversion it was
> found that clk core assume fw_name is always provided with a parent_data
> struct for each parent and never fallback to .name to get parent name even
> if declared.
> 
> This is caused by clk_core_get that only checks for parent .fw_name and
> doesn't handle .name.
> 
> While it's sane to request the dev to correctly do the conversion and
> add both .fw_name and .name in a parent_data struct, it's not sane to
> silently drop parents without a warning.
> 
> Fix this in 2 ways. Add a kernel warning when a wrong implementation is
> used and copy .name in .fw_name in parent map populate function to
> handle clk problems and malfunctions.
> 
> Signed-off-by: Christian Marangi <ansuelsmth@...il.com>

Friendly bump for this?

> ---
>  drivers/clk/clk.c | 13 ++++++++++++-
>  1 file changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> index 57b83665e5c3..dccd4ea6f692 100644
> --- a/drivers/clk/clk.c
> +++ b/drivers/clk/clk.c
> @@ -4015,10 +4015,21 @@ static int clk_core_populate_parent_map(struct clk_core *core,
>  			ret = clk_cpy_name(&parent->name, parent_names[i],
>  					   true);
>  		} else if (parent_data) {
> +			const char *parent_name;
> +
>  			parent->hw = parent_data[i].hw;
>  			parent->index = parent_data[i].index;
> +			parent_name = parent_data[i].fw_name;
> +
> +			if (!parent_name && parent_data[i].name) {
> +				WARN(1, "Empty .fw_name with .name in %s's .parent_data. Using .name for .fw_name declaration.\n",
> +				     core->name);
> +				parent_name = parent_data[i].name;
> +			}
> +
>  			ret = clk_cpy_name(&parent->fw_name,
> -					   parent_data[i].fw_name, false);
> +					   parent_name, false);
> +
>  			if (!ret)
>  				ret = clk_cpy_name(&parent->name,
>  						   parent_data[i].name,
> -- 
> 2.37.2
> 

-- 
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