linux-kernel - Re: [PATCH 25/31] clk: mediatek: pll: Implement error handling in register API

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Date:   Wed, 26 Jan 2022 16:13:38 +0800
From:   Miles Chen <miles.chen@...iatek.com>
To:     <wenst@...omium.org>
CC:     <chun-jie.chen@...iatek.com>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-clk@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <linux-mediatek@...ts.infradead.org>, <matthias.bgg@...il.com>,
        <mturquette@...libre.com>, <sboyd@...nel.org>
Subject: Re: [PATCH 25/31] clk: mediatek: pll: Implement error handling in register API

> The pll clk type registration function does not stop or return errors
> if any clk failed to be registered, nor does it implement an error
> handling path. This may result in a partially working device if any
> step failed.
> 
> Make the register function return proper error codes, and bail out if
> errors occur. Proper cleanup, i.e. unregister any clks that were
> successfully registered, and unmap the I/O space, is done in the new
> error path.
> 
> Signed-off-by: Chen-Yu Tsai <wenst@...omium.org>

Reviewed-by: Miles Chen <miles.chen@...iatek.com>
> ---
>  drivers/clk/mediatek/clk-pll.c | 23 +++++++++++++++++++----
>  drivers/clk/mediatek/clk-pll.h |  6 +++---
>  2 files changed, 22 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/clk/mediatek/clk-pll.c b/drivers/clk/mediatek/clk-pll.c
> index 9698d1c97cd6..1dd15f560659 100644
> --- a/drivers/clk/mediatek/clk-pll.c
> +++ b/drivers/clk/mediatek/clk-pll.c
> @@ -369,8 +369,9 @@ static void mtk_clk_unregister_pll(struct clk *clk)
>  	kfree(pll);
>  }
>  
> -void mtk_clk_register_plls(struct device_node *node,
> -		const struct mtk_pll_data *plls, int num_plls, struct clk_onecell_data *clk_data)
> +int mtk_clk_register_plls(struct device_node *node,
> +			  const struct mtk_pll_data *plls, int num_plls,
> +			  struct clk_onecell_data *clk_data)
>  {
>  	void __iomem *base;
>  	int i;
> @@ -379,7 +380,7 @@ void mtk_clk_register_plls(struct device_node *node,
>  	base = of_iomap(node, 0);
>  	if (!base) {
>  		pr_err("%s(): ioremap failed\n", __func__);
> -		return;
> +		return -EINVAL;
>  	}
>  
>  	for (i = 0; i < num_plls; i++) {
> @@ -389,11 +390,25 @@ void mtk_clk_register_plls(struct device_node *node,
>  
>  		if (IS_ERR(clk)) {
>  			pr_err("Failed to register clk %s: %pe\n", pll->name, clk);
> -			continue;
> +			goto err;
>  		}
>  
>  		clk_data->clks[pll->id] = clk;
>  	}
> +
> +	return 0;
> +
> +err:
> +	while (--i >= 0) {
> +		const struct mtk_pll_data *pll = &plls[i];
> +
> +		mtk_clk_unregister_pll(clk_data->clks[pll->id]);
> +		clk_data->clks[pll->id] = ERR_PTR(-ENOENT);
> +	};
> +
> +	iounmap(base);
> +
> +	return PTR_ERR(clk);
>  }
>  EXPORT_SYMBOL_GPL(mtk_clk_register_plls);
>  
> diff --git a/drivers/clk/mediatek/clk-pll.h b/drivers/clk/mediatek/clk-pll.h
> index a889b1e472e7..bf06e44caef9 100644
> --- a/drivers/clk/mediatek/clk-pll.h
> +++ b/drivers/clk/mediatek/clk-pll.h
> @@ -48,9 +48,9 @@ struct mtk_pll_data {
>  	u8 pll_en_bit; /* Assume 0, indicates BIT(0) by default */
>  };
>  
> -void mtk_clk_register_plls(struct device_node *node,
> -			   const struct mtk_pll_data *plls, int num_plls,
> -			   struct clk_onecell_data *clk_data);
> +int mtk_clk_register_plls(struct device_node *node,
> +			  const struct mtk_pll_data *plls, int num_plls,
> +			  struct clk_onecell_data *clk_data);
>  void mtk_clk_unregister_plls(const struct mtk_pll_data *plls, int num_plls,
>  			     struct clk_onecell_data *clk_data);
>  
> -- 
> 2.35.0.rc0.227.g00780c9af4-goog