linux-kernel - Re: [PATCH net v3] stmmac: dwmac-mediatek: fix clock issue

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Date:   Fri, 8 Jul 2022 11:22:54 +0200
From:   Matthias Brugger <matthias.bgg@...il.com>
To:     Biao Huang <biao.huang@...iatek.com>,
        David Miller <davem@...emloft.net>
Cc:     Giuseppe Cavallaro <peppe.cavallaro@...com>,
        Alexandre Torgue <alexandre.torgue@...s.st.com>,
        Jose Abreu <joabreu@...opsys.com>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>, netdev@...r.kernel.org,
        linux-stm32@...md-mailman.stormreply.com,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-mediatek@...ts.infradead.org, macpaul.lin@...iatek.com
Subject: Re: [PATCH net v3] stmmac: dwmac-mediatek: fix clock issue



On 08/07/2022 10:39, Biao Huang wrote:
> Since clocks are handled in mediatek_dwmac_clks_config(),
> remove the clocks configuration in init()/exit(), and
> invoke mediatek_dwmac_clks_config instead.
> 
> This issue is found in suspend/resume test.
> 

Commit message is rather confusing. Basically you are moving the clock enable 
into probe instead of init and remove it from exit. That means, clocks get 
enabled earlier and don't get disabled if the module gets unloaded. That doesn't 
sound correct, I think we would at least need to disable the clocks in remove 
function.

I suppose that suspend calls exit and that there was a problem when we disable 
the clocks there. Is this a HW issue that has no other possible fix?

Regards,
Matthias

> Fixes: 3186bdad97d5 ("stmmac: dwmac-mediatek: add platform level clocks management")
> Signed-off-by: Biao Huang <biao.huang@...iatek.com>
> ---
>   .../ethernet/stmicro/stmmac/dwmac-mediatek.c  | 36 +++++--------------
>   1 file changed, 9 insertions(+), 27 deletions(-)
> 
> diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-mediatek.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-mediatek.c
> index 6ff88df58767..e86f3e125cb4 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/dwmac-mediatek.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-mediatek.c
> @@ -576,32 +576,7 @@ static int mediatek_dwmac_init(struct platform_device *pdev, void *priv)
>   		}
>   	}
>   
> -	ret = clk_bulk_prepare_enable(variant->num_clks, plat->clks);
> -	if (ret) {
> -		dev_err(plat->dev, "failed to enable clks, err = %d\n", ret);
> -		return ret;
> -	}
> -
> -	ret = clk_prepare_enable(plat->rmii_internal_clk);
> -	if (ret) {
> -		dev_err(plat->dev, "failed to enable rmii internal clk, err = %d\n", ret);
> -		goto err_clk;
> -	}
> -
>   	return 0;
> -
> -err_clk:
> -	clk_bulk_disable_unprepare(variant->num_clks, plat->clks);
> -	return ret;
> -}
> -
> -static void mediatek_dwmac_exit(struct platform_device *pdev, void *priv)
> -{
> -	struct mediatek_dwmac_plat_data *plat = priv;
> -	const struct mediatek_dwmac_variant *variant = plat->variant;
> -
> -	clk_disable_unprepare(plat->rmii_internal_clk);
> -	clk_bulk_disable_unprepare(variant->num_clks, plat->clks);
>   }
>   
>   static int mediatek_dwmac_clks_config(void *priv, bool enabled)
> @@ -643,7 +618,6 @@ static int mediatek_dwmac_common_data(struct platform_device *pdev,
>   	plat->addr64 = priv_plat->variant->dma_bit_mask;
>   	plat->bsp_priv = priv_plat;
>   	plat->init = mediatek_dwmac_init;
> -	plat->exit = mediatek_dwmac_exit;
>   	plat->clks_config = mediatek_dwmac_clks_config;
>   	if (priv_plat->variant->dwmac_fix_mac_speed)
>   		plat->fix_mac_speed = priv_plat->variant->dwmac_fix_mac_speed;
> @@ -712,13 +686,21 @@ static int mediatek_dwmac_probe(struct platform_device *pdev)
>   	mediatek_dwmac_common_data(pdev, plat_dat, priv_plat);
>   	mediatek_dwmac_init(pdev, priv_plat);
>   
> +	ret = mediatek_dwmac_clks_config(priv_plat, true);
> +	if (ret)
> +		return ret;
> +
>   	ret = stmmac_dvr_probe(&pdev->dev, plat_dat, &stmmac_res);
>   	if (ret) {
>   		stmmac_remove_config_dt(pdev, plat_dat);
> -		return ret;
> +		goto err_drv_probe;
>   	}
>   
>   	return 0;
> +
> +err_drv_probe:
> +	mediatek_dwmac_clks_config(priv_plat, false);
> +	return ret;
>   }
>   
>   static const struct of_device_id mediatek_dwmac_match[] = {