netdev - Re: [PATCH net-next v2] net: macb: Add shutdown operation support

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Message-ID: <07d527e5-32d9-4e8c-ad19-92f5a722bfd5@tuxon.dev>
Date: Sat, 7 Jun 2025 15:28:56 +0300
From: Claudiu Beznea <claudiu.beznea@...on.dev>
To: Abin Joseph <abin.joseph@....com>, nicolas.ferre@...rochip.com,
 andrew+netdev@...n.ch, davem@...emloft.net, edumazet@...gle.com,
 kuba@...nel.org, pabeni@...hat.com
Cc: git@....com, netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH net-next v2] net: macb: Add shutdown operation support

Hi, Abin,

On 07.06.2025 10:57, Abin Joseph wrote:
> Implement the shutdown hook to ensure clean and complete deactivation of
> MACB controller. The shutdown sequence is protected with 'rtnl_lock()'
> to serialize access and prevent race conditions while detaching and
> closing the network device. This ensure a safe transition when the Kexec
> utility calls the shutdown hook, facilitating seamless loading and
> booting of a new kernel from the currently running one.
> 
> Signed-off-by: Abin Joseph <abin.joseph@....com>
> ---
> 
> Changes in v2:
> Update the commit description
> Update the code to call the close only when admin is up
> 
> ---
>  drivers/net/ethernet/cadence/macb_main.c | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
> 
> diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
> index e1e8bd2ec155..5bb08f518d54 100644
> --- a/drivers/net/ethernet/cadence/macb_main.c
> +++ b/drivers/net/ethernet/cadence/macb_main.c
> @@ -5650,6 +5650,19 @@ static int __maybe_unused macb_runtime_resume(struct device *dev)
>  	return 0;
>  }
>  
> +static void macb_shutdown(struct platform_device *pdev)
> +{
> +	struct net_device *netdev = platform_get_drvdata(pdev);
> +
> +	rtnl_lock();
> +	netif_device_detach(netdev);
> +
> +	if (netif_running(netdev))
> +		dev_close(netdev);

Apart from closing the interface should we also invoke the remove?

Consider the new loaded kernel will not use this interface and some
hardware resources may remain on while not used by the newly loaded kernel.

E.g., there is this code in macb_remove():

		if (!pm_runtime_suspended(&pdev->dev)) {
			macb_clks_disable(bp->pclk, bp->hclk, bp->tx_clk,
					  bp->rx_clk, bp->tsu_clk);
			pm_runtime_set_suspended(&pdev->dev);
		}


Thank you,
Claudiu

> +
> +	rtnl_unlock();
> +}
> +
>  static const struct dev_pm_ops macb_pm_ops = {
>  	SET_SYSTEM_SLEEP_PM_OPS(macb_suspend, macb_resume)
>  	SET_RUNTIME_PM_OPS(macb_runtime_suspend, macb_runtime_resume, NULL)
> @@ -5663,6 +5676,7 @@ static struct platform_driver macb_driver = {
>  		.of_match_table	= of_match_ptr(macb_dt_ids),
>  		.pm	= &macb_pm_ops,
>  	},
> +	.shutdown	= macb_shutdown,
>  };
>  
>  module_platform_driver(macb_driver);