netdev - Re: [PATCH net-next 3/3] net: fec: add fec_set_hw_mac

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Message-ID: <20250710155728.363bcfd6@fedora>
Date: Thu, 10 Jul 2025 15:57:28 +0200
From: Maxime Chevallier <maxime.chevallier@...tlin.com>
To: Wei Fang <wei.fang@....com>
Cc: shenwei.wang@....com, xiaoning.wang@....com, andrew+netdev@...n.ch,
 davem@...emloft.net, edumazet@...gle.com, kuba@...nel.org,
 pabeni@...hat.com, netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
 imx@...ts.linux.dev
Subject: Re: [PATCH net-next 3/3] net: fec: add fec_set_hw_mac_addr() helper
 function

Hi,

On Thu, 10 Jul 2025 17:09:02 +0800
Wei Fang <wei.fang@....com> wrote:

> In the current driver, the MAC address is set in both fec_restart() and
> fec_set_mac_address(), so a generic helper function fec_set_hw_mac_addr()
> is added to set the hardware MAC address to make the code more compact.
> 
> Signed-off-by: Wei Fang <wei.fang@....com>
> ---
>  drivers/net/ethernet/freescale/fec_main.c | 27 +++++++++++++----------
>  1 file changed, 15 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
> index 00f8be4119ed..883b28e59a3c 100644
> --- a/drivers/net/ethernet/freescale/fec_main.c
> +++ b/drivers/net/ethernet/freescale/fec_main.c
> @@ -1123,6 +1123,18 @@ static void fec_ctrl_reset(struct fec_enet_private *fep, bool allow_wol)
>  	}
>  }
>  
> +static void fec_set_hw_mac_addr(struct net_device *ndev)
> +{
> +	struct fec_enet_private *fep = netdev_priv(ndev);
> +	u32 temp_mac[2];
> +
> +	memcpy(temp_mac, ndev->dev_addr, ETH_ALEN);
> +	writel((__force u32)cpu_to_be32(temp_mac[0]),
> +	       fep->hwp + FEC_ADDR_LOW);
> +	writel((__force u32)cpu_to_be32(temp_mac[1]),
> +	       fep->hwp + FEC_ADDR_HIGH);
> +}

[ ... ]

> -	writel(ndev->dev_addr[3] | (ndev->dev_addr[2] << 8) |
> -		(ndev->dev_addr[1] << 16) | (ndev->dev_addr[0] << 24),
> -		fep->hwp + FEC_ADDR_LOW);
> -	writel((ndev->dev_addr[5] << 16) | (ndev->dev_addr[4] << 24),
> -		fep->hwp + FEC_ADDR_HIGH);
> +	fec_set_hw_mac_addr(ndev);

It's more of a personal preference, but I find this implementation to
be much more readable than the one based on

  writel((__force u32)cpu_to_be32(temp_mac[...]), ...);

Maxime