Re: [PATCH net-next v5 5/7] net: ftgmac100: Require phy-mode for AST2700

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] net: ftgmac100: unreachable AST2700 phy-mode check in ftgmac100_mii_probe()
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commit e655d4e27cbf2e60c068a7ea633651b5660b5493
Author: Jacky Chou <jacky_chou@aspeedtech.com>

net: ftgmac100: Require phy-mode for AST2700

This commit adds a check in ftgmac100_mii_probe() to require the phy-mode
property when probing an AST2700 MAC instead of defaulting to RGMII.

> diff --git a/drivers/net/ethernet/faraday/ftgmac100.c b/drivers/net/ethernet/faraday/ftgmac100.c
> index 9b7becb017262..5a578a62df673 100644
> --- a/drivers/net/ethernet/faraday/ftgmac100.c
> +++ b/drivers/net/ethernet/faraday/ftgmac100.c
> @@ -1526,8 +1526,13 @@ static int ftgmac100_mii_probe(struct net_device *netdev)
>  
>  	/* Default to RGMII. It's a gigabit part after all */
>  	err = of_get_phy_mode(np, &phy_intf);
> -	if (err)
> +	if (err) {
> +		if (priv->mac_id == FTGMAC100_AST2700) {
> +			dev_err(priv->dev, "phy-mode is required for this SoC\n");
> +			return -EINVAL;
> +		}
>  		phy_intf = PHY_INTERFACE_MODE_RGMII;
> +	}

[Severity: Medium]
As reported by Sashiko on v4 [1], can this FTGMAC100_AST2700 check in
ftgmac100_mii_probe() ever be reached?

In ftgmac100_probe(), ftgmac100_setup_mdio() is the only function that
allocates priv->mii_bus, and it is skipped for FTGMAC100_AST2700:

	if (priv->mac_id == FTGMAC100_FARADAY ||
	    priv->mac_id == FTGMAC100_AST2400 ||
	    priv->mac_id == FTGMAC100_AST2500) {
		err = ftgmac100_setup_mdio(netdev);
		if (err)
			return err;
	}

When ftgmac100_probe_dt() falls through to ftgmac100_mii_probe(), the guard at
the beginning of ftgmac100_mii_probe() sees priv->mii_bus == NULL and returns
-ENODEV before reaching of_get_phy_mode():

	if (!priv->mii_bus) {
		dev_err(priv->dev, "No MDIO bus available\n");
		return -ENODEV;
	}

Meanwhile, AST2700 device tree nodes that specify use-ncsi, fixed-link,
phy-handle, or an mdio child node in ftgmac100_probe_dt() do not call
ftgmac100_mii_probe() at all. Should the phy-mode requirement for
FTGMAC100_AST2700 be checked in ftgmac100_probe_dt() instead?

[1] https://lore.kernel.org/r/20261020-support_ast2700-v4-5-4d36b40939b3@aspeedtech.com

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261104-support_ast2700-v5-0-44057f4dde75@aspeedtech.com?part=5