Re: [PATCH net-next v3 4/6] 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:
- [Low] ftgmac100: unreachable phy-mode validation logic for AST2700
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commit bffefbc3de357d0f18231965a919fd90ba100814
Author: Jacky Chou <jacky_chou@aspeedtech.com>

net: ftgmac100: Require phy-mode for AST2700

The driver currently defaults to RGMII when the "phy-mode" property is
missing from the device tree. This patch makes "phy-mode" a required
property for AST2700 and fails probe with an error message 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: Low]
Is this new validation logic for AST2700 reachable?

Looking at ftgmac100_probe(), priv->mii_bus is only initialized for
specific SoCs:

	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;
	}

For FTGMAC100_AST2700, priv->mii_bus appears to remain NULL.

If priv->mii_bus is NULL, when ftgmac100_mii_probe() is called, would it
always hit the early exit condition at the start of the function:

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

and return -ENODEV before it can ever reach the new phy-mode validation?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261015-support_ast2700-v3-0-8d7999171ac4@aspeedtech.com?part=4