Re: [PATCH net-next v2 3/5] net: phy: mxl-gpy: release MxL86211C Super Isolate

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] net: phy: mxl-gpy: firmware version read while PHY is halted
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commit 2628bcaa4964186af3313096275fe989a084332d
Author: Robert Marko <robert.marko@sartura.hr>

net: phy: mxl-gpy: release MxL86211C Super Isolate

This commit modifies the driver to release the MxL86211C Super Isolate
mode in config_init rather than probe. This ensures both MDIO pad voltage
and Super Isolate settings are restored after each hardware reset.

> diff --git a/drivers/net/phy/mxl-gpy.c b/drivers/net/phy/mxl-gpy.c
> index fbac7c49b4759..8bc119655f104 100644
> --- a/drivers/net/phy/mxl-gpy.c
> +++ b/drivers/net/phy/mxl-gpy.c
[ ... ]
> @@ -422,6 +423,23 @@ static int mxl86211c_configure_mdio_voltage(struct phy_device *phydev,
>  			      VSPEC1_PM_CTRL_MDIO_VOL, val);
>  }
>  
> +static int mxl86211c_config_init(struct phy_device *phydev)
> +{
> +	struct gpy_priv *priv = phydev->priv;
> +	int ret;
> +
> +	ret = mxl86211c_configure_mdio_voltage(phydev, priv->vddp);
> +	if (ret)
> +		return ret;
> +
> +	ret = phy_modify_mmd(phydev, MDIO_MMD_VEND1, VSPEC1_PM_CTRL,
> +			     VSPEC1_PM_CTRL_SI, 0);

[Severity: Medium]
Will this delay in releasing Super Isolate cause gpy_probe() to read an
incorrect firmware version?

If the MxL86211C PHY is strapped into Super Isolate mode, it remains halted
after reset. During device registration, mxl86211c_probe() executes and
invokes gpy_probe() which attempts to read the firmware version:

drivers/net/phy/mxl-gpy.c:gpy_probe() {
    ...
    fw_version = phy_read(phydev, PHY_FWV);
    if (fw_version < 0)
        return fw_version;
    priv->fw_major = FIELD_GET(PHY_FWV_MAJOR_MASK, fw_version);
    priv->fw_minor = FIELD_GET(PHY_FWV_MINOR_MASK, fw_version);
    ...
}

Because the release of the Super Isolate bit (VSPEC1_PM_CTRL_SI) is
deferred here to mxl86211c_config_init(), the PHY microcontroller is
still halted during the probe path.

Could this cause the driver to cache an incorrect firmware version
(likely 0.0), potentially breaking firmware-specific logic like the
workarounds in gpy_sgmii_need_reaneg() and gpy115_loopback()?

> +	if (ret)
> +		return ret;
> +
> +	return gpy21x_config_init(phydev);
> +}

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Sashiko AI review · https://sashiko.dev/#/patchset/20261016112033.949026-1-robert.marko@sartura.hr?part=3