[PATCH 1/2] net: dsa: fix phydev->speed being uninitialized for the CPU port fixed PHY

[Ramon Fried]

On Sun, Dec 5, 2021 at 1:01 AM Vladimir Oltean <vladimir.oltean at nxp.com> wrote:
>
> If the DSA API is going to allow drivers to do things such as:
>
> - phy_config in dsa_ops :: port_probe
> - phy_startup in dsa_ops :: port_enable
>
> then it would actually be good if the ->port_probe() method would
> actually be called in all cases before the ->port_enable() is.
>
> Currently this is true for user ports, but not true for the CPU port,
> because the CPU port does not have a udevice registered for it (this is
> all part of DSA's design). So the current issue is that after
> phy_startup has finished for the CPU port, its phydev->speed is an
> uninitialized value, because phy_config() was never called for the
> priv->cpu_port_fixed_phy, and it is precisely phy_config() who copies
> the speed into the phydev in the case of the fixed PHY driver.
>
> So we need to simulate a probing event for the CPU port by manually
> calling the driver's ->port_probe() method for the CPU port.
>
> Fixes: 8a2982574854 ("net: dsa: introduce a .port_probe() method in struct dsa_ops")
> Signed-off-by: Vladimir Oltean <vladimir.oltean at nxp.com>
> ---
>  net/dsa-uclass.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
>
> diff --git a/net/dsa-uclass.c b/net/dsa-uclass.c
> index 606b1539a776..9ff55a02fb23 100644
> --- a/net/dsa-uclass.c
> +++ b/net/dsa-uclass.c
> @@ -466,6 +466,8 @@ static int dsa_pre_probe(struct udevice *dev)
>  {
>         struct dsa_pdata *pdata = dev_get_uclass_plat(dev);
>         struct dsa_priv *priv = dev_get_uclass_priv(dev);
> +       struct dsa_ops *ops = dsa_get_ops(dev);
> +       int err;
>
>         priv->num_ports = pdata->num_ports;
>         priv->cpu_port = pdata->cpu_port;
> @@ -477,6 +479,15 @@ static int dsa_pre_probe(struct udevice *dev)
>
>         uclass_find_device_by_ofnode(UCLASS_ETH, pdata->master_node,
>                                      &priv->master_dev);
> +
> +       /* Simulate a probing event for the CPU port */
> +       if (ops->port_probe) {
> +               err = ops->port_probe(dev, priv->cpu_port,
> +                                     priv->cpu_port_fixed_phy);
> +               if (err)
> +                       return err;
> +       }
> +
>         return 0;
>  }
>
> --
> 2.25.1
>
Reviewed-by: Ramon Fried <rfried.dev at gmail.com>