Re: [PATCH net-next V3 4/4] net: lan743x: Add support to ethtool phylink get and set settings

[Raju Lakkaraju <Raju.Lakkaraju@microchip.com>]

Hi Russell King,

The 07/30/2024 16:11, Russell King (Oracle) wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> 
> On Tue, Jul 30, 2024 at 07:36:19PM +0530, Raju Lakkaraju wrote:
> > diff --git a/drivers/net/ethernet/microchip/lan743x_ethtool.c b/drivers/net/ethernet/microchip/lan743x_ethtool.c
> > index 3a63ec091413..a649ea7442a4 100644
> > --- a/drivers/net/ethernet/microchip/lan743x_ethtool.c
> > +++ b/drivers/net/ethernet/microchip/lan743x_ethtool.c
> > @@ -1058,61 +1058,48 @@ static int lan743x_ethtool_get_eee(struct net_device *netdev,
> >                                  struct ethtool_keee *eee)
> >  {
> >       struct lan743x_adapter *adapter = netdev_priv(netdev);
> > -     struct phy_device *phydev = netdev->phydev;
> > -     u32 buf;
> > -     int ret;
> > -
> > -     if (!phydev)
> > -             return -EIO;
> > -     if (!phydev->drv) {
> > -             netif_err(adapter, drv, adapter->netdev,
> > -                       "Missing PHY Driver\n");
> > -             return -EIO;
> > -     }
> >
> > -     ret = phy_ethtool_get_eee(phydev, eee);
> > -     if (ret < 0)
> > -             return ret;
> > -
> > -     buf = lan743x_csr_read(adapter, MAC_CR);
> > -     if (buf & MAC_CR_EEE_EN_) {
> > -             /* EEE_TX_LPI_REQ_DLY & tx_lpi_timer are same uSec unit */
> > -             buf = lan743x_csr_read(adapter, MAC_EEE_TX_LPI_REQ_DLY_CNT);
> > -             eee->tx_lpi_timer = buf;
> > -     } else {
> > -             eee->tx_lpi_timer = 0;
> > -     }
> > +     eee->tx_lpi_timer = lan743x_csr_read(adapter,
> > +                                          MAC_EEE_TX_LPI_REQ_DLY_CNT);
> > +     eee->eee_enabled = adapter->eee_enabled;
> > +     eee->eee_active = adapter->eee_active;
> > +     eee->tx_lpi_enabled = adapter->tx_lpi_enabled;
> 
> You really need to start paying attention to the commits other people
> make as a result of development to other parts of the kernel.
> 
> First, see:
> 
> commit ef460a8986fa0dae1cdcb158a06127f7af27c92d
> Author: Andrew Lunn <andrew@lunn.ch>
> Date:   Sat Apr 6 15:16:00 2024 -0500
> 
>     net: lan743x: Fixup EEE
> 
> and note that the assignment of eee->eee_enabled, eee->eee_active, and
> eee->tx_lpi_enabled were all removed.
> 

Accepted. I will fix

> Next...
> 
> >
> > -     return 0;
> > +     return phylink_ethtool_get_eee(adapter->phylink, eee);
> 
> phylink_ethtool_get_eee() will call phy_ethtool_get_eee(), which
> in turn calls genphy_c45_ethtool_get_eee() and eeecfg_to_eee().
> 
> genphy_c45_ethtool_get_eee() will do this:
> 
>         data->eee_enabled = is_enabled;
>         data->eee_active = ret;
> 
> thus overwriting your assignment to eee->eee_enabled and
> eee->eee_active.
> 
> eeecfg_to_eee() will overwrite eee->tx_lpi_enabled and
> eee->eee_enabled.
> 
> Thus, writing to these fields and then calling
> phylink_ethtool_get_eee() results in these fields being overwritten.
> 

Ok. I will fix.

> >  static int lan743x_ethtool_set_eee(struct net_device *netdev,
> >                                  struct ethtool_keee *eee)
> >  {
> > -     struct lan743x_adapter *adapter;
> > -     struct phy_device *phydev;
> > -     u32 buf = 0;
> > +     struct lan743x_adapter *adapter = netdev_priv(netdev);
> >
> > -     if (!netdev)
> > -             return -EINVAL;
> > -     adapter = netdev_priv(netdev);
> > -     if (!adapter)
> > -             return -EINVAL;
> > -     phydev = netdev->phydev;
> > -     if (!phydev)
> > -             return -EIO;
> > -     if (!phydev->drv) {
> > -             netif_err(adapter, drv, adapter->netdev,
> > -                       "Missing PHY Driver\n");
> > -             return -EIO;
> > -     }
> > +     if (eee->tx_lpi_enabled)
> > +             lan743x_csr_write(adapter, MAC_EEE_TX_LPI_REQ_DLY_CNT,
> > +                               eee->tx_lpi_timer);
> > +     else
> > +             lan743x_csr_write(adapter, MAC_EEE_TX_LPI_REQ_DLY_CNT, 0);
> >
> > -     if (eee->eee_enabled) {
> > -             buf = (u32)eee->tx_lpi_timer;
> > -             lan743x_csr_write(adapter, MAC_EEE_TX_LPI_REQ_DLY_CNT, buf);
> > -     }
> > +     adapter->eee_enabled = eee->eee_enabled;
> > +     adapter->tx_lpi_enabled = eee->tx_lpi_enabled;
> 
> Given that phylib stores these and overwrites your copies in the get_eee
> method above, do you need to store these?
> 

OK

> > @@ -3013,7 +3025,12 @@ static void lan743x_phylink_mac_link_down(struct phylink_config *config,
> >                                         unsigned int link_an_mode,
> >                                         phy_interface_t interface)
> >  {
> > +     struct net_device *netdev = to_net_dev(config->dev);
> > +     struct lan743x_adapter *adapter = netdev_priv(netdev);
> > +
> >       netif_tx_stop_all_queues(to_net_dev(config->dev));
> > +     adapter->eee_active = false;
> 
> phylib tracks this for you.
> 

Ok

> > +     lan743x_set_eee(adapter, false);
> >  }
> >
> >  static void lan743x_phylink_mac_link_up(struct phylink_config *config,
> > @@ -3055,6 +3072,14 @@ static void lan743x_phylink_mac_link_up(struct phylink_config *config,
> >                                         cap & FLOW_CTRL_TX,
> >                                         cap & FLOW_CTRL_RX);
> >
> > +     if (phydev && adapter->eee_enabled) {
> > +             bool enable;
> > +
> > +             adapter->eee_active = phy_init_eee(phydev, false) >= 0;
> > +             enable = adapter->eee_active && adapter->tx_lpi_enabled;
> 
> No need. Your enable should be conditional on phydev->enable_tx_lpi
> here. See Andrew's commit and understand his changes, rather than
> just ignoring Andrew's work and continuing with your old pattern of
> EEE support. Things have moved forward.

Ok. I will fix

> 
> Thanks.
> 
> --
> RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
> FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!

-- 
Thanks,                                                                         
Raju