Subject: Re: [PATCH net-next V3] net: lan743x: Add support to SGMII register dump for PCI11010/PCI11414 chips

From: Raju Lakkaraju <[email-masked]>
Date: Wed, 12 Oct 2022 10:32:52 +0530

Hi Andrew,

Thank you for review comments.

The 10/10/2022 21:35, Andrew Lunn wrote:
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> 
> >  static int lan743x_get_regs_len(struct net_device *dev)
> >  {
> > -     return MAX_LAN743X_ETH_REGS * sizeof(u32);
> > +     struct lan743x_adapter *adapter = netdev_priv(dev);
> > +     u32 num_regs = MAX_LAN743X_ETH_COMMON_REGS;
> > +
> > +     if (adapter->is_sgmii_en)
> > +             num_regs += MAX_LAN743X_ETH_SGMII_REGS;
> > +
> > +     return num_regs * sizeof(u32);
> >  }
> >
> >  static void lan743x_get_regs(struct net_device *dev,
> >                            struct ethtool_regs *regs, void *p)
> >  {
> > +     struct lan743x_adapter *adapter = netdev_priv(dev);
> > +     int regs_len;
> > +
> > +     regs_len = lan743x_get_regs_len(dev);
> > +     memset(p, 0, regs_len);
> > +
> >       regs->version = LAN743X_ETH_REG_VERSION;
> > +     regs->len = regs_len;
> > +
> > +     lan743x_common_regs(dev, p);
> > +     p = (u32 *)p + MAX_LAN743X_ETH_COMMON_REGS;
> >
> > -     lan743x_common_regs(dev, regs, p);
> > +     if (adapter->is_sgmii_en) {
> > +             lan743x_sgmii_regs(dev, p);
> > +             p = (u32 *)p + MAX_LAN743X_ETH_SGMII_REGS;
> > +     }
> 
> This seems O.K. for the moment, but how does it work when you add the
> next set of optional registers? Say you want to add the PTP registers?

Yes. 
For other modules (i.e. PTP etc) register dumps, i would like
implement ethtool -w/-W option to configure dump flag.
Existing private flag use for EEPROM/OTP access which we don't use same
flag for register dumps to avoid accidental changes which may damage
EEPROM/OTP sensitive data.

> 
> One idea might be to use the LAN743X_ETH_REG_VERSION as a
> bitfield. Bit 0 indicates the common registers are present. Bit 1
> indicates the SGMII registers are present. Bit 2 is for whatever next
> set of optional registers you add, say PTP.

OK. 
Otherwise, I will create LAN743X_ETH_REG_FLAGS and follow your
suggestion.

>     Andrew

--------
Thanks,
Raju