Subject: Re: [PATCH net-next 1/2] net: pcs: xpcs: enable skip xPCS soft reset

From: Wong Vee Khee <[email-masked]>
Date: Wed, 11 Aug 2021 07:50:41 +0800

On Mon, Aug 09, 2021 at 02:06:26PM +0300, Vladimir Oltean wrote:
> Hi VK,
> 
> On Mon, Aug 09, 2021 at 06:22:28PM +0800, Wong Vee Khee wrote:
> > diff --git a/drivers/net/pcs/pcs-xpcs.c b/drivers/net/pcs/pcs-xpcs.c
> > index 63fda3fc40aa..c7a3aa862079 100644
> > --- a/drivers/net/pcs/pcs-xpcs.c
> > +++ b/drivers/net/pcs/pcs-xpcs.c
> > @@ -1081,7 +1081,8 @@ static const struct phylink_pcs_ops xpcs_phylink_ops = {
> >  };
> >  
> >  struct dw_xpcs *xpcs_create(struct mdio_device *mdiodev,
> > -			    phy_interface_t interface)
> > +			    phy_interface_t interface,
> > +			    bool skip_reset)
> >  {
> >  	struct dw_xpcs *xpcs;
> >  	u32 xpcs_id;
> > @@ -1113,9 +1114,16 @@ struct dw_xpcs *xpcs_create(struct mdio_device *mdiodev,
> >  		xpcs->pcs.ops = &xpcs_phylink_ops;
> >  		xpcs->pcs.poll = true;
> >  
> > -		ret = xpcs_soft_reset(xpcs, compat);
> > -		if (ret)
> > -			goto out;
> > +		if (!skip_reset) {
> > +			dev_info(&xpcs->mdiodev->dev, "%s: xPCS soft reset\n",
> > +				 __func__);
> > +			ret = xpcs_soft_reset(xpcs, compat);
> > +			if (ret)
> > +				goto out;
> > +		} else {
> > +			dev_info(&xpcs->mdiodev->dev,
> > +				 "%s: skip xpcs soft reset\n", __func__);
> > +		}
> 
> I don't feel like the prints are really necessary.

Sounds good to me. I'll remove these.

> 
> >  
> >  		return xpcs;
> >  	}
> > diff --git a/include/linux/pcs/pcs-xpcs.h b/include/linux/pcs/pcs-xpcs.h
> > index add077a81b21..0c05a63f3446 100644
> > --- a/include/linux/pcs/pcs-xpcs.h
> > +++ b/include/linux/pcs/pcs-xpcs.h
> > @@ -36,7 +36,8 @@ void xpcs_validate(struct dw_xpcs *xpcs, unsigned long *supported,
> >  int xpcs_config_eee(struct dw_xpcs *xpcs, int mult_fact_100ns,
> >  		    int enable);
> >  struct dw_xpcs *xpcs_create(struct mdio_device *mdiodev,
> > -			    phy_interface_t interface);
> > +			    phy_interface_t interface,
> > +			    bool xpcs_reset);
> >  void xpcs_destroy(struct dw_xpcs *xpcs);
> >  
> 
> How about exporting the reset functionality as a separate function, and
> the Intel Alder Lake stmmac shim just won't call it? Like this:
> 
> -----------------------------[ cut here ]-----------------------------
> diff --git a/drivers/net/dsa/sja1105/sja1105_mdio.c b/drivers/net/dsa/sja1105/sja1105_mdio.c
> index 19aea8fb76f6..5acf6742da4d 100644
> --- a/drivers/net/dsa/sja1105/sja1105_mdio.c
> +++ b/drivers/net/dsa/sja1105/sja1105_mdio.c
> @@ -437,13 +437,17 @@ static int sja1105_mdiobus_pcs_register(struct sja1105_private *priv)
>  			goto out_pcs_free;
>  		}
>  
> -		xpcs = xpcs_create(mdiodev, priv->phy_mode[port]);
> +		xpcs = xpcs_create(mdiodev);
>  		if (IS_ERR(xpcs)) {
>  			rc = PTR_ERR(xpcs);
>  			goto out_pcs_free;
>  		}
>  
>  		priv->xpcs[port] = xpcs;
> +
> +		rc = xpcs_reset(xpcs, priv->phy_mode[port]);
> +		if (rc)
> +			goto out_pcs_free;
>  	}
>  
>  	priv->mdio_pcs = bus;
> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c
> index a5d150c5f3d8..81a145009488 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c
> @@ -401,12 +401,15 @@ int stmmac_xpcs_setup(struct mii_bus *bus)
>  {
>  	struct net_device *ndev = bus->priv;
>  	struct mdio_device *mdiodev;
> +	bool skip_xpcs_soft_reset;
>  	struct stmmac_priv *priv;
>  	struct dw_xpcs *xpcs;
>  	int mode, addr;
> +	int err;
>  
>  	priv = netdev_priv(ndev);
>  	mode = priv->plat->phy_interface;
> +	skip_xpcs_soft_reset = priv->plat->skip_xpcs_soft_reset;
>  
>  	/* Try to probe the XPCS by scanning all addresses. */
>  	for (addr = 0; addr < PHY_MAX_ADDR; addr++) {
> @@ -414,12 +417,21 @@ int stmmac_xpcs_setup(struct mii_bus *bus)
>  		if (IS_ERR(mdiodev))
>  			continue;
>  
> -		xpcs = xpcs_create(mdiodev, mode);
> +		xpcs = xpcs_create(mdiodev);
>  		if (IS_ERR_OR_NULL(xpcs)) {
>  			mdio_device_free(mdiodev);
>  			continue;
>  		}
>  
> +		if (!skip_xpcs_soft_reset) {
> +			err = xpcs_reset(xpcs, mode);
> +			if (err) {
> +				xpcs_destroy(xpcs);
> +				mdio_device_free(mdiodev);
> +				continue;
> +			}
> +		}
> +
>  		priv->hw->xpcs = xpcs;
>  		break;
>  	}
> diff --git a/drivers/net/pcs/pcs-xpcs.c b/drivers/net/pcs/pcs-xpcs.c
> index 63fda3fc40aa..2e721e57bee4 100644
> --- a/drivers/net/pcs/pcs-xpcs.c
> +++ b/drivers/net/pcs/pcs-xpcs.c
> @@ -248,6 +248,18 @@ static int xpcs_soft_reset(struct dw_xpcs *xpcs,
>  	return xpcs_poll_reset(xpcs, dev);
>  }
>  
> +int xpcs_reset(struct dw_xpcs *xpcs, phy_interface_t interface)
> +{
> +	const struct xpcs_compat *compat;
> +
> +	compat = xpcs_find_compat(xpcs->id, interface);
> +	if (!compat)
> +		return -ENODEV;
> +
> +	return xpcs_soft_reset(xpcs, compat);
> +}
> +EXPORT_SYMBOL_GPL(xpcs_reset);
> +
>  #define xpcs_warn(__xpcs, __state, __args...) \
>  ({ \
>  	if ((__state)->link) \
> @@ -1080,12 +1092,11 @@ static const struct phylink_pcs_ops xpcs_phylink_ops = {
>  	.pcs_link_up = xpcs_link_up,
>  };
>  
> -struct dw_xpcs *xpcs_create(struct mdio_device *mdiodev,
> -			    phy_interface_t interface)
> +struct dw_xpcs *xpcs_create(struct mdio_device *mdiodev)
>  {
>  	struct dw_xpcs *xpcs;
>  	u32 xpcs_id;
> -	int i, ret;
> +	int i;
>  
>  	xpcs = kzalloc(sizeof(*xpcs), GFP_KERNEL);
>  	if (!xpcs)
> @@ -1097,35 +1108,18 @@ struct dw_xpcs *xpcs_create(struct mdio_device *mdiodev,
>  
>  	for (i = 0; i < ARRAY_SIZE(xpcs_id_list); i++) {
>  		const struct xpcs_id *entry = &xpcs_id_list[i];
> -		const struct xpcs_compat *compat;
>  
>  		if ((xpcs_id & entry->mask) != entry->id)
>  			continue;
>  
>  		xpcs->id = entry;
> -
> -		compat = xpcs_find_compat(entry, interface);
> -		if (!compat) {
> -			ret = -ENODEV;
> -			goto out;
> -		}
> -
>  		xpcs->pcs.ops = &xpcs_phylink_ops;
>  		xpcs->pcs.poll = true;
>  
> -		ret = xpcs_soft_reset(xpcs, compat);
> -		if (ret)
> -			goto out;
> -
>  		return xpcs;
>  	}
>  
> -	ret = -ENODEV;
> -
> -out:
> -	kfree(xpcs);
> -
> -	return ERR_PTR(ret);
> +	return ERR_PTR(-ENODEV);
>  }
>  EXPORT_SYMBOL_GPL(xpcs_create);
>  
> diff --git a/include/linux/pcs/pcs-xpcs.h b/include/linux/pcs/pcs-xpcs.h
> index add077a81b21..d841f55f12cc 100644
> --- a/include/linux/pcs/pcs-xpcs.h
> +++ b/include/linux/pcs/pcs-xpcs.h
> @@ -35,8 +35,8 @@ void xpcs_validate(struct dw_xpcs *xpcs, unsigned long *supported,
>  		   struct phylink_link_state *state);
>  int xpcs_config_eee(struct dw_xpcs *xpcs, int mult_fact_100ns,
>  		    int enable);
> -struct dw_xpcs *xpcs_create(struct mdio_device *mdiodev,
> -			    phy_interface_t interface);
> +int xpcs_reset(struct dw_xpcs *xpcs, phy_interface_t interface);
> +struct dw_xpcs *xpcs_create(struct mdio_device *mdiodev);
>  void xpcs_destroy(struct dw_xpcs *xpcs);
>  
>  #endif /* __LINUX_PCS_XPCS_H */
> diff --git a/include/linux/stmmac.h b/include/linux/stmmac.h
> index a6f03b36fc4f..0f901773c5e4 100644
> --- a/include/linux/stmmac.h
> +++ b/include/linux/stmmac.h
> @@ -268,5 +268,6 @@ struct plat_stmmacenet_data {
>  	int msi_rx_base_vec;
>  	int msi_tx_base_vec;
>  	bool use_phy_wol;
> +	bool skip_xpcs_soft_reset;
>  };
>  #endif
> -----------------------------[ cut here ]-----------------------------
> 
> I also gave this patch a run on sja1105 and it still works.

Thanks for the suggestion. I tested it out on stmmac and it works.
I will use this as it looks neater. :)

Regards,
 VK