netdev - Re: [RFC PATCH net-next v3 19/20] net: dsa: qca8k: pass switch_revision info to phy dev

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Date:   Sat, 8 May 2021 01:26:02 +0200
From:   Ansuel Smith <ansuelsmth@...il.com>
To:     Vladimir Oltean <olteanv@...il.com>
Cc:     Florian Fainelli <f.fainelli@...il.com>,
        Andrew Lunn <andrew@...n.ch>,
        Vivien Didelot <vivien.didelot@...il.com>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Russell King <linux@...linux.org.uk>, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [RFC PATCH net-next v3 19/20] net: dsa: qca8k: pass
 switch_revision info to phy dev_flags

On Thu, May 06, 2021 at 02:24:58PM +0300, Vladimir Oltean wrote:
> On Wed, May 05, 2021 at 12:29:13AM +0200, Ansuel Smith wrote:
> > Define get_phy_flags to pass switch_Revision needed to tweak the
> > internal PHY with debug values based on the revision.
> > 
> > Signed-off-by: Ansuel Smith <ansuelsmth@...il.com>
> > ---
> >  drivers/net/dsa/qca8k.c | 19 +++++++++++++++++++
> >  1 file changed, 19 insertions(+)
> > 
> > diff --git a/drivers/net/dsa/qca8k.c b/drivers/net/dsa/qca8k.c
> > index b4cd891ad35d..237e09bb1425 100644
> > --- a/drivers/net/dsa/qca8k.c
> > +++ b/drivers/net/dsa/qca8k.c
> > @@ -1654,6 +1654,24 @@ qca8k_port_vlan_del(struct dsa_switch *ds, int port,
> >  	return ret;
> >  }
> >  
> > +static u32 qca8k_get_phy_flags(struct dsa_switch *ds, int port)
> > +{
> > +	struct qca8k_priv *priv = ds->priv;
> > +
> > +	pr_info("revision from phy %d", priv->switch_revision);
> 
> Log spam.
> 
> > +	/* Communicate to the phy internal driver the switch revision.
> > +	 * Based on the switch revision different values needs to be
> > +	 * set to the dbg and mmd reg on the phy.
> > +	 * The first 2 bit are used to communicate the switch revision
> > +	 * to the phy driver.
> > +	 */
> > +	if (port > 0 && port < 6)
> > +		return priv->switch_revision;
> > +
> > +	return 0;
> > +}
> > +
> >  static enum dsa_tag_protocol
> >  qca8k_get_tag_protocol(struct dsa_switch *ds, int port,
> >  		       enum dsa_tag_protocol mp)
> > @@ -1687,6 +1705,7 @@ static const struct dsa_switch_ops qca8k_switch_ops = {
> >  	.phylink_mac_config	= qca8k_phylink_mac_config,
> >  	.phylink_mac_link_down	= qca8k_phylink_mac_link_down,
> >  	.phylink_mac_link_up	= qca8k_phylink_mac_link_up,
> > +	.get_phy_flags		= qca8k_get_phy_flags,
> >  };
> >  
> >  static int qca8k_read_switch_id(struct qca8k_priv *priv)
> > -- 
> > 2.30.2
> > 
> 
> Florian, I think at one point you said that a correct user of
> phydev->dev_flags should first check the PHY revision and not apply
> dev_flags in blind, since they are namespaced to each PHY driver?
> It sounds a bit circular to pass the PHY revision to the PHY through
> phydev->dev_flags, either that or I'm missing some piece.

Just to make sure. This is the SWITCH revision not the PHY revision. It
was pointed out in old version that I should get this value from the PHY
regs but they are different values. This is why the dsa driver needs to
use the dev_flags to pass the SWITCH revision to the phy driver. Am I
implementing this in the wrong way and I should declare something to
pass this value in a more standard way? (anyway i'm pushing v4 so i
don't know if we should continue that there)