From: <Jerry.Ray@microchip.com>
To: <linux@armlinux.org.uk>
Cc: <andrew@lunn.ch>, <f.fainelli@gmail.com>, <olteanv@gmail.com>,
<davem@davemloft.net>, <edumazet@google.com>, <kuba@kernel.org>,
<pabeni@redhat.com>, <jbe@pengutronix.de>,
<netdev@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH net-next v6 6/6] dsa: lan9303: Migrate to PHYLINK
Date: Mon, 16 Jan 2023 17:22:05 +0000 [thread overview]
Message-ID: <MWHPR11MB169301FF4ED0E0BB2305780AEFC19@MWHPR11MB1693.namprd11.prod.outlook.com> (raw)
In-Reply-To: <Y7/zlzcyTsF+z0cN@shell.armlinux.org.uk>
> > +static void lan9303_phylink_get_caps(struct dsa_switch *ds, int port,
> > + struct phylink_config *config)
> > +{
> > + struct lan9303 *chip = ds->priv;
> > +
> > + dev_dbg(chip->dev, "%s(%d) entered.", __func__, port);
> > +
> > + config->mac_capabilities = MAC_10 | MAC_100 | MAC_ASYM_PAUSE |
> > + MAC_SYM_PAUSE;
>
> You indicate that pause modes are supported, but...
>
> > +static void lan9303_phylink_mac_link_up(struct dsa_switch *ds, int port,
> > + unsigned int mode,
> > + phy_interface_t interface,
> > + struct phy_device *phydev, int speed,
> > + int duplex, bool tx_pause,
> > + bool rx_pause)
> > +{
> > + u32 ctl;
> > +
> > + /* On this device, we are only interested in doing something here if
> > + * this is the xMII port. All other ports are 10/100 phys using MDIO
> > + * to control there link settings.
> > + */
> > + if (port != 0)
> > + return;
> > +
> > + ctl = lan9303_phy_read(ds, port, MII_BMCR);
> > +
> > + ctl &= ~BMCR_ANENABLE;
> > +
> > + if (speed == SPEED_100)
> > + ctl |= BMCR_SPEED100;
> > + else if (speed == SPEED_10)
> > + ctl &= ~BMCR_SPEED100;
> > + else
> > + dev_err(ds->dev, "unsupported speed: %d\n", speed);
> > +
> > + if (duplex == DUPLEX_FULL)
> > + ctl |= BMCR_FULLDPLX;
> > + else
> > + ctl &= ~BMCR_FULLDPLX;
> > +
> > + lan9303_phy_write(ds, port, MII_BMCR, ctl);
>
> There is no code here to program the resolved pause modes. Is it handled
> internally within the switch? (Please add a comment to this effect
> either in get_caps or here.)
>
> Thanks.
>
As I look into this, the part does have control flags for advertising
Symmetric and Asymmetric pause toward the link partner. The default is set
by a configuration strap on power-up. I am having trouble mapping the rx and
tx pause parameters into symmetric and asymmetric controls. Where can I find
the proper definitions and mappings?
ctl &= ~( ADVERTISE_PAUSE_CAP | ADVERTISE_PAUSE_AYM);
if(tx_pause)
ctl |= ADVERTISE_PAUSE_CAP;
if(rx_pause)
ctl |= ADVERTISE_PAUSE_AYM;
If I can pause my transmissions (receive pause requests), then advertise
symmetric whether I ever sent pause requests or not.
If I can send pause requests (using flow control on my receive side), then make
sure asymmetric support is also advertised as rx_pause might have been clear.
Not that if both rx and tx pause is supported, we can support either symmetric
or asymmetric operating modes.
If I receive a pause request, it affects my transmit data flow. So one could
argue the rx_pause flag controls my ability to receive pause requests. I tend
to overthink and almost always get these 50/50 propositions wrong.
Regards,
Jerry
next prev parent reply other threads:[~2023-01-16 17:44 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-09 21:18 [PATCH net-next v6 0/6] dsa: lan9303: Move to PHYLINK Jerry Ray
2023-01-09 21:18 ` [PATCH net-next v6 1/6] dsa: lan9303: align dsa_switch_ops members Jerry Ray
2023-01-11 22:04 ` Vladimir Oltean
2023-01-11 22:07 ` Florian Fainelli
2023-01-09 21:18 ` [PATCH net-next v6 2/6] dsa: lan9303: move Turbo Mode bit init Jerry Ray
2023-01-14 20:49 ` Vladimir Oltean
2023-01-16 18:03 ` Jerry.Ray
2023-01-16 18:06 ` Jerry.Ray
2023-01-09 21:18 ` [PATCH net-next v6 3/6] dsa: lan9303: Add exception logic for read failure Jerry Ray
2023-01-09 21:18 ` [PATCH net-next v6 4/6] dsa: lan9303: write reg only if necessary Jerry Ray
2023-01-09 21:18 ` [PATCH net-next v6 5/6] dsa: lan9303: Port 0 is xMII port Jerry Ray
2023-01-14 20:53 ` Vladimir Oltean
2023-01-16 18:05 ` Jerry.Ray
2023-01-09 21:18 ` [PATCH net-next v6 6/6] dsa: lan9303: Migrate to PHYLINK Jerry Ray
2023-01-12 5:22 ` Arun.Ramadoss
2023-01-16 17:33 ` Jerry.Ray
2023-01-12 11:48 ` Russell King (Oracle)
2023-01-16 17:22 ` Jerry.Ray [this message]
2023-01-16 18:03 ` Russell King (Oracle)
2023-01-16 22:48 ` Jerry.Ray
2023-01-17 18:19 ` Russell King (Oracle)
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