[PATCH] net: phy: marvell: Fix pause frame negotiation

[PATCH] net: phy: marvell: Fix pause frame negotiation

[Clemens Gruber]

The negotiation of flow control / pause frame modes was broken since
commit fcf1f59afc67 ("net: phy: marvell: rearrange to use
genphy_read_lpa()") moved the setting of phydev->duplex below the
phy_resolve_aneg_pause call. Due to a check of DUPLEX_FULL in that
function, phydev->pause was no longer set.

Fix it by moving the parsing of the status variable before the blocks
dealing with the pause frames.

Fixes: fcf1f59afc67 ("net: phy: marvell: rearrange to use genphy_read_lpa()")
Cc: stable@vger.kernel.org # v5.6+
Signed-off-by: Clemens Gruber <clemens.gruber@pqgruber.com>
---
 drivers/net/phy/marvell.c | 44 +++++++++++++++++++--------------------
 1 file changed, 22 insertions(+), 22 deletions(-)

diff --git a/drivers/net/phy/marvell.c b/drivers/net/phy/marvell.c
index 4714ca0e0d4b..02cde4c0668c 100644
--- a/drivers/net/phy/marvell.c
+++ b/drivers/net/phy/marvell.c
@@ -1263,6 +1263,28 @@ static int marvell_read_status_page_an(struct phy_device *phydev,
 	int lpa;
 	int err;
 
+	if (!(status & MII_M1011_PHY_STATUS_RESOLVED))
+		return 0;
+
+	if (status & MII_M1011_PHY_STATUS_FULLDUPLEX)
+		phydev->duplex = DUPLEX_FULL;
+	else
+		phydev->duplex = DUPLEX_HALF;
+
+	switch (status & MII_M1011_PHY_STATUS_SPD_MASK) {
+	case MII_M1011_PHY_STATUS_1000:
+		phydev->speed = SPEED_1000;
+		break;
+
+	case MII_M1011_PHY_STATUS_100:
+		phydev->speed = SPEED_100;
+		break;
+
+	default:
+		phydev->speed = SPEED_10;
+		break;
+	}
+
 	if (!fiber) {
 		err = genphy_read_lpa(phydev);
 		if (err < 0)
@@ -1291,28 +1313,6 @@ static int marvell_read_status_page_an(struct phy_device *phydev,
 		}
 	}
 
-	if (!(status & MII_M1011_PHY_STATUS_RESOLVED))
-		return 0;
-
-	if (status & MII_M1011_PHY_STATUS_FULLDUPLEX)
-		phydev->duplex = DUPLEX_FULL;
-	else
-		phydev->duplex = DUPLEX_HALF;
-
-	switch (status & MII_M1011_PHY_STATUS_SPD_MASK) {
-	case MII_M1011_PHY_STATUS_1000:
-		phydev->speed = SPEED_1000;
-		break;
-
-	case MII_M1011_PHY_STATUS_100:
-		phydev->speed = SPEED_100;
-		break;
-
-	default:
-		phydev->speed = SPEED_10;
-		break;
-	}
-
 	return 0;
 }
 
-- 
2.26.0

Re: [PATCH] net: phy: marvell: Fix pause frame negotiation

[Jakub Kicinski]

On Wed,  8 Apr 2020 23:43:26 +0200 Clemens Gruber wrote:
> The negotiation of flow control / pause frame modes was broken since
> commit fcf1f59afc67 ("net: phy: marvell: rearrange to use
> genphy_read_lpa()") moved the setting of phydev->duplex below the
> phy_resolve_aneg_pause call. Due to a check of DUPLEX_FULL in that
> function, phydev->pause was no longer set.
> 
> Fix it by moving the parsing of the status variable before the blocks
> dealing with the pause frames.
> 
> Fixes: fcf1f59afc67 ("net: phy: marvell: rearrange to use genphy_read_lpa()")
> Cc: stable@vger.kernel.org # v5.6+

nit: please don't CC stable on networking patches

> Signed-off-by: Clemens Gruber <clemens.gruber@pqgruber.com>
> ---
>  drivers/net/phy/marvell.c | 44 +++++++++++++++++++--------------------
>  1 file changed, 22 insertions(+), 22 deletions(-)
> 
> diff --git a/drivers/net/phy/marvell.c b/drivers/net/phy/marvell.c
> index 4714ca0e0d4b..02cde4c0668c 100644
> --- a/drivers/net/phy/marvell.c
> +++ b/drivers/net/phy/marvell.c
> @@ -1263,6 +1263,28 @@ static int marvell_read_status_page_an(struct phy_device *phydev,
>  	int lpa;
>  	int err;
>  
> +	if (!(status & MII_M1011_PHY_STATUS_RESOLVED))
> +		return 0;

If we return early here won't we miss updating the advertising bits?
We will no longer call e.g. fiber_lpa_mod_linkmode_lpa_t().

Perhaps extracting info from status should be moved to a helper so we
can return early without affecting the rest of the flow?

Is my understanding correct?  Russell?

> +	if (status & MII_M1011_PHY_STATUS_FULLDUPLEX)
> +		phydev->duplex = DUPLEX_FULL;
> +	else
> +		phydev->duplex = DUPLEX_HALF;
> +
> +	switch (status & MII_M1011_PHY_STATUS_SPD_MASK) {
> +	case MII_M1011_PHY_STATUS_1000:
> +		phydev->speed = SPEED_1000;
> +		break;
> +
> +	case MII_M1011_PHY_STATUS_100:
> +		phydev->speed = SPEED_100;
> +		break;
> +
> +	default:
> +		phydev->speed = SPEED_10;
> +		break;
> +	}
> +
>  	if (!fiber) {
>  		err = genphy_read_lpa(phydev);
>  		if (err < 0)
> @@ -1291,28 +1313,6 @@ static int marvell_read_status_page_an(struct phy_device *phydev,
>  		}
>  	}
>  
> -	if (!(status & MII_M1011_PHY_STATUS_RESOLVED))
> -		return 0;
> -
> -	if (status & MII_M1011_PHY_STATUS_FULLDUPLEX)
> -		phydev->duplex = DUPLEX_FULL;
> -	else
> -		phydev->duplex = DUPLEX_HALF;
> -
> -	switch (status & MII_M1011_PHY_STATUS_SPD_MASK) {
> -	case MII_M1011_PHY_STATUS_1000:
> -		phydev->speed = SPEED_1000;
> -		break;
> -
> -	case MII_M1011_PHY_STATUS_100:
> -		phydev->speed = SPEED_100;
> -		break;
> -
> -	default:
> -		phydev->speed = SPEED_10;
> -		break;
> -	}
> -
>  	return 0;
>  }
>  

Re: [PATCH] net: phy: marvell: Fix pause frame negotiation

[Russell King - ARM Linux admin]

On Fri, Apr 10, 2020 at 05:43:04PM -0700, Jakub Kicinski wrote:
> On Wed,  8 Apr 2020 23:43:26 +0200 Clemens Gruber wrote:
> > The negotiation of flow control / pause frame modes was broken since
> > commit fcf1f59afc67 ("net: phy: marvell: rearrange to use
> > genphy_read_lpa()") moved the setting of phydev->duplex below the
> > phy_resolve_aneg_pause call. Due to a check of DUPLEX_FULL in that
> > function, phydev->pause was no longer set.
> > 
> > Fix it by moving the parsing of the status variable before the blocks
> > dealing with the pause frames.
> > 
> > Fixes: fcf1f59afc67 ("net: phy: marvell: rearrange to use genphy_read_lpa()")
> > Cc: stable@vger.kernel.org # v5.6+
> 
> nit: please don't CC stable on networking patches
> 
> > Signed-off-by: Clemens Gruber <clemens.gruber@pqgruber.com>
> > ---
> >  drivers/net/phy/marvell.c | 44 +++++++++++++++++++--------------------
> >  1 file changed, 22 insertions(+), 22 deletions(-)
> > 
> > diff --git a/drivers/net/phy/marvell.c b/drivers/net/phy/marvell.c
> > index 4714ca0e0d4b..02cde4c0668c 100644
> > --- a/drivers/net/phy/marvell.c
> > +++ b/drivers/net/phy/marvell.c
> > @@ -1263,6 +1263,28 @@ static int marvell_read_status_page_an(struct phy_device *phydev,
> >  	int lpa;
> >  	int err;
> >  
> > +	if (!(status & MII_M1011_PHY_STATUS_RESOLVED))
> > +		return 0;
> 
> If we return early here won't we miss updating the advertising bits?
> We will no longer call e.g. fiber_lpa_mod_linkmode_lpa_t().
> 
> Perhaps extracting info from status should be moved to a helper so we
> can return early without affecting the rest of the flow?
> 
> Is my understanding correct?  Russell?

You are correct - and yes, there is also a problem here.

It is not clear whether the resolved bit is set before or after the
link status reports that link is up - however, the resolved bit
indicates whether the speed and duplex are valid.

What I've done elsewhere is if the resolved bit is not set, then we
force phydev->link to be false, so we don't attempt to process a
link-up status until we can read the link parameters.  I think that's
what needs to happen here, i.o.w.:

	if (!(status & MII_M1011_PHY_STATUS_RESOLVED)) {
		phydev->link = 0;
		return 0;
	}

especially as we're not reading the LPA.

-- 
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