net: dsa: mv88e6xxx: power serdes on/off for 10G interfaces on 6390X [Linux 5.0]

net: dsa: mv88e6xxx: power serdes on/off for 10G interfaces on 6390X [Linux 5.0]

This Linux kernel change "net: dsa: mv88e6xxx: power serdes on/off for 10G interfaces on 6390X" is included in the Linux 5.0 release. This change is authored by Maxime Chevallier <maxime.chevallier [at] bootlin.com> on Thu Feb 28 22:14:33 2019 +0100. The commit for this change in Linux stable tree is d235c48 (patch).

net: dsa: mv88e6xxx: power serdes on/off for 10G interfaces on 6390X

Upon setting the cmode on 6390 and 6390X, the associated serdes
interfaces must be powered off/on.

Both 6390X and 6390 share code to do so, but it currently uses the 6390
specific helper mv88e6390_serdes_power() to disable and enable the
serdes interface.

This call will fail silently on 6390X when trying so set a 10G interface
such as XAUI or RXAUI, since mv88e6390_serdes_power() internally grabs
the lane number based on modes supported by the 6390, and returns 0 when
getting -ENODEV as a lane number.

Using mv88e6390x_serdes_power() should be safe here, since we explicitly
rule-out all ports but the 9 and 10, and because modes supported by 6390
ports 9 and 10 are a subset of those supported on 6390X.

This was tested on 6390X using RXAUI mode.

Fixes: 364e9d7776a3 ("net: dsa: mv88e6xxx: Power on/off SERDES on cmode change")
Signed-off-by: Maxime Chevallier <[email protected]>
Reviewed-by: Andrew Lunn <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

There are 4 lines of Linux source code added/deleted in this change. Code changes to Linux kernel are as follows.

 drivers/net/dsa/mv88e6xxx/port.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/dsa/mv88e6xxx/port.c b/drivers/net/dsa/mv88e6xxx/port.c
index ebd26b6..4b02c96 100644
--- a/drivers/net/dsa/mv88e6xxx/port.c
+++ b/drivers/net/dsa/mv88e6xxx/port.c
@@ -408,7 +408,7 @@ int mv88e6390x_port_set_cmode(struct mv88e6xxx_chip *chip, int port,
            return err;
    }

-   err = mv88e6390_serdes_power(chip, port, false);
+   err = mv88e6390x_serdes_power(chip, port, false);
    if (err)
        return err;

@@ -424,7 +424,7 @@ int mv88e6390x_port_set_cmode(struct mv88e6xxx_chip *chip, int port,
        if (err)
            return err;

-       err = mv88e6390_serdes_power(chip, port, true);
+       err = mv88e6390x_serdes_power(chip, port, true);
        if (err)
            return err;

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