net: dsa: mv88e6xxx: Add fix for erratum 5.2 of 88E6393X family

BugLink: https://bugs.launchpad.net/bugs/1953731
commit 93fd8207bed80ce19aaf59932cbe1c03d418a37d upstream.

Add fix for erratum 5.2 of the 88E6393X (Amethyst) family: for 10gbase-r
mode, some undocumented registers need to be written some special
values.

Fixes: de776d0d316f ("net: dsa: mv88e6xxx: add support for mv88e6393x family")
Signed-off-by: Marek Behún <kabel@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>

diff --git a/drivers/net/dsa/mv88e6xxx/serdes.c b/drivers/net/dsa/mv88e6xxx/serdes.c
index ceb63d7f1f97bd43203f9d5b8c4b043ce3b73747..9e4f18a4adc29ff6ecd50457678325a7f96139f2 100644 (file)
--- a/drivers/net/dsa/mv88e6xxx/serdes.c
+++ b/drivers/net/dsa/mv88e6xxx/serdes.c
@@ -1375,6 +1375,50 @@ static int mv88e6393x_serdes_erratum_4_8(struct mv88e6xxx_chip *chip, int lane)
                                      MV88E6393X_ERRATA_4_8_REG, reg);
 }
 
+static int mv88e6393x_serdes_erratum_5_2(struct mv88e6xxx_chip *chip, int lane,
+                                        u8 cmode)
+{
+       static const struct {
+               u16 dev, reg, val, mask;
+       } fixes[] = {
+               { MDIO_MMD_VEND1, 0x8093, 0xcb5a, 0xffff },
+               { MDIO_MMD_VEND1, 0x8171, 0x7088, 0xffff },
+               { MDIO_MMD_VEND1, 0x80c9, 0x311a, 0xffff },
+               { MDIO_MMD_VEND1, 0x80a2, 0x8000, 0xff7f },
+               { MDIO_MMD_VEND1, 0x80a9, 0x0000, 0xfff0 },
+               { MDIO_MMD_VEND1, 0x80a3, 0x0000, 0xf8ff },
+               { MDIO_MMD_PHYXS, MV88E6393X_SERDES_POC,
+                 MV88E6393X_SERDES_POC_RESET, MV88E6393X_SERDES_POC_RESET },
+       };
+       int err, i;
+       u16 reg;
+
+       /* mv88e6393x family errata 5.2:
+        * For optimal signal integrity the following sequence should be applied
+        * to SERDES operating in 10G mode. These registers only apply to 10G
+        * operation and have no effect on other speeds.
+        */
+       if (cmode != MV88E6393X_PORT_STS_CMODE_10GBASER)
+               return 0;
+
+       for (i = 0; i < ARRAY_SIZE(fixes); ++i) {
+               err = mv88e6390_serdes_read(chip, lane, fixes[i].dev,
+                                           fixes[i].reg, &reg);
+               if (err)
+                       return err;
+
+               reg &= ~fixes[i].mask;
+               reg |= fixes[i].val;
+
+               err = mv88e6390_serdes_write(chip, lane, fixes[i].dev,
+                                            fixes[i].reg, reg);
+               if (err)
+                       return err;
+       }
+
+       return 0;
+}
+
 int mv88e6393x_serdes_power(struct mv88e6xxx_chip *chip, int port, int lane,
                            bool on)
 {
@@ -1389,6 +1433,10 @@ int mv88e6393x_serdes_power(struct mv88e6xxx_chip *chip, int port, int lane,
                if (err)
                        return err;
 
+               err = mv88e6393x_serdes_erratum_5_2(chip, lane, cmode);
+               if (err)
+                       return err;
+
                err = mv88e6393x_serdes_power_lane(chip, lane, true);
                if (err)
                        return err;