[PATCH 5.15 088/207] net: dsa: mv88e6xxx: Add fix for erratum 5.2 of 88E6393X family

Greg Kroah-Hartman
2021-12-06T15:41:09Z

From: Marek Behún <kabel@kernel.org>

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>
---
drivers/net/dsa/mv88e6xxx/serdes.c | 48 +++++++++++++++++++++++++++++++++++++
1 file changed, 48 insertions(+)

--- 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
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 mv88e
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;