mv88e6xxx: Add serdes Rx statistics

If packet checker is enabled in the serdes, then Rx counter registers
start working, and no side effects have been detected.

This patch enables packet checker automatically when powering serdes on,
and exposes Rx counter registers via ethtool statistics interface.

Code partially basded by older attempt by Andrew Lunn.
Signed-off-by: Nikita Yushchenko <nikita.yoush@cogentembedded.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/mv88e6xxx/chip.c

@@ -4424,6 +4424,9 @@ static const struct mv88e6xxx_ops mv88e6390_ops = {
 	.gpio_ops = &mv88e6352_gpio_ops,
 	.avb_ops = &mv88e6390_avb_ops,
 	.ptp_ops = &mv88e6352_ptp_ops,
+	.serdes_get_sset_count = mv88e6390_serdes_get_sset_count,
+	.serdes_get_strings = mv88e6390_serdes_get_strings,
+	.serdes_get_stats = mv88e6390_serdes_get_stats,
 	.phylink_validate = mv88e6390_phylink_validate,
 };
 

drivers/net/dsa/mv88e6xxx/serdes.c

@@ -405,22 +405,116 @@ static int mv88e6390_serdes_power_sgmii(struct mv88e6xxx_chip *chip, u8 lane,
 	return err;
 }
 
+struct mv88e6390_serdes_hw_stat {
+	char string[ETH_GSTRING_LEN];
+	int reg;
+};
+
+static struct mv88e6390_serdes_hw_stat mv88e6390_serdes_hw_stats[] = {
+	{ "serdes_rx_pkts", 0xf021 },
+	{ "serdes_rx_bytes", 0xf024 },
+	{ "serdes_rx_pkts_error", 0xf027 },
+};
+
+int mv88e6390_serdes_get_sset_count(struct mv88e6xxx_chip *chip, int port)
+{
+	if (mv88e6390_serdes_get_lane(chip, port) == 0)
+		return 0;
+
+	return ARRAY_SIZE(mv88e6390_serdes_hw_stats);
+}
+
+int mv88e6390_serdes_get_strings(struct mv88e6xxx_chip *chip,
+				 int port, uint8_t *data)
+{
+	struct mv88e6390_serdes_hw_stat *stat;
+	int i;
+
+	if (mv88e6390_serdes_get_lane(chip, port) == 0)
+		return 0;
+
+	for (i = 0; i < ARRAY_SIZE(mv88e6390_serdes_hw_stats); i++) {
+		stat = &mv88e6390_serdes_hw_stats[i];
+		memcpy(data + i * ETH_GSTRING_LEN, stat->string,
+		       ETH_GSTRING_LEN);
+	}
+	return ARRAY_SIZE(mv88e6390_serdes_hw_stats);
+}
+
+static uint64_t mv88e6390_serdes_get_stat(struct mv88e6xxx_chip *chip, int lane,
+					  struct mv88e6390_serdes_hw_stat *stat)
+{
+	u16 reg[3];
+	int err, i;
+
+	for (i = 0; i < 3; i++) {
+		err = mv88e6390_serdes_read(chip, lane, MDIO_MMD_PHYXS,
+					    stat->reg + i, &reg[i]);
+		if (err) {
+			dev_err(chip->dev, "failed to read statistic\n");
+			return 0;
+		}
+	}
+
+	return reg[0] | ((u64)reg[1] << 16) | ((u64)reg[2] << 32);
+}
+
+int mv88e6390_serdes_get_stats(struct mv88e6xxx_chip *chip, int port,
+			       uint64_t *data)
+{
+	struct mv88e6390_serdes_hw_stat *stat;
+	int lane;
+	int i;
+
+	lane = mv88e6390_serdes_get_lane(chip, port);
+	if (lane == 0)
+		return 0;
+
+	for (i = 0; i < ARRAY_SIZE(mv88e6390_serdes_hw_stats); i++) {
+		stat = &mv88e6390_serdes_hw_stats[i];
+		data[i] = mv88e6390_serdes_get_stat(chip, lane, stat);
+	}
+
+	return ARRAY_SIZE(mv88e6390_serdes_hw_stats);
+}
+
+static int mv88e6390_serdes_enable_checker(struct mv88e6xxx_chip *chip, u8 lane)
+{
+	u16 reg;
+	int err;
+
+	err = mv88e6390_serdes_read(chip, lane, MDIO_MMD_PHYXS,
+				    MV88E6390_PG_CONTROL, &reg);
+	if (err)
+		return err;
+
+	reg |= MV88E6390_PG_CONTROL_ENABLE_PC;
+	return mv88e6390_serdes_write(chip, lane, MDIO_MMD_PHYXS,
+				      MV88E6390_PG_CONTROL, reg);
+}
+
 int mv88e6390_serdes_power(struct mv88e6xxx_chip *chip, int port, u8 lane,
 			   bool up)
 {
 	u8 cmode = chip->ports[port].cmode;
+	int err = 0;
 
 	switch (cmode) {
 	case MV88E6XXX_PORT_STS_CMODE_SGMII:
 	case MV88E6XXX_PORT_STS_CMODE_1000BASEX:
 	case MV88E6XXX_PORT_STS_CMODE_2500BASEX:
-		return mv88e6390_serdes_power_sgmii(chip, lane, up);
+		err = mv88e6390_serdes_power_sgmii(chip, lane, up);
+		break;
 	case MV88E6XXX_PORT_STS_CMODE_XAUI:
 	case MV88E6XXX_PORT_STS_CMODE_RXAUI:
-		return mv88e6390_serdes_power_10g(chip, lane, up);
+		err = mv88e6390_serdes_power_10g(chip, lane, up);
+		break;
 	}
 
-	return 0;
+	if (!err && up)
+		err = mv88e6390_serdes_enable_checker(chip, lane);
+
+	return err;
 }
 
 static void mv88e6390_serdes_irq_link_sgmii(struct mv88e6xxx_chip *chip,

drivers/net/dsa/mv88e6xxx/serdes.h

@@ -74,6 +74,10 @@
 #define MV88E6390_SGMII_PHY_STATUS_SPD_DPL_VALID BIT(11)
 #define MV88E6390_SGMII_PHY_STATUS_LINK		BIT(10)
 
+/* Packet generator pad packet checker */
+#define MV88E6390_PG_CONTROL		0xf010
+#define MV88E6390_PG_CONTROL_ENABLE_PC		BIT(0)
+
 u8 mv88e6341_serdes_get_lane(struct mv88e6xxx_chip *chip, int port);
 u8 mv88e6352_serdes_get_lane(struct mv88e6xxx_chip *chip, int port);
 u8 mv88e6390_serdes_get_lane(struct mv88e6xxx_chip *chip, int port);
@@ -99,6 +103,11 @@ int mv88e6352_serdes_get_strings(struct mv88e6xxx_chip *chip,
 				 int port, uint8_t *data);
 int mv88e6352_serdes_get_stats(struct mv88e6xxx_chip *chip, int port,
 			       uint64_t *data);
+int mv88e6390_serdes_get_sset_count(struct mv88e6xxx_chip *chip, int port);
+int mv88e6390_serdes_get_strings(struct mv88e6xxx_chip *chip,
+				 int port, uint8_t *data);
+int mv88e6390_serdes_get_stats(struct mv88e6xxx_chip *chip, int port,
+			       uint64_t *data);
 
 /* Return the (first) SERDES lane address a port is using, 0 otherwise. */
 static inline u8 mv88e6xxx_serdes_get_lane(struct mv88e6xxx_chip *chip,