Merge branch 'mv88e6xxx-fixes'

Marek Behún says:

====================
mv88e6xxx fixes (mainly 88E6393X family)

sending v2 of these fixes.

Original cover letter:

So I managed to discovered how to fix inband AN for 2500base-x mode on
88E6393x (Amethyst) family.

This series fixes application of erratum 4.8, adds fix for erratum 5.2,
adds support for completely disablign SerDes receiver / transmitter,
fixes inband AN for 2500base-x mode by using 1000base-x mode and simply
changing frequeny to 3.125 GHz, all this for 88E6393X.

The last commit fixes linking when link partner has AN disabled and the
device invokes the AN bypass feature. Currently we fail to link in this
case.

Changes since v1:
- fixed wrong operator in patch 3 (thanks Russell)
- added more comments about why BMCR_ANENABLE is used in patch 6 (thanks
  Russell)
- updated some return statements from
     if (something)
       return func();
     return 0;
  to
     if (something)
       err = func();
     return err;
  (err is set to 0 before the condition)
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/mv88e6xxx/serdes.c

@@ -50,11 +50,22 @@ static int mv88e6390_serdes_write(struct mv88e6xxx_chip *chip,
 }
 
 static int mv88e6xxx_serdes_pcs_get_state(struct mv88e6xxx_chip *chip,
-					  u16 status, u16 lpa,
+					  u16 ctrl, u16 status, u16 lpa,
 					  struct phylink_link_state *state)
 {
-	if (status & MV88E6390_SGMII_PHY_STATUS_SPD_DPL_VALID) {
 	state->link = !!(status & MV88E6390_SGMII_PHY_STATUS_LINK);
+
+	if (status & MV88E6390_SGMII_PHY_STATUS_SPD_DPL_VALID) {
+		/* The Spped and Duplex Resolved register is 1 if AN is enabled
+		 * and complete, or if AN is disabled. So with disabled AN we
+		 * still get here on link up. But we want to set an_complete
+		 * only if AN was enabled, thus we look at BMCR_ANENABLE.
+		 * (According to 802.3-2008 section 22.2.4.2.10, we should be
+		 *  able to get this same value from BMSR_ANEGCAPABLE, but tests
+		 *  show that these Marvell PHYs don't conform to this part of
+		 *  the specificaion - BMSR_ANEGCAPABLE is simply always 1.)
+		 */
+		state->an_complete = !!(ctrl & BMCR_ANENABLE);
 		state->duplex = status &
 				MV88E6390_SGMII_PHY_STATUS_DUPLEX_FULL ?
 			                         DUPLEX_FULL : DUPLEX_HALF;
@@ -81,6 +92,18 @@ static int mv88e6xxx_serdes_pcs_get_state(struct mv88e6xxx_chip *chip,
 			dev_err(chip->dev, "invalid PHY speed\n");
 			return -EINVAL;
 		}
+	} else if (state->link &&
+		   state->interface != PHY_INTERFACE_MODE_SGMII) {
+		/* If Speed and Duplex Resolved register is 0 and link is up, it
+		 * means that AN was enabled, but link partner had it disabled
+		 * and the PHY invoked the Auto-Negotiation Bypass feature and
+		 * linked anyway.
+		 */
+		state->duplex = DUPLEX_FULL;
+		if (state->interface == PHY_INTERFACE_MODE_2500BASEX)
+			state->speed = SPEED_2500;
+		else
+			state->speed = SPEED_1000;
 	} else {
 		state->link = false;
 	}
@@ -168,9 +191,15 @@ int mv88e6352_serdes_pcs_config(struct mv88e6xxx_chip *chip, int port,
 int mv88e6352_serdes_pcs_get_state(struct mv88e6xxx_chip *chip, int port,
 				   int lane, struct phylink_link_state *state)
 {
-	u16 lpa, status;
+	u16 lpa, status, ctrl;
 	int err;
 
+	err = mv88e6352_serdes_read(chip, MII_BMCR, &ctrl);
+	if (err) {
+		dev_err(chip->dev, "can't read Serdes PHY control: %d\n", err);
+		return err;
+	}
+
 	err = mv88e6352_serdes_read(chip, 0x11, &status);
 	if (err) {
 		dev_err(chip->dev, "can't read Serdes PHY status: %d\n", err);
@@ -183,7 +212,7 @@ int mv88e6352_serdes_pcs_get_state(struct mv88e6xxx_chip *chip, int port,
 		return err;
 	}
 
-	return mv88e6xxx_serdes_pcs_get_state(chip, status, lpa, state);
+	return mv88e6xxx_serdes_pcs_get_state(chip, ctrl, status, lpa, state);
 }
 
 int mv88e6352_serdes_pcs_an_restart(struct mv88e6xxx_chip *chip, int port,
@@ -883,9 +912,16 @@ int mv88e6390_serdes_pcs_config(struct mv88e6xxx_chip *chip, int port,
 static int mv88e6390_serdes_pcs_get_state_sgmii(struct mv88e6xxx_chip *chip,
 	int port, int lane, struct phylink_link_state *state)
 {
-	u16 lpa, status;
+	u16 lpa, status, ctrl;
 	int err;
 
+	err = mv88e6390_serdes_read(chip, lane, MDIO_MMD_PHYXS,
+				    MV88E6390_SGMII_BMCR, &ctrl);
+	if (err) {
+		dev_err(chip->dev, "can't read Serdes PHY control: %d\n", err);
+		return err;
+	}
+
 	err = mv88e6390_serdes_read(chip, lane, MDIO_MMD_PHYXS,
 				    MV88E6390_SGMII_PHY_STATUS, &status);
 	if (err) {
@@ -900,7 +936,7 @@ static int mv88e6390_serdes_pcs_get_state_sgmii(struct mv88e6xxx_chip *chip,
 		return err;
 	}
 
-	return mv88e6xxx_serdes_pcs_get_state(chip, status, lpa, state);
+	return mv88e6xxx_serdes_pcs_get_state(chip, ctrl, status, lpa, state);
 }
 
 static int mv88e6390_serdes_pcs_get_state_10g(struct mv88e6xxx_chip *chip,
@@ -1271,9 +1307,31 @@ void mv88e6390_serdes_get_regs(struct mv88e6xxx_chip *chip, int port, void *_p)
 	}
 }
 
-static int mv88e6393x_serdes_port_errata(struct mv88e6xxx_chip *chip, int lane)
+static int mv88e6393x_serdes_power_lane(struct mv88e6xxx_chip *chip, int lane,
+					bool on)
 {
-	u16 reg, pcs;
+	u16 reg;
+	int err;
+
+	err = mv88e6390_serdes_read(chip, lane, MDIO_MMD_PHYXS,
+				    MV88E6393X_SERDES_CTRL1, &reg);
+	if (err)
+		return err;
+
+	if (on)
+		reg &= ~(MV88E6393X_SERDES_CTRL1_TX_PDOWN |
+			 MV88E6393X_SERDES_CTRL1_RX_PDOWN);
+	else
+		reg |= MV88E6393X_SERDES_CTRL1_TX_PDOWN |
+		       MV88E6393X_SERDES_CTRL1_RX_PDOWN;
+
+	return mv88e6390_serdes_write(chip, lane, MDIO_MMD_PHYXS,
+				      MV88E6393X_SERDES_CTRL1, reg);
+}
+
+static int mv88e6393x_serdes_erratum_4_6(struct mv88e6xxx_chip *chip, int lane)
+{
+	u16 reg;
 	int err;
 
 	/* mv88e6393x family errata 4.6:
@@ -1284,10 +1342,7 @@ static int mv88e6393x_serdes_port_errata(struct mv88e6xxx_chip *chip, int lane)
 	 * It seems that after this workaround the SERDES is automatically
 	 * powered up (the bit is cleared), so power it down.
 	 */
-	if (lane == MV88E6393X_PORT0_LANE || lane == MV88E6393X_PORT9_LANE ||
-	    lane == MV88E6393X_PORT10_LANE) {
-		err = mv88e6390_serdes_read(chip, lane,
-					    MDIO_MMD_PHYXS,
+	err = mv88e6390_serdes_read(chip, lane, MDIO_MMD_PHYXS,
 				    MV88E6393X_SERDES_POC, &reg);
 	if (err)
 		return err;
@@ -1303,7 +1358,29 @@ static int mv88e6393x_serdes_port_errata(struct mv88e6xxx_chip *chip, int lane)
 	err = mv88e6390_serdes_power_sgmii(chip, lane, false);
 	if (err)
 		return err;
-	}
+
+	return mv88e6393x_serdes_power_lane(chip, lane, false);
+}
+
+int mv88e6393x_serdes_setup_errata(struct mv88e6xxx_chip *chip)
+{
+	int err;
+
+	err = mv88e6393x_serdes_erratum_4_6(chip, MV88E6393X_PORT0_LANE);
+	if (err)
+		return err;
+
+	err = mv88e6393x_serdes_erratum_4_6(chip, MV88E6393X_PORT9_LANE);
+	if (err)
+		return err;
+
+	return mv88e6393x_serdes_erratum_4_6(chip, MV88E6393X_PORT10_LANE);
+}
+
+static int mv88e6393x_serdes_erratum_4_8(struct mv88e6xxx_chip *chip, int lane)
+{
+	u16 reg, pcs;
+	int err;
 
 	/* mv88e6393x family errata 4.8:
 	 * When a SERDES port is operating in 1000BASE-X or SGMII mode link may
@@ -1334,38 +1411,149 @@ static int mv88e6393x_serdes_port_errata(struct mv88e6xxx_chip *chip, int lane)
 				      MV88E6393X_ERRATA_4_8_REG, reg);
 }
 
-int mv88e6393x_serdes_setup_errata(struct mv88e6xxx_chip *chip)
+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;
+}
+
+static int mv88e6393x_serdes_fix_2500basex_an(struct mv88e6xxx_chip *chip,
+					      int lane, u8 cmode, bool on)
 {
+	u16 reg;
 	int err;
 
-	err = mv88e6393x_serdes_port_errata(chip, MV88E6393X_PORT0_LANE);
+	if (cmode != MV88E6XXX_PORT_STS_CMODE_2500BASEX)
+		return 0;
+
+	/* Inband AN is broken on Amethyst in 2500base-x mode when set by
+	 * standard mechanism (via cmode).
+	 * We can get around this by configuring the PCS mode to 1000base-x
+	 * and then writing value 0x58 to register 1e.8000. (This must be done
+	 * while SerDes receiver and transmitter are disabled, which is, when
+	 * this function is called.)
+	 * It seem that when we do this configuration to 2500base-x mode (by
+	 * changing PCS mode to 1000base-x and frequency to 3.125 GHz from
+	 * 1.25 GHz) and then configure to sgmii or 1000base-x, the device
+	 * thinks that it already has SerDes at 1.25 GHz and does not change
+	 * the 1e.8000 register, leaving SerDes at 3.125 GHz.
+	 * To avoid this, change PCS mode back to 2500base-x when disabling
+	 * SerDes from 2500base-x mode.
+	 */
+	err = mv88e6390_serdes_read(chip, lane, MDIO_MMD_PHYXS,
+				    MV88E6393X_SERDES_POC, &reg);
 	if (err)
 		return err;
 
-	err = mv88e6393x_serdes_port_errata(chip, MV88E6393X_PORT9_LANE);
+	reg &= ~(MV88E6393X_SERDES_POC_PCS_MASK | MV88E6393X_SERDES_POC_AN);
+	if (on)
+		reg |= MV88E6393X_SERDES_POC_PCS_1000BASEX |
+		       MV88E6393X_SERDES_POC_AN;
+	else
+		reg |= MV88E6393X_SERDES_POC_PCS_2500BASEX;
+	reg |= MV88E6393X_SERDES_POC_RESET;
+
+	err = mv88e6390_serdes_write(chip, lane, MDIO_MMD_PHYXS,
+				     MV88E6393X_SERDES_POC, reg);
 	if (err)
 		return err;
 
-	return mv88e6393x_serdes_port_errata(chip, MV88E6393X_PORT10_LANE);
+	err = mv88e6390_serdes_write(chip, lane, MDIO_MMD_VEND1, 0x8000, 0x58);
+	if (err)
+		return err;
+
+	return 0;
 }
 
 int mv88e6393x_serdes_power(struct mv88e6xxx_chip *chip, int port, int lane,
 			    bool on)
 {
 	u8 cmode = chip->ports[port].cmode;
+	int err;
 
 	if (port != 0 && port != 9 && port != 10)
 		return -EOPNOTSUPP;
 
+	if (on) {
+		err = mv88e6393x_serdes_erratum_4_8(chip, lane);
+		if (err)
+			return err;
+
+		err = mv88e6393x_serdes_erratum_5_2(chip, lane, cmode);
+		if (err)
+			return err;
+
+		err = mv88e6393x_serdes_fix_2500basex_an(chip, lane, cmode,
+							 true);
+		if (err)
+			return err;
+
+		err = mv88e6393x_serdes_power_lane(chip, lane, true);
+		if (err)
+			return err;
+	}
+
 	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, on);
+		err = mv88e6390_serdes_power_sgmii(chip, lane, on);
+		break;
 	case MV88E6393X_PORT_STS_CMODE_5GBASER:
 	case MV88E6393X_PORT_STS_CMODE_10GBASER:
-		return mv88e6390_serdes_power_10g(chip, lane, on);
+		err = mv88e6390_serdes_power_10g(chip, lane, on);
+		break;
 	}
 
-	return 0;
+	if (err)
+		return err;
+
+	if (!on) {
+		err = mv88e6393x_serdes_power_lane(chip, lane, false);
+		if (err)
+			return err;
+
+		err = mv88e6393x_serdes_fix_2500basex_an(chip, lane, cmode,
+							 false);
+	}
+
+	return err;
 }

drivers/net/dsa/mv88e6xxx/serdes.h

@@ -93,6 +93,10 @@
 #define MV88E6393X_SERDES_POC_PCS_MASK		0x0007
 #define MV88E6393X_SERDES_POC_RESET		BIT(15)
 #define MV88E6393X_SERDES_POC_PDOWN		BIT(5)
+#define MV88E6393X_SERDES_POC_AN		BIT(3)
+#define MV88E6393X_SERDES_CTRL1			0xf003
+#define MV88E6393X_SERDES_CTRL1_TX_PDOWN	BIT(9)
+#define MV88E6393X_SERDES_CTRL1_RX_PDOWN	BIT(8)
 
 #define MV88E6393X_ERRATA_4_8_REG		0xF074
 #define MV88E6393X_ERRATA_4_8_BIT		BIT(14)