net: phy: marvell: add special handling of Finisar modules with 88E1111

The Finisar FCLF8520P2BTL 1000BaseT SFP module uses a Marvel 88E1111 PHY
with a modified PHY ID. Add support for this ID using the 88E1111
methods.

By default these modules do not have 1000BaseX auto-negotiation enabled,
which is not generally desirable with Linux networking drivers. Add
handling to enable 1000BaseX auto-negotiation when these modules are
used in 1000BaseX mode. Also, some special handling is required to ensure
that 1000BaseT auto-negotiation is enabled properly when desired.

Based on existing handling in the AMD xgbe driver and the information in
the Finisar FAQ:
https://www.finisar.com/sites/default/files/resources/an-2036_1000base-t_sfp_faqreve1.pdf

Signed-off-by: Robert Hancock <[e-mail]>
Reviewed-by: Russell King <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

drivers/net/phy/marvell.c

···
 #define MII_M1111_HWCFG_MODE_FIBER_RGMII	0x3
 #define MII_M1111_HWCFG_MODE_SGMII_NO_CLK	0x4
 #define MII_M1111_HWCFG_MODE_RTBI		0x7
+#define MII_M1111_HWCFG_MODE_COPPER_1000X_AN	0x8
 #define MII_M1111_HWCFG_MODE_COPPER_RTBI	0x9
 #define MII_M1111_HWCFG_MODE_COPPER_RGMII	0xb
+#define MII_M1111_HWCFG_MODE_COPPER_1000X_NOAN	0xc
+#define MII_M1111_HWCFG_SERIAL_AN_BYPASS	BIT(12)
 #define MII_M1111_HWCFG_FIBER_COPPER_RES	BIT(13)
 #define MII_M1111_HWCFG_FIBER_COPPER_AUTO	BIT(15)
 
···
 	return genphy_check_and_restart_aneg(phydev, changed);
 }
 
+static int m88e1111_config_aneg(struct phy_device *phydev)
+{
+	int extsr = phy_read(phydev, MII_M1111_PHY_EXT_SR);
+	int err;
+
+	if (extsr < 0)
+		return extsr;
+
+	/* If not using SGMII or copper 1000BaseX modes, use normal process.
+	 * Steps below are only required for these modes.
+	 */
+	if (phydev->interface != PHY_INTERFACE_MODE_SGMII &&
+	    (extsr & MII_M1111_HWCFG_MODE_MASK) !=
+	    MII_M1111_HWCFG_MODE_COPPER_1000X_AN)
+		return marvell_config_aneg(phydev);
+
+	err = marvell_set_page(phydev, MII_MARVELL_COPPER_PAGE);
+	if (err < 0)
+		goto error;
+
+	/* Configure the copper link first */
+	err = marvell_config_aneg(phydev);
+	if (err < 0)
+		goto error;
+
+	/* Do not touch the fiber page if we're in copper->sgmii mode */
+	if (phydev->interface == PHY_INTERFACE_MODE_SGMII)
+		return 0;
+
+	/* Then the fiber link */
+	err = marvell_set_page(phydev, MII_MARVELL_FIBER_PAGE);
+	if (err < 0)
+		goto error;
+
+	err = marvell_config_aneg_fiber(phydev);
+	if (err < 0)
+		goto error;
+
+	return marvell_set_page(phydev, MII_MARVELL_COPPER_PAGE);
+
+error:
+	marvell_set_page(phydev, MII_MARVELL_COPPER_PAGE);
+	return err;
+}
+
 static int m88e1510_config_aneg(struct phy_device *phydev)
 {
 	int err;
···
 		MII_M1111_HWCFG_FIBER_COPPER_AUTO);
 }
 
+static int m88e1111_config_init_1000basex(struct phy_device *phydev)
+{
+	int extsr = phy_read(phydev, MII_M1111_PHY_EXT_SR);
+	int err, mode;
+
+	if (extsr < 0)
+		return extsr;
+
+	/* If using copper mode, ensure 1000BaseX auto-negotiation is enabled */
+	mode = extsr & MII_M1111_HWCFG_MODE_MASK;
+	if (mode == MII_M1111_HWCFG_MODE_COPPER_1000X_NOAN) {
+		err = phy_modify(phydev, MII_M1111_PHY_EXT_SR,
+				 MII_M1111_HWCFG_MODE_MASK |
+				 MII_M1111_HWCFG_SERIAL_AN_BYPASS,
+				 MII_M1111_HWCFG_MODE_COPPER_1000X_AN |
+				 MII_M1111_HWCFG_SERIAL_AN_BYPASS);
+		if (err < 0)
+			return err;
+	}
+	return 0;
+}
+
 static int m88e1111_config_init(struct phy_device *phydev)
 {
 	int err;
···
 
 	if (phydev->interface == PHY_INTERFACE_MODE_RTBI) {
 		err = m88e1111_config_init_rtbi(phydev);
+		if (err < 0)
+			return err;
+	}
+
+	if (phydev->interface == PHY_INTERFACE_MODE_1000BASEX) {
+		err = m88e1111_config_init_1000basex(phydev);
 		if (err < 0)
 			return err;
 	}
···
 		/* PHY_GBIT_FEATURES */
 		.probe = marvell_probe,
 		.config_init = m88e1111_config_init,
-		.config_aneg = marvell_config_aneg,
+		.config_aneg = m88e1111_config_aneg,
+		.read_status = marvell_read_status,
+		.ack_interrupt = marvell_ack_interrupt,
+		.config_intr = marvell_config_intr,
+		.resume = genphy_resume,
+		.suspend = genphy_suspend,
+		.read_page = marvell_read_page,
+		.write_page = marvell_write_page,
+		.get_sset_count = marvell_get_sset_count,
+		.get_strings = marvell_get_strings,
+		.get_stats = marvell_get_stats,
+		.get_tunable = m88e1111_get_tunable,
+		.set_tunable = m88e1111_set_tunable,
+	},
+	{
+		.phy_id = MARVELL_PHY_ID_88E1111_FINISAR,
+		.phy_id_mask = MARVELL_PHY_ID_MASK,
+		.name = "Marvell 88E1111 (Finisar)",
+		/* PHY_GBIT_FEATURES */
+		.probe = marvell_probe,
+		.config_init = m88e1111_config_init,
+		.config_aneg = m88e1111_config_aneg,
 		.read_status = marvell_read_status,
 		.ack_interrupt = marvell_ack_interrupt,
 		.config_intr = marvell_config_intr,
···
 	{ MARVELL_PHY_ID_88E1101, MARVELL_PHY_ID_MASK },
 	{ MARVELL_PHY_ID_88E1112, MARVELL_PHY_ID_MASK },
 	{ MARVELL_PHY_ID_88E1111, MARVELL_PHY_ID_MASK },
+	{ MARVELL_PHY_ID_88E1111_FINISAR, MARVELL_PHY_ID_MASK },
 	{ MARVELL_PHY_ID_88E1118, MARVELL_PHY_ID_MASK },
 	{ MARVELL_PHY_ID_88E1121R, MARVELL_PHY_ID_MASK },
 	{ MARVELL_PHY_ID_88E1145, MARVELL_PHY_ID_MASK },

include/linux/marvell_phy.h

···
 #define MARVELL_PHY_ID_88X3310		0x002b09a0
 #define MARVELL_PHY_ID_88E2110		0x002b09b0
 
+/* Marvel 88E1111 in Finisar SFP module with modified PHY ID */
+#define MARVELL_PHY_ID_88E1111_FINISAR	0x01ff0cc0
+
 /* The MV88e6390 Ethernet switch contains embedded PHYs. These PHYs do
  * not have a model ID. So the switch driver traps reads to the ID2
  * register and returns the switch family ID