Driver support for bcm84891 SFP+

drivers/net/phy/bcm84881.c

@@ -83,10 +83,24 @@ static int bcm84881_config_init(struct phy_device *phydev)
 
 static int bcm8489x_config_init(struct phy_device *phydev)
 {
+	bcm84881_fill_possible_interfaces(phydev);
 	__set_bit(PHY_INTERFACE_MODE_USXGMII, phydev->possible_interfaces);
 
-	if (phydev->interface != PHY_INTERFACE_MODE_USXGMII)
+	/* The BCM84891 is found both soldered down and attached over
+	 * USXGMII, and inside SFP+ copper modules (e.g. various
+	 * "OEM SFP-10G-T" RollBall modules), where the host-side
+	 * interface is 10GBASE-R with SGMII/2500BASE-X rate switching,
+	 * as with the BCM84881. Accept both attachments.
+	 */
+	switch (phydev->interface) {
+	case PHY_INTERFACE_MODE_SGMII:
+	case PHY_INTERFACE_MODE_2500BASEX:
+	case PHY_INTERFACE_MODE_10GBASER:
+	case PHY_INTERFACE_MODE_USXGMII:
+		break;
+	default:
 		return -ENODEV;
+	}
 
 	/* MDIO_CTRL1_LPOWER is set at boot on the tested platform. Does not
 	 * recur on ifdown/ifup, cable events, or link-partner advertisement
@@ -416,12 +430,30 @@ static unsigned int bcm84881_inband_caps(struct phy_device *phydev,
 	return LINK_INBAND_DISABLE;
 }
 
+static int bcm84881_config_inband(struct phy_device *phydev,
+				  unsigned int modes)
+{
+	/* This PHY does not generate inband signalling in any mode (see
+	 * bcm84881_inband_caps()); inband is permanently disabled in
+	 * hardware. A request to disable inband therefore requires no
+	 * action, but must succeed: phylink treats any error from
+	 * phy_config_inband() (including -EOPNOTSUPP from a missing
+	 * config_inband method) as a major configuration failure which
+	 * forces and holds the link down.
+	 */
+	if (modes == LINK_INBAND_DISABLE)
+		return 0;
+
+	return -EINVAL;
+}
+
 static struct phy_driver bcm84881_drivers[] = {
 	{
 		.phy_id		= 0xae025150,
 		.phy_id_mask	= 0xfffffff0,
 		.name		= "Broadcom BCM84881",
 		.inband_caps	= bcm84881_inband_caps,
+		.config_inband	= bcm84881_config_inband,
 		.config_init	= bcm84881_config_init,
 		.probe		= bcm84881_probe,
 		.get_features	= bcm84881_get_features,
@@ -432,6 +464,7 @@ static struct phy_driver bcm84881_drivers[] = {
 		PHY_ID_MATCH_MODEL(0x35905080),
 		.name		= "Broadcom BCM84891",
 		.inband_caps	= bcm84881_inband_caps,
+		.config_inband	= bcm84881_config_inband,
 		.config_init	= bcm8489x_config_init,
 		.probe		= bcm84881_probe,
 		.get_features	= bcm84881_get_features,
@@ -446,6 +479,7 @@ static struct phy_driver bcm84881_drivers[] = {
 		PHY_ID_MATCH_MODEL(0x359050a0),
 		.name		= "Broadcom BCM84892",
 		.inband_caps	= bcm84881_inband_caps,
+		.config_inband	= bcm84881_config_inband,
 		.config_init	= bcm8489x_config_init,
 		.probe		= bcm84881_probe,
 		.get_features	= bcm84881_get_features,

drivers/net/phy/sfp.c

@@ -1938,6 +1938,75 @@ static int sfp_sm_probe_phy(struct sfp *sfp, int addr, bool is_c45)
 		return PTR_ERR(phy);
 	}
 
+	/* Some RollBall modules stop gating PHY register access (reads
+	 * returning 0xffff) slightly before the PHY's identifier registers
+	 * are stable. A probe landing in this window reads a plausible
+	 * devices-in-package value but all-zero device identifiers, which
+	 * no PHY driver can match. sfp_add_phy() then fails hard with
+	 * -EINVAL and the state machine enters SFP_S_FAIL, requiring a
+	 * physical re-plug. Treat all-zero identifiers as "PHY not ready"
+	 * instead, so the existing R_PHY_RETRY/phy_t_retry logic applies.
+	 */
+	if (is_c45) {
+		u32 devs = phy->c45_ids.devices_in_package;
+		bool ids_valid = false;
+		int ret;
+		int i;
+
+		/* Absent MMDs leave their identifier zero; a gated or
+		 * timed-out RollBall access reads 0xffff, so an identifier
+		 * with either 16-bit half at 0xffff is corrupt. Require at
+		 * least one fully plausible identifier before accepting the
+		 * PHY.
+		 */
+		for (i = 1; i < ARRAY_SIZE(phy->c45_ids.device_ids); i++) {
+			u32 id = phy->c45_ids.device_ids[i];
+
+			if (id && (id & 0xffff) != 0xffff &&
+			    (id >> 16) != 0xffff) {
+				ids_valid = true;
+				break;
+			}
+		}
+
+		/* devices_in_package selects which MMDs are enumerated, so a
+		 * timed-out read leaving either 16-bit half at 0xffff makes
+		 * the map itself untrustworthy -- one clean identifier is not
+		 * enough to accept it. Seen on a BCM84891 that answered PMA
+		 * (0x35905081) while the rest of the mailbox was still gated
+		 * (devs_in_pkg 0xffff009b): the id-only check passed on the
+		 * clean PMA, attached a half-awake PHY, and its reset poll
+		 * then failed -ETIMEDOUT during attach.
+		 */
+		if (!ids_valid ||
+		    (devs & 0xffff) == 0xffff || (devs >> 16) == 0xffff) {
+			dev_info(sfp->dev,
+				 "PHY identifiers unstable (devs_in_pkg 0x%08x), retrying\n",
+				 phy->c45_ids.devices_in_package);
+			phy_device_free(phy);
+			return -ENODEV;
+		}
+
+		/* Plausible identifiers do not guarantee the PMA/PMD control
+		 * register is out of the gated window. phy_init_hw()'s soft
+		 * reset during attach writes MDIO_CTRL1 and polls the reset
+		 * bit to self-clear; a gated read returns 0xffff so the bit
+		 * never clears and sfp_add_phy() fails -ETIMEDOUT (which has
+		 * been seen to later fault the PHY state machine on interface
+		 * teardown). Require that same register to read back live
+		 * before attaching, so the retry logic waits out the wake
+		 * window and the PHY is attached exactly once, cleanly.
+		 */
+		ret = phy_read_mmd(phy, MDIO_MMD_PMAPMD, MDIO_CTRL1);
+		if (ret < 0 || ret == 0xffff || (ret & MDIO_CTRL1_RESET)) {
+			dev_info(sfp->dev,
+				 "PHY control register not ready (0x%04x), retrying\n",
+				 ret);
+			phy_device_free(phy);
+			return -ENODEV;
+		}
+	}
+
 	/* Mark this PHY as being on a SFP module */
 	phy->is_on_sfp_module = true;
 
@@ -1951,6 +2020,13 @@ static int sfp_sm_probe_phy(struct sfp *sfp, int addr, bool is_c45)
 
 	err = sfp_add_phy(sfp->sfp_bus, phy);
 	if (err) {
+		if (is_c45)
+			dev_err(sfp->dev,
+				"PHY c45 ids: PMA 0x%08x PCS 0x%08x AN 0x%08x devs_in_pkg 0x%08x\n",
+				phy->c45_ids.device_ids[MDIO_MMD_PMAPMD],
+				phy->c45_ids.device_ids[MDIO_MMD_PCS],
+				phy->c45_ids.device_ids[MDIO_MMD_AN],
+				phy->c45_ids.devices_in_package);
 		phy_device_remove(phy);
 		phy_device_free(phy);
 		dev_err(sfp->dev, "sfp_add_phy failed: %pe\n", ERR_PTR(err));