net: pcs: xpcs: add CL37 1000BASE-X AN support

For CL37 1000BASE-X AN, DW xPCS does not support C22 method but offers
C45 vendor-specific MII MMD for programming.

We also add the ability to disable Autoneg (through ethtool for certain
network switch that supports 1000BASE-X (1000Mbps and Full-Duplex) but
not Autoneg capability.

v4: Fixes to comment from Russell King. Thanks!
https://patchwork.kernel.org/comment/24894239/
Make xpcs_modify_changed() as private, change to use
mdiodev_modify_changed() for cleaner code.

v3: Fixes to issues spotted by Russell King. Thanks!
https://patchwork.kernel.org/comment/24890210/
Use phylink_mii_c22_pcs_decode_state(), remove unnecessary
interrupt clearing and skip speed & duplex setting if AN
is enabled.

v2: Fixes to issues spotted by Russell King in v1. Thanks!
https://patchwork.kernel.org/comment/24826650/
Use phylink_mii_c22_pcs_encode_advertisement() and implement
C45 MII ADV handling since IP only support C45 access.

Tested-by: Emilio Riva <[e-mail]>
Signed-off-by: Ong Boon Leong <[e-mail]>
Reviewed-by: Russell King (Oracle) <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/pcs/pcs-xpcs.c

···
 	__ETHTOOL_LINK_MODE_MASK_NBITS,
 };
 
+static const int xpcs_1000basex_features[] = {
+	ETHTOOL_LINK_MODE_Pause_BIT,
+	ETHTOOL_LINK_MODE_Asym_Pause_BIT,
+	ETHTOOL_LINK_MODE_Autoneg_BIT,
+	ETHTOOL_LINK_MODE_1000baseX_Full_BIT,
+	__ETHTOOL_LINK_MODE_MASK_NBITS,
+};
+
 static const int xpcs_2500basex_features[] = {
 	ETHTOOL_LINK_MODE_Pause_BIT,
 	ETHTOOL_LINK_MODE_Asym_Pause_BIT,
···
 	PHY_INTERFACE_MODE_SGMII,
 };
 
+static const phy_interface_t xpcs_1000basex_interfaces[] = {
+	PHY_INTERFACE_MODE_1000BASEX,
+};
+
 static const phy_interface_t xpcs_2500basex_interfaces[] = {
 	PHY_INTERFACE_MODE_2500BASEX,
 	PHY_INTERFACE_MODE_MAX,
···
 	DW_XPCS_10GKR,
 	DW_XPCS_XLGMII,
 	DW_XPCS_SGMII,
+	DW_XPCS_1000BASEX,
 	DW_XPCS_2500BASEX,
 	DW_XPCS_INTERFACE_MAX,
 };
···
 	return mdiobus_c45_write(bus, addr, dev, reg, val);
 }
 
+static int xpcs_modify_changed(struct dw_xpcs *xpcs, int dev, u32 reg,
+			       u16 mask, u16 set)
+{
+	u32 reg_addr = mdiobus_c45_addr(dev, reg);
+
+	return mdiodev_modify_changed(xpcs->mdiodev, reg_addr, mask, set);
+}
+
 static int xpcs_read_vendor(struct dw_xpcs *xpcs, int dev, u32 reg)
 {
 	return xpcs_read(xpcs, dev, DW_VENDOR | reg);
···
 		break;
 	case DW_AN_C37_SGMII:
 	case DW_2500BASEX:
+	case DW_AN_C37_1000BASEX:
 		dev = MDIO_MMD_VEND2;
 		break;
 	default:
···
 	return ret;
 }
 
+static int xpcs_config_aneg_c37_1000basex(struct dw_xpcs *xpcs, unsigned int mode,
+					  const unsigned long *advertising)
+{
+	phy_interface_t interface = PHY_INTERFACE_MODE_1000BASEX;
+	int ret, mdio_ctrl, adv;
+	bool changed = 0;
+
+	/* According to Chap 7.12, to set 1000BASE-X C37 AN, AN must
+	 * be disabled first:-
+	 * 1) VR_MII_MMD_CTRL Bit(12)[AN_ENABLE] = 0b
+	 * 2) VR_MII_AN_CTRL Bit(2:1)[PCS_MODE] = 00b (1000BASE-X C37)
+	 */
+	mdio_ctrl = xpcs_read(xpcs, MDIO_MMD_VEND2, DW_VR_MII_MMD_CTRL);
+	if (mdio_ctrl < 0)
+		return mdio_ctrl;
+
+	if (mdio_ctrl & AN_CL37_EN) {
+		ret = xpcs_write(xpcs, MDIO_MMD_VEND2, DW_VR_MII_MMD_CTRL,
+				 mdio_ctrl & ~AN_CL37_EN);
+		if (ret < 0)
+			return ret;
+	}
+
+	ret = xpcs_read(xpcs, MDIO_MMD_VEND2, DW_VR_MII_AN_CTRL);
+	if (ret < 0)
+		return ret;
+
+	ret &= ~DW_VR_MII_PCS_MODE_MASK;
+	ret = xpcs_write(xpcs, MDIO_MMD_VEND2, DW_VR_MII_AN_CTRL, ret);
+	if (ret < 0)
+		return ret;
+
+	/* Check for advertising changes and update the C45 MII ADV
+	 * register accordingly.
+	 */
+	adv = phylink_mii_c22_pcs_encode_advertisement(interface,
+						       advertising);
+	if (adv >= 0) {
+		ret = xpcs_modify_changed(xpcs, MDIO_MMD_VEND2,
+					  MII_ADVERTISE, 0xffff, adv);
+		if (ret < 0)
+			return ret;
+
+		changed = ret;
+	}
+
+	/* Clear CL37 AN complete status */
+	ret = xpcs_write(xpcs, MDIO_MMD_VEND2, DW_VR_MII_AN_INTR_STS, 0);
+	if (ret < 0)
+		return ret;
+
+	if (phylink_autoneg_inband(mode) &&
+	    linkmode_test_bit(ETHTOOL_LINK_MODE_Autoneg_BIT, advertising)) {
+		ret = xpcs_write(xpcs, MDIO_MMD_VEND2, DW_VR_MII_MMD_CTRL,
+				 mdio_ctrl | AN_CL37_EN);
+		if (ret < 0)
+			return ret;
+	}
+
+	return changed;
+}
+
 static int xpcs_config_2500basex(struct dw_xpcs *xpcs)
 {
 	int ret;
···
 		break;
 	case DW_AN_C37_SGMII:
 		ret = xpcs_config_aneg_c37_sgmii(xpcs, mode);
+		if (ret)
+			return ret;
+		break;
+	case DW_AN_C37_1000BASEX:
+		ret = xpcs_config_aneg_c37_1000basex(xpcs, mode,
+						     advertising);
 		if (ret)
 			return ret;
 		break;
···
 	return 0;
 }
 
+static int xpcs_get_state_c37_1000basex(struct dw_xpcs *xpcs,
+					struct phylink_link_state *state)
+{
+	int lpa, bmsr;
+
+	if (state->an_enabled) {
+		/* Reset link state */
+		state->link = false;
+
+		lpa = xpcs_read(xpcs, MDIO_MMD_VEND2, MII_LPA);
+		if (lpa < 0 || lpa & LPA_RFAULT)
+			return lpa;
+
+		bmsr = xpcs_read(xpcs, MDIO_MMD_VEND2, MII_BMSR);
+		if (bmsr < 0)
+			return bmsr;
+
+		phylink_mii_c22_pcs_decode_state(state, bmsr, lpa);
+	}
+
+	return 0;
+}
+
 static void xpcs_get_state(struct phylink_pcs *pcs,
 			   struct phylink_link_state *state)
 {
···
 		ret = xpcs_get_state_c37_sgmii(xpcs, state);
 		if (ret) {
 			pr_err("xpcs_get_state_c37_sgmii returned %pe\n",
+			       ERR_PTR(ret));
+		}
+		break;
+	case DW_AN_C37_1000BASEX:
+		ret = xpcs_get_state_c37_1000basex(xpcs, state);
+		if (ret) {
+			pr_err("xpcs_get_state_c37_1000basex returned %pe\n",
 			       ERR_PTR(ret));
 		}
 		break;
···
 		pr_err("%s: xpcs_write returned %pe\n", __func__, ERR_PTR(ret));
 }
 
+static void xpcs_link_up_1000basex(struct dw_xpcs *xpcs, unsigned int mode,
+				   int speed, int duplex)
+{
+	int val, ret;
+
+	if (phylink_autoneg_inband(mode))
+		return;
+
+	switch (speed) {
+	case SPEED_1000:
+		val = BMCR_SPEED1000;
+		break;
+	case SPEED_100:
+	case SPEED_10:
+	default:
+		pr_err("%s: speed = %d\n", __func__, speed);
+		return;
+	}
+
+	if (duplex == DUPLEX_FULL)
+		val |= BMCR_FULLDPLX;
+	else
+		pr_err("%s: half duplex not supported\n", __func__);
+
+	ret = xpcs_write(xpcs, MDIO_MMD_VEND2, MDIO_CTRL1, val);
+	if (ret)
+		pr_err("%s: xpcs_write returned %pe\n", __func__, ERR_PTR(ret));
+}
+
 void xpcs_link_up(struct phylink_pcs *pcs, unsigned int mode,
 		  phy_interface_t interface, int speed, int duplex)
 {
···
 		return xpcs_config_usxgmii(xpcs, speed);
 	if (interface == PHY_INTERFACE_MODE_SGMII)
 		return xpcs_link_up_sgmii(xpcs, mode, speed, duplex);
+	if (interface == PHY_INTERFACE_MODE_1000BASEX)
+		return xpcs_link_up_1000basex(xpcs, mode, speed, duplex);
 }
 EXPORT_SYMBOL_GPL(xpcs_link_up);
+
+static void xpcs_an_restart(struct phylink_pcs *pcs)
+{
+	struct dw_xpcs *xpcs = phylink_pcs_to_xpcs(pcs);
+	int ret;
+
+	ret = xpcs_read(xpcs, MDIO_MMD_VEND2, MDIO_CTRL1);
+	if (ret >= 0) {
+		ret |= BMCR_ANRESTART;
+		xpcs_write(xpcs, MDIO_MMD_VEND2, MDIO_CTRL1, ret);
+	}
+}
 
 static u32 xpcs_get_id(struct dw_xpcs *xpcs)
 {
···
 		.num_interfaces = ARRAY_SIZE(xpcs_sgmii_interfaces),
 		.an_mode = DW_AN_C37_SGMII,
 	},
+	[DW_XPCS_1000BASEX] = {
+		.supported = xpcs_1000basex_features,
+		.interface = xpcs_1000basex_interfaces,
+		.num_interfaces = ARRAY_SIZE(xpcs_1000basex_interfaces),
+		.an_mode = DW_AN_C37_1000BASEX,
+	},
 	[DW_XPCS_2500BASEX] = {
 		.supported = xpcs_2500basex_features,
 		.interface = xpcs_2500basex_interfaces,
···
 	.pcs_validate = xpcs_validate,
 	.pcs_config = xpcs_config,
 	.pcs_get_state = xpcs_get_state,
+	.pcs_an_restart = xpcs_an_restart,
 	.pcs_link_up = xpcs_link_up,
 };
 

drivers/net/pcs/pcs-xpcs.h

···
 
 int xpcs_read(struct dw_xpcs *xpcs, int dev, u32 reg);
 int xpcs_write(struct dw_xpcs *xpcs, int dev, u32 reg, u16 val);
-
 int nxp_sja1105_sgmii_pma_config(struct dw_xpcs *xpcs);
 int nxp_sja1110_sgmii_pma_config(struct dw_xpcs *xpcs);
 int nxp_sja1110_2500basex_pma_config(struct dw_xpcs *xpcs);

include/linux/pcs/pcs-xpcs.h

···
 #define DW_AN_C73			1
 #define DW_AN_C37_SGMII			2
 #define DW_2500BASEX			3
+#define DW_AN_C37_1000BASEX		4
 
 struct xpcs_id;