net: pcs: add C37 SGMII AN support for intel mGbE controller

XPCS IP supports C37 SGMII AN process and it is used in intel multi-GbE
controller as MAC-side SGMII.

Signed-off-by: Ong Boon Leong <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/pcs/pcs-xpcs.c

···
 #define SYNOPSYS_XPCS_USXGMII_ID	0x7996ced0
 #define SYNOPSYS_XPCS_10GKR_ID		0x7996ced0
 #define SYNOPSYS_XPCS_XLGMII_ID		0x7996ced0
+#define SYNOPSYS_XPCS_SGMII_ID		0x7996ced0
 #define SYNOPSYS_XPCS_MASK		0xffffffff
 
 /* Vendor regs access */
···
 /* AN_LP_ABL3 */
 #define DW_C73_2500KX			BIT(0)
 #define DW_C73_5000KR			BIT(1)
+
+/* Clause 37 Defines */
+/* VR MII MMD registers offsets */
+#define DW_VR_MII_DIG_CTRL1		0x8000
+#define DW_VR_MII_AN_CTRL		0x8001
+#define DW_VR_MII_AN_INTR_STS		0x8002
+
+/* VR_MII_DIG_CTRL1 */
+#define DW_VR_MII_DIG_CTRL1_MAC_AUTO_SW		BIT(9)
+
+/* VR_MII_AN_CTRL */
+#define DW_VR_MII_AN_CTRL_TX_CONFIG_SHIFT	3
+#define DW_VR_MII_TX_CONFIG_MASK		BIT(3)
+#define DW_VR_MII_TX_CONFIG_PHY_SIDE_SGMII	0x1
+#define DW_VR_MII_TX_CONFIG_MAC_SIDE_SGMII	0x0
+#define DW_VR_MII_AN_CTRL_PCS_MODE_SHIFT	1
+#define DW_VR_MII_PCS_MODE_MASK			GENMASK(2, 1)
+#define DW_VR_MII_PCS_MODE_C37_1000BASEX	0x0
+#define DW_VR_MII_PCS_MODE_C37_SGMII		0x2
+
+/* VR_MII_AN_INTR_STS */
+#define DW_VR_MII_AN_STS_C37_ANSGM_FD		BIT(1)
+#define DW_VR_MII_AN_STS_C37_ANSGM_SP_SHIFT	2
+#define DW_VR_MII_AN_STS_C37_ANSGM_SP		GENMASK(3, 2)
+#define DW_VR_MII_C37_ANSGM_SP_10		0x0
+#define DW_VR_MII_C37_ANSGM_SP_100		0x1
+#define DW_VR_MII_C37_ANSGM_SP_1000		0x2
+#define DW_VR_MII_C37_ANSGM_SP_LNKSTS		BIT(4)
 
 static const int xpcs_usxgmii_features[] = {
 	ETHTOOL_LINK_MODE_Pause_BIT,
···
 	__ETHTOOL_LINK_MODE_MASK_NBITS,
 };
 
+static const int xpcs_sgmii_features[] = {
+	ETHTOOL_LINK_MODE_10baseT_Half_BIT,
+	ETHTOOL_LINK_MODE_10baseT_Full_BIT,
+	ETHTOOL_LINK_MODE_100baseT_Half_BIT,
+	ETHTOOL_LINK_MODE_100baseT_Full_BIT,
+	ETHTOOL_LINK_MODE_1000baseT_Half_BIT,
+	ETHTOOL_LINK_MODE_1000baseT_Full_BIT,
+	__ETHTOOL_LINK_MODE_MASK_NBITS,
+};
+
 static const phy_interface_t xpcs_usxgmii_interfaces[] = {
 	PHY_INTERFACE_MODE_USXGMII,
 	PHY_INTERFACE_MODE_MAX,
···
 
 static const phy_interface_t xpcs_xlgmii_interfaces[] = {
 	PHY_INTERFACE_MODE_XLGMII,
+	PHY_INTERFACE_MODE_MAX,
+};
+
+static const phy_interface_t xpcs_sgmii_interfaces[] = {
+	PHY_INTERFACE_MODE_SGMII,
 	PHY_INTERFACE_MODE_MAX,
 };
 
···
 		.supported = xpcs_xlgmii_features,
 		.interface = xpcs_xlgmii_interfaces,
 		.an_mode = DW_AN_C73,
+	}, {
+		.id = SYNOPSYS_XPCS_SGMII_ID,
+		.mask = SYNOPSYS_XPCS_MASK,
+		.supported = xpcs_sgmii_features,
+		.interface = xpcs_sgmii_interfaces,
+		.an_mode = DW_AN_C37_SGMII,
 	},
 };
 
···
 	switch (xpcs->an_mode) {
 	case DW_AN_C73:
 		dev = MDIO_MMD_PCS;
+		break;
+	case DW_AN_C37_SGMII:
+		dev = MDIO_MMD_VEND2;
 		break;
 	default:
 		return -1;
···
 	return 0;
 }
 
+static int xpcs_config_aneg_c37_sgmii(struct mdio_xpcs_args *xpcs)
+{
+	int ret;
+
+	/* For AN for C37 SGMII mode, the settings are :-
+	 * 1) VR_MII_AN_CTRL Bit(2:1)[PCS_MODE] = 10b (SGMII AN)
+	 * 2) VR_MII_AN_CTRL Bit(3) [TX_CONFIG] = 0b (MAC side SGMII)
+	 *    DW xPCS used with DW EQoS MAC is always MAC side SGMII.
+	 * 3) VR_MII_DIG_CTRL1 Bit(9) [MAC_AUTO_SW] = 1b (Automatic
+	 *    speed/duplex mode change by HW after SGMII AN complete)
+	 *
+	 * Note: Since it is MAC side SGMII, there is no need to set
+	 *	 SR_MII_AN_ADV. MAC side SGMII receives AN Tx Config from
+	 *	 PHY about the link state change after C28 AN is completed
+	 *	 between PHY and Link Partner. There is also no need to
+	 *	 trigger AN restart for MAC-side SGMII.
+	 */
+	ret = xpcs_read(xpcs, MDIO_MMD_VEND2, DW_VR_MII_AN_CTRL);
+	if (ret < 0)
+		return ret;
+
+	ret &= ~(DW_VR_MII_PCS_MODE_MASK | DW_VR_MII_TX_CONFIG_MASK);
+	ret |= (DW_VR_MII_PCS_MODE_C37_SGMII <<
+		DW_VR_MII_AN_CTRL_PCS_MODE_SHIFT &
+		DW_VR_MII_PCS_MODE_MASK);
+	ret |= (DW_VR_MII_TX_CONFIG_MAC_SIDE_SGMII <<
+		DW_VR_MII_AN_CTRL_TX_CONFIG_SHIFT &
+		DW_VR_MII_TX_CONFIG_MASK);
+	ret = xpcs_write(xpcs, MDIO_MMD_VEND2, DW_VR_MII_AN_CTRL, ret);
+	if (ret < 0)
+		return ret;
+
+	ret = xpcs_read(xpcs, MDIO_MMD_VEND2, DW_VR_MII_DIG_CTRL1);
+	if (ret < 0)
+		return ret;
+
+	ret |= DW_VR_MII_DIG_CTRL1_MAC_AUTO_SW;
+
+	return xpcs_write(xpcs, MDIO_MMD_VEND2, DW_VR_MII_DIG_CTRL1, ret);
+}
+
 static int xpcs_config(struct mdio_xpcs_args *xpcs,
 		       const struct phylink_link_state *state)
 {
···
 			if (ret)
 				return ret;
 		}
+		break;
+	case DW_AN_C37_SGMII:
+		ret = xpcs_config_aneg_c37_sgmii(xpcs);
+		if (ret)
+			return ret;
 		break;
 	default:
 		return -1;
···
 	return 0;
 }
 
+static int xpcs_get_state_c37_sgmii(struct mdio_xpcs_args *xpcs,
+				    struct phylink_link_state *state)
+{
+	int ret;
+
+	/* Reset link_state */
+	state->link = false;
+	state->speed = SPEED_UNKNOWN;
+	state->duplex = DUPLEX_UNKNOWN;
+	state->pause = 0;
+
+	/* For C37 SGMII mode, we check DW_VR_MII_AN_INTR_STS for link
+	 * status, speed and duplex.
+	 */
+	ret = xpcs_read(xpcs, MDIO_MMD_VEND2, DW_VR_MII_AN_INTR_STS);
+	if (ret < 0)
+		return false;
+
+	if (ret & DW_VR_MII_C37_ANSGM_SP_LNKSTS) {
+		int speed_value;
+
+		state->link = true;
+
+		speed_value = (ret & DW_VR_MII_AN_STS_C37_ANSGM_SP) >>
+			      DW_VR_MII_AN_STS_C37_ANSGM_SP_SHIFT;
+		if (speed_value == DW_VR_MII_C37_ANSGM_SP_1000)
+			state->speed = SPEED_1000;
+		else if (speed_value == DW_VR_MII_C37_ANSGM_SP_100)
+			state->speed = SPEED_100;
+		else
+			state->speed = SPEED_10;
+
+		if (ret & DW_VR_MII_AN_STS_C37_ANSGM_FD)
+			state->duplex = DUPLEX_FULL;
+		else
+			state->duplex = DUPLEX_HALF;
+	}
+
+	return 0;
+}
+
 static int xpcs_get_state(struct mdio_xpcs_args *xpcs,
 			  struct phylink_link_state *state)
 {
···
 	switch (xpcs->an_mode) {
 	case DW_AN_C73:
 		ret = xpcs_get_state_c73(xpcs, state);
+		if (ret)
+			return ret;
+		break;
+	case DW_AN_C37_SGMII:
+		ret = xpcs_get_state_c37_sgmii(xpcs, state);
 		if (ret)
 			return ret;
 		break;
···
 	int ret;
 	u32 id;
 
+	/* First, search C73 PCS using PCS MMD */
 	ret = xpcs_read(xpcs, MDIO_MMD_PCS, MII_PHYSID1);
 	if (ret < 0)
 		return 0xffffffff;
···
 	if (ret < 0)
 		return 0xffffffff;
 
-	return id | ret;
+	/* If Device IDs are not all zeros, we found C73 AN-type device */
+	if (id | ret)
+		return id | ret;
+
+	/* Next, search C37 PCS using Vendor-Specific MII MMD */
+	ret = xpcs_read(xpcs, MDIO_MMD_VEND2, MII_PHYSID1);
+	if (ret < 0)
+		return 0xffffffff;
+
+	id = ret << 16;
+
+	ret = xpcs_read(xpcs, MDIO_MMD_VEND2, MII_PHYSID2);
+	if (ret < 0)
+		return 0xffffffff;
+
+	/* If Device IDs are not all zeros, we found C37 AN-type device */
+	if (id | ret)
+		return id | ret;
+
+	return 0xffffffff;
 }
 
 static bool xpcs_check_features(struct mdio_xpcs_args *xpcs,

include/linux/pcs/pcs-xpcs.h

···
 
 /* AN mode */
 #define DW_AN_C73			1
+#define DW_AN_C37_SGMII			2
 
 struct mdio_xpcs_args {
 	__ETHTOOL_DECLARE_LINK_MODE_MASK(supported);