net: phy: marvell10g: support XFI rate matching mode

When the hardware MACTYPE hardware configuration pins are set to "XFI
with Rate Matching" the PHY interface operate at fixed 10Gbps speed. The
MAC buffer packets in both directions to match various wire speeds.

Read the MAC Type field in the Port Control register, and set the MAC
interface speed accordingly.

Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/phy/marvell10g.c

@@ -80,6 +80,8 @@ enum {
 	MV_V2_PORT_CTRL		= 0xf001,
 	MV_V2_PORT_CTRL_SWRST	= BIT(15),
 	MV_V2_PORT_CTRL_PWRDOWN = BIT(11),
+	MV_V2_PORT_MAC_TYPE_MASK = 0x7,
+	MV_V2_PORT_MAC_TYPE_RATE_MATCH = 0x6,
 	/* Temperature control/read registers (88X3310 only) */
 	MV_V2_TEMP_CTRL		= 0xf08a,
 	MV_V2_TEMP_CTRL_MASK	= 0xc000,
@@ -91,6 +93,7 @@ enum {
 
 struct mv3310_priv {
 	u32 firmware_ver;
+	bool rate_match;
 
 	struct device *hwmon_dev;
 	char *hwmon_name;
@@ -458,7 +461,9 @@ static bool mv3310_has_pma_ngbaset_quirk(struct phy_device *phydev)
 
 static int mv3310_config_init(struct phy_device *phydev)
 {
+	struct mv3310_priv *priv = dev_get_drvdata(&phydev->mdio.dev);
 	int err;
+	int val;
 
 	/* Check that the PHY interface type is compatible */
 	if (phydev->interface != PHY_INTERFACE_MODE_SGMII &&
@@ -475,6 +480,12 @@ static int mv3310_config_init(struct phy_device *phydev)
 	if (err)
 		return err;
 
+	val = phy_read_mmd(phydev, MDIO_MMD_VEND2, MV_V2_PORT_CTRL);
+	if (val < 0)
+		return val;
+	priv->rate_match = ((val & MV_V2_PORT_MAC_TYPE_MASK) ==
+			MV_V2_PORT_MAC_TYPE_RATE_MATCH);
+
 	/* Enable EDPD mode - saving 600mW */
 	return mv3310_set_edpd(phydev, ETHTOOL_PHY_EDPD_DFLT_TX_MSECS);
 }
@@ -581,6 +592,17 @@ static int mv3310_aneg_done(struct phy_device *phydev)
 
 static void mv3310_update_interface(struct phy_device *phydev)
 {
+	struct mv3310_priv *priv = dev_get_drvdata(&phydev->mdio.dev);
+
+	/* In "XFI with Rate Matching" mode the PHY interface is fixed at
+	 * 10Gb. The PHY adapts the rate to actual wire speed with help of
+	 * internal 16KB buffer.
+	 */
+	if (priv->rate_match) {
+		phydev->interface = PHY_INTERFACE_MODE_10GBASER;
+		return;
+	}
+
 	if ((phydev->interface == PHY_INTERFACE_MODE_SGMII ||
 	     phydev->interface == PHY_INTERFACE_MODE_2500BASEX ||
 	     phydev->interface == PHY_INTERFACE_MODE_10GBASER) &&