bnxt_en: Improve link up detection.

In bnxt_update_phy_setting(), ethtool_get_link_ksettings() and
bnxt_disable_an_for_lpbk(), we inconsistently use netif_carrier_ok()
to determine link.  Instead, we should use bp->link_info.link_up
which has the true link state.  The netif_carrier state may be off
during self-test and while the device is being reset and may not always
reflect the true link state.

By always using bp->link_info.link_up, the code is now more
consistent and more correct.  Some unnecessary link toggles are
now prevented with this patch.
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/bnxt/bnxt.c

@@ -9064,7 +9064,7 @@ static int bnxt_update_phy_setting(struct bnxt *bp)
 	/* The last close may have shutdown the link, so need to call
 	 * PHY_CFG to bring it back up.
 	 */
-	if (!netif_carrier_ok(bp->dev))
+	if (!bp->link_info.link_up)
 		update_link = true;
 
 	if (!bnxt_eee_config_ok(bp))

drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c

@@ -1462,15 +1462,15 @@ static int bnxt_get_link_ksettings(struct net_device *dev,
 		ethtool_link_ksettings_add_link_mode(lk_ksettings,
 						     advertising, Autoneg);
 		base->autoneg = AUTONEG_ENABLE;
-		if (link_info->phy_link_status == BNXT_LINK_LINK)
+		base->duplex = DUPLEX_UNKNOWN;
+		if (link_info->phy_link_status == BNXT_LINK_LINK) {
 			bnxt_fw_to_ethtool_lp_adv(link_info, lk_ksettings);
+			if (link_info->duplex & BNXT_LINK_DUPLEX_FULL)
+				base->duplex = DUPLEX_FULL;
+			else
+				base->duplex = DUPLEX_HALF;
+		}
 		ethtool_speed = bnxt_fw_to_ethtool_speed(link_info->link_speed);
-		if (!netif_carrier_ok(dev))
-			base->duplex = DUPLEX_UNKNOWN;
-		else if (link_info->duplex & BNXT_LINK_DUPLEX_FULL)
-			base->duplex = DUPLEX_FULL;
-		else
-			base->duplex = DUPLEX_HALF;
 	} else {
 		base->autoneg = AUTONEG_DISABLE;
 		ethtool_speed =
@@ -2707,7 +2707,7 @@ static int bnxt_disable_an_for_lpbk(struct bnxt *bp,
 		return rc;
 
 	fw_speed = PORT_PHY_CFG_REQ_FORCE_LINK_SPEED_1GB;
-	if (netif_carrier_ok(bp->dev))
+	if (bp->link_info.link_up)
 		fw_speed = bp->link_info.link_speed;
 	else if (fw_advertising & BNXT_LINK_SPEED_MSK_10GB)
 		fw_speed = PORT_PHY_CFG_REQ_FORCE_LINK_SPEED_10GB;