[Intel-wired-lan] igc: fix link speed advertising

[Corinna Vinschen <vinschen@redhat.com>]

Link speed advertising in igc has two problems:

- When setting the advertisement via ethtool, the link speed is converted
  to the legacy 32 bit representation for the intel PHY code.
  This inadvertently drops ETHTOOL_LINK_MODE_2500baseT_Full_BIT (being
  beyond bit 31).  As a result, any call to `ethtool -s ...' drops the
  2500Mbit/s link speed from the PHY settings.  Only reloading the driver
  alleviates that problem.

  Fix this by converting the ETHTOOL_LINK_MODE_2500baseT_Full_BIT to the
  Intel PHY ADVERTISE_2500_FULL bit explicitely.

- Rather than checking the actual PHY setting, the .get_link_ksettings
  function always fills link_modes.advertising with all link speeds
  the device is capable of.

  Fix this by checking the PHY autoneg_advertised settings and report
  only the actually advertised speeds up to ethtool.

Signed-off-by: Corinna Vinschen <vinschen@redhat.com>
---
 drivers/net/ethernet/intel/igc/igc_ethtool.c | 24 +++++++++++++++-----
 1 file changed, 18 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/intel/igc/igc_ethtool.c b/drivers/net/ethernet/intel/igc/igc_ethtool.c
index 61d331ce38cd..75cb4ca36bac 100644
--- a/drivers/net/ethernet/intel/igc/igc_ethtool.c
+++ b/drivers/net/ethernet/intel/igc/igc_ethtool.c
@@ -1675,12 +1675,18 @@ static int igc_ethtool_get_link_ksettings(struct net_device *netdev,
 	cmd->base.phy_address = hw->phy.addr;
 
 	/* advertising link modes */
-	ethtool_link_ksettings_add_link_mode(cmd, advertising, 10baseT_Half);
-	ethtool_link_ksettings_add_link_mode(cmd, advertising, 10baseT_Full);
-	ethtool_link_ksettings_add_link_mode(cmd, advertising, 100baseT_Half);
-	ethtool_link_ksettings_add_link_mode(cmd, advertising, 100baseT_Full);
-	ethtool_link_ksettings_add_link_mode(cmd, advertising, 1000baseT_Full);
-	ethtool_link_ksettings_add_link_mode(cmd, advertising, 2500baseT_Full);
+	if (hw->phy.autoneg_advertised & ADVERTISE_10_HALF)
+		ethtool_link_ksettings_add_link_mode(cmd, advertising, 10baseT_Half);
+	if (hw->phy.autoneg_advertised & ADVERTISE_10_FULL)
+		ethtool_link_ksettings_add_link_mode(cmd, advertising, 10baseT_Full);
+	if (hw->phy.autoneg_advertised & ADVERTISE_100_HALF)
+		ethtool_link_ksettings_add_link_mode(cmd, advertising, 100baseT_Half);
+	if (hw->phy.autoneg_advertised & ADVERTISE_100_FULL)
+		ethtool_link_ksettings_add_link_mode(cmd, advertising, 100baseT_Full);
+	if (hw->phy.autoneg_advertised & ADVERTISE_1000_FULL)
+		ethtool_link_ksettings_add_link_mode(cmd, advertising, 1000baseT_Full);
+	if (hw->phy.autoneg_advertised & ADVERTISE_2500_FULL)
+		ethtool_link_ksettings_add_link_mode(cmd, advertising, 2500baseT_Full);
 
 	/* set autoneg settings */
 	if (hw->mac.autoneg == 1) {
@@ -1792,6 +1798,12 @@ igc_ethtool_set_link_ksettings(struct net_device *netdev,
 
 	ethtool_convert_link_mode_to_legacy_u32(&advertising,
 						cmd->link_modes.advertising);
+	/* Converting to legacy u32 drops ETHTOOL_LINK_MODE_2500baseT_Full_BIT.
+	 * We have to check this and convert it to ADVERTISE_2500_FULL
+	 * (aka ETHTOOL_LINK_MODE_2500baseX_Full_BIT) explicitely.
+	 */
+	if (ethtool_link_ksettings_test_link_mode(cmd, advertising, 2500baseT_Full))
+		advertising |= ADVERTISE_2500_FULL;
 
 	if (cmd->base.autoneg == AUTONEG_ENABLE) {
 		hw->mac.autoneg = 1;
-- 
2.27.0