From: Corinna Vinschen <vinschen@redhat.com>
Date: Tue, 17 Nov 2020 20:50:40 +0100
Subject: igc: fix link speed advertising
Git-commit: 329a3678ec69962aa67c91397efbd46d36635f91
Patch-mainline: v5.11-rc6
References: jsc#SLE-4799

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 explicitly.

- 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.

Fixes: 8c5ad0dae93c ("igc: Add ethtool support")
Signed-off-by: Corinna Vinschen <vinschen@redhat.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/intel/igc/igc_ethtool.c |   24 ++++++++++++++++++------
 1 file changed, 18 insertions(+), 6 deletions(-)

--- a/drivers/net/ethernet/intel/igc/igc_ethtool.c
+++ b/drivers/net/ethernet/intel/igc/igc_ethtool.c
@@ -1670,12 +1670,18 @@ static int igc_get_link_ksettings(struct
 	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) {
@@ -1786,6 +1792,12 @@ static int igc_set_link_ksettings(struct
 
 	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) explicitly.
+	 */
+	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;