net: phy: let phy_speed_down/up support speeds >1Gbps

So far phy_speed_down/up can be used up to 1Gbps only. Remove this
restriction by using new helper __phy_speed_down. New member adv_old
in struct phy_device is used by phy_speed_up to restore the advertised
modes before calling phy_speed_down. Don't simply advertise what is
supported because a user may have intentionally removed modes from
advertisement.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>

drivers/net/phy/phy.c

@@ -608,38 +608,21 @@ static int phy_poll_aneg_done(struct phy_device *phydev)
  */
 int phy_speed_down(struct phy_device *phydev, bool sync)
 {
-	__ETHTOOL_DECLARE_LINK_MODE_MASK(adv_old);
-	__ETHTOOL_DECLARE_LINK_MODE_MASK(adv);
+	__ETHTOOL_DECLARE_LINK_MODE_MASK(adv_tmp);
 	int ret;
 
 	if (phydev->autoneg != AUTONEG_ENABLE)
 		return 0;
 
-	linkmode_copy(adv_old, phydev->advertising);
-	linkmode_copy(adv, phydev->lp_advertising);
-	linkmode_and(adv, adv, phydev->supported);
-
-	if (linkmode_test_bit(ETHTOOL_LINK_MODE_10baseT_Half_BIT, adv) ||
-	    linkmode_test_bit(ETHTOOL_LINK_MODE_10baseT_Full_BIT, adv)) {
-		linkmode_clear_bit(ETHTOOL_LINK_MODE_100baseT_Half_BIT,
-				   phydev->advertising);
-		linkmode_clear_bit(ETHTOOL_LINK_MODE_100baseT_Full_BIT,
-				   phydev->advertising);
-		linkmode_clear_bit(ETHTOOL_LINK_MODE_1000baseT_Half_BIT,
-				   phydev->advertising);
-		linkmode_clear_bit(ETHTOOL_LINK_MODE_1000baseT_Full_BIT,
-				   phydev->advertising);
-	} else if (linkmode_test_bit(ETHTOOL_LINK_MODE_100baseT_Half_BIT,
-				     adv) ||
-		   linkmode_test_bit(ETHTOOL_LINK_MODE_100baseT_Full_BIT,
-				     adv)) {
-		linkmode_clear_bit(ETHTOOL_LINK_MODE_1000baseT_Half_BIT,
-				   phydev->advertising);
-		linkmode_clear_bit(ETHTOOL_LINK_MODE_1000baseT_Full_BIT,
-				   phydev->advertising);
-	}
+	linkmode_copy(adv_tmp, phydev->advertising);
+
+	ret = phy_speed_down_core(phydev);
+	if (ret)
+		return ret;
 
-	if (linkmode_equal(phydev->advertising, adv_old))
+	linkmode_copy(phydev->adv_old, adv_tmp);
+
+	if (linkmode_equal(phydev->advertising, adv_tmp))
 		return 0;
 
 	ret = phy_config_aneg(phydev);
@@ -658,30 +641,19 @@ EXPORT_SYMBOL_GPL(phy_speed_down);
  */
 int phy_speed_up(struct phy_device *phydev)
 {
-	__ETHTOOL_DECLARE_LINK_MODE_MASK(all_speeds) = { 0, };
-	__ETHTOOL_DECLARE_LINK_MODE_MASK(not_speeds);
-	__ETHTOOL_DECLARE_LINK_MODE_MASK(supported);
-	__ETHTOOL_DECLARE_LINK_MODE_MASK(adv_old);
-	__ETHTOOL_DECLARE_LINK_MODE_MASK(speeds);
-
-	linkmode_copy(adv_old, phydev->advertising);
+	__ETHTOOL_DECLARE_LINK_MODE_MASK(adv_tmp);
 
 	if (phydev->autoneg != AUTONEG_ENABLE)
 		return 0;
 
-	linkmode_set_bit(ETHTOOL_LINK_MODE_10baseT_Half_BIT, all_speeds);
-	linkmode_set_bit(ETHTOOL_LINK_MODE_10baseT_Full_BIT, all_speeds);
-	linkmode_set_bit(ETHTOOL_LINK_MODE_100baseT_Half_BIT, all_speeds);
-	linkmode_set_bit(ETHTOOL_LINK_MODE_100baseT_Full_BIT, all_speeds);
-	linkmode_set_bit(ETHTOOL_LINK_MODE_1000baseT_Half_BIT, all_speeds);
-	linkmode_set_bit(ETHTOOL_LINK_MODE_1000baseT_Full_BIT, all_speeds);
+	if (linkmode_empty(phydev->adv_old))
+		return 0;
 
-	linkmode_andnot(not_speeds, adv_old, all_speeds);
-	linkmode_copy(supported, phydev->supported);
-	linkmode_and(speeds, supported, all_speeds);
-	linkmode_or(phydev->advertising, not_speeds, speeds);
+	linkmode_copy(adv_tmp, phydev->advertising);
+	linkmode_copy(phydev->advertising, phydev->adv_old);
+	linkmode_zero(phydev->adv_old);
 
-	if (linkmode_equal(phydev->advertising, adv_old))
+	if (linkmode_equal(phydev->advertising, adv_tmp))
 		return 0;
 
 	return phy_config_aneg(phydev);

include/linux/phy.h

@@ -403,6 +403,8 @@ struct phy_device {
 	__ETHTOOL_DECLARE_LINK_MODE_MASK(supported);
 	__ETHTOOL_DECLARE_LINK_MODE_MASK(advertising);
 	__ETHTOOL_DECLARE_LINK_MODE_MASK(lp_advertising);
+	/* used with phy_speed_down */
+	__ETHTOOL_DECLARE_LINK_MODE_MASK(adv_old);
 
 	/* Energy efficient ethernet modes which should be prohibited */
 	u32 eee_broken_modes;