mii: Add helpers for parsing SGMII auto-negotiation

Typically a MAC PCS auto-configures itself after it receives the
negotiated copper-side link settings from the PHY, but some MAC devices
are more special and need manual interpretation of the SGMII AN result.

In other cases, the PCS exposes the entire tx_config_reg base page as it
is transmitted on the wire during auto-negotiation, so it makes sense to
be able to decode the equivalent lp_advertised bit mask from the raw u16
(of course, "lp" considering the PCS to be the local PHY).

Therefore, add the bit definitions for the SGMII registers 4 and 5
(local device ability, link partner ability), as well as a link_mode
conversion helper that can be used to feed the AN results into
phy_resolve_aneg_linkmode.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 50 insertions, 0 deletions

diff --git a/include/linux/mii.h b/include/linux/mii.h
index 4ce8901a1af6..18c6208f56fc 100644
--- a/include/linux/mii.h
+++ b/include/linux/mii.h
@@ -373,6 +373,56 @@ static inline u32 mii_lpa_to_ethtool_lpa_x(u32 lpa)
 }
 
 /**
+ * mii_lpa_mod_linkmode_adv_sgmii
+ * @lp_advertising: pointer to destination link mode.
+ * @lpa: value of the MII_LPA register
+ *
+ * A small helper function that translates MII_LPA bits to
+ * linkmode advertisement settings for SGMII.
+ * Leaves other bits unchanged.
+ */
+static inline void
+mii_lpa_mod_linkmode_lpa_sgmii(unsigned long *lp_advertising, u32 lpa)
+{
+	u32 speed_duplex = lpa & LPA_SGMII_DPX_SPD_MASK;
+
+	linkmode_mod_bit(ETHTOOL_LINK_MODE_1000baseT_Half_BIT, lp_advertising,
+			 speed_duplex == LPA_SGMII_1000HALF);
+
+	linkmode_mod_bit(ETHTOOL_LINK_MODE_1000baseT_Full_BIT, lp_advertising,
+			 speed_duplex == LPA_SGMII_1000FULL);
+
+	linkmode_mod_bit(ETHTOOL_LINK_MODE_100baseT_Half_BIT, lp_advertising,
+			 speed_duplex == LPA_SGMII_100HALF);
+
+	linkmode_mod_bit(ETHTOOL_LINK_MODE_100baseT_Full_BIT, lp_advertising,
+			 speed_duplex == LPA_SGMII_100FULL);
+
+	linkmode_mod_bit(ETHTOOL_LINK_MODE_10baseT_Half_BIT, lp_advertising,
+			 speed_duplex == LPA_SGMII_10HALF);
+
+	linkmode_mod_bit(ETHTOOL_LINK_MODE_10baseT_Full_BIT, lp_advertising,
+			 speed_duplex == LPA_SGMII_10FULL);
+}
+
+/**
+ * mii_lpa_to_linkmode_adv_sgmii
+ * @advertising: pointer to destination link mode.
+ * @lpa: value of the MII_LPA register
+ *
+ * A small helper function that translates MII_ADVERTISE bits
+ * to linkmode advertisement settings when in SGMII mode.
+ * Clears the old value of advertising.
+ */
+static inline void mii_lpa_to_linkmode_lpa_sgmii(unsigned long *lp_advertising,
+						 u32 lpa)
+{
+	linkmode_zero(lp_advertising);
+
+	mii_lpa_mod_linkmode_lpa_sgmii(lp_advertising, lpa);
+}
+
+/**
  * mii_adv_mod_linkmode_adv_t
  * @advertising:pointer to destination link mode.
  * @adv: value of the MII_ADVERTISE register