net: phy: Fix verification of EEE support in phy_init_eee

phy_init_eee uses phy_find_setting(phydev->speed, phydev->duplex)
to find a valid entry in the settings array for the given speed
and duplex value. For full duplex 1000baseT, this will return
the first matching entry, which is the entry for 1000baseKX_Full.

If the phy eee does not support 1000baseKX_Full, this entry will not
match, causing phy_init_eee to fail for no good reason.

Fixes: 9a9c56cb ("net: phy: fix a bug when verify the EEE support")
Fixes: 3e707706 ("phy: Expand phy speed/duplex settings array")
Cc: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/phy/phy.c

@@ -235,6 +235,25 @@ static inline unsigned int phy_find_valid(unsigned int idx, u32 features)
 	return idx < MAX_NUM_SETTINGS ? idx : MAX_NUM_SETTINGS - 1;
 }
 
+/**
+ * phy_check_valid - check if there is a valid PHY setting which matches
+ *		     speed, duplex, and feature mask
+ * @speed: speed to match
+ * @duplex: duplex to match
+ * @features: A mask of the valid settings
+ *
+ * Description: Returns true if there is a valid setting, false otherwise.
+ */
+static inline bool phy_check_valid(int speed, int duplex, u32 features)
+{
+	unsigned int idx;
+
+	idx = phy_find_valid(phy_find_setting(speed, duplex), features);
+
+	return settings[idx].speed == speed && settings[idx].duplex == duplex &&
+		(settings[idx].setting & features);
+}
+
 /**
  * phy_sanitize_settings - make sure the PHY is set to supported speed and duplex
  * @phydev: the target phy_device struct
@@ -1045,7 +1064,6 @@ int phy_init_eee(struct phy_device *phydev, bool clk_stop_enable)
 		int eee_lp, eee_cap, eee_adv;
 		u32 lp, cap, adv;
 		int status;
-		unsigned int idx;
 
 		/* Read phy status to properly get the right settings */
 		status = phy_read_status(phydev);
@@ -1077,8 +1095,7 @@ int phy_init_eee(struct phy_device *phydev, bool clk_stop_enable)
 
 		adv = mmd_eee_adv_to_ethtool_adv_t(eee_adv);
 		lp = mmd_eee_adv_to_ethtool_adv_t(eee_lp);
-		idx = phy_find_setting(phydev->speed, phydev->duplex);
-		if (!(lp & adv & settings[idx].setting))
+		if (!phy_check_valid(phydev->speed, phydev->duplex, lp & adv))
 			goto eee_exit_err;
 
 		if (clk_stop_enable) {