igb: restore EEPROM values of MDICNFG on reset with 82580

On a reset the MDICNFG.Destination and MDICNFG.COM_MDIO
register fields are not restored to the EEPROM default.
This patch modifies the reset code to read the EEPROM
and restore the default values.

Signed-off-by: Nicholas Nunley <nicholas.d.nunley@intel.com>
Tested-by: Jeff Pieper <jeffrey.e.pieper@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/igb/e1000_82575.c

@@ -1548,6 +1548,43 @@ out:
 	return ret_val;
 }
 
+/**
+ *  igb_reset_mdicnfg_82580 - Reset MDICNFG destination and com_mdio bits
+ *  @hw: pointer to the HW structure
+ *
+ *  This resets the the MDICNFG.Destination and MDICNFG.Com_MDIO bits based on
+ *  the values found in the EEPROM.  This addresses an issue in which these
+ *  bits are not restored from EEPROM after reset.
+ **/
+static s32 igb_reset_mdicnfg_82580(struct e1000_hw *hw)
+{
+	s32 ret_val = 0;
+	u32 mdicnfg;
+	u16 nvm_data;
+
+	if (hw->mac.type != e1000_82580)
+		goto out;
+	if (!igb_sgmii_active_82575(hw))
+		goto out;
+
+	ret_val = hw->nvm.ops.read(hw, NVM_INIT_CONTROL3_PORT_A +
+				   NVM_82580_LAN_FUNC_OFFSET(hw->bus.func), 1,
+				   &nvm_data);
+	if (ret_val) {
+		hw_dbg("NVM Read Error\n");
+		goto out;
+	}
+
+	mdicnfg = rd32(E1000_MDICNFG);
+	if (nvm_data & NVM_WORD24_EXT_MDIO)
+		mdicnfg |= E1000_MDICNFG_EXT_MDIO;
+	if (nvm_data & NVM_WORD24_COM_MDIO)
+		mdicnfg |= E1000_MDICNFG_COM_MDIO;
+	wr32(E1000_MDICNFG, mdicnfg);
+out:
+	return ret_val;
+}
+
 /**
  *  igb_reset_hw_82580 - Reset hardware
  *  @hw: pointer to the HW structure
@@ -1623,6 +1660,10 @@ static s32 igb_reset_hw_82580(struct e1000_hw *hw)
 	wr32(E1000_IMC, 0xffffffff);
 	icr = rd32(E1000_ICR);
 
+	ret_val = igb_reset_mdicnfg_82580(hw);
+	if (ret_val)
+		hw_dbg("Could not reset MDICNFG based on EEPROM\n");
+
 	/* Install any alternate MAC address into RAR0 */
 	ret_val = igb_check_alt_mac_addr(hw);
 

drivers/net/igb/e1000_defines.h

@@ -570,6 +570,10 @@
 
 #define NVM_82580_LAN_FUNC_OFFSET(a) (a ? (0x40 + (0x40 * a)) : 0)
 
+/* Mask bits for fields in Word 0x24 of the NVM */
+#define NVM_WORD24_COM_MDIO         0x0008 /* MDIO interface shared */
+#define NVM_WORD24_EXT_MDIO         0x0004 /* MDIO accesses routed external */
+
 /* Mask bits for fields in Word 0x0f of the NVM */
 #define NVM_WORD0F_PAUSE_MASK       0x3000
 #define NVM_WORD0F_ASM_DIR          0x2000