igb: Add support of SerDes Forced mode for certain hardware

This patch changes the serdes link code to support a forced mode for
some hardware, based on bit set in EEPROM.

Signed-off-by: Carolyn Wyborny <carolyn.wyborny@intel.com>
Tested-by: Jeff Pieper <jeffrey.e.pieper@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/igb/e1000_82575.c

@@ -1156,10 +1156,13 @@ static s32 igb_setup_serdes_link_82575(struct e1000_hw *hw)
 {
 	u32 ctrl_ext, ctrl_reg, reg;
 	bool pcs_autoneg;
+	s32 ret_val = E1000_SUCCESS;
+	u16 data;
 
 	if ((hw->phy.media_type != e1000_media_type_internal_serdes) &&
 	    !igb_sgmii_active_82575(hw))
-		return 0;
+		return ret_val;
+
 
 	/*
 	 * On the 82575, SerDes loopback mode persists until it is
@@ -1203,6 +1206,18 @@ static s32 igb_setup_serdes_link_82575(struct e1000_hw *hw)
 		/* disable PCS autoneg and support parallel detect only */
 		pcs_autoneg = false;
 	default:
+		if (hw->mac.type == e1000_82575 ||
+		    hw->mac.type == e1000_82576) {
+			ret_val = hw->nvm.ops.read(hw, NVM_COMPAT, 1, &data);
+			if (ret_val) {
+				printk(KERN_DEBUG "NVM Read Error\n\n");
+				return ret_val;
+			}
+
+			if (data & E1000_EEPROM_PCS_AUTONEG_DISABLE_BIT)
+				pcs_autoneg = false;
+		}
+
 		/*
 		 * non-SGMII modes only supports a speed of 1000/Full for the
 		 * link so it is best to just force the MAC and let the pcs
@@ -1250,7 +1265,7 @@ static s32 igb_setup_serdes_link_82575(struct e1000_hw *hw)
 	if (!igb_sgmii_active_82575(hw))
 		igb_force_mac_fc(hw);
 
-	return 0;
+	return ret_val;
 }
 
 /**

drivers/net/igb/e1000_82575.h

@@ -243,6 +243,8 @@ struct e1000_adv_tx_context_desc {
 #define E1000_DTXCTL_MDP_EN     0x0020
 #define E1000_DTXCTL_SPOOF_INT  0x0040
 
+#define E1000_EEPROM_PCS_AUTONEG_DISABLE_BIT	(1 << 14)
+
 #define ALL_QUEUES   0xFFFF
 
 /* RX packet buffer size defines */

drivers/net/igb/e1000_defines.h

@@ -437,6 +437,7 @@
 #define E1000_RAH_POOL_1 0x00040000
 
 /* Error Codes */
+#define E1000_SUCCESS      0
 #define E1000_ERR_NVM      1
 #define E1000_ERR_PHY      2
 #define E1000_ERR_CONFIG   3
@@ -587,8 +588,8 @@
 #define E1000_NVM_POLL_READ     0    /* Flag for polling for read complete */
 
 /* NVM Word Offsets */
-#define NVM_ID_LED_SETTINGS        0x0004
-/* For SERDES output amplitude adjustment. */
+#define NVM_COMPAT                 0x0003
+#define NVM_ID_LED_SETTINGS        0x0004 /* SERDES output amplitude */
 #define NVM_INIT_CONTROL2_REG      0x000F
 #define NVM_INIT_CONTROL3_PORT_B   0x0014
 #define NVM_INIT_CONTROL3_PORT_A   0x0024