igb: update comments for serdes config and update to handle duplex

This update corrects the driver so that it handles duplex for serdes links
correctly instead of just forcing full duplex always.

Signed-off-by: Alexander Duyck <alexander.h.duyck@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

@@ -706,9 +706,7 @@ static s32 igb_check_for_link_82575(struct e1000_hw *hw)
 	s32 ret_val;
 	u16 speed, duplex;
 
-	/* SGMII link check is done through the PCS register. */
-	if ((hw->phy.media_type != e1000_media_type_copper) ||
-	    (igb_sgmii_active_82575(hw))) {
+	if (hw->phy.media_type != e1000_media_type_copper) {
 		ret_val = igb_get_pcs_speed_and_duplex_82575(hw, &speed,
 		                                             &duplex);
 		/*
@@ -723,6 +721,7 @@ static s32 igb_check_for_link_82575(struct e1000_hw *hw)
 
 	return ret_val;
 }
+
 /**
  *  igb_get_pcs_speed_and_duplex_82575 - Retrieve current speed/duplex
  *  @hw: pointer to the HW structure
@@ -788,13 +787,23 @@ static s32 igb_get_pcs_speed_and_duplex_82575(struct e1000_hw *hw, u16 *speed,
 void igb_shutdown_serdes_link_82575(struct e1000_hw *hw)
 {
 	u32 reg;
+	u16 eeprom_data = 0;
 
 	if (hw->phy.media_type != e1000_media_type_internal_serdes ||
 	    igb_sgmii_active_82575(hw))
 		return;
 
-	/* if the management interface is not enabled, then power down */
-	if (!igb_enable_mng_pass_thru(hw)) {
+	if (hw->bus.func == E1000_FUNC_0)
+		hw->nvm.ops.read(hw, NVM_INIT_CONTROL3_PORT_A, 1, &eeprom_data);
+	else if (hw->bus.func == E1000_FUNC_1)
+		hw->nvm.ops.read(hw, NVM_INIT_CONTROL3_PORT_B, 1, &eeprom_data);
+
+	/*
+	 * If APM is not enabled in the EEPROM and management interface is
+	 * not enabled, then power down.
+	 */
+	if (!(eeprom_data & E1000_NVM_APME_82575) &&
+	    !igb_enable_mng_pass_thru(hw)) {
 		/* Disable PCS to turn off link */
 		reg = rd32(E1000_PCS_CFG0);
 		reg &= ~E1000_PCS_CFG_PCS_EN;
@@ -1010,10 +1019,13 @@ static s32 igb_setup_copper_link_82575(struct e1000_hw *hw)
 }
 
 /**
- *  igb_setup_serdes_link_82575 - Setup link for fiber/serdes
+ *  igb_setup_serdes_link_82575 - Setup link for serdes
  *  @hw: pointer to the HW structure
  *
- *  Configures speed and duplex for fiber and serdes links.
+ *  Configure the physical coding sub-layer (PCS) link.  The PCS link is
+ *  used on copper connections where the serialized gigabit media independent
+ *  interface (sgmii), or serdes fiber is being used.  Configures the link
+ *  for auto-negotiation or forces speed/duplex.
  **/
 static s32 igb_setup_serdes_link_82575(struct e1000_hw *hw)
 {
@@ -1086,18 +1098,27 @@ static s32 igb_setup_serdes_link_82575(struct e1000_hw *hw)
 	 */
 	if (hw->mac.autoneg || igb_sgmii_active_82575(hw)) {
 		/* Set PCS register for autoneg */
-		reg |= E1000_PCS_LCTL_FSV_1000 |      /* Force 1000    */
-		       E1000_PCS_LCTL_FDV_FULL |      /* SerDes Full duplex */
-		       E1000_PCS_LCTL_AN_ENABLE |     /* Enable Autoneg */
-		       E1000_PCS_LCTL_AN_RESTART;     /* Restart autoneg */
+		reg |= E1000_PCS_LCTL_FSV_1000 |  /* Force 1000 */
+		       E1000_PCS_LCTL_FDV_FULL |  /* SerDes Full dplx */
+		       E1000_PCS_LCTL_AN_ENABLE | /* Enable Autoneg */
+		       E1000_PCS_LCTL_AN_RESTART; /* Restart autoneg */
 		hw_dbg("Configuring Autoneg; PCS_LCTL = 0x%08X\n", reg);
 	} else {
-		/* Set PCS register for forced speed */
-		reg |= E1000_PCS_LCTL_FLV_LINK_UP |   /* Force link up */
-		       E1000_PCS_LCTL_FSV_1000 |      /* Force 1000    */
-		       E1000_PCS_LCTL_FDV_FULL |      /* SerDes Full duplex */
-		       E1000_PCS_LCTL_FSD |           /* Force Speed */
-		       E1000_PCS_LCTL_FORCE_LINK;     /* Force Link */
+		/* Check for duplex first */
+		if (hw->mac.forced_speed_duplex & E1000_ALL_FULL_DUPLEX)
+			reg |= E1000_PCS_LCTL_FDV_FULL;
+
+		/* No need to check for 1000/full since the spec states that
+		 * it requires autoneg to be enabled */
+		/* Now set speed */
+		if (hw->mac.forced_speed_duplex & E1000_ALL_100_SPEED)
+			reg |= E1000_PCS_LCTL_FSV_100;
+
+		/* Force speed and force link */
+		reg |= E1000_PCS_LCTL_FSD |
+		       E1000_PCS_LCTL_FORCE_LINK |
+		       E1000_PCS_LCTL_FLV_LINK_UP;
+
 		hw_dbg("Configuring Forced Link; PCS_LCTL = 0x%08X\n", reg);
 	}
 

drivers/net/igb/e1000_82575.h

@@ -167,6 +167,7 @@ struct e1000_adv_tx_context_desc {
 #define E1000_DCA_TXCTRL_CPUID_SHIFT 24 /* Tx CPUID now in the last byte */
 #define E1000_DCA_RXCTRL_CPUID_SHIFT 24 /* Rx CPUID now in the last byte */
 
+#define E1000_NVM_APME_82575          0x0400
 #define MAX_NUM_VFS                   8
 
 #define E1000_DTXSWC_VMDQ_LOOPBACK_EN (1 << 31)  /* global VF LB enable */

drivers/net/igb/e1000_hw.h

@@ -50,6 +50,7 @@ struct e1000_hw;
 #define E1000_REVISION_2 2
 #define E1000_REVISION_4 4
 
+#define E1000_FUNC_0     0
 #define E1000_FUNC_1     1
 
 enum e1000_mac_type {