e1000e: 82579 unaccounted missed packets

On 82579, there is a hardware bug that can cause received packets to not
get transferred from the PHY to the MAC due to K1 (a power saving feature
of the PHY-MAC interconnect similar to ASPM L1).  Since the MAC controls
the accounting of missed packets, these will go unnoticed.  Workaround the
issue by setting the K1 beacon duration according to the link speed.

Signed-off-by: Bruce Allan <bruce.w.allan@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/e1000e/hw.h

@@ -57,6 +57,7 @@ enum e1e_registers {
 	E1000_SCTL     = 0x00024, /* SerDes Control - RW */
 	E1000_FCAL     = 0x00028, /* Flow Control Address Low - RW */
 	E1000_FCAH     = 0x0002C, /* Flow Control Address High -RW */
+	E1000_FEXTNVM4 = 0x00024, /* Future Extended NVM 4 - RW */
 	E1000_FEXTNVM  = 0x00028, /* Future Extended NVM - RW */
 	E1000_FCT      = 0x00030, /* Flow Control Type - RW */
 	E1000_VET      = 0x00038, /* VLAN Ether Type - RW */

drivers/net/e1000e/ich8lan.c

@@ -105,6 +105,10 @@
 #define E1000_FEXTNVM_SW_CONFIG		1
 #define E1000_FEXTNVM_SW_CONFIG_ICH8M (1 << 27) /* Bit redefined for ICH8M :/ */
 
+#define E1000_FEXTNVM4_BEACON_DURATION_MASK    0x7
+#define E1000_FEXTNVM4_BEACON_DURATION_8USEC   0x7
+#define E1000_FEXTNVM4_BEACON_DURATION_16USEC  0x3
+
 #define PCIE_ICH8_SNOOP_ALL		PCIE_NO_SNOOP_ALL
 
 #define E1000_ICH_RAR_ENTRIES		7
@@ -238,6 +242,7 @@ static s32  e1000_k1_gig_workaround_hv(struct e1000_hw *hw, bool link);
 static s32 e1000_set_mdio_slow_mode_hv(struct e1000_hw *hw);
 static bool e1000_check_mng_mode_ich8lan(struct e1000_hw *hw);
 static bool e1000_check_mng_mode_pchlan(struct e1000_hw *hw);
+static s32 e1000_k1_workaround_lv(struct e1000_hw *hw);
 
 static inline u16 __er16flash(struct e1000_hw *hw, unsigned long reg)
 {
@@ -653,6 +658,12 @@ static s32 e1000_check_for_copper_link_ich8lan(struct e1000_hw *hw)
 			goto out;
 	}
 
+	if (hw->mac.type == e1000_pch2lan) {
+		ret_val = e1000_k1_workaround_lv(hw);
+		if (ret_val)
+			goto out;
+	}
+
 	/*
 	 * Check if there was DownShift, must be checked
 	 * immediately after link-up
@@ -1582,6 +1593,43 @@ out:
 	return ret_val;
 }
 
+/**
+ *  e1000_k1_gig_workaround_lv - K1 Si workaround
+ *  @hw:   pointer to the HW structure
+ *
+ *  Workaround to set the K1 beacon duration for 82579 parts
+ **/
+static s32 e1000_k1_workaround_lv(struct e1000_hw *hw)
+{
+	s32 ret_val = 0;
+	u16 status_reg = 0;
+	u32 mac_reg;
+
+	if (hw->mac.type != e1000_pch2lan)
+		goto out;
+
+	/* Set K1 beacon duration based on 1Gbps speed or otherwise */
+	ret_val = e1e_rphy(hw, HV_M_STATUS, &status_reg);
+	if (ret_val)
+		goto out;
+
+	if ((status_reg & (HV_M_STATUS_LINK_UP | HV_M_STATUS_AUTONEG_COMPLETE))
+	    == (HV_M_STATUS_LINK_UP | HV_M_STATUS_AUTONEG_COMPLETE)) {
+		mac_reg = er32(FEXTNVM4);
+		mac_reg &= ~E1000_FEXTNVM4_BEACON_DURATION_MASK;
+
+		if (status_reg & HV_M_STATUS_SPEED_1000)
+			mac_reg |= E1000_FEXTNVM4_BEACON_DURATION_8USEC;
+		else
+			mac_reg |= E1000_FEXTNVM4_BEACON_DURATION_16USEC;
+
+		ew32(FEXTNVM4, mac_reg);
+	}
+
+out:
+	return ret_val;
+}
+
 /**
  *  e1000_lan_init_done_ich8lan - Check for PHY config completion
  *  @hw: pointer to the HW structure