e1000e: use default settings for Tx Inter Packet Gap timer

Use the default hardware values for TIPG except for 80003es2lan(*).  The
code that is removed in this patch is either unnecessarily writing the TIPG
register with the hardware default values for some devices (82571/2/3/4) or
writing the wrong value for others (ICH/PCH LOMs).  The only change in
functionality is setting the correct default TIPG for the latter devices.

(*) The correct value for 80003es2lan is already set properly in
e1000_init_hw_80003es2lan() and e1000_cfg_kmrn_{10_100|1000}_80003es2lan(),
and the unused flag FLAG_TIPG_MEDIUM_FOR_80003ESLAN is removed.

Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/e1000e/80003es2lan.c

@@ -1502,8 +1502,7 @@ const struct e1000_info e1000_es2_info = {
 				  | FLAG_RX_NEEDS_RESTART /* errata */
 				  | FLAG_TARC_SET_BIT_ZERO /* errata */
 				  | FLAG_APME_CHECK_PORT_B
-				  | FLAG_DISABLE_FC_PAUSE_TIME /* errata */
-				  | FLAG_TIPG_MEDIUM_FOR_80003ESLAN,
+				  | FLAG_DISABLE_FC_PAUSE_TIME, /* errata */
 	.flags2			= FLAG2_DMA_BURST,
 	.pba			= 38,
 	.max_hw_frame_size	= DEFAULT_JUMBO,

drivers/net/ethernet/intel/e1000e/e1000.h

@@ -430,7 +430,7 @@ struct e1000_info {
 #define FLAG_HAS_SMART_POWER_DOWN         (1 << 11)
 #define FLAG_IS_QUAD_PORT_A               (1 << 12)
 #define FLAG_IS_QUAD_PORT                 (1 << 13)
-#define FLAG_TIPG_MEDIUM_FOR_80003ESLAN   (1 << 14)
+/* reserved bit14 */
 #define FLAG_APME_IN_WUC                  (1 << 15)
 #define FLAG_APME_IN_CTRL3                (1 << 16)
 #define FLAG_APME_CHECK_PORT_B            (1 << 17)

drivers/net/ethernet/intel/e1000e/netdev.c

@@ -2770,8 +2770,7 @@ static void e1000_configure_tx(struct e1000_adapter *adapter)
 	struct e1000_hw *hw = &adapter->hw;
 	struct e1000_ring *tx_ring = adapter->tx_ring;
 	u64 tdba;
-	u32 tdlen, tctl, tipg, tarc;
-	u32 ipgr1, ipgr2;
+	u32 tdlen, tctl, tarc;
 
 	/* Setup the HW Tx Head and Tail descriptor pointers */
 	tdba = tx_ring->dma;
@@ -2784,18 +2783,6 @@ static void e1000_configure_tx(struct e1000_adapter *adapter)
 	tx_ring->head = adapter->hw.hw_addr + E1000_TDH;
 	tx_ring->tail = adapter->hw.hw_addr + E1000_TDT;
 
-	/* Set the default values for the Tx Inter Packet Gap timer */
-	tipg = DEFAULT_82543_TIPG_IPGT_COPPER;          /*  8  */
-	ipgr1 = DEFAULT_82543_TIPG_IPGR1;               /*  8  */
-	ipgr2 = DEFAULT_82543_TIPG_IPGR2;               /*  6  */
-
-	if (adapter->flags & FLAG_TIPG_MEDIUM_FOR_80003ESLAN)
-		ipgr2 = DEFAULT_80003ES2LAN_TIPG_IPGR2; /*  7  */
-
-	tipg |= ipgr1 << E1000_TIPG_IPGR1_SHIFT;
-	tipg |= ipgr2 << E1000_TIPG_IPGR2_SHIFT;
-	ew32(TIPG, tipg);
-
 	/* Set the Tx Interrupt Delay register */
 	ew32(TIDV, adapter->tx_int_delay);
 	/* Tx irq moderation */