igb: Loopback functionality supports for i350 devices

This patch adds VMDq loopback pf support for i350 devices. The patch
is necessary since the register that enabled loopback was moved and
renamed from DTXSWC to TXSWC.
Signed-off-by: "Akeem G. Abodunrin" <akeem.g.abodunrin@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/igb/e1000_82575.c

@@ -1580,14 +1580,31 @@ void igb_vmdq_set_anti_spoofing_pf(struct e1000_hw *hw, bool enable, int pf)
  **/
 void igb_vmdq_set_loopback_pf(struct e1000_hw *hw, bool enable)
 {
-	u32 dtxswc = rd32(E1000_DTXSWC);
+	u32 dtxswc;
+
+	switch (hw->mac.type) {
+	case e1000_82576:
+		dtxswc = rd32(E1000_DTXSWC);
+		if (enable)
+			dtxswc |= E1000_DTXSWC_VMDQ_LOOPBACK_EN;
+		else
+			dtxswc &= ~E1000_DTXSWC_VMDQ_LOOPBACK_EN;
+		wr32(E1000_DTXSWC, dtxswc);
+		break;
+	case e1000_i350:
+		dtxswc = rd32(E1000_TXSWC);
+		if (enable)
+			dtxswc |= E1000_DTXSWC_VMDQ_LOOPBACK_EN;
+		else
+			dtxswc &= ~E1000_DTXSWC_VMDQ_LOOPBACK_EN;
+		wr32(E1000_TXSWC, dtxswc);
+		break;
+	default:
+		/* Currently no other hardware supports loopback */
+		break;
+	}
 
-	if (enable)
-		dtxswc |= E1000_DTXSWC_VMDQ_LOOPBACK_EN;
-	else
-		dtxswc &= ~E1000_DTXSWC_VMDQ_LOOPBACK_EN;
 
-	wr32(E1000_DTXSWC, dtxswc);
 }
 
 /**

drivers/net/ethernet/intel/igb/e1000_regs.h

@@ -318,6 +318,7 @@
 #define E1000_RPLOLR    0x05AF0 /* Replication Offload - RW */
 #define E1000_UTA       0x0A000 /* Unicast Table Array - RW */
 #define E1000_IOVTCL    0x05BBC /* IOV Control Register */
+#define E1000_TXSWC     0x05ACC /* Tx Switch Control */
 /* These act per VF so an array friendly macro is used */
 #define E1000_P2VMAILBOX(_n)   (0x00C00 + (4 * (_n)))
 #define E1000_VMBMEM(_n)       (0x00800 + (64 * (_n)))