e1000e: initial support for i219-LM (3)

i219-LM (3) is a LOM that will be available on systems with the
Lewisburg Platform Controller Hub (PCH) chipset from Intel.
This patch provides the initial support for the device.

Signed-off-by: Raanan Avargil <raanan.avargil@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
diff --git a/drivers/net/ethernet/intel/e1000e/ich8lan.c b/drivers/net/ethernet/intel/e1000e/ich8lan.c
index 64c1f36..a049e30 100644
--- a/drivers/net/ethernet/intel/e1000e/ich8lan.c
+++ b/drivers/net/ethernet/intel/e1000e/ich8lan.c
@@ -3093,24 +3093,45 @@
 	struct e1000_nvm_info *nvm = &hw->nvm;
 	u32 bank1_offset = nvm->flash_bank_size * sizeof(u16);
 	u32 act_offset = E1000_ICH_NVM_SIG_WORD * 2 + 1;
+	u32 nvm_dword = 0;
 	u8 sig_byte = 0;
 	s32 ret_val;
 
 	switch (hw->mac.type) {
-		/* In SPT, read from the CTRL_EXT reg instead of
-		 * accessing the sector valid bits from the nvm
-		 */
 	case e1000_pch_spt:
-		*bank = er32(CTRL_EXT)
-		    & E1000_CTRL_EXT_NVMVS;
-		if ((*bank == 0) || (*bank == 1)) {
-			e_dbg("ERROR: No valid NVM bank present\n");
-			return -E1000_ERR_NVM;
-		} else {
-			*bank = *bank - 2;
+		bank1_offset = nvm->flash_bank_size;
+		act_offset = E1000_ICH_NVM_SIG_WORD;
+
+		/* set bank to 0 in case flash read fails */
+		*bank = 0;
+
+		/* Check bank 0 */
+		ret_val = e1000_read_flash_dword_ich8lan(hw, act_offset,
+							 &nvm_dword);
+		if (ret_val)
+			return ret_val;
+		sig_byte = (u8)((nvm_dword & 0xFF00) >> 8);
+		if ((sig_byte & E1000_ICH_NVM_VALID_SIG_MASK) ==
+		    E1000_ICH_NVM_SIG_VALUE) {
+			*bank = 0;
 			return 0;
 		}
-		break;
+
+		/* Check bank 1 */
+		ret_val = e1000_read_flash_dword_ich8lan(hw, act_offset +
+							 bank1_offset,
+							 &nvm_dword);
+		if (ret_val)
+			return ret_val;
+		sig_byte = (u8)((nvm_dword & 0xFF00) >> 8);
+		if ((sig_byte & E1000_ICH_NVM_VALID_SIG_MASK) ==
+		    E1000_ICH_NVM_SIG_VALUE) {
+			*bank = 1;
+			return 0;
+		}
+
+		e_dbg("ERROR: No valid NVM bank present\n");
+		return -E1000_ERR_NVM;
 	case e1000_ich8lan:
 	case e1000_ich9lan:
 		eecd = er32(EECD);