e1000e: Add code to check return values on NVM accesses

Adding code to check and respond to previously ignored return values
from NVM access functions.

Issue discovered through static analysis.

Signed-off-by: Dave Ertman <[e-mail]>
Tested-by: Aaron Brown <[e-mail]>
Signed-off-by: Jeff Kirsher <[e-mail]>

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

···
 	} else if ((hw->mac.type == e1000_82574) ||
 		   (hw->mac.type == e1000_82583)) {
 		u16 data;
+		s32 ret_val;
 
 		factps = er32(FACTPS);
-		e1000_read_nvm(hw, NVM_INIT_CONTROL2_REG, 1, &data);
+		ret_val = e1000_read_nvm(hw, NVM_INIT_CONTROL2_REG, 1, &data);
+		if (ret_val)
+			return false;
 
 		if (!(factps & E1000_FACTPS_MNGCG) &&
 		    ((data & E1000_NVM_INIT_CTRL2_MNGM) ==

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

···
 	int bars, i, err, pci_using_dac;
 	u16 eeprom_data = 0;
 	u16 eeprom_apme_mask = E1000_EEPROM_APME;
+	s32 rval = 0;
 
 	if (ei->flags2 & FLAG2_DISABLE_ASPM_L0S)
 		aspm_disable_flag = PCIE_LINK_STATE_L0S;
···
 	} else if (adapter->flags & FLAG_APME_IN_CTRL3) {
 		if (adapter->flags & FLAG_APME_CHECK_PORT_B &&
 		    (adapter->hw.bus.func == 1))
-			e1000_read_nvm(&adapter->hw, NVM_INIT_CONTROL3_PORT_B,
-				       1, &eeprom_data);
+			rval = e1000_read_nvm(&adapter->hw,
+					      NVM_INIT_CONTROL3_PORT_B,
+					      1, &eeprom_data);
 		else
-			e1000_read_nvm(&adapter->hw, NVM_INIT_CONTROL3_PORT_A,
-				       1, &eeprom_data);
+			rval = e1000_read_nvm(&adapter->hw,
+					      NVM_INIT_CONTROL3_PORT_A,
+					      1, &eeprom_data);
 	}
 
 	/* fetch WoL from EEPROM */
-	if (eeprom_data & eeprom_apme_mask)
+	if (rval)
+		e_dbg("NVM read error getting WoL initial values: %d\n", rval);
+	else if (eeprom_data & eeprom_apme_mask)
 		adapter->eeprom_wol |= E1000_WUFC_MAG;
 
 	/* now that we have the eeprom settings, apply the special cases
···
 		device_wakeup_enable(&pdev->dev);
 
 	/* save off EEPROM version number */
-	e1000_read_nvm(&adapter->hw, 5, 1, &adapter->eeprom_vers);
+	rval = e1000_read_nvm(&adapter->hw, 5, 1, &adapter->eeprom_vers);
+
+	if (rval) {
+		e_dbg("NVM read error getting EEPROM version: %d\n", rval);
+		adapter->eeprom_vers = 0;
+	}
 
 	/* reset the hardware with the new settings */
 	e1000e_reset(adapter);

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

···
 
 		ew32(EERD, eerd);
 		ret_val = e1000e_poll_eerd_eewr_done(hw, E1000_NVM_POLL_READ);
-		if (ret_val)
+		if (ret_val) {
+			e_dbg("NVM read error: %d\n", ret_val);
 			break;
+		}
 
 		data[i] = (er32(EERD) >> E1000_NVM_RW_REG_DATA);
 	}