[PATCH] e1000e: add option not to verify NVM checksum

[Jacek Kowalski]

Many laptops and motherboards including I219-V network card have
invalid NVM checksum. While in most instances checksum is fixed by
e1000e module or by using bootutil, some setups are resistant to NVM
modifications. This result in the network card being completely
unusable.

It seems to be the case on Dell Latitude 5420 where UEFI firmware
corrupts (in this module's sense) checksums on each boot. No set of
BIOS options seems to help.

This commit adds e1000e module option called VerifyNVMChecksum
(defaults to 1) that allows advanced users to skip checkum verification
by setting it to 0.

Signed-off-by: Jacek Kowalski <Jacek@xxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
---
 drivers/net/ethernet/intel/e1000e/e1000.h  |  1 +
 drivers/net/ethernet/intel/e1000e/netdev.c | 22 ++++++++--------
 drivers/net/ethernet/intel/e1000e/param.c  | 30 ++++++++++++++++++++++
 3 files changed, 43 insertions(+), 10 deletions(-)

diff --git a/drivers/net/ethernet/intel/e1000e/e1000.h b/drivers/net/ethernet/intel/e1000e/e1000.h
index ba9c19e6994c..61dcc88dd2ff 100644
--- a/drivers/net/ethernet/intel/e1000e/e1000.h
+++ b/drivers/net/ethernet/intel/e1000e/e1000.h
@@ -461,6 +461,7 @@ s32 e1000e_get_base_timinca(struct e1000_adapter *adapter, u32 *timinca);
 #define FLAG2_CHECK_RX_HWTSTAMP           BIT(13)
 #define FLAG2_CHECK_SYSTIM_OVERFLOW       BIT(14)
 #define FLAG2_ENABLE_S0IX_FLOWS           BIT(15)
+#define FLAG2_VERIFY_NVM_CHECKSUM         BIT(16)
 
 #define E1000_RX_DESC_PS(R, i)	    \
 	(&(((union e1000_rx_desc_packet_split *)((R).desc))[i]))
diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
index 286155efcedf..b99b22dcaba4 100644
--- a/drivers/net/ethernet/intel/e1000e/netdev.c
+++ b/drivers/net/ethernet/intel/e1000e/netdev.c
@@ -7567,16 +7567,18 @@ static int e1000_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	 */
 	adapter->hw.mac.ops.reset_hw(&adapter->hw);
 
-	/* systems with ASPM and others may see the checksum fail on the first
-	 * attempt. Let's give it a few tries
-	 */
-	for (i = 0;; i++) {
-		if (e1000_validate_nvm_checksum(&adapter->hw) >= 0)
-			break;
-		if (i == 2) {
-			dev_err(&pdev->dev, "The NVM Checksum Is Not Valid\n");
-			err = -EIO;
-			goto err_eeprom;
+	if (adapter->flags2 & FLAG2_VERIFY_NVM_CHECKSUM) {
+		/* systems with ASPM and others may see the checksum fail on the first
+		* attempt. Let's give it a few tries
+		*/
+		for (i = 0;; i++) {
+			if (e1000_validate_nvm_checksum(&adapter->hw) >= 0)
+				break;
+			if (i == 2) {
+				dev_err(&pdev->dev, "The NVM Checksum Is Not Valid\n");
+				err = -EIO;
+				goto err_eeprom;
+			}
 		}
 	}
 
diff --git a/drivers/net/ethernet/intel/e1000e/param.c b/drivers/net/ethernet/intel/e1000e/param.c
index 3132d8f2f207..8711eb10dd11 100644
--- a/drivers/net/ethernet/intel/e1000e/param.c
+++ b/drivers/net/ethernet/intel/e1000e/param.c
@@ -127,6 +127,15 @@ E1000_PARAM(KumeranLockLoss, "Enable Kumeran lock loss workaround");
 E1000_PARAM(WriteProtectNVM,
 	    "Write-protect NVM [WARNING: disabling this can lead to corrupted NVM]");
 
+/* Verify NVM Checksum
+ *
+ * Valid Range: 0, 1
+ *
+ * Default Value: 1 (enabled)
+ */
+E1000_PARAM(VerifyNVMChecksum,
+	    "Verify NVM checksum [WARNING: disabling can cause invalid behavior]");
+
 /* Enable CRC Stripping
  *
  * Valid Range: 0, 1
@@ -524,4 +533,25 @@ void e1000e_check_options(struct e1000_adapter *adapter)
 			}
 		}
 	}
+	/* Verify NVM checksum */
+	{
+		static const struct e1000_option opt = {
+			.type = enable_option,
+			.name = "Verify NVM checksum",
+			.err  = "defaulting to Enabled",
+			.def  = OPTION_ENABLED
+		};
+
+		if (num_VerifyNVMChecksum > bd) {
+			unsigned int verify_nvm_checksum =
+				VerifyNVMChecksum[bd];
+			e1000_validate_option(&verify_nvm_checksum, &opt,
+						adapter);
+			if (verify_nvm_checksum)
+				adapter->flags2 |= FLAG2_VERIFY_NVM_CHECKSUM;
+		} else {
+			if (opt.def)
+				adapter->flags2 |= FLAG2_VERIFY_NVM_CHECKSUM;
+		}
+	}
 }
-- 
2.39.5