[net-next 09/14] ixgbe: cleanup checksum to allow error results

[Jeff Kirsher <jeffrey.t.kirsher@intel.com>]

From: Don Skidmore <donald.c.skidmore@intel.com>

Currently the shared code checksum calculation function only
returns a u16 and cannot return an error code. Unfortunately
a variety of errors can happen that completely prevent the
calculation of a checksum. So, change the function return value
from a u16 to an s32 and return a negative value on error, or the
positive checksum value when there is no error.

Signed-off-by: Don Skidmore <donald.c.skidmore@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
---
 drivers/net/ethernet/intel/ixgbe/ixgbe_common.c | 86 ++++++++++++++++---------
 drivers/net/ethernet/intel/ixgbe/ixgbe_common.h |  2 +-
 drivers/net/ethernet/intel/ixgbe/ixgbe_type.h   |  2 +-
 drivers/net/ethernet/intel/ixgbe/ixgbe_x540.c   | 59 +++++++++++------
 4 files changed, 96 insertions(+), 53 deletions(-)

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_common.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_common.c
index 2c77539..7633ba1 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_common.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_common.c
@@ -1625,7 +1625,7 @@ static void ixgbe_release_eeprom(struct ixgbe_hw *hw)
  *  ixgbe_calc_eeprom_checksum_generic - Calculates and returns the checksum
  *  @hw: pointer to hardware structure
  **/
-u16 ixgbe_calc_eeprom_checksum_generic(struct ixgbe_hw *hw)
+s32 ixgbe_calc_eeprom_checksum_generic(struct ixgbe_hw *hw)
 {
 	u16 i;
 	u16 j;
@@ -1636,7 +1636,7 @@ u16 ixgbe_calc_eeprom_checksum_generic(struct ixgbe_hw *hw)
 
 	/* Include 0x0-0x3F in the checksum */
 	for (i = 0; i < IXGBE_EEPROM_CHECKSUM; i++) {
-		if (hw->eeprom.ops.read(hw, i, &word) != 0) {
+		if (hw->eeprom.ops.read(hw, i, &word)) {
 			hw_dbg(hw, "EEPROM read failed\n");
 			break;
 		}
@@ -1645,24 +1645,35 @@ u16 ixgbe_calc_eeprom_checksum_generic(struct ixgbe_hw *hw)
 
 	/* Include all data from pointers except for the fw pointer */
 	for (i = IXGBE_PCIE_ANALOG_PTR; i < IXGBE_FW_PTR; i++) {
-		hw->eeprom.ops.read(hw, i, &pointer);
+		if (hw->eeprom.ops.read(hw, i, &pointer)) {
+			hw_dbg(hw, "EEPROM read failed\n");
+			return IXGBE_ERR_EEPROM;
+		}
+
+		/* If the pointer seems invalid */
+		if (pointer == 0xFFFF || pointer == 0)
+			continue;
+
+		if (hw->eeprom.ops.read(hw, pointer, &length)) {
+			hw_dbg(hw, "EEPROM read failed\n");
+			return IXGBE_ERR_EEPROM;
+		}
 
-		/* Make sure the pointer seems valid */
-		if (pointer != 0xFFFF && pointer != 0) {
-			hw->eeprom.ops.read(hw, pointer, &length);
+		if (length == 0xFFFF || length == 0)
+			continue;
 
-			if (length != 0xFFFF && length != 0) {
-				for (j = pointer+1; j <= pointer+length; j++) {
-					hw->eeprom.ops.read(hw, j, &word);
-					checksum += word;
-				}
+		for (j = pointer + 1; j <= pointer + length; j++) {
+			if (hw->eeprom.ops.read(hw, j, &word)) {
+				hw_dbg(hw, "EEPROM read failed\n");
+				return IXGBE_ERR_EEPROM;
 			}
+			checksum += word;
 		}
 	}
 
 	checksum = (u16)IXGBE_EEPROM_SUM - checksum;
 
-	return checksum;
+	return (s32)checksum;
 }
 
 /**
@@ -1686,26 +1697,33 @@ s32 ixgbe_validate_eeprom_checksum_generic(struct ixgbe_hw *hw,
 	 * EEPROM read fails
 	 */
 	status = hw->eeprom.ops.read(hw, 0, &checksum);
+	if (status) {
+		hw_dbg(hw, "EEPROM read failed\n");
+		return status;
+	}
 
-	if (status == 0) {
-		checksum = hw->eeprom.ops.calc_checksum(hw);
+	status = hw->eeprom.ops.calc_checksum(hw);
+	if (status < 0)
+		return status;
 
-		hw->eeprom.ops.read(hw, IXGBE_EEPROM_CHECKSUM, &read_checksum);
+	checksum = (u16)(status & 0xffff);
 
-		/*
-		 * Verify read checksum from EEPROM is the same as
-		 * calculated checksum
-		 */
-		if (read_checksum != checksum)
-			status = IXGBE_ERR_EEPROM_CHECKSUM;
-
-		/* If the user cares, return the calculated checksum */
-		if (checksum_val)
-			*checksum_val = checksum;
-	} else {
+	status = hw->eeprom.ops.read(hw, IXGBE_EEPROM_CHECKSUM, &read_checksum);
+	if (status) {
 		hw_dbg(hw, "EEPROM read failed\n");
+		return status;
 	}
 
+	/* Verify read checksum from EEPROM is the same as
+	 * calculated checksum
+	 */
+	if (read_checksum != checksum)
+		status = IXGBE_ERR_EEPROM_CHECKSUM;
+
+	/* If the user cares, return the calculated checksum */
+	if (checksum_val)
+		*checksum_val = checksum;
+
 	return status;
 }
 
@@ -1724,15 +1742,19 @@ s32 ixgbe_update_eeprom_checksum_generic(struct ixgbe_hw *hw)
 	 * EEPROM read fails
 	 */
 	status = hw->eeprom.ops.read(hw, 0, &checksum);
-
-	if (status == 0) {
-		checksum = hw->eeprom.ops.calc_checksum(hw);
-		status = hw->eeprom.ops.write(hw, IXGBE_EEPROM_CHECKSUM,
-					      checksum);
-	} else {
+	if (status) {
 		hw_dbg(hw, "EEPROM read failed\n");
+		return status;
 	}
 
+	status = hw->eeprom.ops.calc_checksum(hw);
+	if (status < 0)
+		return status;
+
+	checksum = (u16)(status & 0xffff);
+
+	status = hw->eeprom.ops.write(hw, IXGBE_EEPROM_CHECKSUM, checksum);
+
 	return status;
 }
 
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_common.h b/drivers/net/ethernet/intel/ixgbe/ixgbe_common.h
index 62dc8c5..fdf42c1 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_common.h
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_common.h
@@ -64,7 +64,7 @@ s32 ixgbe_read_eeprom_bit_bang_generic(struct ixgbe_hw *hw, u16 offset,
 				       u16 *data);
 s32 ixgbe_read_eeprom_buffer_bit_bang_generic(struct ixgbe_hw *hw, u16 offset,
 					      u16 words, u16 *data);
-u16 ixgbe_calc_eeprom_checksum_generic(struct ixgbe_hw *hw);
+s32 ixgbe_calc_eeprom_checksum_generic(struct ixgbe_hw *hw);
 s32 ixgbe_validate_eeprom_checksum_generic(struct ixgbe_hw *hw,
 					   u16 *checksum_val);
 s32 ixgbe_update_eeprom_checksum_generic(struct ixgbe_hw *hw);
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_type.h b/drivers/net/ethernet/intel/ixgbe/ixgbe_type.h
index 14b43b9..20673b3 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_type.h
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_type.h
@@ -2871,7 +2871,7 @@ struct ixgbe_eeprom_operations {
 	s32 (*write_buffer)(struct ixgbe_hw *, u16, u16, u16 *);
 	s32 (*validate_checksum)(struct ixgbe_hw *, u16 *);
 	s32 (*update_checksum)(struct ixgbe_hw *);
-	u16 (*calc_checksum)(struct ixgbe_hw *);
+	s32 (*calc_checksum)(struct ixgbe_hw *);
 };
 
 struct ixgbe_mac_operations {
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_x540.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_x540.c
index d88f75f..4b0b1cc 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_x540.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_x540.c
@@ -316,7 +316,7 @@ static s32 ixgbe_write_eewr_buffer_X540(struct ixgbe_hw *hw,
  *
  *  @hw: pointer to hardware structure
  **/
-static u16 ixgbe_calc_eeprom_checksum_X540(struct ixgbe_hw *hw)
+static s32 ixgbe_calc_eeprom_checksum_X540(struct ixgbe_hw *hw)
 {
 	u16 i;
 	u16 j;
@@ -324,6 +324,8 @@ static u16 ixgbe_calc_eeprom_checksum_X540(struct ixgbe_hw *hw)
 	u16 length = 0;
 	u16 pointer = 0;
 	u16 word = 0;
+	u16 checksum_last_word = IXGBE_EEPROM_CHECKSUM;
+	u16 ptr_start = IXGBE_PCIE_ANALOG_PTR;
 
 	/*
 	 * Do not use hw->eeprom.ops.read because we do not want to take
@@ -332,10 +334,10 @@ static u16 ixgbe_calc_eeprom_checksum_X540(struct ixgbe_hw *hw)
 	 */
 
 	/* Include 0x0-0x3F in the checksum */
-	for (i = 0; i < IXGBE_EEPROM_CHECKSUM; i++) {
-		if (ixgbe_read_eerd_generic(hw, i, &word) != 0) {
+	for (i = 0; i < checksum_last_word; i++) {
+		if (ixgbe_read_eerd_generic(hw, i, &word)) {
 			hw_dbg(hw, "EEPROM read failed\n");
-			break;
+			return IXGBE_ERR_EEPROM;
 		}
 		checksum += word;
 	}
@@ -344,11 +346,11 @@ static u16 ixgbe_calc_eeprom_checksum_X540(struct ixgbe_hw *hw)
 	 * Include all data from pointers 0x3, 0x6-0xE.  This excludes the
 	 * FW, PHY module, and PCIe Expansion/Option ROM pointers.
 	 */
-	for (i = IXGBE_PCIE_ANALOG_PTR; i < IXGBE_FW_PTR; i++) {
+	for (i = ptr_start; i < IXGBE_FW_PTR; i++) {
 		if (i == IXGBE_PHY_PTR || i == IXGBE_OPTION_ROM_PTR)
 			continue;
 
-		if (ixgbe_read_eerd_generic(hw, i, &pointer) != 0) {
+		if (ixgbe_read_eerd_generic(hw, i, &pointer)) {
 			hw_dbg(hw, "EEPROM read failed\n");
 			break;
 		}
@@ -358,8 +360,9 @@ static u16 ixgbe_calc_eeprom_checksum_X540(struct ixgbe_hw *hw)
 		    pointer >= hw->eeprom.word_size)
 			continue;
 
-		if (ixgbe_read_eerd_generic(hw, pointer, &length) != 0) {
+		if (ixgbe_read_eerd_generic(hw, pointer, &length)) {
 			hw_dbg(hw, "EEPROM read failed\n");
+			return IXGBE_ERR_EEPROM;
 			break;
 		}
 
@@ -368,10 +371,10 @@ static u16 ixgbe_calc_eeprom_checksum_X540(struct ixgbe_hw *hw)
 		    (pointer + length) >= hw->eeprom.word_size)
 			continue;
 
-		for (j = pointer+1; j <= pointer+length; j++) {
-			if (ixgbe_read_eerd_generic(hw, j, &word) != 0) {
+		for (j = pointer + 1; j <= pointer + length; j++) {
+			if (ixgbe_read_eerd_generic(hw, j, &word)) {
 				hw_dbg(hw, "EEPROM read failed\n");
-				break;
+				return IXGBE_ERR_EEPROM;
 			}
 			checksum += word;
 		}
@@ -379,7 +382,7 @@ static u16 ixgbe_calc_eeprom_checksum_X540(struct ixgbe_hw *hw)
 
 	checksum = (u16)IXGBE_EEPROM_SUM - checksum;
 
-	return checksum;
+	return (s32)checksum;
 }
 
 /**
@@ -410,23 +413,34 @@ static s32 ixgbe_validate_eeprom_checksum_X540(struct ixgbe_hw *hw,
 	if (hw->mac.ops.acquire_swfw_sync(hw, IXGBE_GSSR_EEP_SM))
 		return IXGBE_ERR_SWFW_SYNC;
 
-	checksum = hw->eeprom.ops.calc_checksum(hw);
+	status = hw->eeprom.ops.calc_checksum(hw);
+	if (status < 0)
+		goto out;
+
+	checksum = (u16)(status & 0xffff);
 
 	/* Do not use hw->eeprom.ops.read because we do not want to take
 	 * the synchronization semaphores twice here.
 	 */
 	status = ixgbe_read_eerd_generic(hw, IXGBE_EEPROM_CHECKSUM,
 					 &read_checksum);
+	if (status)
+		goto out;
 
-	hw->mac.ops.release_swfw_sync(hw, IXGBE_GSSR_EEP_SM);
+	/* Verify read checksum from EEPROM is the same as
+	 * calculated checksum
+	 */
+	if (read_checksum != checksum) {
+		hw_dbg(hw, "Invalid EEPROM checksum");
+		status = IXGBE_ERR_EEPROM_CHECKSUM;
+	}
 
 	/* If the user cares, return the calculated checksum */
 	if (checksum_val)
 		*checksum_val = checksum;
 
-	/* Verify read and calculated checksums are the same */
-	if (read_checksum != checksum)
-		return IXGBE_ERR_EEPROM_CHECKSUM;
+out:
+	hw->mac.ops.release_swfw_sync(hw, IXGBE_GSSR_EEP_SM);
 
 	return status;
 }
@@ -457,15 +471,22 @@ static s32 ixgbe_update_eeprom_checksum_X540(struct ixgbe_hw *hw)
 	if (hw->mac.ops.acquire_swfw_sync(hw, IXGBE_GSSR_EEP_SM))
 		return  IXGBE_ERR_SWFW_SYNC;
 
-	checksum = hw->eeprom.ops.calc_checksum(hw);
+	status = hw->eeprom.ops.calc_checksum(hw);
+	if (status < 0)
+		goto out;
+
+	checksum = (u16)(status & 0xffff);
 
 	/* Do not use hw->eeprom.ops.write because we do not want to
 	 * take the synchronization semaphores twice here.
 	 */
 	status = ixgbe_write_eewr_generic(hw, IXGBE_EEPROM_CHECKSUM, checksum);
-	if (!status)
-		status = ixgbe_update_flash_X540(hw);
+	if (status)
+		goto out;
+
+	status = ixgbe_update_flash_X540(hw);
 
+out:
 	hw->mac.ops.release_swfw_sync(hw, IXGBE_GSSR_EEP_SM);
 	return status;
 }
-- 
1.9.3