ice: Reimplement module reads used by ethtool

There was an excessive increment of the QSFP page, which is
now fixed. Additionally, this new update now reads 8 bytes
at a time and will retry each request if the module/bus is
busy.

Also, prevent reading from upper pages if module does not
support those pages.
Signed-off-by: Scott W Taylor <scott.w.taylor@intel.com>
Tested-by: Tony Brelinski <tonyx.brelinski@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

drivers/net/ethernet/intel/ice/ice_ethtool.c

@@ -3914,30 +3914,33 @@ ice_get_module_eeprom(struct net_device *netdev,
 		      struct ethtool_eeprom *ee, u8 *data)
 {
 	struct ice_netdev_priv *np = netdev_priv(netdev);
+#define SFF_READ_BLOCK_SIZE 8
+	u8 value[SFF_READ_BLOCK_SIZE] = { 0 };
 	u8 addr = ICE_I2C_EEPROM_DEV_ADDR;
 	struct ice_vsi *vsi = np->vsi;
 	struct ice_pf *pf = vsi->back;
 	struct ice_hw *hw = &pf->hw;
 	enum ice_status status;
 	bool is_sfp = false;
-	unsigned int i;
+	unsigned int i, j;
 	u16 offset = 0;
-	u8 value = 0;
 	u8 page = 0;
 
 	if (!ee || !ee->len || !data)
 		return -EINVAL;
 
-	status = ice_aq_sff_eeprom(hw, 0, addr, offset, page, 0, &value, 1, 0,
+	status = ice_aq_sff_eeprom(hw, 0, addr, offset, page, 0, value, 1, 0,
 				   NULL);
 	if (status)
 		return -EIO;
 
-	if (value == ICE_MODULE_TYPE_SFP)
+	if (value[0] == ICE_MODULE_TYPE_SFP)
 		is_sfp = true;
 
-	for (i = 0; i < ee->len; i++) {
+	memset(data, 0, ee->len);
+	for (i = 0; i < ee->len; i += SFF_READ_BLOCK_SIZE) {
 		offset = i + ee->offset;
+		page = 0;
 
 		/* Check if we need to access the other memory page */
 		if (is_sfp) {
@@ -3953,11 +3956,37 @@ ice_get_module_eeprom(struct net_device *netdev,
 			}
 		}
 
-		status = ice_aq_sff_eeprom(hw, 0, addr, offset, page, !is_sfp,
-					   &value, 1, 0, NULL);
-		if (status)
-			value = 0;
-		data[i] = value;
+		/* Bit 2 of EEPROM address 0x02 declares upper
+		 * pages are disabled on QSFP modules.
+		 * SFP modules only ever use page 0.
+		 */
+		if (page == 0 || !(data[0x2] & 0x4)) {
+			/* If i2c bus is busy due to slow page change or
+			 * link management access, call can fail. This is normal.
+			 * So we retry this a few times.
+			 */
+			for (j = 0; j < 4; j++) {
+				status = ice_aq_sff_eeprom(hw, 0, addr, offset, page,
+							   !is_sfp, value,
+							   SFF_READ_BLOCK_SIZE,
+							   0, NULL);
+				netdev_dbg(netdev, "SFF %02X %02X %02X %X = %02X%02X%02X%02X.%02X%02X%02X%02X (%X)\n",
+					   addr, offset, page, is_sfp,
+					   value[0], value[1], value[2], value[3],
+					   value[4], value[5], value[6], value[7],
+					   status);
+				if (status) {
+					usleep_range(1500, 2500);
+					memset(value, 0, SFF_READ_BLOCK_SIZE);
+					continue;
+				}
+				break;
+			}
+
+			/* Make sure we have enough room for the new block */
+			if ((i + SFF_READ_BLOCK_SIZE) < ee->len)
+				memcpy(data + i, value, SFF_READ_BLOCK_SIZE);
+		}
 	}
 	return 0;
 }