mlxsw: core: Fix wrong SFP EEPROM reading for upper pages 1-3

Fix wrong reading of upper pages for SFP EEPROM. According to "Memory
Organization" figure in SFF-8472 spec: When reading upper pages 1, 2 and
3 the offset should be set relative to zero and I2C high address 0x51
[1010001X (A2h)] is to be used.

Fixes: a45bfb5 ("mlxsw: core: Extend QSFP EEPROM size for ethtool")
Signed-off-by: Vadim Pasternak <vadimp@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlxsw/core_env.c

@@ -45,7 +45,7 @@ static int mlxsw_env_validate_cable_ident(struct mlxsw_core *core, int id,
 static int
 mlxsw_env_query_module_eeprom(struct mlxsw_core *mlxsw_core, int module,
 			      u16 offset, u16 size, void *data,
-			      unsigned int *p_read_size)
+			      bool qsfp, unsigned int *p_read_size)
 {
 	char eeprom_tmp[MLXSW_REG_MCIA_EEPROM_SIZE];
 	char mcia_pl[MLXSW_REG_MCIA_LEN];
@@ -54,6 +54,10 @@ mlxsw_env_query_module_eeprom(struct mlxsw_core *mlxsw_core, int module,
 	int status;
 	int err;
 
+	/* MCIA register accepts buffer size <= 48. Page of size 128 should be
+	 * read by chunks of size 48, 48, 32. Align the size of the last chunk
+	 * to avoid reading after the end of the page.
+	 */
 	size = min_t(u16, size, MLXSW_REG_MCIA_EEPROM_SIZE);
 
 	if (offset < MLXSW_REG_MCIA_EEPROM_PAGE_LENGTH &&
@@ -63,18 +67,25 @@ mlxsw_env_query_module_eeprom(struct mlxsw_core *mlxsw_core, int module,
 
 	i2c_addr = MLXSW_REG_MCIA_I2C_ADDR_LOW;
 	if (offset >= MLXSW_REG_MCIA_EEPROM_PAGE_LENGTH) {
-		page = MLXSW_REG_MCIA_PAGE_GET(offset);
-		offset -= MLXSW_REG_MCIA_EEPROM_UP_PAGE_LENGTH * page;
-		/* When reading upper pages 1, 2 and 3 the offset starts at
-		 * 128. Please refer to "QSFP+ Memory Map" figure in SFF-8436
-		 * specification for graphical depiction.
-		 * MCIA register accepts buffer size <= 48. Page of size 128
-		 * should be read by chunks of size 48, 48, 32. Align the size
-		 * of the last chunk to avoid reading after the end of the
-		 * page.
-		 */
-		if (offset + size > MLXSW_REG_MCIA_EEPROM_PAGE_LENGTH)
-			size = MLXSW_REG_MCIA_EEPROM_PAGE_LENGTH - offset;
+		if (qsfp) {
+			/* When reading upper pages 1, 2 and 3 the offset
+			 * starts at 128. Please refer to "QSFP+ Memory Map"
+			 * figure in SFF-8436 specification for graphical
+			 * depiction.
+			 */
+			page = MLXSW_REG_MCIA_PAGE_GET(offset);
+			offset -= MLXSW_REG_MCIA_EEPROM_UP_PAGE_LENGTH * page;
+			if (offset + size > MLXSW_REG_MCIA_EEPROM_PAGE_LENGTH)
+				size = MLXSW_REG_MCIA_EEPROM_PAGE_LENGTH - offset;
+		} else {
+			/* When reading upper pages 1, 2 and 3 the offset
+			 * starts at 0 and I2C high address is used. Please refer
+			 * refer to "Memory Organization" figure in SFF-8472
+			 * specification for graphical depiction.
+			 */
+			i2c_addr = MLXSW_REG_MCIA_I2C_ADDR_HIGH;
+			offset -= MLXSW_REG_MCIA_EEPROM_PAGE_LENGTH;
+		}
 	}
 
 	mlxsw_reg_mcia_pack(mcia_pl, module, 0, page, offset, size, i2c_addr);
@@ -166,7 +177,7 @@ int mlxsw_env_get_module_info(struct mlxsw_core *mlxsw_core, int module,
 	int err;
 
 	err = mlxsw_env_query_module_eeprom(mlxsw_core, module, 0, offset,
-					    module_info, &read_size);
+					    module_info, false, &read_size);
 	if (err)
 		return err;
 
@@ -197,7 +208,7 @@ int mlxsw_env_get_module_info(struct mlxsw_core *mlxsw_core, int module,
 		/* Verify if transceiver provides diagnostic monitoring page */
 		err = mlxsw_env_query_module_eeprom(mlxsw_core, module,
 						    SFP_DIAGMON, 1, &diag_mon,
-						    &read_size);
+						    false, &read_size);
 		if (err)
 			return err;
 
@@ -225,17 +236,22 @@ int mlxsw_env_get_module_eeprom(struct net_device *netdev,
 	int offset = ee->offset;
 	unsigned int read_size;
 	int i = 0;
+	bool qsfp;
 	int err;
 
 	if (!ee->len)
 		return -EINVAL;
 
 	memset(data, 0, ee->len);
+	/* Validate module identifier value. */
+	err = mlxsw_env_validate_cable_ident(mlxsw_core, module, &qsfp);
+	if (err)
+		return err;
 
 	while (i < ee->len) {
 		err = mlxsw_env_query_module_eeprom(mlxsw_core, module, offset,
 						    ee->len - i, data + i,
-						    &read_size);
+						    qsfp, &read_size);
 		if (err) {
 			netdev_err(netdev, "Eeprom query failed\n");
 			return err;