mlxsw: core: Extend QSFP EEPROM size for ethtool

Extend the size of QSFP EEPROM for the cable types SSF8436 and SFF8636
from 256 to 640 bytes in order to expose all the EEPROM pages by
ethtool.

For SFF-8636 and SFF-8436 specifications, the driver exposes 256 bytes
of data for ethtool's get_module_eeprom() callback. This is because the
driver uses the below defines to specify SFF module length in ethtool's
get_module_info() callback:
'ETH_MODULE_SFF_8636_LEN' and 'ETH_MODULE_SFF_8436_LEN' (both are 256).

As a result of exposing 256 bytes only, ethtool shows wrong "zero" info
for pages 1, 2, 3.

The patch changes the length returned by callback for get_module_info()
to the values from the next defines: 'ETH_MODULE_SFF_8636_MAX_LEN' and
'ETH_MODULE_SFF_8436_MAX_LEN' (both are 640) to allow exposing of upper
page 1, 2 and 3.
Signed-off-by: Vadim Pasternak <vadimp@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>

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

@@ -50,6 +50,7 @@ mlxsw_env_query_module_eeprom(struct mlxsw_core *mlxsw_core, int module,
 	char eeprom_tmp[MLXSW_REG_MCIA_EEPROM_SIZE];
 	char mcia_pl[MLXSW_REG_MCIA_LEN];
 	u16 i2c_addr;
+	u8 page = 0;
 	int status;
 	int err;
 
@@ -62,11 +63,21 @@ 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) {
-		i2c_addr = MLXSW_REG_MCIA_I2C_ADDR_HIGH;
-		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;
 	}
 
-	mlxsw_reg_mcia_pack(mcia_pl, module, 0, 0, offset, size, i2c_addr);
+	mlxsw_reg_mcia_pack(mcia_pl, module, 0, page, offset, size, i2c_addr);
 
 	err = mlxsw_reg_query(mlxsw_core, MLXSW_REG(mcia), mcia_pl);
 	if (err)
@@ -168,7 +179,7 @@ int mlxsw_env_get_module_info(struct mlxsw_core *mlxsw_core, int module,
 	switch (module_id) {
 	case MLXSW_REG_MCIA_EEPROM_MODULE_INFO_ID_QSFP:
 		modinfo->type       = ETH_MODULE_SFF_8436;
-		modinfo->eeprom_len = ETH_MODULE_SFF_8436_LEN;
+		modinfo->eeprom_len = ETH_MODULE_SFF_8436_MAX_LEN;
 		break;
 	case MLXSW_REG_MCIA_EEPROM_MODULE_INFO_ID_QSFP_PLUS: /* fall-through */
 	case MLXSW_REG_MCIA_EEPROM_MODULE_INFO_ID_QSFP28:
@@ -176,10 +187,10 @@ int mlxsw_env_get_module_info(struct mlxsw_core *mlxsw_core, int module,
 		    module_rev_id >=
 		    MLXSW_REG_MCIA_EEPROM_MODULE_INFO_REV_ID_8636) {
 			modinfo->type       = ETH_MODULE_SFF_8636;
-			modinfo->eeprom_len = ETH_MODULE_SFF_8636_LEN;
+			modinfo->eeprom_len = ETH_MODULE_SFF_8636_MAX_LEN;
 		} else {
 			modinfo->type       = ETH_MODULE_SFF_8436;
-			modinfo->eeprom_len = ETH_MODULE_SFF_8436_LEN;
+			modinfo->eeprom_len = ETH_MODULE_SFF_8436_MAX_LEN;
 		}
 		break;
 	case MLXSW_REG_MCIA_EEPROM_MODULE_INFO_ID_SFP: