mlxsw: spectrum_fid: Split a helper out of mlxsw_sp_fid_flood_table_mid()

In future patches, for CFF flood mode support, we will need a way to
determine a PGT base dynamically, as an op. Therefore, for symmetry,
split out a helper, mlxsw_sp_fid_pgt_base_ctl(), that determines a PGT base
in the controlled mode as well.

Now that the helper is available, use it in mlxsw_sp_fid_flood_table_init()
which currently invokes the FID->MID helper to that end.
Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Amit Cohen <amcohen@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://lore.kernel.org/r/fd41c66a1df4df6499d3da34f40e7b9efa15bc3e.1701183892.git.petrm@nvidia.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

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

@@ -329,14 +329,21 @@ mlxsw_sp_fid_family_pgt_size(const struct mlxsw_sp_fid_family *fid_family)
 }
 
 static u16
-mlxsw_sp_fid_flood_table_mid(const struct mlxsw_sp_fid_family *fid_family,
-			     const struct mlxsw_sp_flood_table *flood_table,
-			     u16 fid_offset)
+mlxsw_sp_fid_pgt_base_ctl(const struct mlxsw_sp_fid_family *fid_family,
+			  const struct mlxsw_sp_flood_table *flood_table)
 {
 	u16 num_fids;
 
 	num_fids = mlxsw_sp_fid_family_num_fids(fid_family);
-	return fid_family->pgt_base + num_fids * flood_table->table_index +
+	return fid_family->pgt_base + num_fids * flood_table->table_index;
+}
+
+static u16
+mlxsw_sp_fid_flood_table_mid(const struct mlxsw_sp_fid_family *fid_family,
+			     const struct mlxsw_sp_flood_table *flood_table,
+			     u16 fid_offset)
+{
+	return mlxsw_sp_fid_pgt_base_ctl(fid_family, flood_table) +
 	       fid_offset;
 }
 
@@ -1671,7 +1678,7 @@ mlxsw_sp_fid_flood_table_init(struct mlxsw_sp_fid_family *fid_family,
 	u16 mid_base;
 	int err, i;
 
-	mid_base = mlxsw_sp_fid_flood_table_mid(fid_family, flood_table, 0);
+	mid_base = mlxsw_sp_fid_pgt_base_ctl(fid_family, flood_table);
 
 	sfgc_packet_types = mlxsw_sp_packet_type_sfgc_types[packet_type];
 	for (i = 0; i < MLXSW_REG_SFGC_TYPE_MAX; i++) {