net/mlx5: E-Switch: Fix using fwd and modify when firmware doesn't support it

Currently, if firmware doesn't support fwd and modify, driver fails
initializing eswitch chains while entering switchdev mode.

Instead, on such cases, disable the chains and prio feature (as we can't
restore the chain on miss) and the usage of fwd and modify.

Fixes: 8f1e0b97 ("net/mlx5: E-Switch, Mark miss packets with new chain id mapping")
Signed-off-by: Paul Blakey <paulb@mellanox.com>
Reviewed-by: Oz Shlomo <ozsh@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

drivers/net/ethernet/mellanox/mlx5/core/eswitch_offloads_chains.c

@@ -23,6 +23,8 @@
 #define tc_end_fdb(esw) (esw_chains_priv(esw)->tc_end_fdb)
 #define fdb_ignore_flow_level_supported(esw) \
 	(MLX5_CAP_ESW_FLOWTABLE_FDB((esw)->dev, ignore_flow_level))
+#define fdb_modify_header_fwd_to_table_supported(esw) \
+	(MLX5_CAP_ESW_FLOWTABLE((esw)->dev, fdb_modify_header_fwd_to_table))
 
 /* Firmware currently has 4 pool of 4 sizes that it supports (ESW_POOLS),
  * and a virtual memory region of 16M (ESW_SIZE), this region is duplicated
@@ -107,7 +109,8 @@ bool mlx5_esw_chains_prios_supported(struct mlx5_eswitch *esw)
 
 bool mlx5_esw_chains_backwards_supported(struct mlx5_eswitch *esw)
 {
-	return fdb_ignore_flow_level_supported(esw);
+	return mlx5_esw_chains_prios_supported(esw) &&
+	       fdb_ignore_flow_level_supported(esw);
 }
 
 u32 mlx5_esw_chains_get_chain_range(struct mlx5_eswitch *esw)
@@ -419,7 +422,8 @@ mlx5_esw_chains_add_miss_rule(struct fdb_chain *fdb_chain,
 	dest.type  = MLX5_FLOW_DESTINATION_TYPE_FLOW_TABLE;
 	dest.ft = next_fdb;
 
-	if (fdb_chain->chain != mlx5_esw_chains_get_ft_chain(esw)) {
+	if (fdb_chain->chain != mlx5_esw_chains_get_ft_chain(esw) &&
+	    fdb_modify_header_fwd_to_table_supported(esw)) {
 		act.modify_hdr = fdb_chain->miss_modify_hdr;
 		act.action |= MLX5_FLOW_CONTEXT_ACTION_MOD_HDR;
 	}
@@ -779,6 +783,13 @@ mlx5_esw_chains_init(struct mlx5_eswitch *esw)
 	    esw->offloads.encap != DEVLINK_ESWITCH_ENCAP_MODE_NONE) {
 		esw->fdb_table.flags &= ~ESW_FDB_CHAINS_AND_PRIOS_SUPPORTED;
 		esw_warn(dev, "Tc chains and priorities offload aren't supported, update firmware if needed\n");
+	} else if (!fdb_modify_header_fwd_to_table_supported(esw)) {
+		/* Disabled when ttl workaround is needed, e.g
+		 * when ESWITCH_IPV4_TTL_MODIFY_ENABLE = true in mlxconfig
+		 */
+		esw_warn(dev,
+			 "Tc chains and priorities offload aren't supported, check firmware version, or mlxconfig settings\n");
+		esw->fdb_table.flags &= ~ESW_FDB_CHAINS_AND_PRIOS_SUPPORTED;
 	} else {
 		esw->fdb_table.flags |= ESW_FDB_CHAINS_AND_PRIOS_SUPPORTED;
 		esw_info(dev, "Supported tc offload range - chains: %u, prios: %u\n",