net/mlx5: DR, Avoid unnecessary csum recalculation on supporting devices

If as part of the actions the TTL of the packet is modified, the packet's
checksum needs to be recalculated. Connect-X6DX can handle this csum
recalculation natively. Older devices require this additional recalculation.
Signed-off-by: Yevgeny Kliteynik <kliteyn@nvidia.com>
Reviewed-by: Alex Vesker <valex@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

drivers/net/ethernet/mellanox/mlx5/core/steering/dr_action.c

@@ -447,7 +447,8 @@ int mlx5dr_actions_build_ste_arr(struct mlx5dr_matcher *matcher,
 		case DR_ACTION_TYP_MODIFY_HDR:
 			attr.modify_index = action->rewrite.index;
 			attr.modify_actions = action->rewrite.num_of_actions;
-			recalc_cs_required = action->rewrite.modify_ttl;
+			recalc_cs_required = action->rewrite.modify_ttl &&
+					     !mlx5dr_ste_supp_ttl_cs_recalc(&dmn->info.caps);
 			break;
 		case DR_ACTION_TYP_L2_TO_TNL_L2:
 		case DR_ACTION_TYP_L2_TO_TNL_L3:
@@ -501,9 +502,9 @@ int mlx5dr_actions_build_ste_arr(struct mlx5dr_matcher *matcher,
 	*new_hw_ste_arr_sz = nic_matcher->num_of_builders;
 	last_ste = ste_arr + DR_STE_SIZE * (nic_matcher->num_of_builders - 1);
 
-	/* Due to a HW bug, modifying TTL on RX flows will cause an incorrect
-	 * checksum calculation. In this case we will use a FW table to
-	 * recalculate.
+	/* Due to a HW bug in some devices, modifying TTL on RX flows will
+	 * cause an incorrect checksum calculation. In this case we will
+	 * use a FW table to recalculate.
 	 */
 	if (dmn->type == MLX5DR_DOMAIN_TYPE_FDB &&
 	    rx_rule && recalc_cs_required && dest_action) {

drivers/net/ethernet/mellanox/mlx5/core/steering/dr_ste.c

@@ -18,6 +18,11 @@ static u32 dr_ste_crc32_calc(const void *input_data, size_t length)
 	return (__force u32)htonl(crc);
 }
 
+bool mlx5dr_ste_supp_ttl_cs_recalc(struct mlx5dr_cmd_caps *caps)
+{
+	return caps->sw_format_ver > MLX5_STEERING_FORMAT_CONNECTX_5;
+}
+
 u32 mlx5dr_ste_calc_hash_index(u8 *hw_ste_p, struct mlx5dr_ste_htbl *htbl)
 {
 	struct dr_hw_ste_format *hw_ste = (struct dr_hw_ste_format *)hw_ste_p;

drivers/net/ethernet/mellanox/mlx5/core/steering/dr_types.h

@@ -1211,6 +1211,8 @@ int mlx5dr_cmd_set_fte(struct mlx5_core_dev *dev,
 		       u32 group_id,
 		       struct mlx5dr_cmd_fte_info *fte);
 
+bool mlx5dr_ste_supp_ttl_cs_recalc(struct mlx5dr_cmd_caps *caps);
+
 struct mlx5dr_fw_recalc_cs_ft {
 	u64 rx_icm_addr;
 	u32 table_id;