net/mlx5e: Correct the calculation of max channels for rep

Correct the calculation of maximum channels of rep to better utilize
the hardware resources and allow a larger scale of reps.

This will allow creation of all virtual ports configured.

Fixes: 473baf2 ("net/mlx5e: Allow profile-specific limitation on max num of channels")
Signed-off-by: Moshe Tal <moshet@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

drivers/net/ethernet/mellanox/mlx5/core/en.h

@@ -1220,6 +1220,7 @@ mlx5e_tx_mpwqe_supported(struct mlx5_core_dev *mdev)
 		MLX5_CAP_ETH(mdev, enhanced_multi_pkt_send_wqe);
 }
 
+int mlx5e_get_pf_num_tirs(struct mlx5_core_dev *mdev);
 int mlx5e_priv_init(struct mlx5e_priv *priv,
 		    const struct mlx5e_profile *profile,
 		    struct net_device *netdev,

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

@@ -5221,6 +5221,15 @@ mlx5e_calc_max_nch(struct mlx5_core_dev *mdev, struct net_device *netdev,
 	return max_nch;
 }
 
+int mlx5e_get_pf_num_tirs(struct mlx5_core_dev *mdev)
+{
+	/* Indirect TIRS: 2 sets of TTCs (inner + outer steering)
+	 * and 1 set of direct TIRS
+	 */
+	return 2 * MLX5E_NUM_INDIR_TIRS
+		+ mlx5e_profile_max_num_channels(mdev, &mlx5e_nic_profile);
+}
+
 /* mlx5e generic netdev management API (move to en_common.c) */
 int mlx5e_priv_init(struct mlx5e_priv *priv,
 		    const struct mlx5e_profile *profile,

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

@@ -604,10 +604,16 @@ bool mlx5e_eswitch_vf_rep(const struct net_device *netdev)
 	return netdev->netdev_ops == &mlx5e_netdev_ops_rep;
 }
 
+/* One indirect TIR set for outer. Inner not supported in reps. */
+#define REP_NUM_INDIR_TIRS MLX5E_NUM_INDIR_TIRS
+
 static int mlx5e_rep_max_nch_limit(struct mlx5_core_dev *mdev)
 {
-	return (1 << MLX5_CAP_GEN(mdev, log_max_tir)) /
-		mlx5_eswitch_get_total_vports(mdev);
+	int max_tir_num = 1 << MLX5_CAP_GEN(mdev, log_max_tir);
+	int num_vports = mlx5_eswitch_get_total_vports(mdev);
+
+	return (max_tir_num - mlx5e_get_pf_num_tirs(mdev)
+		- (num_vports * REP_NUM_INDIR_TIRS)) / num_vports;
 }
 
 static void mlx5e_build_rep_params(struct net_device *netdev)