net/mlx5e: Add Ethernet driver debugfs

Similar to the mlx5_core debugfs, lay the groundwork for mlx5e debugfs
files under /sys/kernel/debug/mlx5/<pci>/nic/..
Signed-off-by: Gal Pressman <gal@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

@@ -968,6 +968,7 @@ struct mlx5e_priv {
 	struct mlx5e_scratchpad    scratchpad;
 	struct mlx5e_htb          *htb;
 	struct mlx5e_mqprio_rl    *mqprio_rl;
+	struct dentry             *dfs_root;
 };
 
 struct mlx5e_rx_handlers {

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

@@ -35,6 +35,7 @@
 #include <net/vxlan.h>
 #include <net/geneve.h>
 #include <linux/bpf.h>
+#include <linux/debugfs.h>
 #include <linux/if_bridge.h>
 #include <linux/filter.h>
 #include <net/page_pool.h>
@@ -5931,6 +5932,9 @@ static int mlx5e_probe(struct auxiliary_device *adev,
 	priv->profile = profile;
 	priv->ppriv = NULL;
 
+	priv->dfs_root = debugfs_create_dir("nic",
+					    mlx5_debugfs_get_dev_root(priv->mdev));
+
 	err = mlx5e_devlink_port_register(priv);
 	if (err) {
 		mlx5_core_err(mdev, "mlx5e_devlink_port_register failed, %d\n", err);
@@ -5968,6 +5972,7 @@ static int mlx5e_probe(struct auxiliary_device *adev,
 err_devlink_cleanup:
 	mlx5e_devlink_port_unregister(priv);
 err_destroy_netdev:
+	debugfs_remove_recursive(priv->dfs_root);
 	mlx5e_destroy_netdev(priv);
 	return err;
 }
@@ -5982,6 +5987,7 @@ static void mlx5e_remove(struct auxiliary_device *adev)
 	mlx5e_suspend(adev, state);
 	priv->profile->cleanup(priv);
 	mlx5e_devlink_port_unregister(priv);
+	debugfs_remove_recursive(priv->dfs_root);
 	mlx5e_destroy_netdev(priv);
 }