[PATCH net-next 10/10] net/mlx5e: Enable the data direct netdev feature

[Tariq Toukan <tariqt@nvidia.com>]

From: Dragos Tatulea <dtatulea@nvidia.com>

Add the implementation of the data direct private flag.
This enables the feature altogether.

Do not allow state changes while dmabufs are still bound
to the netdev.

Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
---
 .../ethernet/mellanox/mlx5/core/en_ethtool.c  | 36 ++++++++++++++++++-
 1 file changed, 35 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c b/drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c
index b3eced1dd43f..8ab1150ce3f2 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c
@@ -32,6 +32,7 @@
 
 #include <linux/dim.h>
 #include <linux/ethtool_netlink.h>
+#include <linux/mlx5/data_direct.h>
 #include <net/netdev_queues.h>
 
 #include "en.h"
@@ -2402,7 +2403,40 @@ static int set_pflag_tx_port_ts(struct net_device *netdev, bool enable)
 
 static int set_pflag_data_direct(struct net_device *netdev, bool enable)
 {
-	return -EOPNOTSUPP;
+	struct mlx5e_priv *priv = netdev_priv(netdev);
+	struct mlx5_core_dev *mdev = priv->mdev;
+	struct mlx5e_params new_params;
+
+	if (enable) {
+		if (!mlx5_data_direct_supported(mdev) ||
+		    !MLX5_CAP_GEN(mdev, crossing_vhca_mkey)) {
+			netdev_err(netdev, "data_direct is not supported by the device\n");
+			return -EOPNOTSUPP;
+		}
+
+		if (!MLX5_CAP_GEN(mdev, shampo)) {
+			netdev_err(netdev, "data_direct requires SHAMPO (Header-Data Split) support\n");
+			return -EOPNOTSUPP;
+		}
+
+		if (!mlx5_data_direct_get_dev(mdev->data_direct)) {
+			netdev_err(netdev, "data_direct device not bound\n");
+			return -ENODEV;
+		}
+	}
+
+	/* Changing the flag reopens the channels with a different DMA device,
+	 * which would break any dmabuf currently bound to this netdev.
+	 */
+	if (netdev_has_dmabuf_binding(netdev, NULL)) {
+		netdev_err(netdev, "Can't change data_direct while dmabufs are bound\n");
+		return -EBUSY;
+	}
+
+	new_params = priv->channels.params;
+	MLX5E_SET_PFLAG(&new_params, MLX5E_PFLAG_DATA_DIRECT, enable);
+
+	return mlx5e_safe_switch_params(priv, &new_params, NULL, NULL, true);
 }
 
 static const struct pflag_desc mlx5e_priv_flags[MLX5E_NUM_PFLAGS] = {
-- 
2.44.0