net/mlx5_core: Set/Query port MTU commands

Introduce set/Query low level functions to access MTU in hardware. To be
used by the netdev.
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>
Signed-off-by: NAmir Vadai <amirv@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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

@@ -211,3 +211,56 @@ int mlx5_query_port_status(struct mlx5_core_dev *dev, u8 *status)
 	*status = MLX5_GET(paos_reg, out, oper_status);
 	return err;
 }
+
+static int mlx5_query_port_mtu(struct mlx5_core_dev *dev,
+			       int *admin_mtu, int *max_mtu, int *oper_mtu)
+{
+	u32 in[MLX5_ST_SZ_DW(pmtu_reg)];
+	u32 out[MLX5_ST_SZ_DW(pmtu_reg)];
+	int err;
+
+	memset(in, 0, sizeof(in));
+
+	MLX5_SET(pmtu_reg, in, local_port, 1);
+
+	err = mlx5_core_access_reg(dev, in, sizeof(in), out,
+				   sizeof(out), MLX5_REG_PMTU, 0, 0);
+	if (err)
+		return err;
+
+	if (max_mtu)
+		*max_mtu  = MLX5_GET(pmtu_reg, out, max_mtu);
+	if (oper_mtu)
+		*oper_mtu = MLX5_GET(pmtu_reg, out, oper_mtu);
+	if (admin_mtu)
+		*admin_mtu = MLX5_GET(pmtu_reg, out, admin_mtu);
+
+	return 0;
+}
+
+int mlx5_set_port_mtu(struct mlx5_core_dev *dev, int mtu)
+{
+	u32 in[MLX5_ST_SZ_DW(pmtu_reg)];
+	u32 out[MLX5_ST_SZ_DW(pmtu_reg)];
+
+	memset(in, 0, sizeof(in));
+
+	MLX5_SET(pmtu_reg, in, admin_mtu, mtu);
+	MLX5_SET(pmtu_reg, in, local_port, 1);
+
+	return mlx5_core_access_reg(dev, in, sizeof(in), out, sizeof(out),
+				    MLX5_REG_PMTU, 0, 1);
+}
+EXPORT_SYMBOL_GPL(mlx5_set_port_mtu);
+
+int mlx5_query_port_max_mtu(struct mlx5_core_dev *dev, int *max_mtu)
+{
+	return mlx5_query_port_mtu(dev, NULL, max_mtu, NULL);
+}
+EXPORT_SYMBOL_GPL(mlx5_query_port_max_mtu);
+
+int mlx5_query_port_oper_mtu(struct mlx5_core_dev *dev, int *oper_mtu)
+{
+	return mlx5_query_port_mtu(dev, NULL, NULL, oper_mtu);
+}
+EXPORT_SYMBOL_GPL(mlx5_query_port_oper_mtu);

include/linux/mlx5/driver.h

@@ -710,6 +710,10 @@ int mlx5_set_port_status(struct mlx5_core_dev *dev,
 			 enum mlx5_port_status status);
 int mlx5_query_port_status(struct mlx5_core_dev *dev, u8 *status);
 
+int mlx5_set_port_mtu(struct mlx5_core_dev *dev, int mtu);
+int mlx5_query_port_max_mtu(struct mlx5_core_dev *dev, int *max_mtu);
+int mlx5_query_port_oper_mtu(struct mlx5_core_dev *dev, int *oper_mtu);
+
 int mlx5_debug_eq_add(struct mlx5_core_dev *dev, struct mlx5_eq *eq);
 void mlx5_debug_eq_remove(struct mlx5_core_dev *dev, struct mlx5_eq *eq);
 int mlx5_core_eq_query(struct mlx5_core_dev *dev, struct mlx5_eq *eq,