[PATCH net-next 2/2] net/mlx4_en: Support for configurable RSS hash function

[Amir Vadai <amirv@mellanox.com>]

From: Eyal Perry <eyalpe@mellanox.com>

The ConnectX HW is capable of using one of the following hash functions:
Toeplitz and an XOR hash function.
This patch implements ethtool_ops {get,set}_rxfh_func callbacks for the
mlx4_en driver in order to query and configure the RSS hash function to
be used by the device.

Signed-off-by: Eyal Perry <eyalpe@mellanox.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
---
 drivers/net/ethernet/mellanox/mlx4/en_ethtool.c | 40 +++++++++++++++++++++++++
 drivers/net/ethernet/mellanox/mlx4/en_netdev.c  |  9 ++++++
 drivers/net/ethernet/mellanox/mlx4/en_rx.c      | 11 ++++---
 drivers/net/ethernet/mellanox/mlx4/mlx4_en.h    |  3 +-
 4 files changed, 58 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx4/en_ethtool.c b/drivers/net/ethernet/mellanox/mlx4/en_ethtool.c
index 8ea4d5b..f33785a 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_ethtool.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_ethtool.c
@@ -973,6 +973,44 @@ static u32 mlx4_en_get_rxfh_indir_size(struct net_device *dev)
 	return priv->rx_ring_num;
 }
 
+static u32 mlx4_en_get_rxfh_func(struct net_device *dev)
+{
+	struct mlx4_en_priv *priv = netdev_priv(dev);
+
+	return priv->rss_hash_fn;
+}
+
+static int mlx4_en_set_rxfh_func(struct net_device *dev, u32 hfunc)
+{
+	struct mlx4_en_priv *priv = netdev_priv(dev);
+	struct mlx4_en_dev *mdev = priv->mdev;
+	u32 prev_rss_hash_fn = priv->rss_hash_fn;
+	int err = 0;
+
+	if (!(hfunc & priv->rss_hash_fn_caps))
+		return -EINVAL;
+
+	priv->rss_hash_fn = hfunc;
+	if (hfunc == RSS_HASH_TOP && !(dev->features & NETIF_F_RXHASH))
+		en_warn(priv,
+			"Toeplitz hash function should be used in conjunction with RX hashing for optimal performance\n");
+	if (hfunc == RSS_HASH_XOR && (dev->features & NETIF_F_RXHASH))
+		en_warn(priv,
+			"Enabling both XOR Hash function and RX Hashing can limit RPS functionality\n");
+
+	mutex_lock(&mdev->state_lock);
+	if (priv->port_up && priv->rss_hash_fn != prev_rss_hash_fn) {
+		mlx4_en_stop_port(dev, 1);
+		err = mlx4_en_start_port(dev);
+	}
+	mutex_unlock(&mdev->state_lock);
+
+	if (err)
+		en_err(priv, "Failed to restart port %d\n", priv->port);
+
+	return err;
+}
+
 static int mlx4_en_get_rxfh(struct net_device *dev, u32 *ring_index, u8 *key)
 {
 	struct mlx4_en_priv *priv = netdev_priv(dev);
@@ -1799,6 +1837,8 @@ const struct ethtool_ops mlx4_en_ethtool_ops = {
 	.get_rxnfc = mlx4_en_get_rxnfc,
 	.set_rxnfc = mlx4_en_set_rxnfc,
 	.get_rxfh_indir_size = mlx4_en_get_rxfh_indir_size,
+	.get_rxfh_func = mlx4_en_get_rxfh_func,
+	.set_rxfh_func = mlx4_en_set_rxfh_func,
 	.get_rxfh = mlx4_en_get_rxfh,
 	.set_rxfh = mlx4_en_set_rxfh,
 	.get_channels = mlx4_en_get_channels,
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
index 0efbae9..a9e96a6 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
@@ -2585,6 +2585,15 @@ int mlx4_en_init_netdev(struct mlx4_en_dev *mdev, int port,
 		dev->features    |= NETIF_F_GSO_UDP_TUNNEL;
 	}
 
+	if (mdev->dev->caps.flags2 & MLX4_DEV_CAP_FLAG2_RSS_XOR) {
+		priv->rss_hash_fn_caps |= RSS_HASH_XOR;
+		priv->rss_hash_fn = RSS_HASH_XOR;
+	}
+	if (mdev->dev->caps.flags2 & MLX4_DEV_CAP_FLAG2_RSS_TOP) {
+		priv->rss_hash_fn_caps |= RSS_HASH_TOP;
+		priv->rss_hash_fn = RSS_HASH_TOP;
+	}
+
 	mdev->pndev[port] = dev;
 
 	netif_carrier_off(dev);
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_rx.c b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
index b173a0c..41c1ff9 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_rx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
@@ -1113,10 +1113,13 @@ int mlx4_en_config_rss_steer(struct mlx4_en_priv *priv)
 	}
 
 	rss_context->flags = rss_mask;
-	rss_context->hash_fn = MLX4_RSS_HASH_TOP;
-	for (i = 0; i < 10; i++)
-		rss_context->rss_key[i] = cpu_to_be32(rsskey[i]);
-
+	if (priv->rss_hash_fn & MLX4_RSS_HASH_XOR) {
+		rss_context->hash_fn = MLX4_RSS_HASH_XOR;
+	} else {
+		rss_context->hash_fn = MLX4_RSS_HASH_TOP;
+		for (i = 0; i < 10; i++)
+			rss_context->rss_key[i] = cpu_to_be32(rsskey[i]);
+	}
 	err = mlx4_qp_to_ready(mdev->dev, &priv->res.mtt, &context,
 			       &rss_map->indir_qp, &rss_map->indir_state);
 	if (err)
diff --git a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
index ef83d12..e1c3364 100644
--- a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
+++ b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
@@ -375,7 +375,6 @@ struct mlx4_en_port_profile {
 };
 
 struct mlx4_en_profile {
-	int rss_xor;
 	int udp_rss;
 	u8 rss_mask;
 	u32 active_ports;
@@ -615,6 +614,8 @@ struct mlx4_en_priv {
 	__be16 vxlan_port;
 
 	u32 pflags;
+	u8 rss_hash_fn;
+	u8 rss_hash_fn_caps;
 };
 
 enum mlx4_en_wol {
-- 
1.8.3.4