mlx5: add pause frame stats

Plumb through all the indirection and copy some code from
ethtool -S. The names of the group indicate that these are
the stats we are after (and Saeed confirms it).

v3:
 - fix build in mlx5_rep
v2:
 - drop the ethool helper and call stats directly
 - don't pass 0 as initialized to in buffer
 - use local buffer
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -1341,6 +1341,14 @@ static int mlx5e_set_tunable(struct net_device *dev,
 	return err;
 }
 
+static void mlx5e_get_pause_stats(struct net_device *netdev,
+				  struct ethtool_pause_stats *pause_stats)
+{
+	struct mlx5e_priv *priv = netdev_priv(netdev);
+
+	mlx5e_stats_pause_get(priv, pause_stats);
+}
+
 void mlx5e_ethtool_get_pauseparam(struct mlx5e_priv *priv,
 				  struct ethtool_pauseparam *pauseparam)
 {
@@ -2033,6 +2041,7 @@ const struct ethtool_ops mlx5e_ethtool_ops = {
 	.set_rxnfc         = mlx5e_set_rxnfc,
 	.get_tunable       = mlx5e_get_tunable,
 	.set_tunable       = mlx5e_set_tunable,
+	.get_pause_stats   = mlx5e_get_pause_stats,
 	.get_pauseparam    = mlx5e_get_pauseparam,
 	.set_pauseparam    = mlx5e_set_pauseparam,
 	.get_ts_info       = mlx5e_get_ts_info,

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

@@ -288,6 +288,14 @@ static u32 mlx5e_rep_get_rxfh_indir_size(struct net_device *netdev)
 	return mlx5e_ethtool_get_rxfh_indir_size(priv);
 }
 
+static void mlx5e_uplink_rep_get_pause_stats(struct net_device *netdev,
+					     struct ethtool_pause_stats *stats)
+{
+	struct mlx5e_priv *priv = netdev_priv(netdev);
+
+	mlx5e_stats_pause_get(priv, stats);
+}
+
 static void mlx5e_uplink_rep_get_pauseparam(struct net_device *netdev,
 					    struct ethtool_pauseparam *pauseparam)
 {
@@ -362,6 +370,7 @@ static const struct ethtool_ops mlx5e_uplink_rep_ethtool_ops = {
 	.set_rxfh          = mlx5e_set_rxfh,
 	.get_rxnfc         = mlx5e_get_rxnfc,
 	.set_rxnfc         = mlx5e_set_rxnfc,
+	.get_pause_stats   = mlx5e_uplink_rep_get_pause_stats,
 	.get_pauseparam    = mlx5e_uplink_rep_get_pauseparam,
 	.set_pauseparam    = mlx5e_uplink_rep_set_pauseparam,
 };

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

@@ -677,6 +677,35 @@ static MLX5E_DECLARE_STATS_GRP_OP_UPDATE_STATS(802_3)
 	mlx5_core_access_reg(mdev, in, sz, out, sz, MLX5_REG_PPCNT, 0, 0);
 }
 
+#define MLX5E_READ_CTR64_BE_F(ptr, c)			\
+	be64_to_cpu(*(__be64 *)((char *)ptr +		\
+		MLX5_BYTE_OFF(ppcnt_reg,		\
+			counter_set.eth_802_3_cntrs_grp_data_layout.c##_high)))
+
+void mlx5e_stats_pause_get(struct mlx5e_priv *priv,
+			   struct ethtool_pause_stats *pause_stats)
+{
+	u32 ppcnt_ieee_802_3[MLX5_ST_SZ_DW(ppcnt_reg)];
+	struct mlx5_core_dev *mdev = priv->mdev;
+	u32 in[MLX5_ST_SZ_DW(ppcnt_reg)] = {};
+	int sz = MLX5_ST_SZ_BYTES(ppcnt_reg);
+
+	if (!MLX5_BASIC_PPCNT_SUPPORTED(mdev))
+		return;
+
+	MLX5_SET(ppcnt_reg, in, local_port, 1);
+	MLX5_SET(ppcnt_reg, in, grp, MLX5_IEEE_802_3_COUNTERS_GROUP);
+	mlx5_core_access_reg(mdev, in, sz, ppcnt_ieee_802_3,
+			     sz, MLX5_REG_PPCNT, 0, 0);
+
+	pause_stats->tx_pause_frames =
+		MLX5E_READ_CTR64_BE_F(ppcnt_ieee_802_3,
+				      a_pause_mac_ctrl_frames_transmitted);
+	pause_stats->rx_pause_frames =
+		MLX5E_READ_CTR64_BE_F(ppcnt_ieee_802_3,
+				      a_pause_mac_ctrl_frames_received);
+}
+
 #define PPORT_2863_OFF(c) \
 	MLX5_BYTE_OFF(ppcnt_reg, \
 		      counter_set.eth_2863_cntrs_grp_data_layout.c##_high)

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

@@ -104,6 +104,9 @@ void mlx5e_stats_update(struct mlx5e_priv *priv);
 void mlx5e_stats_fill(struct mlx5e_priv *priv, u64 *data, int idx);
 void mlx5e_stats_fill_strings(struct mlx5e_priv *priv, u8 *data);
 
+void mlx5e_stats_pause_get(struct mlx5e_priv *priv,
+			   struct ethtool_pause_stats *pause_stats);
+
 /* Concrete NIC Stats */
 
 struct mlx5e_sw_stats {