mlxsw: spectrum_ptp: Add counters for GC events

On Spectrum-1, timestamped PTP packets and the corresponding timestamps need to
be kept in caches until both are available, at which point they are matched up
and packets forwarded as appropriate. However, not all packets will ever see
their timestamp, and not all timestamps will ever see their packet. It is
necessary to dispose of such abandoned entries, so a garbage collector was
introduced in commit 5d23e4159772 ("mlxsw: spectrum: PTP: Garbage-collect
unmatched entries").

If these GC events happen often, it is a sign of a problem. However because this
whole mechanism is taking place behind the scenes, there is no direct way to
determine whether garbage collection took place.

Therefore to fix this, on Spectrum-1 only, expose four artificial ethtool
counters for the GC events: GCd timestamps and packets, in TX and RX directions.

Cc: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: Petr Machata <petrm@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 67 insertions, 0 deletions

diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_ptp.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_ptp.c
index 38bb1cfe4e8c..ec2ff3d7f41c 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_ptp.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_ptp.c
@@ -630,6 +630,8 @@ static void
 mlxsw_sp1_ptp_ht_gc_collect(struct mlxsw_sp_ptp_state *ptp_state,
 			    struct mlxsw_sp1_ptp_unmatched *unmatched)
 {
+	struct mlxsw_sp_ptp_port_dir_stats *stats;
+	struct mlxsw_sp_port *mlxsw_sp_port;
 	int err;
 
 	/* If an unmatched entry has an SKB, it has to be handed over to the
@@ -650,6 +652,17 @@ mlxsw_sp1_ptp_ht_gc_collect(struct mlxsw_sp_ptp_state *ptp_state,
 		/* The packet was matched with timestamp during the walk. */
 		goto out;
 
+	mlxsw_sp_port = ptp_state->mlxsw_sp->ports[unmatched->key.local_port];
+	if (mlxsw_sp_port) {
+		stats = unmatched->key.ingress ?
+			&mlxsw_sp_port->ptp.stats.rx_gcd :
+			&mlxsw_sp_port->ptp.stats.tx_gcd;
+		if (unmatched->skb)
+			stats->packets++;
+		else
+			stats->timestamps++;
+	}
+
 	/* mlxsw_sp1_ptp_unmatched_finish() invokes netif_receive_skb(). While
 	 * the comment at that function states that it can only be called in
 	 * soft IRQ context, this pattern of local_bh_disable() +
@@ -1098,3 +1111,57 @@ int mlxsw_sp1_ptp_get_ts_info(struct mlxsw_sp *mlxsw_sp,
 
 	return 0;
 }
+
+struct mlxsw_sp_ptp_port_stat {
+	char str[ETH_GSTRING_LEN];
+	ptrdiff_t offset;
+};
+
+#define MLXSW_SP_PTP_PORT_STAT(NAME, FIELD)				\
+	{								\
+		.str = NAME,						\
+		.offset = offsetof(struct mlxsw_sp_ptp_port_stats,	\
+				    FIELD),				\
+	}
+
+static const struct mlxsw_sp_ptp_port_stat mlxsw_sp_ptp_port_stats[] = {
+	MLXSW_SP_PTP_PORT_STAT("ptp_rx_gcd_packets",    rx_gcd.packets),
+	MLXSW_SP_PTP_PORT_STAT("ptp_rx_gcd_timestamps", rx_gcd.timestamps),
+	MLXSW_SP_PTP_PORT_STAT("ptp_tx_gcd_packets",    tx_gcd.packets),
+	MLXSW_SP_PTP_PORT_STAT("ptp_tx_gcd_timestamps", tx_gcd.timestamps),
+};
+
+#undef MLXSW_SP_PTP_PORT_STAT
+
+#define MLXSW_SP_PTP_PORT_STATS_LEN \
+	ARRAY_SIZE(mlxsw_sp_ptp_port_stats)
+
+int mlxsw_sp1_get_stats_count(void)
+{
+	return MLXSW_SP_PTP_PORT_STATS_LEN;
+}
+
+void mlxsw_sp1_get_stats_strings(u8 **p)
+{
+	int i;
+
+	for (i = 0; i < MLXSW_SP_PTP_PORT_STATS_LEN; i++) {
+		memcpy(*p, mlxsw_sp_ptp_port_stats[i].str,
+		       ETH_GSTRING_LEN);
+		*p += ETH_GSTRING_LEN;
+	}
+}
+
+void mlxsw_sp1_get_stats(struct mlxsw_sp_port *mlxsw_sp_port,
+			 u64 *data, int data_index)
+{
+	void *stats = &mlxsw_sp_port->ptp.stats;
+	ptrdiff_t offset;
+	int i;
+
+	data += data_index;
+	for (i = 0; i < MLXSW_SP_PTP_PORT_STATS_LEN; i++) {
+		offset = mlxsw_sp_ptp_port_stats[i].offset;
+		*data++ = *(u64 *)(stats + offset);
+	}
+}