net: mscc: ocelot: add TX timestamping statistics

Add an u64 hardware timestamping statistics structure for each ocelot
port. Export a function from the common switch library for reporting
them to ethtool. This is called by the ocelot switchdev front-end for
now.

Note that for the switchdev driver, we report the one-step PTP packets
as unconfirmed, even though in principle, for some transmission
mechanisms like FDMA, we may be able to confirm transmission and bump
the "pkts" counter in ocelot_fdma_tx_cleanup() instead. I don't have
access to hardware which uses the switchdev front-end, and I've kept the
implementation simple.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Link: https://patch.msgid.link/20250116104628.123555-4-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 37 insertions, 0 deletions

diff --git a/drivers/net/ethernet/mscc/ocelot_stats.c b/drivers/net/ethernet/mscc/ocelot_stats.c
index c018783757fb..545710dadcf5 100644
--- a/drivers/net/ethernet/mscc/ocelot_stats.c
+++ b/drivers/net/ethernet/mscc/ocelot_stats.c
@@ -821,6 +821,26 @@ void ocelot_port_get_eth_phy_stats(struct ocelot *ocelot, int port,
 }
 EXPORT_SYMBOL_GPL(ocelot_port_get_eth_phy_stats);
 
+void ocelot_port_get_ts_stats(struct ocelot *ocelot, int port,
+			      struct ethtool_ts_stats *ts_stats)
+{
+	struct ocelot_port *ocelot_port = ocelot->ports[port];
+	struct ocelot_ts_stats *stats = ocelot_port->ts_stats;
+	unsigned int start;
+
+	if (!ocelot->ptp)
+		return;
+
+	do {
+		start = u64_stats_fetch_begin(&stats->syncp);
+		ts_stats->pkts = stats->pkts;
+		ts_stats->onestep_pkts_unconfirmed = stats->onestep_pkts_unconfirmed;
+		ts_stats->lost = stats->lost;
+		ts_stats->err = stats->err;
+	} while (u64_stats_fetch_retry(&stats->syncp, start));
+}
+EXPORT_SYMBOL_GPL(ocelot_port_get_ts_stats);
+
 void ocelot_port_get_stats64(struct ocelot *ocelot, int port,
 			     struct rtnl_link_stats64 *stats)
 {
@@ -960,6 +980,23 @@ int ocelot_stats_init(struct ocelot *ocelot)
 	if (!ocelot->stats)
 		return -ENOMEM;
 
+	if (ocelot->ptp) {
+		for (int port = 0; port < ocelot->num_phys_ports; port++) {
+			struct ocelot_port *ocelot_port = ocelot->ports[port];
+
+			if (!ocelot_port)
+				continue;
+
+			ocelot_port->ts_stats = devm_kzalloc(ocelot->dev,
+							     sizeof(*ocelot_port->ts_stats),
+							     GFP_KERNEL);
+			if (!ocelot_port->ts_stats)
+				return -ENOMEM;
+
+			u64_stats_init(&ocelot_port->ts_stats->syncp);
+		}
+	}
+
 	snprintf(queue_name, sizeof(queue_name), "%s-stats",
 		 dev_name(ocelot->dev));
 	ocelot->stats_queue = create_singlethread_workqueue(queue_name);