[PATCH RFC v2 2/6] net/mlx5e: Introduce lost_cqe statistic counter for PTP Tx port timestamping CQ

[Rahul Rameshbabu <rrameshbabu@nvidia.com>]

Track the number of times a CQE was expected to not be delivered on PTP Tx
port timestamping CQ. A CQE is expected to not be delivered if a certain
amount of time passes since the corresponding CQE containing the DMA
timestamp information has arrived. Increment the late_cqe counter when such
a CQE does manage to be delivered to the CQ.

Signed-off-by: Rahul Rameshbabu <rrameshbabu@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
---
 .../device_drivers/ethernet/mellanox/mlx5/counters.rst      | 6 ++++++
 drivers/net/ethernet/mellanox/mlx5/core/en/ptp.c            | 1 +
 drivers/net/ethernet/mellanox/mlx5/core/en_stats.c          | 1 +
 drivers/net/ethernet/mellanox/mlx5/core/en_stats.h          | 1 +
 4 files changed, 9 insertions(+)

diff --git a/Documentation/networking/device_drivers/ethernet/mellanox/mlx5/counters.rst b/Documentation/networking/device_drivers/ethernet/mellanox/mlx5/counters.rst
index f69ee1ebee01..5464cd9e2694 100644
--- a/Documentation/networking/device_drivers/ethernet/mellanox/mlx5/counters.rst
+++ b/Documentation/networking/device_drivers/ethernet/mellanox/mlx5/counters.rst
@@ -702,6 +702,12 @@ the software port.
        the device typically ensures not posting the CQE.
      - Error
 
+   * - `ptp_cq[i]_lost_cqe`
+     - Number of times a CQE is expected to not be delivered on the PTP
+       timestamping CQE by the device due to a time delta elapsing. If such a
+       CQE is somehow delivered, `ptp_cq[i]_late_cqe` is incremented.
+     - Error
+
 .. [#ring_global] The corresponding ring and global counters do not share the
                   same name (i.e. do not follow the common naming scheme).
 
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/ptp.c b/drivers/net/ethernet/mellanox/mlx5/core/en/ptp.c
index fd4ef6431142..1dd4bf7f7dbe 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/ptp.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/ptp.c
@@ -169,6 +169,7 @@ static void mlx5e_ptpsq_mark_ts_cqes_undelivered(struct mlx5e_ptpsq *ptpsq,
 		WARN_ON_ONCE(!pos->inuse);
 		pos->inuse = false;
 		list_del(&pos->entry);
+		ptpsq->cq_stats->lost_cqe++;
 	}
 	spin_unlock(&cqe_list->tracker_list_lock);
 }
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_stats.c b/drivers/net/ethernet/mellanox/mlx5/core/en_stats.c
index 4b96ad657145..7e63d7c88894 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_stats.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_stats.c
@@ -2158,6 +2158,7 @@ static const struct counter_desc ptp_cq_stats_desc[] = {
 	{ MLX5E_DECLARE_PTP_CQ_STAT(struct mlx5e_ptp_cq_stats, abort) },
 	{ MLX5E_DECLARE_PTP_CQ_STAT(struct mlx5e_ptp_cq_stats, abort_abs_diff_ns) },
 	{ MLX5E_DECLARE_PTP_CQ_STAT(struct mlx5e_ptp_cq_stats, late_cqe) },
+	{ MLX5E_DECLARE_PTP_CQ_STAT(struct mlx5e_ptp_cq_stats, lost_cqe) },
 };
 
 static const struct counter_desc ptp_rq_stats_desc[] = {
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_stats.h b/drivers/net/ethernet/mellanox/mlx5/core/en_stats.h
index 12b3607afecd..03f6265d3ed5 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_stats.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_stats.h
@@ -461,6 +461,7 @@ struct mlx5e_ptp_cq_stats {
 	u64 abort;
 	u64 abort_abs_diff_ns;
 	u64 late_cqe;
+	u64 lost_cqe;
 };
 
 struct mlx5e_rep_stats {
-- 
2.42.0