net/mlx4_en: Add a service task

Add a service task to run tasks that needed to be executed periodically.
Currently the only task is a watchdog to catch NIC clock overflow, to make
timestamping accurate.
Will move the statistics task into this framework in a later patch.

Signed-off-by: Amir Vadai <amirv@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 19 insertions, 0 deletions

diff --git a/drivers/net/ethernet/mellanox/mlx4/en_clock.c b/drivers/net/ethernet/mellanox/mlx4/en_clock.c
index 501c72f1fbeb..2f181219662e 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_clock.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_clock.c
@@ -129,4 +129,23 @@ void mlx4_en_init_timestamp(struct mlx4_en_dev *mdev)
 
         timecounter_init(&mdev->clock, &mdev->cycles,
                          ktime_to_ns(ktime_get_real()));
+
+        /* Calculate period in seconds to call the overflow watchdog - to make
+         * sure counter is checked at least once every wrap around.
+         */
+        mdev->overflow_period =
+                (cyclecounter_cyc2ns(&mdev->cycles,
+                                    mdev->cycles.mask) / NSEC_PER_SEC / 2)
+                * HZ;
+}
+
+void mlx4_en_ptp_overflow_check(struct mlx4_en_dev *mdev)
+{
+        bool timeout = time_is_before_jiffies(mdev->last_overflow_check +
+                                              mdev->overflow_period);
+
+        if (timeout) {
+                timecounter_read(&mdev->clock);
+                mdev->last_overflow_check = jiffies;
+        }
 }