net/mlx5: Add cyc2time HW translation mode support

Device timestamp can be in real time mode (cycles to time translation is
offloaded into the Hardware). With real time mode, HW provides timestamp
which is already translated into nanoseconds.

With this mode, driver adjusts both the HW and timecounter (to keep
clock_info_page updated) using callbacks: adjfreq, adjtime and settime.
HW clock modifications are done via MTUTC access reg commands. Driver is
allowed to modify HW real time clock only if MCAM ptpcyc2realtime_modify
capability is set.

Add MTUTC set function to be used for configuring the HW real time
clock. Modify existing code to support both internal timer (with
conversion via timecounter_cyc2time() and real time (no conversions).

Align the signatures of the helpers converting from timestamp to
nanoseconds. With that, when allocating a queue assign the corresponding
callback with respect to the capability.

Adjust 1PPS timestamp calculation flows based on the timestamp mode.

Cyc2time offload brings two major advantages:
- Improve MTAE (Max Time Absolute Error) for HW TS by up to 160 ns over a
  100% loaded CPU.
- Faster data-path timestamp to nanoseconds, as translation is
  lock-less and done in HW.

On real time mode, timestamp format is 32 high bits of seconds and 32
low bits of nanoseconds. On some flows, driver shall convert this format
into nanoseconds wall-clock with REAL_TIME_TO_NS macro.

HW supports a single clock, and it is shared by all functions on a
device. In case real time clock is used, it is recommended to use
a single GM to all device's functions.

Signed-off-by: Eran Ben Elisha <eranbe@mellanox.com>
Signed-off-by: Aya Levin <ayal@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

1 files changed, 33 insertions, 0 deletions

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/lib/clock.h b/drivers/net/ethernet/mellanox/mlx5/core/lib/clock.h
index 6e8804ebc773..a12c7da618a7 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/lib/clock.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/lib/clock.h
@@ -33,6 +33,24 @@
 #ifndef __LIB_CLOCK_H__
 #define __LIB_CLOCK_H__
 
+static inline bool mlx5_is_real_time_rq(struct mlx5_core_dev *mdev)
+{
+	u8 rq_ts_format_cap = MLX5_CAP_GEN(mdev, rq_ts_format);
+
+	return (rq_ts_format_cap == MLX5_RQ_TIMESTAMP_FORMAT_CAP_REAL_TIME  ||
+		rq_ts_format_cap == MLX5_RQ_TIMESTAMP_FORMAT_CAP_FREE_RUNNING_AND_REAL_TIME);
+}
+
+static inline bool mlx5_is_real_time_sq(struct mlx5_core_dev *mdev)
+{
+	u8 sq_ts_format_cap = MLX5_CAP_GEN(mdev, sq_ts_format);
+
+	return (sq_ts_format_cap == MLX5_SQ_TIMESTAMP_FORMAT_CAP_REAL_TIME  ||
+		sq_ts_format_cap == MLX5_SQ_TIMESTAMP_FORMAT_CAP_FREE_RUNNING_AND_REAL_TIME);
+}
+
+typedef ktime_t (*cqe_ts_to_ns)(struct mlx5_clock *, u64);
+
 #if IS_ENABLED(CONFIG_PTP_1588_CLOCK)
 void mlx5_init_clock(struct mlx5_core_dev *mdev);
 void mlx5_cleanup_clock(struct mlx5_core_dev *mdev);
@@ -57,6 +75,15 @@ static inline ktime_t mlx5_timecounter_cyc2time(struct mlx5_clock *clock,
 	return ns_to_ktime(nsec);
 }
 
+#define REAL_TIME_TO_NS(hi, low) (((u64)hi) * NSEC_PER_SEC + ((u64)low))
+
+static inline ktime_t mlx5_real_time_cyc2time(struct mlx5_clock *clock,
+					      u64 timestamp)
+{
+	u64 time = REAL_TIME_TO_NS(timestamp >> 32, timestamp & 0xFFFFFFFF);
+
+	return ns_to_ktime(time);
+}
 #else
 static inline void mlx5_init_clock(struct mlx5_core_dev *mdev) {}
 static inline void mlx5_cleanup_clock(struct mlx5_core_dev *mdev) {}
@@ -70,6 +97,12 @@ static inline ktime_t mlx5_timecounter_cyc2time(struct mlx5_clock *clock,
 {
 	return 0;
 }
+
+static inline ktime_t mlx5_real_time_cyc2time(struct mlx5_clock *clock,
+					      u64 timestamp)
+{
+	return 0;
+}
 #endif
 
 #endif