[PATCH net-next V2 2/3] net/mlx5: Extract MTCTR register read logic into helper function

From: Tariq Toukan
Date: Tue Aug 12 2025 - 10:31:20 EST


From: Carolina Jubran <cjubran@xxxxxxxxxx>

Refactor the MTCTR register reading logic into a dedicated helper to
lay the groundwork for the next patch.

Signed-off-by: Carolina Jubran <cjubran@xxxxxxxxxx>
Reviewed-by: Dragos Tatulea <dtatulea@xxxxxxxxxx>
Signed-off-by: Tariq Toukan <tariqt@xxxxxxxxxx>
---
.../ethernet/mellanox/mlx5/core/lib/clock.c | 39 +++++++++++++------
1 file changed, 27 insertions(+), 12 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/lib/clock.c b/drivers/net/ethernet/mellanox/mlx5/core/lib/clock.c
index 214d732d18e9..9b49bdc339ad 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/lib/clock.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/lib/clock.c
@@ -247,27 +247,24 @@ static bool mlx5_is_ptm_source_time_available(struct mlx5_core_dev *dev)
return !!MLX5_GET(mtptm_reg, out, psta);
}

-static int mlx5_mtctr_syncdevicetime(ktime_t *device_time,
- struct system_counterval_t *sys_counterval,
- void *ctx)
+static int mlx5_mtctr_read(struct mlx5_core_dev *mdev,
+ bool real_time_mode,
+ struct system_counterval_t *sys_counterval,
+ u64 *device)
{
u32 out[MLX5_ST_SZ_DW(mtctr_reg)] = {0};
u32 in[MLX5_ST_SZ_DW(mtctr_reg)] = {0};
- struct mlx5_core_dev *mdev = ctx;
- bool real_time_mode;
- u64 host, device;
+ u64 host;
int err;

- real_time_mode = mlx5_real_time_mode(mdev);
-
MLX5_SET(mtctr_reg, in, first_clock_timestamp_request,
MLX5_MTCTR_REQUEST_PTM_ROOT_CLOCK);
MLX5_SET(mtctr_reg, in, second_clock_timestamp_request,
real_time_mode ? MLX5_MTCTR_REQUEST_REAL_TIME_CLOCK :
- MLX5_MTCTR_REQUEST_FREE_RUNNING_COUNTER);
+ MLX5_MTCTR_REQUEST_FREE_RUNNING_COUNTER);

- err = mlx5_core_access_reg(mdev, in, sizeof(in), out, sizeof(out), MLX5_REG_MTCTR,
- 0, 0);
+ err = mlx5_core_access_reg(mdev, in, sizeof(in), out, sizeof(out),
+ MLX5_REG_MTCTR, 0, 0);
if (err)
return err;

@@ -281,8 +278,26 @@ static int mlx5_mtctr_syncdevicetime(ktime_t *device_time,
.cs_id = CSID_X86_ART,
.use_nsecs = true,
};
+ *device = MLX5_GET64(mtctr_reg, out, second_clock_timestamp);
+
+ return 0;
+}
+
+static int mlx5_mtctr_syncdevicetime(ktime_t *device_time,
+ struct system_counterval_t *sys_counterval,
+ void *ctx)
+{
+ struct mlx5_core_dev *mdev = ctx;
+ bool real_time_mode;
+ u64 device;
+ int err;
+
+ real_time_mode = mlx5_real_time_mode(mdev);
+
+ err = mlx5_mtctr_read(mdev, real_time_mode, sys_counterval, &device);
+ if (err)
+ return err;

- device = MLX5_GET64(mtctr_reg, out, second_clock_timestamp);
if (real_time_mode)
*device_time = ns_to_ktime(REAL_TIME_TO_NS(device >> 32, device & U32_MAX));
else
--
2.40.1