Re: [PATCH net-next 3/3] net/mlx5: Support getcyclesx and getcrosscycles

[Paolo Abeni <pabeni@redhat.com>]

On 7/15/25 7:15 AM, Tariq Toukan wrote:
> From: Carolina Jubran <cjubran@nvidia.com>
> 
> Implement the getcyclesx64 and getcrosscycles callbacks in ptp_info to
> expose the device’s raw free-running counter.
> 
> Signed-off-by: Carolina Jubran <cjubran@nvidia.com>
> Reviewed-by: Dragos Tatulea <dtatulea@nvidia.com>
> Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
> ---
>  .../ethernet/mellanox/mlx5/core/lib/clock.c   | 74 ++++++++++++++++++-
>  1 file changed, 73 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/lib/clock.c b/drivers/net/ethernet/mellanox/mlx5/core/lib/clock.c
> index b1e2deeefc0c..2f75726674a9 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/lib/clock.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/lib/clock.c
> @@ -306,6 +306,23 @@ static int mlx5_mtctr_syncdevicetime(ktime_t *device_time,
>  	return 0;
>  }
>  
> +static int
> +mlx5_mtctr_syncdevicecyclestime(ktime_t *device_time,
> +				struct system_counterval_t *sys_counterval,
> +				void *ctx)
> +{
> +	struct mlx5_core_dev *mdev = ctx;
> +	u64 device;
> +	int err;
> +
> +	err = mlx5_mtctr_read(mdev, false, sys_counterval, &device);
> +	if (err)
> +		return err;
> +	*device_time = ns_to_ktime(device);

If the goal is providing a raw cycle counter, why still using a timespec
to the user space? A plain u64 would possibly be less ambiguous.

/P