From: Ido Schimmel <idosch@nvidia.com>
To: Richard Cochran <richardcochran@gmail.com>
Cc: netdev@vger.kernel.org, davem@davemloft.net, kuba@kernel.org,
pabeni@redhat.com, edumazet@google.com, petrm@nvidia.com,
amcohen@nvidia.com, danieller@nvidia.com, mlxsw@nvidia.com
Subject: Re: [PATCH net-next 0/9] mlxsw: Add PTP support for Spectrum-2 and newer ASICs
Date: Wed, 27 Jul 2022 17:44:49 +0300 [thread overview]
Message-ID: <YuFPYS10iXdco5rM@shredder> (raw)
In-Reply-To: <YuFIvxvB2AxKt9PV@hoboy.vegasvil.org>
On Wed, Jul 27, 2022 at 07:16:31AM -0700, Richard Cochran wrote:
> On Wed, Jul 27, 2022 at 09:23:19AM +0300, Ido Schimmel wrote:
>
> > Specifically, the hardware will subtract the current time stamp from the
> > correction field at the ingress port and will add the current time stamp
> > to the correction field at the egress port.
>
> Doing this in pure HW TC mode, the time scale of the switch's clock
> does not matter at all. It can be a free running counter.
It is done in hardware.
>
> > For the purpose of an
> > ordinary or boundary clock (this patchset), the correction field will
> > always be adjusted between the CPU port and one of the front panel
> > ports, but never between two front panel ports.
>
> To clarify, the only reason why you say "never between two front panel
> ports" is because the switch will configured not to forward PTP frames
> over the front panel ports, for BC mode. For TC operation, the switch
> will apply the correction, right?
Right. The hardware can support a TC operation, but I did not find any
Linux interfaces to configure it (did I miss something?) nor got any
requirements to support it at the moment.
next prev parent reply other threads:[~2022-07-27 14:45 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-27 6:23 [PATCH net-next 0/9] mlxsw: Add PTP support for Spectrum-2 and newer ASICs Ido Schimmel
2022-07-27 6:23 ` [PATCH net-next 1/9] mlxsw: spectrum_ptp: Add helper functions to configure PTP traps Ido Schimmel
2022-07-27 6:23 ` [PATCH net-next 2/9] mlxsw: Support CQEv2 for SDQ in Spectrum-2 and newer ASICs Ido Schimmel
2022-07-27 6:23 ` [PATCH net-next 3/9] mlxsw: spectrum_ptp: Add PTP initialization / finalization for Spectrum-2 Ido Schimmel
2022-07-27 6:23 ` [PATCH net-next 4/9] mlxsw: Query UTC sec and nsec PCI offsets and values Ido Schimmel
2022-07-27 6:23 ` [PATCH net-next 5/9] mlxsw: spectrum_ptp: Add implementation for physical hardware clock operations Ido Schimmel
2022-07-27 6:23 ` [PATCH net-next 6/9] mlxsw: Send PTP packets as data packets to overcome a limitation Ido Schimmel
2022-07-27 6:23 ` [PATCH net-next 7/9] mlxsw: spectrum: Support time stamping on Spectrum-2 Ido Schimmel
2022-07-27 6:23 ` [PATCH net-next 8/9] mlxsw: spectrum_ptp: Support SIOCGHWTSTAMP, SIOCSHWTSTAMP ioctls Ido Schimmel
2022-07-27 6:23 ` [PATCH net-next 9/9] mlxsw: spectrum: Support ethtool 'get_ts_info' callback in Spectrum-2 Ido Schimmel
2022-07-27 14:05 ` [PATCH net-next 0/9] mlxsw: Add PTP support for Spectrum-2 and newer ASICs Richard Cochran
2022-07-27 14:48 ` Ido Schimmel
2022-07-27 14:16 ` Richard Cochran
2022-07-27 14:44 ` Ido Schimmel [this message]
2022-07-28 3:09 ` Richard Cochran
2022-07-28 7:03 ` Ido Schimmel
2022-07-29 10:30 ` patchwork-bot+netdevbpf
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