From: Richard Cochran <richardcochran@gmail.com>
To: Siddharth Vadapalli <s-vadapalli@ti.com>
Cc: davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
pabeni@redhat.com, rogerq@kernel.org, jacob.e.keller@intel.com,
leon@kernel.org, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, srk@ti.com
Subject: Re: [PATCH net-next] net: ethernet: ti: am65-cpts: adjust estf following ptp changes
Date: Tue, 21 Mar 2023 21:19:39 -0700 [thread overview]
Message-ID: <ZBqB28RyKHYPPgEF@hoboy.vegasvil.org> (raw)
In-Reply-To: <20230321062600.2539544-1-s-vadapalli@ti.com>
On Tue, Mar 21, 2023 at 11:56:00AM +0530, Siddharth Vadapalli wrote:
> From: Grygorii Strashko <grygorii.strashko@ti.com>
>
> When the CPTS clock is synced/adjusted by running linuxptp (ptp4l/phc2sys),
> it will cause the TSN EST schedule to drift away over time. This is because
> the schedule is driven by the EstF periodic counter whose pulse length is
> defined in ref_clk cycles and it does not automatically sync to CPTS clock.
> _______
> _|
> ^
> expected cycle start time boundary
> _______________
> _|_|___|_|
> ^
> EstF drifted away -> direction
>
> To fix it, the same PPM adjustment has to be applied to EstF as done to the
> PHC CPTS clock, in order to correct the TSN EST cycle length and keep them
> in sync.
>
> Drifted cycle:
> AM65_CPTS_EVT: 7 e1:01770001 e2:000000ff t:1635968230373377017
> AM65_CPTS_EVT: 7 e1:01770001 e2:000000ff t:1635968230373877017
> AM65_CPTS_EVT: 7 e1:01770001 e2:000000ff t:1635968230374377017
> AM65_CPTS_EVT: 7 e1:01770001 e2:000000ff t:1635968230374877017
> AM65_CPTS_EVT: 7 e1:01770001 e2:000000ff t:1635968230375377017
> AM65_CPTS_EVT: 7 e1:01770001 e2:000000ff t:1635968230375877023
> AM65_CPTS_EVT: 7 e1:01770001 e2:000000ff t:1635968230376377018
> AM65_CPTS_EVT: 7 e1:01770001 e2:000000ff t:1635968230376877018
> AM65_CPTS_EVT: 7 e1:01770001 e2:000000ff t:1635968230377377018
>
> Stable cycle:
> AM65_CPTS_EVT: 7 e1:01770001 e2:000000ff t:1635966863193375473
> AM65_CPTS_EVT: 7 e1:01770001 e2:000000ff t:1635966863193875473
> AM65_CPTS_EVT: 7 e1:01770001 e2:000000ff t:1635966863194375473
> AM65_CPTS_EVT: 7 e1:01770001 e2:000000ff t:1635966863194875473
> AM65_CPTS_EVT: 7 e1:01770001 e2:000000ff t:1635966863195375473
> AM65_CPTS_EVT: 7 e1:01770001 e2:000000ff t:1635966863195875473
> AM65_CPTS_EVT: 7 e1:01770001 e2:000000ff t:1635966863196375473
>
> Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
> Signed-off-by: Siddharth Vadapalli <s-vadapalli@ti.com>
Acked-by: Richard Cochran <richardcochran@gmail.com>
next prev parent reply other threads:[~2023-03-22 4:20 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-21 6:26 Siddharth Vadapalli
2023-03-21 9:25 ` Roger Quadros
2023-03-22 4:19 ` Richard Cochran [this message]
2023-03-22 12:30 ` patchwork-bot+netdevbpf
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