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From: Roger Quadros <rogerq@kernel.org>
To: Siddharth Vadapalli <s-vadapalli@ti.com>,
	davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
	pabeni@redhat.com, jacob.e.keller@intel.com,
	richardcochran@gmail.com, leon@kernel.org
Cc: 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 11:25:32 +0200	[thread overview]
Message-ID: <1dddf2d3-ea82-732b-ffaa-7e59f8617a7b@kernel.org> (raw)
In-Reply-To: <20230321062600.2539544-1-s-vadapalli@ti.com>



On 21/03/2023 08:26, 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>

Reviewed-by: Roger Quadros <rogerq@kernel.org>

  reply	other threads:[~2023-03-21  9:25 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-21  6:26 [PATCH net-next] net: ethernet: ti: am65-cpts: adjust estf following ptp changes Siddharth Vadapalli
2023-03-21  9:25 ` Roger Quadros [this message]
2023-03-22  4:19 ` Richard Cochran
2023-03-22 12:30 ` patchwork-bot+netdevbpf

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