From: "Keller, Jacob E" <jacob.e.keller@intel.com>
To: Chintan Vankar <c-vankar@ti.com>,
Dan Carpenter <dan.carpenter@linaro.org>,
Roger Quadros <rogerq@kernel.org>,
"Siddharth Vadapalli" <s-vadapalli@ti.com>,
Richard Cochran <richardcochran@gmail.com>,
Paolo Abeni <pabeni@redhat.com>, Jakub Kicinski <kuba@kernel.org>,
"Eric Dumazet" <edumazet@google.com>,
"David S. Miller" <davem@davemloft.net>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>
Subject: RE: [PATCH net-next 2/2] net: ethernet: ti: am65-cpsw: Enable RX HW timestamp only for PTP packets
Date: Fri, 1 Mar 2024 21:32:16 +0000 [thread overview]
Message-ID: <CO1PR11MB5089BB1C2C43E1616FAE3342D65E2@CO1PR11MB5089.namprd11.prod.outlook.com> (raw)
In-Reply-To: <ef948e8e-b1ae-476f-b07f-4bda6d33c51b@ti.com>
> -----Original Message-----
> From: Chintan Vankar <c-vankar@ti.com>
> Sent: Friday, March 1, 2024 2:49 AM
> To: Keller, Jacob E <jacob.e.keller@intel.com>; Dan Carpenter
> <dan.carpenter@linaro.org>; Roger Quadros <rogerq@kernel.org>; Siddharth
> Vadapalli <s-vadapalli@ti.com>; Richard Cochran <richardcochran@gmail.com>;
> Paolo Abeni <pabeni@redhat.com>; Jakub Kicinski <kuba@kernel.org>; Eric
> Dumazet <edumazet@google.com>; David S. Miller <davem@davemloft.net>
> Cc: linux-kernel@vger.kernel.org; netdev@vger.kernel.org
> Subject: Re: [PATCH net-next 2/2] net: ethernet: ti: am65-cpsw: Enable RX HW
> timestamp only for PTP packets
>
>
>
> On 17/02/24 03:51, Jacob Keller wrote:
> >
> >
> > On 2/15/2024 3:09 AM, Chintan Vankar wrote:
> >> The CPSW peripherals on J7AHP, J7VCL, J7AEP, J7ES, AM64 SoCs have
> >> an errata i2401 "CPSW: Host Timestamps Cause CPSW Port to Lock up".
> >>
> >
> > What's different about timestamping only PTP packets that prevents this
> > port lock up?
>
> The difference is the way we are timestamping the packets. Instead of
> getting the timestamp from CPTS module, we are getting the timestamp
> from CPTS Event FIFO.
>
> In the current mechanism of timestamping, am65-cpsw-nuss driver
> timestamps all received packets by setting the TSTAMP_EN bit in
> CPTS_CONTROL register, which directs the CPTS module to timestamp all
> received packets, followed by passing timestamp via DMA descriptors.
> This mechanism was responsible for the CPSW port to lock up in certain
> condition. We are preventing port lock up by disabling TSTAMP_EN bit in
> CPTS_CONTROL register.
>
> The mechanism we are following in this patch, utilizes the CPTS Event
> FIFO that records timestamps corresponding to certain events, with one
> such event being the reception of an Ethernet packet with EtherType
> field set to PTP.
Ok that explains it. Thanks!
Regards,
Jake
next prev parent reply other threads:[~2024-03-01 21:32 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-15 11:09 [PATCH net-next 1/2] net: ethernet: ti: am65-cpts: Enable PTP RX HW timestamp using CPTS FIFO Chintan Vankar
2024-02-15 11:09 ` [PATCH net-next 2/2] net: ethernet: ti: am65-cpsw: Enable RX HW timestamp only for PTP packets Chintan Vankar
2024-02-16 22:21 ` Jacob Keller
2024-03-01 10:48 ` Chintan Vankar
2024-03-01 21:32 ` Keller, Jacob E [this message]
2024-02-19 10:59 ` Roger Quadros
2024-02-24 8:59 ` Siddharth Vadapalli
2024-02-26 12:18 ` Roger Quadros
2024-02-27 6:15 ` Chintan Vankar
2024-02-16 22:20 ` [PATCH net-next 1/2] net: ethernet: ti: am65-cpts: Enable PTP RX HW timestamp using CPTS FIFO Jacob Keller
2024-02-19 10:25 ` Roger Quadros
2024-02-19 11:24 ` Roger Quadros
2024-02-26 9:08 ` Chintan Vankar
2024-02-26 12:49 ` Roger Quadros
2024-03-01 11:06 ` Chintan Vankar
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