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Message-ID: <67c7f423-18ce-4804-8be9-cc4521733cd2@ti.com>
Date: Mon, 22 Apr 2024 17:09:41 +0530
From: Chintan Vankar <c-vankar@...com>
To: Julien Panis <jpanis@...libre.com>, Arnd Bergmann <arnd@...db.de>,
Dan
Carpenter <dan.carpenter@...aro.org>,
Heiner Kallweit <hkallweit1@...il.com>,
Vladimir Oltean <vladimir.oltean@....com>,
Andrew Lunn <andrew@...n.ch>, Roger Quadros <rogerq@...nel.org>,
Richard Cochran
<richardcochran@...il.com>,
Paolo Abeni <pabeni@...hat.com>, Jakub Kicinski
<kuba@...nel.org>,
Eric Dumazet <edumazet@...gle.com>,
"David S. Miller"
<davem@...emloft.net>, <s-vadapalli@...com>
CC: <linux-kernel@...r.kernel.org>, <netdev@...r.kernel.org>
Subject: Re: [PATCH net-next v8 0/2] Enable RX HW timestamp for PTP packets
using CPTS FIFO
On 19/04/24 13:56, Chintan Vankar wrote:
> The CPSW offers two mechanisms for communicating packet ingress timestamp
> information to the host.
>
> The first mechanism is via the CPTS Event FIFO which records timestamp
> when triggered by certain events. One such event is the reception of an
> Ethernet packet with a specified EtherType field. This is used to capture
> ingress timestamps for PTP packets. With this mechanism the host must
> read the timestamp (from the CPTS FIFO) separately from the packet payload
> which is delivered via DMA.
>
> In the second mechanism of timestamping, CPSW driver enables hardware
> timestamping for 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 is responsible for triggering errata i2401:
> "CPSW: Host Timestamps Cause CPSW Port to Lock up."
>
> The errata affects all K3 SoCs. Link to errata for AM64x:
> https://www.ti.com/lit/er/sprz457h/sprz457h.pdf
>
> As a workaround we can use first mechanism to timestamp received
> packets.
>
> Series is based on linux-next tagged next-20240419.
>
> Link to v7:
> https://lore.kernel.org/r/20240417120913.3811519-1-c-vankar@ti.com/
>
> Changes from v7 to v8:
> - Removed empty lines between trailers in [PATCH v7 2/2] as suggested
> by Jakub.
>
Is it possible to merge this series if no further comment ?
> Chintan Vankar (2):
> net: ethernet: ti: am65-cpts: Enable RX HW timestamp for PTP packets
> using CPTS FIFO
> net: ethernet: ti: am65-cpsw/ethtool: Enable RX HW timestamp only for
> PTP packets
>
> drivers/net/ethernet/ti/am65-cpsw-ethtool.c | 13 ++-
> drivers/net/ethernet/ti/am65-cpsw-nuss.c | 51 +++++-----
> drivers/net/ethernet/ti/am65-cpts.c | 107 ++++++++++++++------
> drivers/net/ethernet/ti/am65-cpts.h | 11 +-
> 4 files changed, 118 insertions(+), 64 deletions(-)
>
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