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Message-ID: <fc4f148d-d4d3-4994-8d36-c382c13ba52b@kernel.org>
Date: Mon, 26 Feb 2024 14:18:22 +0200
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Subject: Re: [PATCH net-next 2/2] net: ethernet: ti: am65-cpsw: Enable RX HW
 timestamp only for PTP packets
To: Siddharth Vadapalli <s-vadapalli@ti.com>
Cc: Chintan Vankar <c-vankar@ti.com>, Dan Carpenter
 <dan.carpenter@linaro.org>, 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>,
 linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
 Pekka Varis <p-varis@ti.com>
References: <20240215110953.3225099-1-c-vankar@ti.com>
 <20240215110953.3225099-2-c-vankar@ti.com>
 <4c82705d-b05c-4ee8-88ed-42f944a023ac@kernel.org>
 <03d53049-e649-4714-8ad4-49619a5e9475@ti.com>
Content-Language: en-US
From: Roger Quadros <rogerq@kernel.org>
In-Reply-To: <03d53049-e649-4714-8ad4-49619a5e9475@ti.com>
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On 24/02/2024 10:59, Siddharth Vadapalli wrote:
> On Mon, Feb 19, 2024 at 12:59:55PM +0200, Roger Quadros wrote:
>> Hi,
>>
>> On 15/02/2024 13:09, 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".
>>
> ...
> 
>>>  
>>> @@ -856,6 +852,9 @@ static int am65_cpsw_nuss_rx_packets(struct am65_cpsw_common *common,
>>>  		ndev_priv = netdev_priv(ndev);
>>>  		am65_cpsw_nuss_set_offload_fwd_mark(skb, ndev_priv->offload_fwd_mark);
>>>  		skb_put(skb, pkt_len);
>>> +		skb_reset_mac_header(skb);
>>
>> Why do you need to add skb_reset_mac_header here?
>>
>>> +		if (port->rx_ts_enabled)
>>> +			am65_cpts_rx_timestamp(common->cpts, skb);
>>
>> The timestamp should be added before you do skb_put().
> 
> Roger,
> 
> Could you please clarify why the timestamp should be added before
> skb_put()?

My bad. hwtimestamps lies after skb->end so it doesn't matter.

-- 
cheers,
-roger