[PATCH net-next] net: stmmac: Fix E2E delay mechanism

[G Thomas, Rohan]

Hi Russell,

Thanks for reviewing the patch.

On 11/26/2025 4:49 AM, Russell King (Oracle) wrote:
> On Tue, Nov 25, 2025 at 10:50:02PM +0800, Rohan G Thomas via B4 Relay wrote:
>> From: Rohan G Thomas <rohan.g.thomas at altera.com>
>>
>> For E2E delay mechanism, "received DELAY_REQ without timestamp" error
>> messages shows up for dwmac v3.70+ and dwxgmac IPs.
>>
>> This issue affects socfpga platforms, Agilex7 (dwmac 3.70) and
>> Agilex5 (dwxgmac). According to the databook, to enable timestamping
>> for all events, the SNAPTYPSEL bit in the MAC_Timestamp_Control
> 
> bits

Sure, will fix this in the next version.

> 
>> register must be set to 2'b00, and the TSEVNTENA bit must be cleared
>> to 0'b0.
> 
> Are you sure 3.70 is the appropriate point. According to the 3.74
> databook, SNAPTYPSEL changed between 3.5 and 3.6.
> 

I’m not entirely sure. As per the dwmac databook notes that SNAPTYPSEL
is not backward compatible with functions described in release 3.50a,
but it’s unclear if this specifically relates to TSEVNTENA. My
understanding is that at least from 3.70a, TSEVNTENA must be cleared to
enable time stamping for all the events.

Best Regards,
Rohan