Phy delays for Intel 82574L

[Santharaju20]

I am working on supporting gPTP for One of the Intel 82574L chip.

But i could not find the Phy delays for particular chip in the Datasheet "https://www.intel.com/content/dam/doc/datasheet/82574l-gbe-controller-datasheet.pdf".

I found that the PHY delays (PHY_DELAY_MB_TX_I20, PHY_DELAY_MB_RX_I20) for i210 are derived from "https://www.intel.com/content/www/us/en/embedded/products/networking/i210-ethernet-controller-datasheet.html".

Is there any common derived Phy delays for all the NIC's.

[andrew-elder]

Any Intel folks lurking out there?

[Santharaju20]

Any Intel folks lurking out there?

No Andrew, I couldn't able to reach-out the correct/respective INTEL folks.

Can we use the below generic macros as PHY delays which are defined in linux_hal_generic.cpp?????

define TX_PHY_TIME 184

define RX_PHY_TIME 382

[andrew-elder]

I have pinged some folks I know at Intel. It may take a few days to get an update....

[Santharaju20]

I have pinged some folks I know at Intel. It may take a few days to get an update....

Thank you very much Andrew.

I have also raised a question in the Intel Ethernet products forum.

https://forums.intel.com/s/question/0D50P00004YecphSAB/packet-timestamp-sampling-latency-information-not-available-for-82574l-chip

Could you please let me know once you get the update.

[eric-mann]

I’m not aware we ever characterized the PHY delays to the same level of precision as the I210. The ‘574 has a different PHY IP. The fundamental MAC design is ~the same as the i210.

If anything I expect lower time stamp jitter from the ‘574 but potentially less accuracy at 100mbps.

Eric Mann / Intel Networking Division

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From: Santharaju20 notifications@github.com Sent: Tuesday, January 7, 2020 8:54:40 AM To: AVnu/gptp gptp@noreply.github.com Cc: Subscribed subscribed@noreply.github.com Subject: Re: [AVnu/gptp] Phy delays for Intel 82574L (#30)

I have pinged some folks I know at Intel. It may take a few days to get an update....

Thank you very much Andrew.

I have also raised a question in the Intel Ethernet products forum.

https://forums.intel.com/s/question/0D50P00004YecphSAB/packet-timestamp-sampling-latency-information-not-available-for-82574l-chiphttps://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fforums.intel.com%2Fs%2Fquestion%2F0D50P00004YecphSAB%2Fpacket-timestamp-sampling-latency-information-not-available-for-82574l-chip&data=02%7C01%7C%7C3e92becd37e64efc4e2c08d793924a0f%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637140128824866033&sdata=uafO8Pz%2FzzDLMy2K9k022bdN8ARIayqaXc28x30L5eQ%3D&reserved=0

Could you please let me know once you get the update.

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[andrew-elder]

@eric-mann - Thank you for posting a reply.

@Santharaju20 - it seems the information you are looking for is not available. I think your choices are to go with approximate PHY delays, or switch to an i210. The might be a way to "tune" the PHY delay constants by doing some experiments with a known cable length and an i210 on the other side of the link. That would be something you would have to work out how to do yourself.

[Santharaju20]

@eric-mann - Thank you for posting a reply.

@Santharaju20 - it seems the information you are looking for is not available. I think your choices are to go with approximate PHY delays, or switch to an i210. The might be a way to "tune" the PHY delay constants by doing some experiments with a known cable length and an i210 on the other side of the link. That would be something you would have to work out how to do yourself.

Thank you Very Much Andrew.

I am currently using the approximate PHY delays as below.

define TX_PHY_TIME 184

define RX_PHY_TIME 382

But I would like to measure the actual delays with the setup. I was not sure about how to do that measurement.

Could you please assist me on how to calculate this.

[andrew-elder]

gPTP provides the neighbor delay. That is a good starting point. I think you might have to figure some more things out from there yourself. I haven't tried to do this before, so I would be trying to do the same things you are. Maybe someone else watching this has more insight.