Re: [PATCH net-next 2/2] bindings: net: stmmac: Add documentation for TSN parameters

[Jose Abreu <Jose.Abreu@synopsys.com>]

Hi Jesus,

On 26-10-2017 17:23, Jesus Sanchez-Palencia wrote:
> Hi Jose,
>
>
> On 10/26/2017 03:08 AM, Jose Abreu wrote:
>> Hi Andrew,
>>
>> On 26-10-2017 10:03, Andrew Lunn wrote:
>>>> These parameters may also need to change in runtime depending on
>>>> the scheduled traffic. Unfortunately, net subsystem does not yet
>>>> support TSN so this will have to wait and for now we will use
>>>> fixed parameters.
>>> Hi Jose
>>>
>>> what you should do is help Linux get support for TSN. Please take part
>>> in this discussion:
>>>
>>> https://urldefense.proofpoint.com/v2/url?u=https-3A__patchwork.ozlabs.org_cover_808504_&d=DwIBAg&c=DPL6_X_6JkXFx7AXWqB0tg&r=WHDsc6kcWAl4i96Vm5hJ_19IJiuxx_p_Rzo2g-uHDKw&m=8yzdm5iHyWm9cVsYIYUtQNul5WnLO4nLnIxb3WDu-WU&s=6UJ2YJm5jXq6vTWpNRwRzNEuukPboceO61DQgDIpSj0&e=
>>>
>>> Test the RFC, make sure the concepts will work for your hardware. Make
>>> you hardware work with these RFC patches. Help drive TSN forward. Once
>>> the core TSN code lands, then you can post patches for your driver.
>> After reading more carefully the RFC I noticed that for now it
>> only supports CBS. CBS is already supported by stmmac since:
>> "net: stmmac: configuration of CBS in case of a TX AVB queue"
>> [1]. My main objective now is to add support for EST and FP
>> features in stmmac.
>>
>> As I am a recent contributor to net subsystem I am afraid my
>> expertise won't be of much value for now as far as the RFC goes.
>>
>
> Please note that our RFC covered more than CBS. We've only provided
> patches for the cbs qdisc so far, but we've shared ideas of another
> qdisc we've designed and prototyped for EST and FP: taprio. It was a
> quite extensive thread, so I recommend reading it all so you can have
> a better picture of how the ideas were received back then [1].
>
> In addition to our RFC, there is also the related discussion about
> SO_TXTIME proposed by Richard Cochran [2], which I believe might
> also be of interest to you.

Thanks for this info! I guess I have a lot to read this weekend :)

>
>
>> About my patches, what I think would be better now would be to
>> drop the configuration by DT and integrate the remaining
>> configuration, letting the EST parameters be populated by SoC
>> specific wrappers. I will then integrate this with the RFC
>> patches once they get in and I also intend to contribute with the
>> discussion once a new version is sent.
>
> The CBS qdisc patchset is ready to be merged, and based on previous
> feedback should go in anytime now.

Nice! I will start studying the integration of this in stmmac.

>
>
>> I need also to say that this was fully tested and its working as
>> expected so, there is no real setback in integrating this now and
>> it will save us time in the future because then we will only need
>> to implement the callbacks.
>
> Which is great, sure. I believe the point others are making here is
> just that there have been some discussions recently that you should
> take part of. The goal is getting the *standard* interfaces into
> the kernel so we can then provide device driver implementations
> through them.

And we are all in favor about making this a standard interface. I
was just mentioning that my expertise in the net subsystem is
very low but I will review the threads. If you could add me in cc
for the relevant threads it would be nice because I don't have
them saved here.

Thanks and Best Regards,
Jose Miguel Abreu

>
> Thanks,
> Jesus
>
> [1] https://urldefense.proofpoint.com/v2/url?u=https-3A__www.mail-2Darchive.com_netdev-40vger.kernel.org_msg186431.html&d=DwIC-g&c=DPL6_X_6JkXFx7AXWqB0tg&r=WHDsc6kcWAl4i96Vm5hJ_19IJiuxx_p_Rzo2g-uHDKw&m=9feTUzfFG49lrNpaBinz8J4S1cKj1qEZur1JlzfQdWU&s=zjR6UPefwbqwHVbaTrepj_ZQnxBMGKDlTq4obkLlfkk&e=
> [2] https://urldefense.proofpoint.com/v2/url?u=https-3A__www.mail-2Darchive.com_netdev-40vger.kernel.org_msg188385.html&d=DwIC-g&c=DPL6_X_6JkXFx7AXWqB0tg&r=WHDsc6kcWAl4i96Vm5hJ_19IJiuxx_p_Rzo2g-uHDKw&m=9feTUzfFG49lrNpaBinz8J4S1cKj1qEZur1JlzfQdWU&s=6aZXBf8OndxVnh1cl3UvvfDqWp1Xa6ql_cCVB3xAQa8&e=
>
>
>> Best regards,
>> Jose Miguel Abreu
>>
>> [1]
>> https://urldefense.proofpoint.com/v2/url?u=https-3A__git.kernel.org_pub_scm_linux_kernel_git_davem_net-2Dnext.git_commit_drivers_net_ethernet_stmicro_stmmac-3Fid-3D19d9187317979cf0c25f67017d2676149abc46b2&d=DwIC-g&c=DPL6_X_6JkXFx7AXWqB0tg&r=WHDsc6kcWAl4i96Vm5hJ_19IJiuxx_p_Rzo2g-uHDKw&m=9feTUzfFG49lrNpaBinz8J4S1cKj1qEZur1JlzfQdWU&s=kN0fG9BlqONAd9z6vji-mnCxaVpJ-oX-Bv4c6DXNhaQ&e=
>>
>>>     Andrew