Porting RT net driver to dovetail

Porting RT net driver to dovetail

[François Legal]

Hello list,

could anybody point me to some example NIC driver for dovetail. I'm starting to transition from ipipe/rtdm to dovetail.

Thanks in advance

François

RE: Porting RT net driver to dovetail

[Chen, Hongzhan]

>-----Original Message-----
>From: François Legal <devel@thom.fr.eu.org>
>Sent: Wednesday, June 12, 2024 3:08 PM
>To: xenomai@lists.linux.dev
>Subject: Porting RT net driver to dovetail
>
>Hello list,
>
>could anybody point me to some example NIC driver for dovetail. I'm starting

Theoretically, the existing NIC drivers in Xenomai 3.2 is compatible with Dovetail. 
The drivers works with I-PIPE still works with Dovetail. I just had tested rt_igb and rt_igc
on limited NICs and platforms two years ago and cannot suggest more.

Regards

Hongzhan Chen

>to transition from ipipe/rtdm to dovetail.
>
>Thanks in advance
>
>François
>

RE: Porting RT net driver to dovetail

[François Legal]

Thanks for the answer.

Maybe I mixed things up, but I thought that with dovetail, one would somehow use  linux network stack with special OOB drivers, and have no more to rely on RTNET. Is that correct ?

François

Le Mercredi, Juin 12, 2024 10:07 CEST, "Chen, Hongzhan" <hongzhan.chen@intel.com> a écrit:

>
>
> >-----Original Message-----
> >From: François Legal <devel@thom.fr.eu.org>
> >Sent: Wednesday, June 12, 2024 3:08 PM
> >To: xenomai@lists.linux.dev
> >Subject: Porting RT net driver to dovetail
> >
> >Hello list,
> >
> >could anybody point me to some example NIC driver for dovetail. I'm starting
>
> Theoretically, the existing NIC drivers in Xenomai 3.2 is compatible with Dovetail.
> The drivers works with I-PIPE still works with Dovetail. I just had tested rt_igb and rt_igc
> on limited NICs and platforms two years ago and cannot suggest more.
>
> Regards
>
> Hongzhan Chen
>
> >to transition from ipipe/rtdm to dovetail.
> >
> >Thanks in advance
> >
> >François
> >
>

Re: Porting RT net driver to dovetail

[Richard Weinberger]

On Wed, Jun 12, 2024 at 2:09 PM François Legal <devel@thom.fr.eu.org> wrote:
>
> Thanks for the answer.
>
> Maybe I mixed things up, but I thought that with dovetail, one would somehow use  linux network stack with special OOB drivers, and have no more to rely on RTNET. Is that correct ?

It depends on whether you want to use Xenomai or EVL.

-- 
Thanks,
//richard

Re: Porting RT net driver to dovetail

[François Legal]

Well, I'm not sure but last time I checked, RTNET would not be part of xenomai 4 IIRC. So I guess EVL is the way to go.

François

Le Mercredi, Juin 12, 2024 14:40 CEST, Richard Weinberger <richard.weinberger@gmail.com> a écrit:

> On Wed, Jun 12, 2024 at 2:09 PM François Legal <devel@thom.fr.eu.org> wrote:
> >
> > Thanks for the answer.
> >
> > Maybe I mixed things up, but I thought that with dovetail, one would somehow use  linux network stack with special OOB drivers, and have no more to rely on RTNET. Is that correct ?
>
> It depends on whether you want to use Xenomai or EVL.
>
> --
> Thanks,
> //richard

Re: Porting RT net driver to dovetail

[Philippe Gerum]

François Legal <devel@thom.fr.eu.org> writes:

> Well, I'm not sure but last time I checked, RTNET would not be part of xenomai 4 IIRC. So I guess EVL is the way to go.
>

Correct, this is the one providing a real-time net stack based on the
dovetail net services (which RTnet does not use). This work is ongoing
(see the wip/net branch of the linux-evl tree). ETA: mid-july for a
complete UDP stack. ATM, we only have a real-time capable raw socket
interface.

-- 
Philippe.

Re: Porting RT net driver to dovetail

[François Legal]

Thanks for the clarification.

I'm not sure I understand the sentence "ATM, we only have a real-time capable raw socket interface".
In my application, we only use RTNET for level 2 communication. Is this already available.

And so, back to the original question, how do I transition from an RTNET/RTDM NIC to an EVL/??? one ?

Thanks in advance

François

Le Mercredi, Juin 12, 2024 17:09 CEST, Philippe Gerum <rpm@xenomai.org> a écrit:

>
> François Legal <devel@thom.fr.eu.org> writes:
>
> > Well, I'm not sure but last time I checked, RTNET would not be part of xenomai 4 IIRC. So I guess EVL is the way to go.
> >
>
> Correct, this is the one providing a real-time net stack based on the
> dovetail net services (which RTnet does not use). This work is ongoing
> (see the wip/net branch of the linux-evl tree). ETA: mid-july for a
> complete UDP stack. ATM, we only have a real-time capable raw socket
> interface.
>
> --
> Philippe.

Re: Porting RT net driver to dovetail

[Philippe Gerum]

François Legal <devel@thom.fr.eu.org> writes:

> Thanks for the clarification.
>
> I'm not sure I understand the sentence "ATM, we only have a real-time capable raw socket interface".

See https://source.denx.de/Xenomai/xenomai4/libevl/-/blob/master/tidbits/oob-net-icmp.c?ref_type=heads

> In my application, we only use RTNET for level 2 communication. Is this already available.
>
> And so, back to the original question, how do I transition from an RTNET/RTDM NIC to an EVL/??? one ?
>

When the upcoming EVL netstack is fully available (i.e. including the
driver<->evl interface along with the UDP layer), you will add
out-of-band support code to the vanilla driver directly. Typically, a
couple of handlers added to struct net_device_ops, such as:

#ifdef CONFIG_NET_OOB
	int			(*ndo_enable_oob)(struct net_device *dev);
	void			(*ndo_disable_oob)(struct net_device *dev);
	struct sk_buff *	(*ndo_alloc_tx_oob)(struct net_device *ndev);
#endif

The idea is to reuse the vanilla infrastructure as much as possible
instead of forking the driver code. There are a few techniques to have
in mind for doing so while preventing too many merge conflicts whenever
the upstream code changes, the netstack will come with the FEC driver
adapted that way as an illustration.

ETA: end of july.

-- 
Philippe.