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SubjectRe: [PATCH v6 01/10] i3c: Add core I3C infrastructure
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Hi Przemyslaw


On 28-08-2018 13:55, Przemyslaw Gaj wrote:
> Hi Vitor,
>
> I have already implemented Mastership request/handover but we are waiting for Boris’s patch to be accepted and merged. Anyway, my comments below.
>
> On 8/28/18, 2:02 PM, "Boris Brezillon" <boris.brezillon@bootlin.com> wrote:
>
> EXTERNAL MAIL
>
>
> Hi Vitor,
>
> On Tue, 28 Aug 2018 12:50:12 +0100
> vitor <Vitor.Soares@synopsys.com> wrote:
>
> > Hi Boris,
> >
> > The DT Bindings say "The node describing an I3C bus should be named
> > i3c-master.". Do you have a field for secondary master?
>
> I think we don’t need separate field for secondary master. Main and secondary masters
> support similar functionalities. It’s enough to have this state internally and do mastership it it's needed.

Yes, you are right.

>
> >
> > On 24-08-2018 19:16, Boris Brezillon wrote:
> > > Well, before even considering supporting secondary master registration,
> > > we need to handle mastership handover. As for the DAA operation, it's
> > > likely to be host specific, so we'll have to add a new hook to the
> > > i3c_master_controller_ops struct.
> > Do you mean when master try to delegate the bus ownership through
> > GETACCMST? or to get the bus ownership with IBI-MR?
>
> I think we need to support both.
>
> I agree.

That's ok to me.

>
> >
> > I think that could be useful to pass the ibi type on request_ibi(),
> > there is some case where the master doesn't support IBI-MR.
>
> Actually, I was planning on making it completely separate from
> regular slave IBIs. That is, the master controller driver would demux
> the slave, MR and Hot Join IBIs, and if there's an MR request, queue a
> mastership handover work to the workqueue (pretty much what we do for
> Hot-Join already). Mastership handover is anyway likely to be IP
> specific, so I don't think there's a need to make it look like a
> regular IBI.
>
> I think it's better to have separate function to do mastership request.
>
> Regarding whether IBI-MR support should be exposed to the I3C framework
> or not depends on how much will be automated on the framework side. I
> don't the answer yet, but that's probably something will figure out
> along the road.
>
> My current implementation is: when request_mastership field
> of i3c_master_controller_ops structure is set, master driver supports mastership requests.
> That's how I check if this is supported or not.
>
> Regards,
>
> Boris
>
> Regards,
> Przemek
>
when you say request_mastership, do you mean the current master do the
mastership hand-off or the secondary master request to be current master?

So, per my understanding since the Main master support the hand-off of
the bus you accept all incoming MR, right? Or do you check all devices BCR?

Best regards,
Vitor Soares

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