Re: [PATCH v6 01/10] i3c: Add core I3C infrastructure

[vitor]

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?

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 that could be useful to pass the ibi type on request_ibi(), 
there is some case where the master doesn't support IBI-MR.

> Once you've done that, we'll have trigger a mastership handover
> everytime an I3C driver tries to send a frame on the bus, and the
> master this frame should do through is not in control of the bus. That
> should be pretty easy for the nominal case, but error cases are likely
> to be hard to deal with.
> Note that I have a ->cur_master field in the i3c_bus object which
> stores allows us to track whose the currently active master. If
> master->this != master->bus->cur_master that means you need to start a
> mastership handover procedure.
>
> That's all I thought about for now, and we'll probably face other
> problems when implementing it. Let me know if you have other questions,
> and don't hesitate to share your code early during the development
> phase.
>
> Also note that the bus representation is likely to change based on
> Arnd's feedback, so you might have to rework your implementation a bit
> at some point.
>
> Regards,
>
> Boris

Best regards,
Vitor Soares