On Mittwoch, 22. Mai 2024 08:49:43 MESZ Krzysztof Kozlowski wrote:
> On 21/05/2024 22:35, Luca Weiss wrote:
> > On Dienstag, 21. Mai 2024 10:58:07 MESZ Krzysztof Kozlowski wrote:
> >> On 20/05/2024 17:11, Luca Weiss wrote:
> >>> Hi Krzysztof
> >>>
> >>> Ack, sounds good.
> >>>
> >>> Maybe also from you, any opinion between these two binding styles?
> >>>
> >>> So first using index of mboxes for the numbering, where for the known
> >>> usages the first element (and sometimes the 3rd - ipc-2) are empty <>.
> >>>
> >>> The second variant is using mbox-names to get the correct channel-mbox
> >>> mapping.
> >>>
> >>> - qcom,ipc-1 = <&apcs 8 13>;
> >>> - qcom,ipc-2 = <&apcs 8 9>;
> >>> - qcom,ipc-3 = <&apcs 8 19>;
> >>> + mboxes = <0>, <&apcs 13>, <&apcs 9>, <&apcs 19>;
> >>>
> >>> vs.
> >>>
> >>> - qcom,ipc-1 = <&apcs 8 13>;
> >>> - qcom,ipc-2 = <&apcs 8 9>;
> >>> - qcom,ipc-3 = <&apcs 8 19>;
> >>> + mboxes = <&apcs 13>, <&apcs 9>, <&apcs 19>;
> >>> + mbox-names = "ipc-1", "ipc-2", "ipc-3";
> >>
> >> Sorry, don't get, ipc-1 is the first mailbox, so why would there be <0>
> >> in first case?
> >
> > Actually not, ipc-0 would be permissible by the driver, used for the 0th host
> >
> > e.g. from:
> >
> > /* Iterate over all hosts to check whom wants a kick */
> > for (host = 0; host < smsm->num_hosts; host++) {
> > hostp = &smsm->hosts[host];
> >
> > Even though no mailbox is specified in any upstream dts for this 0th host I
> > didn't want the bindings to restrict that, that's why in the first example
> > there's an empty element (<0>) for the 0th smsm host
> >
> >> Anyway, the question is if you need to know that some
> >> mailbox is missing. But then it is weird to name them "ipc-1" etc.
> >
> > In either case we'd just query the mbox (either by name or index) and then
> > see if it's there? Not quite sure I understand the sentence..
> > Pretty sure either binding would work the same way.
>
> The question is: does the driver care only about having some mailboxes
> or the driver cares about each specific mailbox? IOW, is skipping ipc-0
> important for the driver?
There's nothing special from driver side about any mailbox. Some SoCs have
a mailbox for e.g. hosts 1&2&3, some have only 1&3, and apq8064 even has
1&2&3&4.
And if the driver doesn't find a mailbox for a host, it just ignores it
but then of course it can't 'ring' the mailbox for that host when necessary.
Not sure how much more I can add here, to be fair I barely understand what
this driver is doing myself apart from the obvious.
Regards
Luca
>
>
> Best regards,
> Krzysztof
>
>
