Re: [PATCH RFC v6 2/6] dpll: Add DPLL framework base functions

[Jiri Pirko <jiri@resnulli.us>]

Thu, May 04, 2023 at 08:44:21PM CEST, kuba@kernel.org wrote:
>On Thu, 4 May 2023 19:51:38 +0200 Jiri Pirko wrote:
>> >> What is the next intelligible element to identify DPLL device here?  
>> >
>> >I don't know. We can always add more as needed.
>> >We presuppose that the devices are identifiable, so whatever info
>> >is used to identify them goes here.  
>> 
>> Allright. So in case of ptp_ocp and mlx5, module_name and clock_id
>> are enough. In case of ice, DPLL_A_TYPE, attr is the one to make
>> distinction between the 2 dpll instances there
>> 
>> So for now, we can have:
>>  CMD_GET_ID
>>    -> DPLL_A_MODULE_NAME  
>>       DPLL_A_CLOCK_ID
>>       DPLL_A_TYPE
>>    <- DPLL_A_ID
>> 
>> 
>> if user passes a subset which would not provide a single match, we error
>> out with -EINVAL and proper exack message. Makes sense?
>
>Yup, that sounds good to me.
>
>> >Same answer. Could be a name of the pin according to ASIC docs.
>> >Could be the ball name for a BGA package. Anything that's meaningful.  
>> 
>> Okay, for pin, the type and label would probably do:
>>  CMD_GET_PIN_ID
>>    -> DPLL_A_MODULE_NAME  
>>       DPLL_A_CLOCK_ID
>>       DPLL_A_PIN_TYPE
>>       DPLL_A_PIN_LABEL
>
>Label sounds dangerously open ended, too. Would that be the SMA

Well, every string is. And past RFCs of this patchset demonstrated guys
did serialize a lot of stuff in strings.


>connector label (i.e. front panel label)? Or also applicable to
>internal pins? It'd be easier to talk details if we had the user
>facing documentation that ships with these products.

I think is is use case specific. Some of the pins face the user over
physical port, they it is a front panel label. Others are internal
names. I have no clue how to define and mainly enforce rules here.

But as an example, if you have 2 pins of the same type, only difference
is they are connected to front panel connector "A" and "B", this is the
label you have to pass to the ID query. Do you see any other way?


>
>>    <- DPLL_A_PIN_ID
>> 
>> Again, if user passes a subset which would not provide a single match,
>> we error out with -EINVAL and proper exack message.
>> 
>> If there is only one pin for example, user query of DPLL_A_MODULE_NAME
>> and DPLL_A_CLOCK_ID would do return a single match. No need to pass
>> anything else.
>> 
>> I think this could work with both ice and ptp_ocp, correct guys?
>> 
>> For mlx5, I will have 2 or more pins with same module name, clock id
>> and type. For these SyncE pins the label does not really make sense.
>> But I don't have to query, because the PIN_ID is going to be exposed for
>> netdev over RT netlink. Clicks.
>> 
>> Makes sense?