Messages in this thread | | | Subject | Re: [PATCH v5 00/13] SCMI Notifications Core Support | From | Cristian Marussi <> | Date | Mon, 23 Mar 2020 08:54:41 +0000 |
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Hi Lukasz
On 3/18/20 9:01 AM, Lukasz Luba wrote: > Hi Cristian, > > On 3/16/20 3:03 PM, Cristian Marussi wrote: >> Hi all, >> >> this series wants to introduce SCMI Notification Support, built on top of >> the standard Kernel notification chain subsystem. >> >> At initialization time each SCMI Protocol takes care to register with the >> new SCMI notification core the set of its own events which it intends to >> support. >> >> Using the API exposed via scmi_handle.notify_ops a Kernel user can register >> its own notifier_t callback (via a notifier_block as usual) against any >> registered event as identified by the tuple: >> >> (proto_id, event_id, src_id) >> >> where src_id represents a generic source identifier which is protocol >> dependent like domain_id, performance_id, sensor_id and so forth. >> (users can anyway do NOT provide any src_id, and subscribe instead to ALL >> the existing (if any) src_id sources for that proto_id/evt_id combination) >> >> Each of the above tuple-specified event will be served on its own dedicated >> blocking notification chain, dynamically allocated on-demand when at least >> one user has shown interest on that event. >> >> Upon a notification delivery all the users' registered notifier_t callbacks >> will be in turn invoked and fed with the event_id as @action param and a >> generated custom per-event struct _report as @data param. >> (as in include/linux/scmi_protocol.h) >> >> The final step of notification delivery via users' callback invocation is >> instead delegated to a pool of deferred workers (Kernel cmwq): each >> SCMI protocol has its own dedicated worker and dedicated queue to push >> events from the rx ISR to the worker. >> > > Could you give an example how the notification would be delivered > further to the upper layers, like hwmon driver, cpufreq or thermal?
Sure. I tested registering various callbacks against PERF events (since they're what I have available on my platform implementation); I used probe() in scmi-genpd and scmi-cpufreq to register generic testing callbacks like:
scmi_cpufrq_probe()
... src_id = 0x00; handle->notify_ops->register_event_notifier(handle, SCMI_PROTOCOL_PERF, 0x1, &src_id, &my_cpufreq_nb);
and removing similarly in remove().
I'll send you my debug patches that includes genpd/cpufreq callbacks registration and an additional dummy driver that just registers perf callbacks so you can have a better idea of the intended usage.
> For example, for sensor protocol which delivers event > SENSOR_TRIP_POINT_EVENT indicating a trip point was crossed. >
Regarding sensors it could be something like:
sensor_id = 0x00;
handle->notify_ops->register_event_notifier(handle, SCMI_PROTOCOL_SENSOR, 0x0, &sensor_id, &my_sensor_nb);
handle->sensor_ops->trip_point_config(handle, sensor_id, 0, 10000); Note that the notification core takes care on its own of enabling the specific events generation when you register the first callback for a specific event as identified by (proto_id, event_id, src_id) but in the case of the sensor protocol you'll need to explicitly setup the trip_point too.
As a result when the trip point is crossed you'll receive in your callback a sensor_report (as in include/linux/scmi_protocol.h) as your data arg.
I just realized that being the notification enable method (trip_notify) also exposed by the ops directly, I should probably add some sort of alert for a user...since it is not meant to be used directly when the notification subsystem is being used....I'll think about this pitfall.
> Would it be possible for: > drivers/hwmon/scmi-hwmon.c > to get this temperature events like an interrupt? >
Sorry I did not get what you mean here.
Regards
Cristian
> I couldn't find it in the implementation of the registered handlers. > > Regards, > Lukasz
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