| Message ID | 20200120122333.46217-1-cristian.marussi@arm.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | SCMI Notifications Support | expand |
Hi On 20/01/2020 12:23, Cristian Marussi wrote: > Hi all, > > this series wants to introduce SCMI Notification Support, built on top of > the standard Kernel notification chain subsystem. > [snip] > > Based on scmi-next [1], on top of: > > commit 257d0e20ec4f ("include: trace: Add SCMI header with trace events") Sorry but I've got this is wrong, the series is based in fact on top of the very following commit on scmi-next [1]: 729d3530a504 drivers: firmware: scmi: Extend SCMI transport layer by trace events Thanks Jim for reporting this. Regards Cristian > > This series has been tested on JUNO with an experimental firmware only > supporting Perf Notifications. > > Any thoughts ? > > Thanks > > Cristian > ---- > > [1] git://git.kernel.org/pub/scm/linux/kernel/git/sudeep.holla/linux.git > > Cristian Marussi (8): > firmware: arm_scmi: Add core notifications support > firmware: arm_scmi: Add notifications anti-tampering > firmware: arm_scmi: Enable core notifications > firmware: arm_scmi: Add Power notifications support > firmware: arm_scmi: Add Perf notifications support > firmware: arm_scmi: Add Sensor notifications support > firmware: arm_scmi: Add Reset notifications support > firmware: arm_scmi: Add Base notifications support > > Sudeep Holla (3): > firmware: arm_scmi: Add receive buffer support for notifications > firmware: arm_scmi: Update protocol commands and notification list > firmware: arm_scmi: Add support for notifications message processing > > drivers/firmware/arm_scmi/Makefile | 2 +- > drivers/firmware/arm_scmi/base.c | 132 ++++ > drivers/firmware/arm_scmi/bus.c | 3 + > drivers/firmware/arm_scmi/common.h | 4 + > drivers/firmware/arm_scmi/driver.c | 121 +++- > drivers/firmware/arm_scmi/notify.c | 1047 +++++++++++++++++++++++++++ > drivers/firmware/arm_scmi/notify.h | 79 ++ > drivers/firmware/arm_scmi/perf.c | 167 ++++- > drivers/firmware/arm_scmi/power.c | 161 +++- > drivers/firmware/arm_scmi/reset.c | 126 +++- > drivers/firmware/arm_scmi/sensors.c | 105 ++- > include/linux/scmi_protocol.h | 82 +++ > 12 files changed, 1991 insertions(+), 38 deletions(-) > create mode 100644 drivers/firmware/arm_scmi/notify.c > create mode 100644 drivers/firmware/arm_scmi/notify.h >
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 a possibly proposed API in scmi_protocol.h (not finalized though, NO EXPORTs_) a Kernel user can register its own notifier_t callback (so 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; given the great number of possible events, and the extensibility of the SCMI Protocol itself, all the underlying machinery of notifications chains it is dynamically created and destroyed at run-time on-demand, depending on the number of effective registered users: no users no allocations at all. 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 report struct as @data param. Each event report carries also a timestamp, gathered when the notification message had first entered the richOS world in the SCMI rx ISR. 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 queue to push events from the rx ISR to the worker. Additionally, since the original Kernel notification chain mechanism does not stop users' registered callbacks from interacting with the notification delivery itself (like cutting the chain with a NOTIFY_STOP or mangling the *data report struct along the way), it was thought that such behaviour was generally undesirable for a notification delivery service, and a possible 'anti-tampering' solution is proposed in patch [02/11] ("firmware: arm_scmi: Add notifications anti-tampering") but maybe this attempt is not worth the cost of the additional complication or simply deemed not needed (being anyway in Kernel land), in such a case the above anti-tampering commit can simply be dropped from the series. The series is marked as RFC mainly because: - the API as said is tentative and not EXPORTed; currently consisting of a per-protocol interface like: scmi_register_<proto>_event_notifier(evt_id, *src_id, *nb) but it could be simplified to one single simpler generic one like: scmi_register_event_notifier(proto_id, evt_id, *src_id, *nb) It's open for discussion. - no Event priorization has been considered: each protocol has its own queue and deferred worker instance, so as to avoid that one protocol flooding can overrun a single queue and influence other protocols' notifications' delivery. But that's it, all the workers are unbound, low_pri cmwq workers. Should we enforce some sort of built-in prio amongst the events ? Should this priority instead be compile time configurable ? Again, open for discussion. - no configuration is possible: it can be imagined that on a real platform events' priority (if any) and events queues' depth could be something somehow compile-time configurable, but this is not addressed by this series at all. Based on scmi-next [1], on top of: commit 257d0e20ec4f ("include: trace: Add SCMI header with trace events") This series has been tested on JUNO with an experimental firmware only supporting Perf Notifications. Any thoughts ? Thanks Cristian ---- [1] git://git.kernel.org/pub/scm/linux/kernel/git/sudeep.holla/linux.git Cristian Marussi (8): firmware: arm_scmi: Add core notifications support firmware: arm_scmi: Add notifications anti-tampering firmware: arm_scmi: Enable core notifications firmware: arm_scmi: Add Power notifications support firmware: arm_scmi: Add Perf notifications support firmware: arm_scmi: Add Sensor notifications support firmware: arm_scmi: Add Reset notifications support firmware: arm_scmi: Add Base notifications support Sudeep Holla (3): firmware: arm_scmi: Add receive buffer support for notifications firmware: arm_scmi: Update protocol commands and notification list firmware: arm_scmi: Add support for notifications message processing drivers/firmware/arm_scmi/Makefile | 2 +- drivers/firmware/arm_scmi/base.c | 132 ++++ drivers/firmware/arm_scmi/bus.c | 3 + drivers/firmware/arm_scmi/common.h | 4 + drivers/firmware/arm_scmi/driver.c | 121 +++- drivers/firmware/arm_scmi/notify.c | 1047 +++++++++++++++++++++++++++ drivers/firmware/arm_scmi/notify.h | 79 ++ drivers/firmware/arm_scmi/perf.c | 167 ++++- drivers/firmware/arm_scmi/power.c | 161 +++- drivers/firmware/arm_scmi/reset.c | 126 +++- drivers/firmware/arm_scmi/sensors.c | 105 ++- include/linux/scmi_protocol.h | 82 +++ 12 files changed, 1991 insertions(+), 38 deletions(-) create mode 100644 drivers/firmware/arm_scmi/notify.c create mode 100644 drivers/firmware/arm_scmi/notify.h