The thresholds exist but there is no notification neither action code
related to them yet.
These changes implement the netlink for the notifications when the
thresholds are crossed, added, deleted or flushed as well as the
commands which allows to get the list of the thresholds, flush them,
add and delete.
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Link: https://patch.msgid.link/20241022155147.463475-3-daniel.lezcano@linaro.org
[ rjw: Use the thermal_zone guard for locking, subject edit ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The user thresholds mechanism is a way to have the userspace to tell
the thermal framework to send a notification when a temperature limit
is crossed. There is no id, no hysteresis, just the temperature and
the direction of the limit crossing. That means we can be notified
when a threshold is crossed the way up only, or the way down only or
both ways. That allows to create hysteresis values if it is needed.
A threshold can be added, deleted or flushed. The latter means all
thresholds belonging to a thermal zone will be deleted.
When a threshold is added:
- if the same threshold (temperature and direction) exists, an error
is returned
- if a threshold is specified with the same temperature but a
different direction, the specified direction is added
- if there is no threshold with the same temperature then it is
created
When a threshold is deleted:
- if the same threshold (temperature and direction) exists, it is
deleted
- if a threshold is specified with the same temperature but a
different direction, the specified direction is removed
- if there is no threshold with the same temperature, then an error
is returned
When the threshold are flushed:
- All thresholds related to a thermal zone are deleted
When a threshold is crossed:
- the userspace does not need to know which threshold(s) have been
crossed, it will be notified with the current temperature and the
previous temperature
- if multiple thresholds have been crossed between two updates only
one notification will be send to the userspace, it is pointless to
send a notification per thresholds crossed as the userspace can
handle that easily when it has the temperature delta information
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://patch.msgid.link/20240923100005.2532430-2-daniel.lezcano@linaro.org
[ rjw: Subject edit, use BIT(0) and BIT(1) in symbol definitions ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
