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2022-07-15Documentation: EM: Switch to micro-Watts scaleLukasz Luba1-7/+7
The EM now uses the micro-Watts scale for the power values. Update related documentation to reflect that fact. Fix also a problematic sentence in the doc "to:" which triggers test scripts complaining about wrong email address. Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org> Signed-off-by: Lukasz Luba <lukasz.luba@arm.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2022-04-13Documentation: EM: Add artificial EM registration descriptionLukasz Luba1-0/+20
Add description about new artificial EM registration and use cases. Update also the documentation with the new .get_cost() callback description and usage. Signed-off-by: Lukasz Luba <lukasz.luba@arm.com> Reviewed-by: Ionela Voinescu <ionela.voinescu@arm.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2022-04-13PM: EM: Change the order of arguments in the .active_power() callbackLukasz Luba1-2/+2
The .active_power() callback passes the device pointer when it's called. Aligned with a convetion present in other subsystems and pass the 'dev' as a first argument. It looks more cleaner. Adjust all affected drivers which implement that API callback. Suggested-by: Ionela Voinescu <ionela.voinescu@arm.com> Signed-off-by: Lukasz Luba <lukasz.luba@arm.com> Reviewed-by: Ionela Voinescu <ionela.voinescu@arm.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2022-03-03Documentation: EM: Describe new registration method using DTLukasz Luba1-0/+10
The new registration method allows to get power values from the DT OPP definition. The new OPP entry property "opp-microwatt" contains total power expressed in micro-Watts. Align the EM documentation with this new possible registration method of EM. Signed-off-by: Lukasz Luba <lukasz.luba@arm.com> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
2021-11-10Documentation: power: Describe 'advanced' and 'simple' EM modelsLukasz Luba1-0/+22
The Energy Model (EM) can be registered in two ways: 1) Using a helper function, which under the hood relies on OPP framework and DT entry in CPU node: 'dynamic-power-coefficient'. This is a 'simple' EM because it's tied to the math formula: Power = dynamic-power-coefficient * V^2 * f 2) Using em_dev_register_perf_domain() API function with a driver custom callback which provides power for each performance state. This is 'advanced' EM, since it can better reflect real power measurements for each performance state. It's not limited to any math formula and can better reflect real physics of the device. Add description of these two methods to the documentation, so developers could choose the suitable registration method (option). Signed-off-by: Lukasz Luba <lukasz.luba@arm.com> [ rjw: Changelog edits ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2021-11-10Documentation: power: Add description about new callback for EM registrationLukasz Luba1-15/+16
The Energy Model (EM) registration for CPUs should now be done using a dedicated callback added recently into CPUFreq framework and drivers. Commit c17495b01b72 ("cpufreq: Add callback to register with energy model") The callback guaranties that the EM registration is called at the right time during driver setup. To avoid mistakes update the documentation to align with the existing code implementation. Signed-off-by: Lukasz Luba <lukasz.luba@arm.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2021-09-07Documentation: power: include kernel-doc in Energy Model docLukasz Luba1-3/+12
Improve the existing documentation of the Energy Model and add kernel-doc comments. This extends an API description and helps better understanding the usage. Signed-off-by: Lukasz Luba <lukasz.luba@arm.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-11-10PM: EM: Update Energy Model with new flag indicating power scaleLukasz Luba1-5/+12
Update description and meaning of a new flag, which indicates the type of power scale used for a registered Energy Model (EM) device. Reviewed-by: Quentin Perret <qperret@google.com> Signed-off-by: Lukasz Luba <lukasz.luba@arm.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-11-10PM: EM: Clarify abstract scale usage for power values in Energy ModelLukasz Luba1-0/+13
The Energy Model (EM) can store power values in milli-Watts or in abstract scale. This might cause issues in the subsystems which use the EM for estimating the device power, such as: - mixing of different scales in a subsystem which uses multiple (cooling) devices (e.g. thermal Intelligent Power Allocation (IPA)) - assuming that energy [milli-Joules] can be derived from the EM power values which might not be possible since the power scale doesn't have to be in milli-Watts To avoid misconfiguration add the requisite documentation to the EM and related subsystems: EAS and IPA. Signed-off-by: Lukasz Luba <lukasz.luba@arm.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-06-24Documentation: power: update Energy Model descriptionLukasz Luba1-60/+75
The Energy Model framework supports also other devices than CPUs. Update related information and add description for the new usage. Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org> Acked-by: Quentin Perret <qperret@google.com> Signed-off-by: Lukasz Luba <lukasz.luba@arm.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-06-15docs: power: convert docs to ReST and rename to *.rstMauro Carvalho Chehab1-0/+147
Convert the PM documents to ReST, in order to allow them to build with Sphinx. The conversion is actually: - add blank lines and indentation in order to identify paragraphs; - fix tables markups; - add some lists markups; - mark literal blocks; - adjust title markups. At its new index.rst, let's add a :orphan: while this is not linked to the main index.rst file, in order to avoid build warnings. Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Acked-by: Mark Brown <broonie@kernel.org> Acked-by: Srivatsa S. Bhat (VMware) <srivatsa@csail.mit.edu>