To enable better debug of PM domains, keep a track of successful
and failing attempts to enter each domain idle state.
This statistics are exported in debugfs when reading the
idle_states node associated with each PM domain.
Signed-off-by: Lina Iyer <ilina@codeaurora.org>
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
A device may have specific HW constraints that must be obeyed to, before
its corresponding PM domain (genpd) can be powered off - and vice verse at
power on. These constraints can't be managed through the regular runtime PM
based deployment for a device, because the access pattern for it, isn't
always request based. In other words, using the runtime PM callbacks to
deal with the constraints doesn't work for these cases.
For these reasons, let's instead add a PM domain power on/off notification
mechanism to genpd. To add/remove a notifier for a device, the device must
already have been attached to the genpd, which also means that it needs to
be a part of the PM domain topology.
To add/remove a notifier, let's introduce two genpd specific functions:
- dev_pm_genpd_add|remove_notifier()
Note that, to further clarify when genpd power on/off notifiers may be
used, one can compare with the existing CPU_CLUSTER_PM_ENTER|EXIT
notifiers. In the long run, the genpd power on/off notifiers should be able
to replace them, but that requires additional genpd based platform support
for the current users.
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Tested-by: Lina Iyer <ilina@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
To clarify the code a bit, let's rename GPD_STATE_ACTIVE into
GENPD_STATE_ON and GPD_STATE_POWER_OFF to GENPD_STATE_OFF.
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
[ rjw: Subject edit ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The rename of generic_pm_domain.slave_links to
generic_pm_domain.child_links accidentally dropped the TAB to align the
member's comment. Re-add the lost TAB to restore indentation.
Fixes: 8d87ae48ce ("PM: domains: Fix up terminology with parent/child")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
[ rjw: Minor subject edit ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The genpd infrastructure uses the terms master/slave, but such uses have
no external exposures (not even in Documentation/driver-api/pm/*) and are
not mandated by nor associated with any external specifications. Change
the language used through-out to parent/child.
There was one possible exception in the debugfs node
"pm_genpd/pm_genpd_summary" but its path has no hits outside of the
kernel itself when performing a code search[1], and it seems even this
single usage has been non-functional since it was introduced due to a
typo in the Python ("apend" instead of correct "append"). Fix the typo
while we're at it.
Link: https://codesearch.debian.net/ # [1]
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
We already have the of_genpd_add_subdomain() helper, but no corresponding
of_genpd_remove_subdomain(), so let's add it. Subsequent changes starts to
make use of it.
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
For a subsystem/driver that either doesn't support runtime PM or makes use
of pm_runtime_set_active() during ->probe(), may try to access its device
when probing, even if it may not be fully powered on from the PM domain's
point of view. This may be the case when the used PM domain is a genpd
provider, that implements genpd's ->start|stop() device callbacks.
There are cases where the subsystem/driver managed to avoid the above
problem, simply by calling pm_runtime_enable() and pm_runtime_get_sync()
during ->probe(). However, this approach comes with a drawback, especially
if the subsystem/driver implements a ->runtime_resume() callback.
More precisely, the subsystem/driver then needs to use a device flag, which
is checked in its ->runtime_resume() callback, as to avoid powering on its
resources the first time the callback is invoked. This is needed because
the subsystem/driver has already powered on the resources for the device,
during ->probe() and before it called pm_runtime_get_sync().
In a way to avoid this boilerplate code and the inefficient check for "if
(first_time_suspend)" in the ->runtime_resume() callback for these
subsystems/drivers, let's introduce and export a dev_pm_domain_start()
function, that may be called during ->probe() instead.
Moreover, let the dev_pm_domain_start() invoke an optional ->start()
callback, added to the struct dev_pm_domain, as to allow a PM domain
specific implementation.
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Align in-parameter names for the declarations of pm_genpd_add|
remove_subdomain() and of_genpd_add_subdomain() according to their
implementations, as to improve consistency.
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Attaching a device via genpd_dev_pm_attach_by_id|name() makes
genpd allocate a virtual device that it attaches instead. This
leads to a problem in case when the base device belongs to a CPU.
More precisely, it means genpd_get_cpu() compares against the
virtual device, thus it fails to find a matching CPU device.
Address this limitation by passing the base device to genpd_get_cpu()
rather than the virtual device.
Moreover, to deal with detach correctly from genpd_remove_device(),
store the CPU number in struct generic_pm_domain_data, so as to be
able to clear the corresponding bit in the cpumask for the genpd.
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
After some preceding changes, PM domains managed by genpd may contain
CPU devices, so idle state residency values should be taken into
account during the state selection process. [The residency value is
the minimum amount of time to be spent by a CPU (or a group of CPUs)
in an idle state in order to save more energy than could be saved
by picking up a shallower idle state.]
For this purpose, add a new genpd governor, pm_domain_cpu_gov, to be
used for selecting idle states of PM domains with CPU devices attached
either directly or through subdomains.
The new governor computes the minimum expected idle duration for all
online CPUs attached to a PM domain and its subdomains. Next, it
finds the deepest idle state whose target residency is within the
expected idle duration and selects it as the target idle state of
the domain.
It should be noted that the minimum expected idle duration computation
is based on the closest timer event information stored in the per-CPU
variables cpuidle_devices for all of the CPUs in the domain. That
needs to be revisited in future, as obviously there are other reasons
why a CPU may be woken up from idle.
Co-developed-by: Lina Iyer <lina.iyer@linaro.org>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
[ rjw: Changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
To enable a CPU device to be attached to a PM domain managed by genpd,
make a few changes to it for convenience.
To be able to quickly find out what CPUs are attached to a genpd,
which typically becomes useful from a genpd governor as subsequent
changes are about to show, add a cpumask to struct generic_pm_domain
to be updated when a CPU device gets attached to the genpd containing
that cpumask. Also, propagate the cpumask changes upwards in the
domain hierarchy to the master PM domains. This way, the cpumask for
a genpd hierarchically reflects all CPUs attached to the topology
below it.
Finally, make this an opt-in feature, to avoid having to manage CPUs
and the cpumask for a genpd that don't need it. To that end, add
a new genpd configuration bit, GENPD_FLAG_CPU_DOMAIN.
Co-developed-by: Lina Iyer <lina.iyer@linaro.org>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
[ rjw: Changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Add a data pointer to the genpd_power_state struct, to allow a genpd
backend driver to store per-state specific data. To introduce the
pointer, change the way genpd deals with freeing of the corresponding
allocated data.
More precisely, clarify the responsibility of whom that shall free the
data, by adding a ->free_states() callback to the generic_pm_domain
structure. The one allocating the data will be expected to set the
callback, to allow genpd to invoke it from genpd_remove().
Co-developed-by: Lina Iyer <lina.iyer@linaro.org>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
[ rjw: Subject & changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
As of the patch ("PM / Domains: Mark "name" const in
genpd_dev_pm_attach_by_name()") it's clear that the name in
dev_pm_domain_attach_by_name() can be const. Mark it as so. This
allows drivers to pass in a name that was declared "const" in a
driver.
Fixes: 27dceb81f4 ("PM / Domains: Introduce dev_pm_domain_attach_by_name()")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The genpd_dev_pm_attach_by_name() simply takes the name and passes it
to of_property_match_string() where the argument is "const char *".
Adding a const here allows a later patch to add a const to
dev_pm_domain_attach_by_name() which allows drivers to pass in a name
that was declared "const" in a driver.
Fixes: 5d6be70add ("PM / Domains: Introduce option to attach a device by name to genpd")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Currently a genpd only handles the performance state requirements from
the devices under its control. This commit extends that to also handle
the performance state requirement(s) put on the master genpd by its
sub-domains. There is a separate value required for each master that
the genpd has and so a new field is added to the struct gpd_link
(link->performance_state), which represents the link between a genpd and
its master. The struct gpd_link also got another field
prev_performance_state, which is used by genpd core as a temporary
variable during transitions.
On a call to dev_pm_genpd_set_performance_state(), the genpd core first
updates the performance state of the masters of the device's genpd and
then updates the performance state of the genpd. The masters do the same
and propagate performance state updates to their masters before updating
their own. The performance state transition from genpd to its master is
done with the help of dev_pm_opp_xlate_performance_state(), which looks
at the OPP tables of both the domains to translate the state.
Tested-by: Rajendra Nayak <rnayak@codeaurora.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
dev_pm_genpd_set_performance_state() will be required to call
dev_pm_opp_xlate_performance_state() going forward to translate from
performance state of a sub-domain to performance state of its master.
And dev_pm_opp_xlate_performance_state() needs pointers to the OPP
tables of both genpd and its master.
Lets fetch and save them while the OPP tables are added. Fetching the
OPP tables should never fail as we just added the OPP tables and so add
a WARN_ON() for such a bug instead of full error paths.
Tested-by: Rajendra Nayak <rnayak@codeaurora.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
The OPP core already has the performance state values for each of the
genpd's OPPs and there is no need to call the genpd callback again to
get the performance state for the case where the end device doesn't have
an OPP table and has the "required-opps" property directly in its node.
This commit renames of_genpd_opp_to_performance_state() as
of_get_required_opp_performance_state() and moves it to the OPP core, as
it is all about OPP stuff now.
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
The OPP core currently stores the performance state in the consumer
device's OPP table, but that is going to change going forward and
performance state will rather be set directly in the genpd's OPP table.
For that we need to get the performance state for genpd's device
structure (genpd->dev) instead of the consumer device's structure. Add a
new helper to do that.
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
The current documented description of the GENPD_FLAG_* flags, are too
simplified, so let's extend them.
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
For the multiple PM domain case, let's introduce a new API called
dev_pm_domain_attach_by_name(). This allows a consumer driver to associate
its device with one of its PM domains, by using a name based lookup.
Do note that, currently it's only genpd that supports multiple PM domains
per device, but dev_pm_domain_attach_by_name() can easily by extended to
cover other PM domain types, if/when needed.
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Tested-by: Rajendra Nayak <rnayak@codeaurora.org>
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
For the multiple PM domain case, let's introduce a new function called
genpd_dev_pm_attach_by_name(). This allows a device to be associated with
its PM domain through genpd, by using a name based lookup.
Note that, genpd_dev_pm_attach_by_name() shall only be called by the driver
core / PM core, similar to how the existing dev_pm_domain_attach_by_id()
makes use of genpd_dev_pm_attach_by_id(). However, this is implemented by
following changes on top.
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Tested-by: Rajendra Nayak <rnayak@codeaurora.org>
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The DT node passed here isn't necessarily an OPP node, as this routine
can also be used for cases where the "required-opps" property is present
directly in the device's node. Rename it.
This also removes a stale comment.
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
