Some events needs to be handled with a very low latency constraint.
If the system is in deep sleep, exit latency from this low level state
exceeds sometimes the maximum latency constraint of these events.
Before suspending the system, select which events is happening sooner,
kernel events or normal events.
CPU will be up just before the next event occurs taking into account the
exit latency of the current power state
Change also the policy event API to take as argument absolute time in HW
cycles instead of time in us
Signed-off-by: Riadh Ghaddab <rghaddab@baylibre.com>
Move information about device power state constraints from device
to policy.
It slows down the constraints lookup since we now have to find the
constraints for a device in a global array, but it saves resources
because we don't need to add a reference to constraints in all devices
instances.
Signed-off-by: Flavio Ceolin <flavio.ceolin@intel.com>
Add a symbol to enable device power state constraints this
saves resources when this feature is not needed.
Signed-off-by: Flavio Ceolin <flavio.ceolin@intel.com>
Declare power state constraints for a device in devicetree.
It allows a map between device instances and power states that disable
their power. This information is used by a new API
(pm_policy_device_power_lock_put/get) that automically set/release
pm state constraints.
Signed-off-by: Flavio Ceolin <flavio.ceolin@intel.com>
In the follow expression:
cyc_evt += UINT32_MAX + 1U
first it is evaluated (UINT32_MAX + 1U), since both types
interpreted as uint32_t, this operation causes an overflow resulting
in 0U.Then we have
cyc_evt = (uint64_t)cyc_evt + 0U
Fix it casting of the operands in the first operation to uint64_t.
Signed-off-by: Flavio Ceolin <flavio.ceolin@intel.com>
Add check for device busy when CONFIG_PM_NEED_ALL_DEVICES_IDLE is
set to y because one or more devices may still in busy and causes
problem when system go into low power in Intel ISH platform.
Signed-off-by: Leifu Zhao <leifu.zhao@intel.com>
Coverity is complaining:
CID 316017: Control flow issues (NO_EFFECT)
>>> This less-than-zero comparison of an unsigned value is never true.
148 for (size_t i = 0; i < ARRAY_SIZE(substate_lock_t); i++) {
This is a false positive but we can still optimize the code and making
coverity happy by simply avoiding compiling the offending code when no
power states are defined into the DT.
Signed-off-by: Carlo Caione <ccaione@baylibre.com>
Events in the power-management policy context are defined as any source
that will wake up the system at a known time in the future. By
registering such event, the policy manager will be able to decide wether
certain power states are worth entering or not.
Events will bypass the ticks argument received by the policy manager if
they occur earlier.
Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>
Latency is always specified in microseconds, so apend `us` to the
relevant variables. Also, make it clear that latency request structures
are private (they are just exposed publicly to allow static allocation).
Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>
Current API allowed to get notified when the maximum system latency
changes, however, a single callback was allowed. The design was intended
for SoC specific actions when latency changes. However, in some cases
drivers may also want to know the current maximum latency to perform
local actions if other parts of the system modify it.
This patch updates the API with a pair of subscribe/unsubscribe calls to
achieve such goal. Tests have been updated to show how the API can be
used.
Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>
When new latency requirements are introduced/updated, the microseconds
value gets converted down to ticks. Ticks usually have a coarse
resolution compared to the microseconds scale. This is fine for making
PM state change decisions, however, when getting notified about latency
changes, we may want to know the real value in microseconds, even if the
system rounds to ticks internally. This patch stores the value in both
us and ticks (in ticks to cache the conversion, really), so that the
user will get notified with precise latency values.
Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>
In order to bring consistency in-tree, migrate all subsystems code to
the new prefix <zephyr/...>. Note that the conversion has been scripted,
refer to zephyrproject-rtos#45388 for more details.
Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>
Add a new API that allows to register a callback that is called when the
maximum latency value changes. This can be used by SoC code to perform
actions based on certain latency values.
Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>
Add a new API that allows to configure maximum latency requirements.
When the policy manager computes the next state, it will check if the
state brings too much latency based on requirements. This can be useful,
for example, if a certain driver or the application want a system to
respond fast, since any low power state that brings too much latency
will not be used.
Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>
The state lock get/put calls should always be balanced: first call get
and then put. Add an assertion in case lock counter is about to go
negative, indicating a programming error.
Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>
The pm_constraint_* APIs were effectively used by the policy manager
only. This patch renames the API to the policy namespace and makes its
naming more explicit:
- pm_constraint_set -> pm_policy_state_lock_get()
- pm_constraint_release -> pm_policy_state_lock_put()
- pm_constraint_get -> pm_policy_state_lock_is_active()
The reason for these changes is that constraints can be of many types:
allow/disallow states, impose latency requirements, etc. The new naming
also makes explicit that the API calls will influence the PM policy
behavior.
All drivers and documentation have been updated accordingly.
Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>
The policy file does not perform any logging, so just drop logging
include and declaration.
Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>
Move policy code one level up for simplicity, since there is a single
source file. Source file has been renamed to "policy.c" to make things
clear.
Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>
