2015-08-13 |
PSCI: Implement platform compatibility layer
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The new PSCI topology framework and PSCI extended State framework introduces
a breaking change in the platform port APIs. To ease the migration of the
platform ports to the new porting interface, a compatibility layer is
introduced which essentially defines the new platform API in terms of the
old API. The old PSCI helpers to retrieve the power-state, its associated
fields and the highest coordinated physical OFF affinity level of a core
are also implemented for compatibility. This allows the existing
platform ports to work with the new PSCI framework without significant
rework. This layer will be enabled by default once the switch to the new
PSCI framework is done and is controlled by the build flag ENABLE_PLAT_COMPAT.
Change-Id: I4b17cac3a4f3375910a36dba6b03d8f1700d07e3
Soby Mathew
authored
on 10 Jun 2015
Achin Gupta
committed
on 13 Aug 2015
|
PSCI: Unify warm reset entry points
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There used to be 2 warm reset entry points:
- the "on finisher", for when the core has been turned on using a
PSCI CPU_ON call;
- the "suspend finisher", entered upon resumption from a previous
PSCI CPU_SUSPEND call.
The appropriate warm reset entry point used to be programmed into the
mailboxes by the power management hooks.
However, it is not required to provide this information to the PSCI
entry point code, as it can figure it out by itself. By querying affinity
info state, a core is able to determine on which execution path it is.
If the state is ON_PENDING then it means it's been turned on else
it is resuming from suspend.
This patch unifies the 2 warm reset entry points into a single one:
psci_entrypoint(). The patch also implements the necessary logic
to distinguish between the 2 types of warm resets in the power up
finisher.
The plat_setup_psci_ops() API now takes the
secure entry point as an additional parameter to enable the platforms
to configure their mailbox. The platform hooks `pwr_domain_on`
and `pwr_domain_suspend` no longer take secure entry point as
a parameter.
Change-Id: I7d1c93787b54213aefdbc046b8cd66a555dfbfd9
Sandrine Bailleux
authored
on 11 Jun 2015
Achin Gupta
committed
on 13 Aug 2015
|
PSCI: Add framework to handle composite power states
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The state-id field in the power-state parameter of a CPU_SUSPEND call can be
used to describe composite power states specific to a platform. The current PSCI
implementation does not interpret the state-id field. It relies on the target
power level and the state type fields in the power-state parameter to perform
state coordination and power management operations. The framework introduced
in this patch allows the PSCI implementation to intepret generic global states
like RUN, RETENTION or OFF from the State-ID to make global state coordination
decisions and reduce the complexity of platform ports. It adds support to
involve the platform in state coordination which facilitates the use of
composite power states and improves the support for entering standby states
at multiple power domains.
The patch also includes support for extended state-id format for the power
state parameter as specified by PSCIv1.0.
The PSCI implementation now defines a generic representation of the power-state
parameter. It depends on the platform port to convert the power-state parameter
(possibly encoding a composite power state) passed in a CPU_SUSPEND call to this
representation via the `validate_power_state()` plat_psci_ops handler. It is an
array where each index corresponds to a power level. Each entry contains the
local power state the power domain at that power level could enter.
The meaning of the local power state values is platform defined, and may vary
between levels in a single platform. The PSCI implementation constrains the
values only so that it can classify the state as RUN, RETENTION or OFF as
required by the specification:
* zero means RUN
* all OFF state values at all levels must be higher than all RETENTION
state values at all levels
* the platform provides PLAT_MAX_RET_STATE and PLAT_MAX_OFF_STATE values
to the framework
The platform also must define the macros PLAT_MAX_RET_STATE and
PLAT_MAX_OFF_STATE which lets the PSCI implementation find out which power
domains have been requested to enter a retention or power down state. The PSCI
implementation does not interpret the local power states defined by the
platform. The only constraint is that the PLAT_MAX_RET_STATE <
PLAT_MAX_OFF_STATE.
For a power domain tree, the generic implementation maintains an array of local
power states. These are the states requested for each power domain by all the
cores contained within the domain. During a request to place multiple power
domains in a low power state, the platform is passed an array of requested
power-states for each power domain through the plat_get_target_pwr_state()
API. It coordinates amongst these states to determine a target local power
state for the power domain. A default weak implementation of this API is
provided in the platform layer which returns the minimum of the requested
power-states back to the PSCI state coordination.
Finally, the plat_psci_ops power management handlers are passed the target
local power states for each affected power domain using the generic
representation described above. The platform executes operations specific to
these target states.
The platform power management handler for placing a power domain in a standby
state (plat_pm_ops_t.pwr_domain_standby()) is now only used as a fast path for
placing a core power domain into a standby or retention state should now be
used to only place the core power domain in a standby or retention state.
The extended state-id power state format can be enabled by setting the
build flag PSCI_EXTENDED_STATE_ID=1 and it is disabled by default.
Change-Id: I9d4123d97e179529802c1f589baaa4101759d80c
Soby Mathew
authored
on 7 Apr 2015
Achin Gupta
committed
on 13 Aug 2015
|
PSCI: Introduce new platform interface to describe topology
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This patch removes the assumption in the current PSCI implementation that MPIDR
based affinity levels map directly to levels in a power domain tree. This
enables PSCI generic code to support complex power domain topologies as
envisaged by PSCIv1.0 specification. The platform interface for querying
the power domain topology has been changed such that:
1. The generic PSCI code does not generate MPIDRs and use them to query the
platform about the number of power domains at a particular power level. The
platform now provides a description of the power domain tree on the SoC
through a data structure. The existing platform APIs to provide the same
information have been removed.
2. The linear indices returned by plat_core_pos_by_mpidr() and
plat_my_core_pos() are used to retrieve core power domain nodes from the
power domain tree. Power domains above the core level are accessed using a
'parent' field in the tree node descriptors.
The platform describes the power domain tree in an array of 'unsigned
char's. The first entry in the array specifies the number of power domains at
the highest power level implemented in the system. Each susbsequent entry
corresponds to a power domain and contains the number of power domains that are
its direct children. This array is exported to the generic PSCI implementation
via the new `plat_get_power_domain_tree_desc()` platform API.
The PSCI generic code uses this array to populate its internal power domain tree
using the Breadth First Search like algorithm. The tree is split into two
arrays:
1. An array that contains all the core power domain nodes
2. An array that contains all the other power domain nodes
A separate array for core nodes allows certain core specific optimisations to
be implemented e.g. remove the bakery lock, re-use per-cpu data framework for
storing some information.
Entries in the core power domain array are allocated such that the
array index of the domain is equal to the linear index returned by
plat_core_pos_by_mpidr() and plat_my_core_pos() for the MPIDR
corresponding to that domain. This relationship is key to be able to use
an MPIDR to find the corresponding core power domain node, traverse to higher
power domain nodes and index into arrays that contain core specific
information.
An introductory document has been added to briefly describe the new interface.
Change-Id: I4b444719e8e927ba391cae48a23558308447da13
Soby Mathew
authored
on 8 Apr 2015
Achin Gupta
committed
on 13 Aug 2015
|
2015-08-05 |
PSCI: Remove references to affinity based power management
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As per Section 4.2.2. in the PSCI specification, the term "affinity"
is used in the context of describing the hierarchical arrangement
of cores. This often, but not always, maps directly to the processor
power domain topology of the system. The current PSCI implementation
assumes that this is always the case i.e. MPIDR based levels of
affinity always map to levels in a power domain topology tree.
This patch is the first in a series of patches which remove this
assumption. It removes all occurences of the terms "affinity
instances and levels" when used to describe the power domain
topology. Only the terminology is changed in this patch. Subsequent
patches will implement functional changes to remove the above
mentioned assumption.
Change-Id: Iee162f051b228828310610c5a320ff9d31009b4e
Soby Mathew
committed
on 5 Aug 2015
|
PSCI: Invoke PM hooks only for the highest level
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This patch optimizes the invocation of the platform power management hooks for
ON, OFF and SUSPEND such that they are called only for the highest affinity
level which will be powered off/on. Earlier, the hooks were being invoked for
all the intermediate levels as well.
This patch requires that the platforms migrate to the new semantics of the PM
hooks. It also removes the `state` parameter from the pm hooks as the `afflvl`
parameter now indicates the highest affinity level for which power management
operations are required.
Change-Id: I57c87931d8a2723aeade14acc710e5b78ac41732
Soby Mathew
committed
on 5 Aug 2015
|
PSCI: Create new directory to implement new frameworks
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This patch creates a copy of the existing PSCI files and related psci.h and
platform.h header files in a new `PSCI1.0` directory. The changes for the
new PSCI power domain topology and extended state-ID frameworks will be
added incrementally to these files. This incremental approach will
aid in review and in understanding the changes better. Once all the
changes have been introduced, these files will replace the existing PSCI
files.
Change-Id: Ibb8a52e265daa4204e34829ed050bddd7e3316ff
Soby Mathew
committed
on 5 Aug 2015
|