856 lines
30 KiB
YAML
856 lines
30 KiB
YAML
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# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
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%YAML 1.2
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---
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$id: http://devicetree.org/schemas/cpu/idle-states.yaml#
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$schema: http://devicetree.org/meta-schemas/core.yaml#
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title: Idle states
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maintainers:
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- Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
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- Anup Patel <anup@brainfault.org>
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description: |+
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==========================================
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1 - Introduction
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==========================================
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ARM and RISC-V systems contain HW capable of managing power consumption
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dynamically, where cores can be put in different low-power states (ranging
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from simple wfi to power gating) according to OS PM policies. The CPU states
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representing the range of dynamic idle states that a processor can enter at
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run-time, can be specified through device tree bindings representing the
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parameters required to enter/exit specific idle states on a given processor.
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==========================================
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2 - ARM idle states
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==========================================
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According to the Server Base System Architecture document (SBSA, [3]), the
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power states an ARM CPU can be put into are identified by the following list:
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- Running
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- Idle_standby
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- Idle_retention
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- Sleep
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- Off
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The power states described in the SBSA document define the basic CPU states on
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top of which ARM platforms implement power management schemes that allow an OS
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PM implementation to put the processor in different idle states (which include
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states listed above; "off" state is not an idle state since it does not have
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wake-up capabilities, hence it is not considered in this document).
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Idle state parameters (e.g. entry latency) are platform specific and need to
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be characterized with bindings that provide the required information to OS PM
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code so that it can build the required tables and use them at runtime.
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The device tree binding definition for ARM idle states is the subject of this
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document.
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==========================================
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3 - RISC-V idle states
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==========================================
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On RISC-V systems, the HARTs (or CPUs) [6] can be put in platform specific
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suspend (or idle) states (ranging from simple WFI, power gating, etc). The
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RISC-V SBI v0.3 (or higher) [7] hart state management extension provides a
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standard mechanism for OS to request HART state transitions.
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The platform specific suspend (or idle) states of a hart can be either
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retentive or non-rententive in nature. A retentive suspend state will
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preserve HART registers and CSR values for all privilege modes whereas
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a non-retentive suspend state will not preserve HART registers and CSR
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values.
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===========================================
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4 - idle-states definitions
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===========================================
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Idle states are characterized for a specific system through a set of
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timing and energy related properties, that underline the HW behaviour
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triggered upon idle states entry and exit.
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The following diagram depicts the CPU execution phases and related timing
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properties required to enter and exit an idle state:
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..__[EXEC]__|__[PREP]__|__[ENTRY]__|__[IDLE]__|__[EXIT]__|__[EXEC]__..
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|<------ entry ------->|
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| latency |
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|<- exit ->|
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| latency |
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|<-------- min-residency -------->|
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|<------- wakeup-latency ------->|
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Diagram 1: CPU idle state execution phases
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EXEC: Normal CPU execution.
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PREP: Preparation phase before committing the hardware to idle mode
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like cache flushing. This is abortable on pending wake-up
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event conditions. The abort latency is assumed to be negligible
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(i.e. less than the ENTRY + EXIT duration). If aborted, CPU
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goes back to EXEC. This phase is optional. If not abortable,
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this should be included in the ENTRY phase instead.
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ENTRY: The hardware is committed to idle mode. This period must run
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to completion up to IDLE before anything else can happen.
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IDLE: This is the actual energy-saving idle period. This may last
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between 0 and infinite time, until a wake-up event occurs.
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EXIT: Period during which the CPU is brought back to operational
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mode (EXEC).
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entry-latency: Worst case latency required to enter the idle state. The
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exit-latency may be guaranteed only after entry-latency has passed.
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min-residency: Minimum period, including preparation and entry, for a given
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idle state to be worthwhile energywise.
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wakeup-latency: Maximum delay between the signaling of a wake-up event and the
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CPU being able to execute normal code again. If not specified, this is assumed
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to be entry-latency + exit-latency.
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These timing parameters can be used by an OS in different circumstances.
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An idle CPU requires the expected min-residency time to select the most
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appropriate idle state based on the expected expiry time of the next IRQ
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(i.e. wake-up) that causes the CPU to return to the EXEC phase.
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An operating system scheduler may need to compute the shortest wake-up delay
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for CPUs in the system by detecting how long will it take to get a CPU out
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of an idle state, e.g.:
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wakeup-delay = exit-latency + max(entry-latency - (now - entry-timestamp), 0)
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In other words, the scheduler can make its scheduling decision by selecting
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(e.g. waking-up) the CPU with the shortest wake-up delay.
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The wake-up delay must take into account the entry latency if that period
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has not expired. The abortable nature of the PREP period can be ignored
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if it cannot be relied upon (e.g. the PREP deadline may occur much sooner than
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the worst case since it depends on the CPU operating conditions, i.e. caches
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state).
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An OS has to reliably probe the wakeup-latency since some devices can enforce
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latency constraint guarantees to work properly, so the OS has to detect the
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worst case wake-up latency it can incur if a CPU is allowed to enter an
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idle state, and possibly to prevent that to guarantee reliable device
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functioning.
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The min-residency time parameter deserves further explanation since it is
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expressed in time units but must factor in energy consumption coefficients.
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The energy consumption of a cpu when it enters a power state can be roughly
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characterised by the following graph:
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e |
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n | /---
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e | /------
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r | /------
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g | /-----
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y | /------
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| ----
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| /|
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| / |
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| / |
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|/ |
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-----|-------+----------------------------------
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0| 1 time(ms)
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Graph 1: Energy vs time example
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The graph is split in two parts delimited by time 1ms on the X-axis.
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The graph curve with X-axis values = { x | 0 < x < 1ms } has a steep slope
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and denotes the energy costs incurred while entering and leaving the idle
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state.
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The graph curve in the area delimited by X-axis values = {x | x > 1ms } has
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shallower slope and essentially represents the energy consumption of the idle
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state.
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min-residency is defined for a given idle state as the minimum expected
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residency time for a state (inclusive of preparation and entry) after
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which choosing that state become the most energy efficient option. A good
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way to visualise this, is by taking the same graph above and comparing some
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states energy consumptions plots.
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For sake of simplicity, let's consider a system with two idle states IDLE1,
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and IDLE2:
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| /-- IDLE1
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e | /---
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n | /----
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e | /---
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r | /-----/--------- IDLE2
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g | /-------/---------
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y | ------------ /---|
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| / /---- |
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| / /--- |
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| / /---- |
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| / /--- |
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| --- |
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|/ | time
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---/----------------------------+------------------------
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|IDLE1-energy < IDLE2-energy | IDLE2-energy < IDLE1-energy
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IDLE2-min-residency
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Graph 2: idle states min-residency example
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In graph 2 above, that takes into account idle states entry/exit energy
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costs, it is clear that if the idle state residency time (i.e. time till next
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wake-up IRQ) is less than IDLE2-min-residency, IDLE1 is the better idle state
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choice energywise.
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This is mainly down to the fact that IDLE1 entry/exit energy costs are lower
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than IDLE2.
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However, the lower power consumption (i.e. shallower energy curve slope) of
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idle state IDLE2 implies that after a suitable time, IDLE2 becomes more energy
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efficient.
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The time at which IDLE2 becomes more energy efficient than IDLE1 (and other
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shallower states in a system with multiple idle states) is defined
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IDLE2-min-residency and corresponds to the time when energy consumption of
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IDLE1 and IDLE2 states breaks even.
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The definitions provided in this section underpin the idle states
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properties specification that is the subject of the following sections.
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===========================================
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5 - idle-states node
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===========================================
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The processor idle states are defined within the idle-states node, which is
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a direct child of the cpus node [1] and provides a container where the
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processor idle states, defined as device tree nodes, are listed.
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On ARM systems, it is a container of processor idle states nodes. If the
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system does not provide CPU power management capabilities, or the processor
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just supports idle_standby, an idle-states node is not required.
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===========================================
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6 - References
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===========================================
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[1] ARM Linux Kernel documentation - CPUs bindings
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Documentation/devicetree/bindings/arm/cpus.yaml
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[2] ARM Linux Kernel documentation - PSCI bindings
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Documentation/devicetree/bindings/arm/psci.yaml
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[3] ARM Server Base System Architecture (SBSA)
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http://infocenter.arm.com/help/index.jsp
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[4] ARM Architecture Reference Manuals
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http://infocenter.arm.com/help/index.jsp
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[5] ARM Linux Kernel documentation - Booting AArch64 Linux
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Documentation/arm64/booting.rst
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[6] RISC-V Linux Kernel documentation - CPUs bindings
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Documentation/devicetree/bindings/riscv/cpus.yaml
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[7] RISC-V Supervisor Binary Interface (SBI)
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http://github.com/riscv/riscv-sbi-doc/riscv-sbi.adoc
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properties:
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$nodename:
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const: idle-states
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entry-method:
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description: |
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Usage and definition depend on ARM architecture version.
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On ARM v8 64-bit this property is required.
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On ARM 32-bit systems this property is optional
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This assumes that the "enable-method" property is set to "psci" in the cpu
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node[5] that is responsible for setting up CPU idle management in the OS
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implementation.
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const: psci
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patternProperties:
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"^(cpu|cluster)-":
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type: object
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description: |
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Each state node represents an idle state description and must be defined
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as follows.
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The idle state entered by executing the wfi instruction (idle_standby
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SBSA,[3][4]) is considered standard on all ARM and RISC-V platforms and
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therefore must not be listed.
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In addition to the properties listed above, a state node may require
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additional properties specific to the entry-method defined in the
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idle-states node. Please refer to the entry-method bindings
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documentation for properties definitions.
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properties:
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compatible:
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enum:
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- arm,idle-state
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- riscv,idle-state
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arm,psci-suspend-param:
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$ref: /schemas/types.yaml#/definitions/uint32
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description: |
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power_state parameter to pass to the ARM PSCI suspend call.
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Device tree nodes that require usage of PSCI CPU_SUSPEND function
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(i.e. idle states node with entry-method property is set to "psci")
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must specify this property.
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riscv,sbi-suspend-param:
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$ref: /schemas/types.yaml#/definitions/uint32
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description: |
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suspend_type parameter to pass to the RISC-V SBI HSM suspend call.
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This property is required in idle state nodes of device tree meant
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for RISC-V systems. For more details on the suspend_type parameter
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refer the SBI specifiation v0.3 (or higher) [7].
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local-timer-stop:
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description:
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If present the CPU local timer control logic is
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lost on state entry, otherwise it is retained.
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type: boolean
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entry-latency-us:
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description:
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Worst case latency in microseconds required to enter the idle state.
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exit-latency-us:
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description:
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Worst case latency in microseconds required to exit the idle state.
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The exit-latency-us duration may be guaranteed only after
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entry-latency-us has passed.
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min-residency-us:
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description:
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Minimum residency duration in microseconds, inclusive of preparation
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and entry, for this idle state to be considered worthwhile energy wise
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(refer to section 2 of this document for a complete description).
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wakeup-latency-us:
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description: |
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Maximum delay between the signaling of a wake-up event and the CPU
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being able to execute normal code again. If omitted, this is assumed
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to be equal to:
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entry-latency-us + exit-latency-us
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It is important to supply this value on systems where the duration of
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PREP phase (see diagram 1, section 2) is non-neglibigle. In such
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systems entry-latency-us + exit-latency-us will exceed
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wakeup-latency-us by this duration.
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idle-state-name:
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$ref: /schemas/types.yaml#/definitions/string
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description:
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A string used as a descriptive name for the idle state.
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additionalProperties: false
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required:
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- compatible
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- entry-latency-us
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- exit-latency-us
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- min-residency-us
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additionalProperties: false
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examples:
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- |
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cpus {
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#size-cells = <0>;
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||
|
|
#address-cells = <2>;
|
||
|
|
|
||
|
|
cpu@0 {
|
||
|
|
device_type = "cpu";
|
||
|
|
compatible = "arm,cortex-a57";
|
||
|
|
reg = <0x0 0x0>;
|
||
|
|
enable-method = "psci";
|
||
|
|
cpu-idle-states = <&CPU_RETENTION_0_0>, <&CPU_SLEEP_0_0>,
|
||
|
|
<&CLUSTER_RETENTION_0>, <&CLUSTER_SLEEP_0>;
|
||
|
|
};
|
||
|
|
|
||
|
|
cpu@1 {
|
||
|
|
device_type = "cpu";
|
||
|
|
compatible = "arm,cortex-a57";
|
||
|
|
reg = <0x0 0x1>;
|
||
|
|
enable-method = "psci";
|
||
|
|
cpu-idle-states = <&CPU_RETENTION_0_0>, <&CPU_SLEEP_0_0>,
|
||
|
|
<&CLUSTER_RETENTION_0>, <&CLUSTER_SLEEP_0>;
|
||
|
|
};
|
||
|
|
|
||
|
|
cpu@100 {
|
||
|
|
device_type = "cpu";
|
||
|
|
compatible = "arm,cortex-a57";
|
||
|
|
reg = <0x0 0x100>;
|
||
|
|
enable-method = "psci";
|
||
|
|
cpu-idle-states = <&CPU_RETENTION_0_0>, <&CPU_SLEEP_0_0>,
|
||
|
|
<&CLUSTER_RETENTION_0>, <&CLUSTER_SLEEP_0>;
|
||
|
|
};
|
||
|
|
|
||
|
|
cpu@101 {
|
||
|
|
device_type = "cpu";
|
||
|
|
compatible = "arm,cortex-a57";
|
||
|
|
reg = <0x0 0x101>;
|
||
|
|
enable-method = "psci";
|
||
|
|
cpu-idle-states = <&CPU_RETENTION_0_0>, <&CPU_SLEEP_0_0>,
|
||
|
|
<&CLUSTER_RETENTION_0>, <&CLUSTER_SLEEP_0>;
|
||
|
|
};
|
||
|
|
|
||
|
|
cpu@10000 {
|
||
|
|
device_type = "cpu";
|
||
|
|
compatible = "arm,cortex-a57";
|
||
|
|
reg = <0x0 0x10000>;
|
||
|
|
enable-method = "psci";
|
||
|
|
cpu-idle-states = <&CPU_RETENTION_0_0>, <&CPU_SLEEP_0_0>,
|
||
|
|
<&CLUSTER_RETENTION_0>, <&CLUSTER_SLEEP_0>;
|
||
|
|
};
|
||
|
|
|
||
|
|
cpu@10001 {
|
||
|
|
device_type = "cpu";
|
||
|
|
compatible = "arm,cortex-a57";
|
||
|
|
reg = <0x0 0x10001>;
|
||
|
|
enable-method = "psci";
|
||
|
|
cpu-idle-states = <&CPU_RETENTION_0_0>, <&CPU_SLEEP_0_0>,
|
||
|
|
<&CLUSTER_RETENTION_0>, <&CLUSTER_SLEEP_0>;
|
||
|
|
};
|
||
|
|
|
||
|
|
cpu@10100 {
|
||
|
|
device_type = "cpu";
|
||
|
|
compatible = "arm,cortex-a57";
|
||
|
|
reg = <0x0 0x10100>;
|
||
|
|
enable-method = "psci";
|
||
|
|
cpu-idle-states = <&CPU_RETENTION_0_0>, <&CPU_SLEEP_0_0>,
|
||
|
|
<&CLUSTER_RETENTION_0>, <&CLUSTER_SLEEP_0>;
|
||
|
|
};
|
||
|
|
|
||
|
|
cpu@10101 {
|
||
|
|
device_type = "cpu";
|
||
|
|
compatible = "arm,cortex-a57";
|
||
|
|
reg = <0x0 0x10101>;
|
||
|
|
enable-method = "psci";
|
||
|
|
cpu-idle-states = <&CPU_RETENTION_0_0>, <&CPU_SLEEP_0_0>,
|
||
|
|
<&CLUSTER_RETENTION_0>, <&CLUSTER_SLEEP_0>;
|
||
|
|
};
|
||
|
|
|
||
|
|
cpu@100000000 {
|
||
|
|
device_type = "cpu";
|
||
|
|
compatible = "arm,cortex-a53";
|
||
|
|
reg = <0x1 0x0>;
|
||
|
|
enable-method = "psci";
|
||
|
|
cpu-idle-states = <&CPU_RETENTION_1_0>, <&CPU_SLEEP_1_0>,
|
||
|
|
<&CLUSTER_RETENTION_1>, <&CLUSTER_SLEEP_1>;
|
||
|
|
};
|
||
|
|
|
||
|
|
cpu@100000001 {
|
||
|
|
device_type = "cpu";
|
||
|
|
compatible = "arm,cortex-a53";
|
||
|
|
reg = <0x1 0x1>;
|
||
|
|
enable-method = "psci";
|
||
|
|
cpu-idle-states = <&CPU_RETENTION_1_0>, <&CPU_SLEEP_1_0>,
|
||
|
|
<&CLUSTER_RETENTION_1>, <&CLUSTER_SLEEP_1>;
|
||
|
|
};
|
||
|
|
|
||
|
|
cpu@100000100 {
|
||
|
|
device_type = "cpu";
|
||
|
|
compatible = "arm,cortex-a53";
|
||
|
|
reg = <0x1 0x100>;
|
||
|
|
enable-method = "psci";
|
||
|
|
cpu-idle-states = <&CPU_RETENTION_1_0>, <&CPU_SLEEP_1_0>,
|
||
|
|
<&CLUSTER_RETENTION_1>, <&CLUSTER_SLEEP_1>;
|
||
|
|
};
|
||
|
|
|
||
|
|
cpu@100000101 {
|
||
|
|
device_type = "cpu";
|
||
|
|
compatible = "arm,cortex-a53";
|
||
|
|
reg = <0x1 0x101>;
|
||
|
|
enable-method = "psci";
|
||
|
|
cpu-idle-states = <&CPU_RETENTION_1_0>, <&CPU_SLEEP_1_0>,
|
||
|
|
<&CLUSTER_RETENTION_1>, <&CLUSTER_SLEEP_1>;
|
||
|
|
};
|
||
|
|
|
||
|
|
cpu@100010000 {
|
||
|
|
device_type = "cpu";
|
||
|
|
compatible = "arm,cortex-a53";
|
||
|
|
reg = <0x1 0x10000>;
|
||
|
|
enable-method = "psci";
|
||
|
|
cpu-idle-states = <&CPU_RETENTION_1_0>, <&CPU_SLEEP_1_0>,
|
||
|
|
<&CLUSTER_RETENTION_1>, <&CLUSTER_SLEEP_1>;
|
||
|
|
};
|
||
|
|
|
||
|
|
cpu@100010001 {
|
||
|
|
device_type = "cpu";
|
||
|
|
compatible = "arm,cortex-a53";
|
||
|
|
reg = <0x1 0x10001>;
|
||
|
|
enable-method = "psci";
|
||
|
|
cpu-idle-states = <&CPU_RETENTION_1_0>, <&CPU_SLEEP_1_0>,
|
||
|
|
<&CLUSTER_RETENTION_1>, <&CLUSTER_SLEEP_1>;
|
||
|
|
};
|
||
|
|
|
||
|
|
cpu@100010100 {
|
||
|
|
device_type = "cpu";
|
||
|
|
compatible = "arm,cortex-a53";
|
||
|
|
reg = <0x1 0x10100>;
|
||
|
|
enable-method = "psci";
|
||
|
|
cpu-idle-states = <&CPU_RETENTION_1_0>, <&CPU_SLEEP_1_0>,
|
||
|
|
<&CLUSTER_RETENTION_1>, <&CLUSTER_SLEEP_1>;
|
||
|
|
};
|
||
|
|
|
||
|
|
cpu@100010101 {
|
||
|
|
device_type = "cpu";
|
||
|
|
compatible = "arm,cortex-a53";
|
||
|
|
reg = <0x1 0x10101>;
|
||
|
|
enable-method = "psci";
|
||
|
|
cpu-idle-states = <&CPU_RETENTION_1_0>, <&CPU_SLEEP_1_0>,
|
||
|
|
<&CLUSTER_RETENTION_1>, <&CLUSTER_SLEEP_1>;
|
||
|
|
};
|
||
|
|
|
||
|
|
idle-states {
|
||
|
|
entry-method = "psci";
|
||
|
|
|
||
|
|
CPU_RETENTION_0_0: cpu-retention-0-0 {
|
||
|
|
compatible = "arm,idle-state";
|
||
|
|
arm,psci-suspend-param = <0x0010000>;
|
||
|
|
entry-latency-us = <20>;
|
||
|
|
exit-latency-us = <40>;
|
||
|
|
min-residency-us = <80>;
|
||
|
|
};
|
||
|
|
|
||
|
|
CLUSTER_RETENTION_0: cluster-retention-0 {
|
||
|
|
compatible = "arm,idle-state";
|
||
|
|
local-timer-stop;
|
||
|
|
arm,psci-suspend-param = <0x1010000>;
|
||
|
|
entry-latency-us = <50>;
|
||
|
|
exit-latency-us = <100>;
|
||
|
|
min-residency-us = <250>;
|
||
|
|
wakeup-latency-us = <130>;
|
||
|
|
};
|
||
|
|
|
||
|
|
CPU_SLEEP_0_0: cpu-sleep-0-0 {
|
||
|
|
compatible = "arm,idle-state";
|
||
|
|
local-timer-stop;
|
||
|
|
arm,psci-suspend-param = <0x0010000>;
|
||
|
|
entry-latency-us = <250>;
|
||
|
|
exit-latency-us = <500>;
|
||
|
|
min-residency-us = <950>;
|
||
|
|
};
|
||
|
|
|
||
|
|
CLUSTER_SLEEP_0: cluster-sleep-0 {
|
||
|
|
compatible = "arm,idle-state";
|
||
|
|
local-timer-stop;
|
||
|
|
arm,psci-suspend-param = <0x1010000>;
|
||
|
|
entry-latency-us = <600>;
|
||
|
|
exit-latency-us = <1100>;
|
||
|
|
min-residency-us = <2700>;
|
||
|
|
wakeup-latency-us = <1500>;
|
||
|
|
};
|
||
|
|
|
||
|
|
CPU_RETENTION_1_0: cpu-retention-1-0 {
|
||
|
|
compatible = "arm,idle-state";
|
||
|
|
arm,psci-suspend-param = <0x0010000>;
|
||
|
|
entry-latency-us = <20>;
|
||
|
|
exit-latency-us = <40>;
|
||
|
|
min-residency-us = <90>;
|
||
|
|
};
|
||
|
|
|
||
|
|
CLUSTER_RETENTION_1: cluster-retention-1 {
|
||
|
|
compatible = "arm,idle-state";
|
||
|
|
local-timer-stop;
|
||
|
|
arm,psci-suspend-param = <0x1010000>;
|
||
|
|
entry-latency-us = <50>;
|
||
|
|
exit-latency-us = <100>;
|
||
|
|
min-residency-us = <270>;
|
||
|
|
wakeup-latency-us = <100>;
|
||
|
|
};
|
||
|
|
|
||
|
|
CPU_SLEEP_1_0: cpu-sleep-1-0 {
|
||
|
|
compatible = "arm,idle-state";
|
||
|
|
local-timer-stop;
|
||
|
|
arm,psci-suspend-param = <0x0010000>;
|
||
|
|
entry-latency-us = <70>;
|
||
|
|
exit-latency-us = <100>;
|
||
|
|
min-residency-us = <300>;
|
||
|
|
wakeup-latency-us = <150>;
|
||
|
|
};
|
||
|
|
|
||
|
|
CLUSTER_SLEEP_1: cluster-sleep-1 {
|
||
|
|
compatible = "arm,idle-state";
|
||
|
|
local-timer-stop;
|
||
|
|
arm,psci-suspend-param = <0x1010000>;
|
||
|
|
entry-latency-us = <500>;
|
||
|
|
exit-latency-us = <1200>;
|
||
|
|
min-residency-us = <3500>;
|
||
|
|
wakeup-latency-us = <1300>;
|
||
|
|
};
|
||
|
|
};
|
||
|
|
};
|
||
|
|
|
||
|
|
- |
|
||
|
|
// Example 2 (ARM 32-bit, 8-cpu system, two clusters):
|
||
|
|
|
||
|
|
cpus {
|
||
|
|
#size-cells = <0>;
|
||
|
|
#address-cells = <1>;
|
||
|
|
|
||
|
|
cpu@0 {
|
||
|
|
device_type = "cpu";
|
||
|
|
compatible = "arm,cortex-a15";
|
||
|
|
reg = <0x0>;
|
||
|
|
cpu-idle-states = <&cpu_sleep_0_0>, <&cluster_sleep_0>;
|
||
|
|
};
|
||
|
|
|
||
|
|
cpu@1 {
|
||
|
|
device_type = "cpu";
|
||
|
|
compatible = "arm,cortex-a15";
|
||
|
|
reg = <0x1>;
|
||
|
|
cpu-idle-states = <&cpu_sleep_0_0>, <&cluster_sleep_0>;
|
||
|
|
};
|
||
|
|
|
||
|
|
cpu@2 {
|
||
|
|
device_type = "cpu";
|
||
|
|
compatible = "arm,cortex-a15";
|
||
|
|
reg = <0x2>;
|
||
|
|
cpu-idle-states = <&cpu_sleep_0_0>, <&cluster_sleep_0>;
|
||
|
|
};
|
||
|
|
|
||
|
|
cpu@3 {
|
||
|
|
device_type = "cpu";
|
||
|
|
compatible = "arm,cortex-a15";
|
||
|
|
reg = <0x3>;
|
||
|
|
cpu-idle-states = <&cpu_sleep_0_0>, <&cluster_sleep_0>;
|
||
|
|
};
|
||
|
|
|
||
|
|
cpu@100 {
|
||
|
|
device_type = "cpu";
|
||
|
|
compatible = "arm,cortex-a7";
|
||
|
|
reg = <0x100>;
|
||
|
|
cpu-idle-states = <&cpu_sleep_1_0>, <&cluster_sleep_1>;
|
||
|
|
};
|
||
|
|
|
||
|
|
cpu@101 {
|
||
|
|
device_type = "cpu";
|
||
|
|
compatible = "arm,cortex-a7";
|
||
|
|
reg = <0x101>;
|
||
|
|
cpu-idle-states = <&cpu_sleep_1_0>, <&cluster_sleep_1>;
|
||
|
|
};
|
||
|
|
|
||
|
|
cpu@102 {
|
||
|
|
device_type = "cpu";
|
||
|
|
compatible = "arm,cortex-a7";
|
||
|
|
reg = <0x102>;
|
||
|
|
cpu-idle-states = <&cpu_sleep_1_0>, <&cluster_sleep_1>;
|
||
|
|
};
|
||
|
|
|
||
|
|
cpu@103 {
|
||
|
|
device_type = "cpu";
|
||
|
|
compatible = "arm,cortex-a7";
|
||
|
|
reg = <0x103>;
|
||
|
|
cpu-idle-states = <&cpu_sleep_1_0>, <&cluster_sleep_1>;
|
||
|
|
};
|
||
|
|
|
||
|
|
idle-states {
|
||
|
|
cpu_sleep_0_0: cpu-sleep-0-0 {
|
||
|
|
compatible = "arm,idle-state";
|
||
|
|
local-timer-stop;
|
||
|
|
entry-latency-us = <200>;
|
||
|
|
exit-latency-us = <100>;
|
||
|
|
min-residency-us = <400>;
|
||
|
|
wakeup-latency-us = <250>;
|
||
|
|
};
|
||
|
|
|
||
|
|
cluster_sleep_0: cluster-sleep-0 {
|
||
|
|
compatible = "arm,idle-state";
|
||
|
|
local-timer-stop;
|
||
|
|
entry-latency-us = <500>;
|
||
|
|
exit-latency-us = <1500>;
|
||
|
|
min-residency-us = <2500>;
|
||
|
|
wakeup-latency-us = <1700>;
|
||
|
|
};
|
||
|
|
|
||
|
|
cpu_sleep_1_0: cpu-sleep-1-0 {
|
||
|
|
compatible = "arm,idle-state";
|
||
|
|
local-timer-stop;
|
||
|
|
entry-latency-us = <300>;
|
||
|
|
exit-latency-us = <500>;
|
||
|
|
min-residency-us = <900>;
|
||
|
|
wakeup-latency-us = <600>;
|
||
|
|
};
|
||
|
|
|
||
|
|
cluster_sleep_1: cluster-sleep-1 {
|
||
|
|
compatible = "arm,idle-state";
|
||
|
|
local-timer-stop;
|
||
|
|
entry-latency-us = <800>;
|
||
|
|
exit-latency-us = <2000>;
|
||
|
|
min-residency-us = <6500>;
|
||
|
|
wakeup-latency-us = <2300>;
|
||
|
|
};
|
||
|
|
};
|
||
|
|
};
|
||
|
|
|
||
|
|
- |
|
||
|
|
// Example 3 (RISC-V 64-bit, 4-cpu systems, two clusters):
|
||
|
|
|
||
|
|
cpus {
|
||
|
|
#size-cells = <0>;
|
||
|
|
#address-cells = <1>;
|
||
|
|
|
||
|
|
cpu@0 {
|
||
|
|
device_type = "cpu";
|
||
|
|
compatible = "riscv";
|
||
|
|
reg = <0x0>;
|
||
|
|
riscv,isa = "rv64imafdc";
|
||
|
|
mmu-type = "riscv,sv48";
|
||
|
|
cpu-idle-states = <&CPU_RET_0_0>, <&CPU_NONRET_0_0>,
|
||
|
|
<&CLUSTER_RET_0>, <&CLUSTER_NONRET_0>;
|
||
|
|
|
||
|
|
cpu_intc0: interrupt-controller {
|
||
|
|
#interrupt-cells = <1>;
|
||
|
|
compatible = "riscv,cpu-intc";
|
||
|
|
interrupt-controller;
|
||
|
|
};
|
||
|
|
};
|
||
|
|
|
||
|
|
cpu@1 {
|
||
|
|
device_type = "cpu";
|
||
|
|
compatible = "riscv";
|
||
|
|
reg = <0x1>;
|
||
|
|
riscv,isa = "rv64imafdc";
|
||
|
|
mmu-type = "riscv,sv48";
|
||
|
|
cpu-idle-states = <&CPU_RET_0_0>, <&CPU_NONRET_0_0>,
|
||
|
|
<&CLUSTER_RET_0>, <&CLUSTER_NONRET_0>;
|
||
|
|
|
||
|
|
cpu_intc1: interrupt-controller {
|
||
|
|
#interrupt-cells = <1>;
|
||
|
|
compatible = "riscv,cpu-intc";
|
||
|
|
interrupt-controller;
|
||
|
|
};
|
||
|
|
};
|
||
|
|
|
||
|
|
cpu@10 {
|
||
|
|
device_type = "cpu";
|
||
|
|
compatible = "riscv";
|
||
|
|
reg = <0x10>;
|
||
|
|
riscv,isa = "rv64imafdc";
|
||
|
|
mmu-type = "riscv,sv48";
|
||
|
|
cpu-idle-states = <&CPU_RET_1_0>, <&CPU_NONRET_1_0>,
|
||
|
|
<&CLUSTER_RET_1>, <&CLUSTER_NONRET_1>;
|
||
|
|
|
||
|
|
cpu_intc10: interrupt-controller {
|
||
|
|
#interrupt-cells = <1>;
|
||
|
|
compatible = "riscv,cpu-intc";
|
||
|
|
interrupt-controller;
|
||
|
|
};
|
||
|
|
};
|
||
|
|
|
||
|
|
cpu@11 {
|
||
|
|
device_type = "cpu";
|
||
|
|
compatible = "riscv";
|
||
|
|
reg = <0x11>;
|
||
|
|
riscv,isa = "rv64imafdc";
|
||
|
|
mmu-type = "riscv,sv48";
|
||
|
|
cpu-idle-states = <&CPU_RET_1_0>, <&CPU_NONRET_1_0>,
|
||
|
|
<&CLUSTER_RET_1>, <&CLUSTER_NONRET_1>;
|
||
|
|
|
||
|
|
cpu_intc11: interrupt-controller {
|
||
|
|
#interrupt-cells = <1>;
|
||
|
|
compatible = "riscv,cpu-intc";
|
||
|
|
interrupt-controller;
|
||
|
|
};
|
||
|
|
};
|
||
|
|
|
||
|
|
idle-states {
|
||
|
|
CPU_RET_0_0: cpu-retentive-0-0 {
|
||
|
|
compatible = "riscv,idle-state";
|
||
|
|
riscv,sbi-suspend-param = <0x10000000>;
|
||
|
|
entry-latency-us = <20>;
|
||
|
|
exit-latency-us = <40>;
|
||
|
|
min-residency-us = <80>;
|
||
|
|
};
|
||
|
|
|
||
|
|
CPU_NONRET_0_0: cpu-nonretentive-0-0 {
|
||
|
|
compatible = "riscv,idle-state";
|
||
|
|
riscv,sbi-suspend-param = <0x90000000>;
|
||
|
|
entry-latency-us = <250>;
|
||
|
|
exit-latency-us = <500>;
|
||
|
|
min-residency-us = <950>;
|
||
|
|
};
|
||
|
|
|
||
|
|
CLUSTER_RET_0: cluster-retentive-0 {
|
||
|
|
compatible = "riscv,idle-state";
|
||
|
|
riscv,sbi-suspend-param = <0x11000000>;
|
||
|
|
local-timer-stop;
|
||
|
|
entry-latency-us = <50>;
|
||
|
|
exit-latency-us = <100>;
|
||
|
|
min-residency-us = <250>;
|
||
|
|
wakeup-latency-us = <130>;
|
||
|
|
};
|
||
|
|
|
||
|
|
CLUSTER_NONRET_0: cluster-nonretentive-0 {
|
||
|
|
compatible = "riscv,idle-state";
|
||
|
|
riscv,sbi-suspend-param = <0x91000000>;
|
||
|
|
local-timer-stop;
|
||
|
|
entry-latency-us = <600>;
|
||
|
|
exit-latency-us = <1100>;
|
||
|
|
min-residency-us = <2700>;
|
||
|
|
wakeup-latency-us = <1500>;
|
||
|
|
};
|
||
|
|
|
||
|
|
CPU_RET_1_0: cpu-retentive-1-0 {
|
||
|
|
compatible = "riscv,idle-state";
|
||
|
|
riscv,sbi-suspend-param = <0x10000010>;
|
||
|
|
entry-latency-us = <20>;
|
||
|
|
exit-latency-us = <40>;
|
||
|
|
min-residency-us = <80>;
|
||
|
|
};
|
||
|
|
|
||
|
|
CPU_NONRET_1_0: cpu-nonretentive-1-0 {
|
||
|
|
compatible = "riscv,idle-state";
|
||
|
|
riscv,sbi-suspend-param = <0x90000010>;
|
||
|
|
entry-latency-us = <250>;
|
||
|
|
exit-latency-us = <500>;
|
||
|
|
min-residency-us = <950>;
|
||
|
|
};
|
||
|
|
|
||
|
|
CLUSTER_RET_1: cluster-retentive-1 {
|
||
|
|
compatible = "riscv,idle-state";
|
||
|
|
riscv,sbi-suspend-param = <0x11000010>;
|
||
|
|
local-timer-stop;
|
||
|
|
entry-latency-us = <50>;
|
||
|
|
exit-latency-us = <100>;
|
||
|
|
min-residency-us = <250>;
|
||
|
|
wakeup-latency-us = <130>;
|
||
|
|
};
|
||
|
|
|
||
|
|
CLUSTER_NONRET_1: cluster-nonretentive-1 {
|
||
|
|
compatible = "riscv,idle-state";
|
||
|
|
riscv,sbi-suspend-param = <0x91000010>;
|
||
|
|
local-timer-stop;
|
||
|
|
entry-latency-us = <600>;
|
||
|
|
exit-latency-us = <1100>;
|
||
|
|
min-residency-us = <2700>;
|
||
|
|
wakeup-latency-us = <1500>;
|
||
|
|
};
|
||
|
|
};
|
||
|
|
};
|
||
|
|
|
||
|
|
...
|