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f9901f6453
The runtime Power Management of CPU topology is not compatible with
PREEMPT_RT:
1. Core cpuidle path disables IRQs.
2. Core cpuidle calls cpuidle-psci.
3. cpuidle-psci in __psci_enter_domain_idle_state() calls
pm_runtime_put_sync_suspend() and pm_runtime_get_sync() which use
spinlocks (which are sleeping on PREEMPT_RT).
Deep sleep modes are not a priority of Realtime kernels because the
latencies might become unpredictable. On the other hand the PSCI CPU
idle power domain is a parent of other devices and power domain
controllers, thus it cannot be simply skipped (e.g. on Qualcomm SM8250).
Disable the idle callbacks in cpuidle-psci and mark the domain as
always on. This is a trade-off between making PREEMPT_RT working and
still having a proper power domain hierarchy in the system.
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Tested-by: Adrien Thierry <athierry@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
132 lines
4.4 KiB
Text
132 lines
4.4 KiB
Text
# SPDX-License-Identifier: GPL-2.0-only
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#
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# ARM CPU Idle drivers
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#
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config ARM_CPUIDLE
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bool "Generic ARM CPU idle Driver"
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depends on ARM
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select DT_IDLE_STATES
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select CPU_IDLE_MULTIPLE_DRIVERS
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help
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Select this to enable generic cpuidle driver for ARM.
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It provides a generic idle driver whose idle states are configured
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at run-time through DT nodes. The CPUidle suspend backend is
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initialized by calling the CPU operations init idle hook
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provided by architecture code.
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config ARM_PSCI_CPUIDLE
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bool "PSCI CPU idle Driver"
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depends on ARM_PSCI_FW
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select DT_IDLE_STATES
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select CPU_IDLE_MULTIPLE_DRIVERS
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help
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Select this to enable PSCI firmware based CPUidle driver for ARM.
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It provides an idle driver that is capable of detecting and
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managing idle states through the PSCI firmware interface.
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The driver has limitations when used with PREEMPT_RT:
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- If the idle states are described with the non-hierarchical layout,
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all idle states are still available.
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- If the idle states are described with the hierarchical layout,
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only the idle states defined per CPU are available, but not the ones
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being shared among a group of CPUs (aka cluster idle states).
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config ARM_PSCI_CPUIDLE_DOMAIN
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bool "PSCI CPU idle Domain"
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depends on ARM_PSCI_CPUIDLE
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depends on PM_GENERIC_DOMAINS_OF
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select DT_IDLE_GENPD
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default y
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help
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Select this to enable the PSCI based CPUidle driver to use PM domains,
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which is needed to support the hierarchical DT based layout of the
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idle states.
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config ARM_BIG_LITTLE_CPUIDLE
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bool "Support for ARM big.LITTLE processors"
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depends on ARCH_VEXPRESS_TC2_PM || ARCH_EXYNOS || COMPILE_TEST
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depends on MCPM && !ARM64
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select ARM_CPU_SUSPEND
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select CPU_IDLE_MULTIPLE_DRIVERS
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select DT_IDLE_STATES
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help
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Select this option to enable CPU idle driver for big.LITTLE based
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ARM systems. Driver manages CPUs coordination through MCPM and
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define different C-states for little and big cores through the
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multiple CPU idle drivers infrastructure.
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config ARM_CLPS711X_CPUIDLE
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bool "CPU Idle Driver for CLPS711X processors"
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depends on ARCH_CLPS711X && !ARM64 || COMPILE_TEST
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help
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Select this to enable cpuidle on Cirrus Logic CLPS711X SOCs.
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config ARM_HIGHBANK_CPUIDLE
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bool "CPU Idle Driver for Calxeda processors"
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depends on ARM_PSCI && !ARM64
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select ARM_CPU_SUSPEND
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help
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Select this to enable cpuidle on Calxeda processors.
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config ARM_KIRKWOOD_CPUIDLE
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bool "CPU Idle Driver for Marvell Kirkwood SoCs"
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depends on (MACH_KIRKWOOD || COMPILE_TEST) && !ARM64
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help
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This adds the CPU Idle driver for Marvell Kirkwood SoCs.
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config ARM_ZYNQ_CPUIDLE
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bool "CPU Idle Driver for Xilinx Zynq processors"
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depends on (ARCH_ZYNQ || COMPILE_TEST) && !ARM64
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help
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Select this to enable cpuidle on Xilinx Zynq processors.
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config ARM_U8500_CPUIDLE
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bool "Cpu Idle Driver for the ST-E u8500 processors"
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depends on ARCH_U8500 && !ARM64
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help
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Select this to enable cpuidle for ST-E u8500 processors.
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config ARM_AT91_CPUIDLE
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bool "Cpu Idle Driver for the AT91 processors"
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default y
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depends on (ARCH_AT91 || COMPILE_TEST) && !ARM64
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help
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Select this to enable cpuidle for AT91 processors.
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config ARM_EXYNOS_CPUIDLE
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bool "Cpu Idle Driver for the Exynos processors"
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depends on (ARCH_EXYNOS || COMPILE_TEST) && !ARM64
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select ARCH_NEEDS_CPU_IDLE_COUPLED if SMP
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help
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Select this to enable cpuidle for Exynos processors.
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config ARM_MVEBU_V7_CPUIDLE
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bool "CPU Idle Driver for mvebu v7 family processors"
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depends on (ARCH_MVEBU || COMPILE_TEST) && !ARM64
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help
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Select this to enable cpuidle on Armada 370, 38x and XP processors.
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config ARM_TEGRA_CPUIDLE
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bool "CPU Idle Driver for NVIDIA Tegra SoCs"
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depends on (ARCH_TEGRA || COMPILE_TEST) && !ARM64 && MMU
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depends on ARCH_SUSPEND_POSSIBLE
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select ARCH_NEEDS_CPU_IDLE_COUPLED if SMP
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select ARM_CPU_SUSPEND
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help
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Select this to enable cpuidle for NVIDIA Tegra20/30/114/124 SoCs.
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config ARM_QCOM_SPM_CPUIDLE
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bool "CPU Idle Driver for Qualcomm Subsystem Power Manager (SPM)"
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depends on (ARCH_QCOM || COMPILE_TEST) && !ARM64 && MMU
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depends on ARCH_SUSPEND_POSSIBLE
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select ARM_CPU_SUSPEND
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select CPU_IDLE_MULTIPLE_DRIVERS
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select DT_IDLE_STATES
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select QCOM_SCM
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select QCOM_SPM
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help
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Select this to enable cpuidle for Qualcomm processors.
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The Subsystem Power Manager (SPM) controls low power modes for the
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CPU and L2 cores. It interface with various system drivers to put
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the cores in low power modes.
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