linux-stable/drivers/cpuidle/Kconfig.arm
Krzysztof Kozlowski f9901f6453 cpuidle: psci: Do not suspend topology CPUs on PREEMPT_RT
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>
2023-02-13 17:15:42 +01:00

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# SPDX-License-Identifier: GPL-2.0-only
#
# ARM CPU Idle drivers
#
config ARM_CPUIDLE
bool "Generic ARM CPU idle Driver"
depends on ARM
select DT_IDLE_STATES
select CPU_IDLE_MULTIPLE_DRIVERS
help
Select this to enable generic cpuidle driver for ARM.
It provides a generic idle driver whose idle states are configured
at run-time through DT nodes. The CPUidle suspend backend is
initialized by calling the CPU operations init idle hook
provided by architecture code.
config ARM_PSCI_CPUIDLE
bool "PSCI CPU idle Driver"
depends on ARM_PSCI_FW
select DT_IDLE_STATES
select CPU_IDLE_MULTIPLE_DRIVERS
help
Select this to enable PSCI firmware based CPUidle driver for ARM.
It provides an idle driver that is capable of detecting and
managing idle states through the PSCI firmware interface.
The driver has limitations when used with PREEMPT_RT:
- If the idle states are described with the non-hierarchical layout,
all idle states are still available.
- If the idle states are described with the hierarchical layout,
only the idle states defined per CPU are available, but not the ones
being shared among a group of CPUs (aka cluster idle states).
config ARM_PSCI_CPUIDLE_DOMAIN
bool "PSCI CPU idle Domain"
depends on ARM_PSCI_CPUIDLE
depends on PM_GENERIC_DOMAINS_OF
select DT_IDLE_GENPD
default y
help
Select this to enable the PSCI based CPUidle driver to use PM domains,
which is needed to support the hierarchical DT based layout of the
idle states.
config ARM_BIG_LITTLE_CPUIDLE
bool "Support for ARM big.LITTLE processors"
depends on ARCH_VEXPRESS_TC2_PM || ARCH_EXYNOS || COMPILE_TEST
depends on MCPM && !ARM64
select ARM_CPU_SUSPEND
select CPU_IDLE_MULTIPLE_DRIVERS
select DT_IDLE_STATES
help
Select this option to enable CPU idle driver for big.LITTLE based
ARM systems. Driver manages CPUs coordination through MCPM and
define different C-states for little and big cores through the
multiple CPU idle drivers infrastructure.
config ARM_CLPS711X_CPUIDLE
bool "CPU Idle Driver for CLPS711X processors"
depends on ARCH_CLPS711X && !ARM64 || COMPILE_TEST
help
Select this to enable cpuidle on Cirrus Logic CLPS711X SOCs.
config ARM_HIGHBANK_CPUIDLE
bool "CPU Idle Driver for Calxeda processors"
depends on ARM_PSCI && !ARM64
select ARM_CPU_SUSPEND
help
Select this to enable cpuidle on Calxeda processors.
config ARM_KIRKWOOD_CPUIDLE
bool "CPU Idle Driver for Marvell Kirkwood SoCs"
depends on (MACH_KIRKWOOD || COMPILE_TEST) && !ARM64
help
This adds the CPU Idle driver for Marvell Kirkwood SoCs.
config ARM_ZYNQ_CPUIDLE
bool "CPU Idle Driver for Xilinx Zynq processors"
depends on (ARCH_ZYNQ || COMPILE_TEST) && !ARM64
help
Select this to enable cpuidle on Xilinx Zynq processors.
config ARM_U8500_CPUIDLE
bool "Cpu Idle Driver for the ST-E u8500 processors"
depends on ARCH_U8500 && !ARM64
help
Select this to enable cpuidle for ST-E u8500 processors.
config ARM_AT91_CPUIDLE
bool "Cpu Idle Driver for the AT91 processors"
default y
depends on (ARCH_AT91 || COMPILE_TEST) && !ARM64
help
Select this to enable cpuidle for AT91 processors.
config ARM_EXYNOS_CPUIDLE
bool "Cpu Idle Driver for the Exynos processors"
depends on (ARCH_EXYNOS || COMPILE_TEST) && !ARM64
select ARCH_NEEDS_CPU_IDLE_COUPLED if SMP
help
Select this to enable cpuidle for Exynos processors.
config ARM_MVEBU_V7_CPUIDLE
bool "CPU Idle Driver for mvebu v7 family processors"
depends on (ARCH_MVEBU || COMPILE_TEST) && !ARM64
help
Select this to enable cpuidle on Armada 370, 38x and XP processors.
config ARM_TEGRA_CPUIDLE
bool "CPU Idle Driver for NVIDIA Tegra SoCs"
depends on (ARCH_TEGRA || COMPILE_TEST) && !ARM64 && MMU
depends on ARCH_SUSPEND_POSSIBLE
select ARCH_NEEDS_CPU_IDLE_COUPLED if SMP
select ARM_CPU_SUSPEND
help
Select this to enable cpuidle for NVIDIA Tegra20/30/114/124 SoCs.
config ARM_QCOM_SPM_CPUIDLE
bool "CPU Idle Driver for Qualcomm Subsystem Power Manager (SPM)"
depends on (ARCH_QCOM || COMPILE_TEST) && !ARM64 && MMU
depends on ARCH_SUSPEND_POSSIBLE
select ARM_CPU_SUSPEND
select CPU_IDLE_MULTIPLE_DRIVERS
select DT_IDLE_STATES
select QCOM_SCM
select QCOM_SPM
help
Select this to enable cpuidle for Qualcomm processors.
The Subsystem Power Manager (SPM) controls low power modes for the
CPU and L2 cores. It interface with various system drivers to put
the cores in low power modes.