mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-24 13:13:57 +08:00
8b9951ed7e
CPU_PM_CPU_IDLE_ENTER_RETENTION skips calling cpu_pm_enter() and cpu_pm_exit(). By not calling cpu_pm functions in idle entry/exit paths we can reduce the latency involved in entering and exiting the low power idle state. On ARM64 based Qualcomm server platform we measured below overhead for calling cpu_pm_enter and cpu_pm_exit for retention states. workload: stress --hdd #CPUs --hdd-bytes 32M -t 30 Average overhead of cpu_pm_enter - 1.2us Average overhead of cpu_pm_exit - 3.1us Acked-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Prashanth Prakash <pprakash@codeaurora.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
66 lines
1.5 KiB
C
66 lines
1.5 KiB
C
/*
|
|
* ARM64 CPU idle arch support
|
|
*
|
|
* Copyright (C) 2014 ARM Ltd.
|
|
* Author: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 as
|
|
* published by the Free Software Foundation.
|
|
*/
|
|
|
|
#include <linux/acpi.h>
|
|
#include <linux/cpuidle.h>
|
|
#include <linux/cpu_pm.h>
|
|
#include <linux/of.h>
|
|
#include <linux/of_device.h>
|
|
|
|
#include <asm/cpuidle.h>
|
|
#include <asm/cpu_ops.h>
|
|
|
|
int arm_cpuidle_init(unsigned int cpu)
|
|
{
|
|
int ret = -EOPNOTSUPP;
|
|
|
|
if (cpu_ops[cpu] && cpu_ops[cpu]->cpu_suspend &&
|
|
cpu_ops[cpu]->cpu_init_idle)
|
|
ret = cpu_ops[cpu]->cpu_init_idle(cpu);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* arm_cpuidle_suspend() - function to enter a low-power idle state
|
|
* @arg: argument to pass to CPU suspend operations
|
|
*
|
|
* Return: 0 on success, -EOPNOTSUPP if CPU suspend hook not initialized, CPU
|
|
* operations back-end error code otherwise.
|
|
*/
|
|
int arm_cpuidle_suspend(int index)
|
|
{
|
|
int cpu = smp_processor_id();
|
|
|
|
return cpu_ops[cpu]->cpu_suspend(index);
|
|
}
|
|
|
|
#ifdef CONFIG_ACPI
|
|
|
|
#include <acpi/processor.h>
|
|
|
|
#define ARM64_LPI_IS_RETENTION_STATE(arch_flags) (!(arch_flags))
|
|
|
|
int acpi_processor_ffh_lpi_probe(unsigned int cpu)
|
|
{
|
|
return arm_cpuidle_init(cpu);
|
|
}
|
|
|
|
int acpi_processor_ffh_lpi_enter(struct acpi_lpi_state *lpi)
|
|
{
|
|
if (ARM64_LPI_IS_RETENTION_STATE(lpi->arch_flags))
|
|
return CPU_PM_CPU_IDLE_ENTER_RETENTION(arm_cpuidle_suspend,
|
|
lpi->index);
|
|
else
|
|
return CPU_PM_CPU_IDLE_ENTER(arm_cpuidle_suspend, lpi->index);
|
|
}
|
|
#endif
|