linux/arch/arm64/kernel/cpuidle.c
Lorenzo Pieralisi 9ffeb6d08c PSCI: cpuidle: Refactor CPU suspend power_state parameter handling
Current PSCI code handles idle state entry through the
psci_cpu_suspend_enter() API, that takes an idle state index as a
parameter and convert the index into a previously initialized
power_state parameter before calling the PSCI.CPU_SUSPEND() with it.

This is unwieldly, since it forces the PSCI firmware layer to keep track
of power_state parameter for every idle state so that the
index->power_state conversion can be made in the PSCI firmware layer
instead of the CPUidle driver implementations.

Move the power_state handling out of drivers/firmware/psci
into the respective ACPI/DT PSCI CPUidle backends and convert
the psci_cpu_suspend_enter() API to get the power_state
parameter as input, which makes it closer to its firmware
interface PSCI.CPU_SUSPEND() API.

A notable side effect is that the PSCI ACPI/DT CPUidle backends
now can directly handle (and if needed update) power_state
parameters before handing them over to the PSCI firmware
interface to trigger PSCI.CPU_SUSPEND() calls.

Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Signed-off-by: Will Deacon <will@kernel.org>
2019-08-09 17:51:39 +01:00

105 lines
2.3 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* ARM64 CPU idle arch support
*
* Copyright (C) 2014 ARM Ltd.
* Author: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
*/
#include <linux/acpi.h>
#include <linux/cpuidle.h>
#include <linux/cpu_pm.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/psci.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))
static int psci_acpi_cpu_init_idle(unsigned int cpu)
{
int i, count;
struct acpi_lpi_state *lpi;
struct acpi_processor *pr = per_cpu(processors, cpu);
/*
* If the PSCI cpu_suspend function hook has not been initialized
* idle states must not be enabled, so bail out
*/
if (!psci_ops.cpu_suspend)
return -EOPNOTSUPP;
if (unlikely(!pr || !pr->flags.has_lpi))
return -EINVAL;
count = pr->power.count - 1;
if (count <= 0)
return -ENODEV;
for (i = 0; i < count; i++) {
u32 state;
lpi = &pr->power.lpi_states[i + 1];
/*
* Only bits[31:0] represent a PSCI power_state while
* bits[63:32] must be 0x0 as per ARM ACPI FFH Specification
*/
state = lpi->address;
if (!psci_power_state_is_valid(state)) {
pr_warn("Invalid PSCI power state %#x\n", state);
return -EINVAL;
}
}
return 0;
}
int acpi_processor_ffh_lpi_probe(unsigned int cpu)
{
return psci_acpi_cpu_init_idle(cpu);
}
int acpi_processor_ffh_lpi_enter(struct acpi_lpi_state *lpi)
{
u32 state = lpi->address;
if (ARM64_LPI_IS_RETENTION_STATE(lpi->arch_flags))
return CPU_PM_CPU_IDLE_ENTER_RETENTION_PARAM(psci_cpu_suspend_enter,
lpi->index, state);
else
return CPU_PM_CPU_IDLE_ENTER_PARAM(psci_cpu_suspend_enter,
lpi->index, state);
}
#endif