1 // SPDX-License-Identifier: GPL-2.0-only
3 * ARM64 CPU idle arch support
5 * Copyright (C) 2014 ARM Ltd.
6 * Author: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
9 #include <linux/acpi.h>
10 #include <linux/cpuidle.h>
11 #include <linux/cpu_pm.h>
13 #include <linux/of_device.h>
14 #include <linux/psci.h>
16 #include <asm/cpuidle.h>
17 #include <asm/cpu_ops.h>
19 int arm_cpuidle_init(unsigned int cpu)
21 int ret = -EOPNOTSUPP;
23 if (cpu_ops[cpu] && cpu_ops[cpu]->cpu_suspend &&
24 cpu_ops[cpu]->cpu_init_idle)
25 ret = cpu_ops[cpu]->cpu_init_idle(cpu);
31 * arm_cpuidle_suspend() - function to enter a low-power idle state
32 * @arg: argument to pass to CPU suspend operations
34 * Return: 0 on success, -EOPNOTSUPP if CPU suspend hook not initialized, CPU
35 * operations back-end error code otherwise.
37 int arm_cpuidle_suspend(int index)
39 int cpu = smp_processor_id();
41 return cpu_ops[cpu]->cpu_suspend(index);
46 #include <acpi/processor.h>
48 #define ARM64_LPI_IS_RETENTION_STATE(arch_flags) (!(arch_flags))
50 static int psci_acpi_cpu_init_idle(unsigned int cpu)
53 struct acpi_lpi_state *lpi;
54 struct acpi_processor *pr = per_cpu(processors, cpu);
56 if (unlikely(!pr || !pr->flags.has_lpi))
60 * If the PSCI cpu_suspend function hook has not been initialized
61 * idle states must not be enabled, so bail out
63 if (!psci_ops.cpu_suspend)
66 count = pr->power.count - 1;
70 for (i = 0; i < count; i++) {
73 lpi = &pr->power.lpi_states[i + 1];
75 * Only bits[31:0] represent a PSCI power_state while
76 * bits[63:32] must be 0x0 as per ARM ACPI FFH Specification
79 if (!psci_power_state_is_valid(state)) {
80 pr_warn("Invalid PSCI power state %#x\n", state);
88 int acpi_processor_ffh_lpi_probe(unsigned int cpu)
90 return psci_acpi_cpu_init_idle(cpu);
93 int acpi_processor_ffh_lpi_enter(struct acpi_lpi_state *lpi)
95 u32 state = lpi->address;
97 if (ARM64_LPI_IS_RETENTION_STATE(lpi->arch_flags))
98 return CPU_PM_CPU_IDLE_ENTER_RETENTION_PARAM(psci_cpu_suspend_enter,
101 return CPU_PM_CPU_IDLE_ENTER_PARAM(psci_cpu_suspend_enter,