1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * ARM64 CPU idle arch support
4 *
5 * Copyright (C) 2014 ARM Ltd.
6 * Author: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
7 */
8
9#include <linux/acpi.h>
10#include <linux/cpuidle.h>
11#include <linux/cpu_pm.h>
12#include <linux/psci.h>
13
14#ifdef CONFIG_ACPI_PROCESSOR_IDLE
15
16#include <acpi/processor.h>
17
18#define ARM64_LPI_IS_RETENTION_STATE(arch_flags) (!(arch_flags))
19
20static int psci_acpi_cpu_init_idle(unsigned int cpu)
21{
22	int i, count;
23	struct acpi_lpi_state *lpi;
24	struct acpi_processor *pr = per_cpu(processors, cpu);
25
26	if (unlikely(!pr || !pr->flags.has_lpi))
27		return -EINVAL;
28
29	/*
30	 * If the PSCI cpu_suspend function hook has not been initialized
31	 * idle states must not be enabled, so bail out
32	 */
33	if (!psci_ops.cpu_suspend)
34		return -EOPNOTSUPP;
35
36	count = pr->power.count - 1;
37	if (count <= 0)
38		return -ENODEV;
39
40	for (i = 0; i < count; i++) {
41		u32 state;
42
43		lpi = &pr->power.lpi_states[i + 1];
44		/*
45		 * Only bits[31:0] represent a PSCI power_state while
46		 * bits[63:32] must be 0x0 as per ARM ACPI FFH Specification
47		 */
48		state = lpi->address;
49		if (!psci_power_state_is_valid(state)) {
50			pr_warn("Invalid PSCI power state %#x\n", state);
51			return -EINVAL;
52		}
53	}
54
55	return 0;
56}
57
58int acpi_processor_ffh_lpi_probe(unsigned int cpu)
59{
60	return psci_acpi_cpu_init_idle(cpu);
61}
62
63__cpuidle int acpi_processor_ffh_lpi_enter(struct acpi_lpi_state *lpi)
64{
65	u32 state = lpi->address;
66
67	if (ARM64_LPI_IS_RETENTION_STATE(lpi->arch_flags))
68		return CPU_PM_CPU_IDLE_ENTER_RETENTION_PARAM_RCU(psci_cpu_suspend_enter,
69						lpi->index, state);
70	else
71		return CPU_PM_CPU_IDLE_ENTER_PARAM_RCU(psci_cpu_suspend_enter,
72					     lpi->index, state);
73}
74#endif
75