tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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#include <acpi/processor.h>
14
15#define ARM64_LPI_IS_RETENTION_STATE(arch_flags) (!(arch_flags))
16
17static int psci_acpi_cpu_init_idle(unsigned int cpu)
18{
19 int i, count;
20 struct acpi_lpi_state *lpi;
21 struct acpi_processor *pr = per_cpu(processors, cpu);
22
23 if (unlikely(!pr || !pr->flags.has_lpi))
24 return -EINVAL;
25
26 /*
27 * If the PSCI cpu_suspend function hook has not been initialized
28 * idle states must not be enabled, so bail out
29 */
30 if (!psci_ops.cpu_suspend)
31 return -EOPNOTSUPP;
32
33 count = pr->power.count - 1;
34 if (count <= 0)
35 return -ENODEV;
36
37 for (i = 0; i < count; i++) {
38 u32 state;
39
40 lpi = &pr->power.lpi_states[i + 1];
41 /*
42 * Only bits[31:0] represent a PSCI power_state while
43 * bits[63:32] must be 0x0 as per ARM ACPI FFH Specification
44 */
45 state = lpi->address;
46 if (!psci_power_state_is_valid(state)) {
47 pr_warn("Invalid PSCI power state %#x\n", state);
48 return -EINVAL;
49 }
50 }
51
52 return 0;
53}
54
55int acpi_processor_ffh_lpi_probe(unsigned int cpu)
56{
57 return psci_acpi_cpu_init_idle(cpu);
58}
59
60__cpuidle int acpi_processor_ffh_lpi_enter(struct acpi_lpi_state *lpi)
61{
62 u32 state = lpi->address;
63
64 if (ARM64_LPI_IS_RETENTION_STATE(lpi->arch_flags))
65 return CPU_PM_CPU_IDLE_ENTER_RETENTION_PARAM_RCU(psci_cpu_suspend_enter,
66 lpi->index, state);
67 else
68 return CPU_PM_CPU_IDLE_ENTER_PARAM_RCU(psci_cpu_suspend_enter,
69 lpi->index, state);
70}