1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 *
4 * Copyright (C) 2013 ARM Limited
5 *
6 * Author: Will Deacon <will.deacon@arm.com>
7 */
8
9#define pr_fmt(fmt) "psci: " fmt
10
11#include <linux/init.h>
12#include <linux/of.h>
13#include <linux/smp.h>
14#include <linux/delay.h>
15#include <linux/psci.h>
16#include <linux/mm.h>
17
18#include <uapi/linux/psci.h>
19
20#include <asm/cpu_ops.h>
21#include <asm/errno.h>
22#include <asm/smp_plat.h>
23
24static int __init cpu_psci_cpu_init(unsigned int cpu)
25{
26	return 0;
27}
28
29static int __init cpu_psci_cpu_prepare(unsigned int cpu)
30{
31	if (!psci_ops.cpu_on) {
32		pr_err("no cpu_on method, not booting CPU%d\n", cpu);
33		return -ENODEV;
34	}
35
36	return 0;
37}
38
39static int cpu_psci_cpu_boot(unsigned int cpu)
40{
41	phys_addr_t pa_secondary_entry = __pa_symbol(secondary_entry);
42	int err = psci_ops.cpu_on(cpu_logical_map(cpu), pa_secondary_entry);
43	if (err)
44		pr_err("failed to boot CPU%d (%d)\n", cpu, err);
45
46	return err;
47}
48
49#ifdef CONFIG_HOTPLUG_CPU
50static bool cpu_psci_cpu_can_disable(unsigned int cpu)
51{
52	return !psci_tos_resident_on(cpu);
53}
54
55static int cpu_psci_cpu_disable(unsigned int cpu)
56{
57	/* Fail early if we don't have CPU_OFF support */
58	if (!psci_ops.cpu_off)
59		return -EOPNOTSUPP;
60
61	/* Trusted OS will deny CPU_OFF */
62	if (psci_tos_resident_on(cpu))
63		return -EPERM;
64
65	return 0;
66}
67
68static void cpu_psci_cpu_die(unsigned int cpu)
69{
70	/*
71	 * There are no known implementations of PSCI actually using the
72	 * power state field, pass a sensible default for now.
73	 */
74	u32 state = PSCI_POWER_STATE_TYPE_POWER_DOWN <<
75		    PSCI_0_2_POWER_STATE_TYPE_SHIFT;
76
77	psci_ops.cpu_off(state);
78}
79
80static int cpu_psci_cpu_kill(unsigned int cpu)
81{
82	int err;
83	unsigned long start, end;
84
85	if (!psci_ops.affinity_info)
86		return 0;
87	/*
88	 * cpu_kill could race with cpu_die and we can
89	 * potentially end up declaring this cpu undead
90	 * while it is dying. So, try again a few times.
91	 */
92
93	start = jiffies;
94	end = start + msecs_to_jiffies(100);
95	do {
96		err = psci_ops.affinity_info(cpu_logical_map(cpu), 0);
97		if (err == PSCI_0_2_AFFINITY_LEVEL_OFF) {
98			pr_info("CPU%d killed (polled %d ms)\n", cpu,
99				jiffies_to_msecs(jiffies - start));
100			return 0;
101		}
102
103		usleep_range(100, 1000);
104	} while (time_before(jiffies, end));
105
106	pr_warn("CPU%d may not have shut down cleanly (AFFINITY_INFO reports %d)\n",
107			cpu, err);
108	return -ETIMEDOUT;
109}
110#endif
111
112const struct cpu_operations cpu_psci_ops = {
113	.name		= "psci",
114	.cpu_init	= cpu_psci_cpu_init,
115	.cpu_prepare	= cpu_psci_cpu_prepare,
116	.cpu_boot	= cpu_psci_cpu_boot,
117#ifdef CONFIG_HOTPLUG_CPU
118	.cpu_can_disable = cpu_psci_cpu_can_disable,
119	.cpu_disable	= cpu_psci_cpu_disable,
120	.cpu_die	= cpu_psci_cpu_die,
121	.cpu_kill	= cpu_psci_cpu_kill,
122#endif
123};
124
125