1// SPDX-License-Identifier: GPL-2.0
 2/*
 3 * Copyright (C) 2020 Western Digital Corporation or its affiliates.
 4 */
 5
 6#include <linux/kernel.h>
 7#include <linux/mm.h>
 8#include <linux/sched.h>
 9#include <linux/err.h>
10#include <linux/irq.h>
11#include <linux/cpu.h>
12#include <linux/sched/hotplug.h>
13#include <asm/irq.h>
14#include <asm/cpu_ops.h>
15#include <asm/sbi.h>
16
17void cpu_stop(void);
18void arch_cpu_idle_dead(void)
19{
20	cpu_stop();
21}
22
23bool cpu_has_hotplug(unsigned int cpu)
24{
25	if (cpu_ops[cpu]->cpu_stop)
26		return true;
27
28	return false;
29}
30
31/*
32 * __cpu_disable runs on the processor to be shutdown.
33 */
34int __cpu_disable(void)
35{
36	int ret = 0;
37	unsigned int cpu = smp_processor_id();
38
39	if (!cpu_ops[cpu] || !cpu_ops[cpu]->cpu_stop)
40		return -EOPNOTSUPP;
41
42	if (cpu_ops[cpu]->cpu_disable)
43		ret = cpu_ops[cpu]->cpu_disable(cpu);
44
45	if (ret)
46		return ret;
47
48	remove_cpu_topology(cpu);
49	set_cpu_online(cpu, false);
50	irq_migrate_all_off_this_cpu();
51
52	return ret;
53}
54
55/*
56 * Called on the thread which is asking for a CPU to be shutdown.
57 */
58void __cpu_die(unsigned int cpu)
59{
60	int ret = 0;
61
62	if (!cpu_wait_death(cpu, 5)) {
63		pr_err("CPU %u: didn't die\n", cpu);
64		return;
65	}
66	pr_notice("CPU%u: off\n", cpu);
67
68	/* Verify from the firmware if the cpu is really stopped*/
69	if (cpu_ops[cpu]->cpu_is_stopped)
70		ret = cpu_ops[cpu]->cpu_is_stopped(cpu);
71	if (ret)
72		pr_warn("CPU%d may not have stopped: %d\n", cpu, ret);
73}
74
75/*
76 * Called from the idle thread for the CPU which has been shutdown.
77 */
78void cpu_stop(void)
79{
80	idle_task_exit();
81
82	(void)cpu_report_death();
83
84	cpu_ops[smp_processor_id()]->cpu_stop();
85	/* It should never reach here */
86	BUG();
87}