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