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