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	int err = psci_ops.cpu_on(cpu_logical_map(cpu), __pa_symbol(secondary_entry));
 42	if (err)
 43		pr_err("failed to boot CPU%d (%d)\n", cpu, err);
 44
 45	return err;
 46}
 47
 48#ifdef CONFIG_HOTPLUG_CPU
 49static bool cpu_psci_cpu_can_disable(unsigned int cpu)
 50{
 51	return !psci_tos_resident_on(cpu);
 52}
 53
 54static int cpu_psci_cpu_disable(unsigned int cpu)
 55{
 56	/* Fail early if we don't have CPU_OFF support */
 57	if (!psci_ops.cpu_off)
 58		return -EOPNOTSUPP;
 59
 60	/* Trusted OS will deny CPU_OFF */
 61	if (psci_tos_resident_on(cpu))
 62		return -EPERM;
 63
 64	return 0;
 65}
 66
 67static void cpu_psci_cpu_die(unsigned int cpu)
 68{
 69	int ret;
 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	ret = psci_ops.cpu_off(state);
 78
 79	pr_crit("unable to power off CPU%u (%d)\n", cpu, ret);
 80}
 81
 82static int cpu_psci_cpu_kill(unsigned int cpu)
 83{
 84	int err;
 85	unsigned long start, end;
 86
 87	if (!psci_ops.affinity_info)
 88		return 0;
 89	/*
 90	 * cpu_kill could race with cpu_die and we can
 91	 * potentially end up declaring this cpu undead
 92	 * while it is dying. So, try again a few times.
 93	 */
 94
 95	start = jiffies;
 96	end = start + msecs_to_jiffies(100);
 97	do {
 98		err = psci_ops.affinity_info(cpu_logical_map(cpu), 0);
 99		if (err == PSCI_0_2_AFFINITY_LEVEL_OFF) {
100			pr_info("CPU%d killed (polled %d ms)\n", cpu,
101				jiffies_to_msecs(jiffies - start));
102			return 0;
103		}
104
105		usleep_range(100, 1000);
106	} while (time_before(jiffies, end));
107
108	pr_warn("CPU%d may not have shut down cleanly (AFFINITY_INFO reports %d)\n",
109			cpu, err);
110	return -ETIMEDOUT;
111}
112#endif
113
114const struct cpu_operations cpu_psci_ops = {
115	.name		= "psci",
116	.cpu_init	= cpu_psci_cpu_init,
117	.cpu_prepare	= cpu_psci_cpu_prepare,
118	.cpu_boot	= cpu_psci_cpu_boot,
119#ifdef CONFIG_HOTPLUG_CPU
120	.cpu_can_disable = cpu_psci_cpu_can_disable,
121	.cpu_disable	= cpu_psci_cpu_disable,
122	.cpu_die	= cpu_psci_cpu_die,
123	.cpu_kill	= cpu_psci_cpu_kill,
124#endif
125};
126