1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 *
  4 * Copyright (C) 2012 ARM Limited
  5 *
  6 * Author: Will Deacon <will.deacon@arm.com>
  7 */
  8
  9#include <linux/init.h>
 10#include <linux/smp.h>
 11#include <linux/of.h>
 12#include <linux/delay.h>
 13#include <linux/psci.h>
 14
 15#include <uapi/linux/psci.h>
 16
 17#include <asm/psci.h>
 18#include <asm/smp_plat.h>
 19
 20/*
 21 * psci_smp assumes that the following is true about PSCI:
 22 *
 23 * cpu_suspend   Suspend the execution on a CPU
 24 * @state        we don't currently describe affinity levels, so just pass 0.
 25 * @entry_point  the first instruction to be executed on return
 26 * returns 0  success, < 0 on failure
 27 *
 28 * cpu_off       Power down a CPU
 29 * @state        we don't currently describe affinity levels, so just pass 0.
 30 * no return on successful call
 31 *
 32 * cpu_on        Power up a CPU
 33 * @cpuid        cpuid of target CPU, as from MPIDR
 34 * @entry_point  the first instruction to be executed on return
 35 * returns 0  success, < 0 on failure
 36 *
 37 * migrate       Migrate the context to a different CPU
 38 * @cpuid        cpuid of target CPU, as from MPIDR
 39 * returns 0  success, < 0 on failure
 40 *
 41 */
 42
 43extern void secondary_startup(void);
 44
 45static int psci_boot_secondary(unsigned int cpu, struct task_struct *idle)
 46{
 47	if (psci_ops.cpu_on)
 48		return psci_ops.cpu_on(cpu_logical_map(cpu),
 49					virt_to_idmap(&secondary_startup));
 50	return -ENODEV;
 51}
 52
 53#ifdef CONFIG_HOTPLUG_CPU
 54int 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
 67void psci_cpu_die(unsigned int cpu)
 68{
 69	u32 state = PSCI_POWER_STATE_TYPE_POWER_DOWN <<
 70		    PSCI_0_2_POWER_STATE_TYPE_SHIFT;
 71
 72	if (psci_ops.cpu_off)
 73		psci_ops.cpu_off(state);
 74
 75	/* We should never return */
 76	panic("psci: cpu %d failed to shutdown\n", cpu);
 77}
 78
 79int psci_cpu_kill(unsigned int cpu)
 80{
 81	int err, i;
 82
 83	if (!psci_ops.affinity_info)
 84		return 1;
 85	/*
 86	 * cpu_kill could race with cpu_die and we can
 87	 * potentially end up declaring this cpu undead
 88	 * while it is dying. So, try again a few times.
 89	 */
 90
 91	for (i = 0; i < 10; i++) {
 92		err = psci_ops.affinity_info(cpu_logical_map(cpu), 0);
 93		if (err == PSCI_0_2_AFFINITY_LEVEL_OFF) {
 94			pr_info("CPU%d killed.\n", cpu);
 95			return 1;
 96		}
 97
 98		msleep(10);
 99		pr_info("Retrying again to check for CPU kill\n");
100	}
101
102	pr_warn("CPU%d may not have shut down cleanly (AFFINITY_INFO reports %d)\n",
103			cpu, err);
104	/* Make platform_cpu_kill() fail. */
105	return 0;
106}
107
108#endif
109
110bool __init psci_smp_available(void)
111{
112	/* is cpu_on available at least? */
113	return (psci_ops.cpu_on != NULL);
114}
115
116const struct smp_operations psci_smp_ops __initconst = {
117	.smp_boot_secondary	= psci_boot_secondary,
118#ifdef CONFIG_HOTPLUG_CPU
119	.cpu_disable		= psci_cpu_disable,
120	.cpu_die		= psci_cpu_die,
121	.cpu_kill		= psci_cpu_kill,
122#endif
123};