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#ifdef CONFIG_XIP_KERNEL
 49		return psci_ops.cpu_on(cpu_logical_map(cpu),
 50			((phys_addr_t)(&secondary_startup)
 51			- XIP_VIRT_ADDR(CONFIG_XIP_PHYS_ADDR)
 52			+ CONFIG_XIP_PHYS_ADDR));
 53#else
 54		return psci_ops.cpu_on(cpu_logical_map(cpu),
 55					virt_to_idmap(&secondary_startup));
 56#endif
 57	return -ENODEV;
 58}
 59
 60#ifdef CONFIG_HOTPLUG_CPU
 61static int psci_cpu_disable(unsigned int cpu)
 62{
 63	/* Fail early if we don't have CPU_OFF support */
 64	if (!psci_ops.cpu_off)
 65		return -EOPNOTSUPP;
 66
 67	/* Trusted OS will deny CPU_OFF */
 68	if (psci_tos_resident_on(cpu))
 69		return -EPERM;
 70
 71	return 0;
 72}
 73
 74static void psci_cpu_die(unsigned int cpu)
 75{
 76	u32 state = PSCI_POWER_STATE_TYPE_POWER_DOWN <<
 77		    PSCI_0_2_POWER_STATE_TYPE_SHIFT;
 78
 79	if (psci_ops.cpu_off)
 80		psci_ops.cpu_off(state);
 81
 82	/* We should never return */
 83	panic("psci: cpu %d failed to shutdown\n", cpu);
 84}
 85
 86static int psci_cpu_kill(unsigned int cpu)
 87{
 88	int err, i;
 89
 90	if (!psci_ops.affinity_info)
 91		return 1;
 92	/*
 93	 * cpu_kill could race with cpu_die and we can
 94	 * potentially end up declaring this cpu undead
 95	 * while it is dying. So, try again a few times.
 96	 */
 97
 98	for (i = 0; i < 10; i++) {
 99		err = psci_ops.affinity_info(cpu_logical_map(cpu), 0);
100		if (err == PSCI_0_2_AFFINITY_LEVEL_OFF) {
101			pr_info("CPU%d killed.\n", cpu);
102			return 1;
103		}
104
105		msleep(10);
106		pr_info("Retrying again to check for CPU kill\n");
107	}
108
109	pr_warn("CPU%d may not have shut down cleanly (AFFINITY_INFO reports %d)\n",
110			cpu, err);
111	/* Make platform_cpu_kill() fail. */
112	return 0;
113}
114
115#endif
116
117bool __init psci_smp_available(void)
118{
119	/* is cpu_on available at least? */
120	return (psci_ops.cpu_on != NULL);
121}
122
123const struct smp_operations psci_smp_ops __initconst = {
124	.smp_boot_secondary	= psci_boot_secondary,
125#ifdef CONFIG_HOTPLUG_CPU
126	.cpu_disable		= psci_cpu_disable,
127	.cpu_die		= psci_cpu_die,
128	.cpu_kill		= psci_cpu_kill,
129#endif
130};