1/*
  2 * This program is free software; you can redistribute it and/or modify
  3 * it under the terms of the GNU General Public License version 2 as
  4 * published by the Free Software Foundation.
  5 *
  6 * This program is distributed in the hope that it will be useful,
  7 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  8 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  9 * GNU General Public License for more details.
 10 *
 11 * Copyright (C) 2012 ARM Limited
 12 *
 13 * Author: Will Deacon <will.deacon@arm.com>
 14 */
 15
 16#include <linux/init.h>
 17#include <linux/smp.h>
 18#include <linux/of.h>
 19#include <linux/delay.h>
 20#include <linux/psci.h>
 21
 22#include <uapi/linux/psci.h>
 23
 24#include <asm/psci.h>
 25#include <asm/smp_plat.h>
 26
 27/*
 28 * psci_smp assumes that the following is true about PSCI:
 29 *
 30 * cpu_suspend   Suspend the execution on a CPU
 31 * @state        we don't currently describe affinity levels, so just pass 0.
 32 * @entry_point  the first instruction to be executed on return
 33 * returns 0  success, < 0 on failure
 34 *
 35 * cpu_off       Power down a CPU
 36 * @state        we don't currently describe affinity levels, so just pass 0.
 37 * no return on successful call
 38 *
 39 * cpu_on        Power up a CPU
 40 * @cpuid        cpuid of target CPU, as from MPIDR
 41 * @entry_point  the first instruction to be executed on return
 42 * returns 0  success, < 0 on failure
 43 *
 44 * migrate       Migrate the context to a different CPU
 45 * @cpuid        cpuid of target CPU, as from MPIDR
 46 * returns 0  success, < 0 on failure
 47 *
 48 */
 49
 50extern void secondary_startup(void);
 51
 52static int psci_boot_secondary(unsigned int cpu, struct task_struct *idle)
 53{
 54	if (psci_ops.cpu_on)
 55		return psci_ops.cpu_on(cpu_logical_map(cpu),
 56					virt_to_idmap(&secondary_startup));
 57	return -ENODEV;
 58}
 59
 60#ifdef CONFIG_HOTPLUG_CPU
 61int 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
 74void 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
 86int 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};