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) 2013 ARM Limited
 12 *
 13 * Author: Will Deacon <will.deacon@arm.com>
 14 */
 15
 16#define pr_fmt(fmt) "psci: " fmt
 17
 18#include <linux/init.h>
 19#include <linux/of.h>
 20#include <linux/smp.h>
 21#include <linux/delay.h>
 22#include <linux/psci.h>
 23
 24#include <uapi/linux/psci.h>
 25
 26#include <asm/compiler.h>
 27#include <asm/cpu_ops.h>
 28#include <asm/errno.h>
 29#include <asm/smp_plat.h>
 30
 31static int __init cpu_psci_cpu_init(unsigned int cpu)
 32{
 33	return 0;
 34}
 35
 36static int __init cpu_psci_cpu_prepare(unsigned int cpu)
 37{
 38	if (!psci_ops.cpu_on) {
 39		pr_err("no cpu_on method, not booting CPU%d\n", cpu);
 40		return -ENODEV;
 41	}
 42
 43	return 0;
 44}
 45
 46static int cpu_psci_cpu_boot(unsigned int cpu)
 47{
 48	int err = psci_ops.cpu_on(cpu_logical_map(cpu), __pa(secondary_entry));
 49	if (err)
 50		pr_err("failed to boot CPU%d (%d)\n", cpu, err);
 51
 52	return err;
 53}
 54
 55#ifdef CONFIG_HOTPLUG_CPU
 56static int cpu_psci_cpu_disable(unsigned int cpu)
 57{
 58	/* Fail early if we don't have CPU_OFF support */
 59	if (!psci_ops.cpu_off)
 60		return -EOPNOTSUPP;
 61
 62	/* Trusted OS will deny CPU_OFF */
 63	if (psci_tos_resident_on(cpu))
 64		return -EPERM;
 65
 66	return 0;
 67}
 68
 69static void cpu_psci_cpu_die(unsigned int cpu)
 70{
 71	int ret;
 72	/*
 73	 * There are no known implementations of PSCI actually using the
 74	 * power state field, pass a sensible default for now.
 75	 */
 76	u32 state = PSCI_POWER_STATE_TYPE_POWER_DOWN <<
 77		    PSCI_0_2_POWER_STATE_TYPE_SHIFT;
 78
 79	ret = psci_ops.cpu_off(state);
 80
 81	pr_crit("unable to power off CPU%u (%d)\n", cpu, ret);
 82}
 83
 84static int cpu_psci_cpu_kill(unsigned int cpu)
 85{
 86	int err, i;
 87
 88	if (!psci_ops.affinity_info)
 89		return 0;
 90	/*
 91	 * cpu_kill could race with cpu_die and we can
 92	 * potentially end up declaring this cpu undead
 93	 * while it is dying. So, try again a few times.
 94	 */
 95
 96	for (i = 0; i < 10; i++) {
 97		err = psci_ops.affinity_info(cpu_logical_map(cpu), 0);
 98		if (err == PSCI_0_2_AFFINITY_LEVEL_OFF) {
 99			pr_info("CPU%d killed.\n", cpu);
100			return 0;
101		}
102
103		msleep(10);
104		pr_info("Retrying again to check for CPU kill\n");
105	}
106
107	pr_warn("CPU%d may not have shut down cleanly (AFFINITY_INFO reports %d)\n",
108			cpu, err);
109	return -ETIMEDOUT;
110}
111#endif
112
113const struct cpu_operations cpu_psci_ops = {
114	.name		= "psci",
115#ifdef CONFIG_CPU_IDLE
116	.cpu_init_idle	= psci_cpu_init_idle,
117	.cpu_suspend	= psci_cpu_suspend_enter,
118#endif
119	.cpu_init	= cpu_psci_cpu_init,
120	.cpu_prepare	= cpu_psci_cpu_prepare,
121	.cpu_boot	= cpu_psci_cpu_boot,
122#ifdef CONFIG_HOTPLUG_CPU
123	.cpu_disable	= cpu_psci_cpu_disable,
124	.cpu_die	= cpu_psci_cpu_die,
125	.cpu_kill	= cpu_psci_cpu_kill,
126#endif
127};
128