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
123struct smp_operations __initdata psci_smp_ops = {
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};
131