1/*
2 * CPU kernel entry/exit control
3 *
4 * Copyright (C) 2013 ARM Ltd.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
17 */
18
19#include <linux/acpi.h>
20#include <linux/errno.h>
21#include <linux/of.h>
22#include <linux/string.h>
23#include <asm/acpi.h>
24#include <asm/cpu_ops.h>
25#include <asm/smp_plat.h>
26
27extern const struct cpu_operations smp_spin_table_ops;
28extern const struct cpu_operations cpu_psci_ops;
29
30const struct cpu_operations *cpu_ops[NR_CPUS];
31
32static const struct cpu_operations *supported_cpu_ops[] __initconst = {
33	&smp_spin_table_ops,
34	&cpu_psci_ops,
35	NULL,
36};
37
38static const struct cpu_operations * __init cpu_get_ops(const char *name)
39{
40	const struct cpu_operations **ops = supported_cpu_ops;
41
42	while (*ops) {
43		if (!strcmp(name, (*ops)->name))
44			return *ops;
45
46		ops++;
47	}
48
49	return NULL;
50}
51
52static const char *__init cpu_read_enable_method(int cpu)
53{
54	const char *enable_method;
55
56	if (acpi_disabled) {
57		struct device_node *dn = of_get_cpu_node(cpu, NULL);
58
59		if (!dn) {
60			if (!cpu)
61				pr_err("Failed to find device node for boot cpu\n");
62			return NULL;
63		}
64
65		enable_method = of_get_property(dn, "enable-method", NULL);
66		if (!enable_method) {
67			/*
68			 * The boot CPU may not have an enable method (e.g.
69			 * when spin-table is used for secondaries).
70			 * Don't warn spuriously.
71			 */
72			if (cpu != 0)
73				pr_err("%s: missing enable-method property\n",
74					dn->full_name);
75		}
76	} else {
77		enable_method = acpi_get_enable_method(cpu);
78		if (!enable_method)
79			pr_err("Unsupported ACPI enable-method\n");
80	}
81
82	return enable_method;
83}
84/*
85 * Read a cpu's enable method and record it in cpu_ops.
86 */
87int __init cpu_read_ops(int cpu)
88{
89	const char *enable_method = cpu_read_enable_method(cpu);
90
91	if (!enable_method)
92		return -ENODEV;
93
94	cpu_ops[cpu] = cpu_get_ops(enable_method);
95	if (!cpu_ops[cpu]) {
96		pr_warn("Unsupported enable-method: %s\n", enable_method);
97		return -EOPNOTSUPP;
98	}
99
100	return 0;
101}
102