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
27 extern const struct cpu_operations smp_spin_table_ops;
28 extern const struct cpu_operations acpi_parking_protocol_ops;
29 extern const struct cpu_operations cpu_psci_ops;
30
31 const struct cpu_operations *cpu_ops[NR_CPUS];
32
33 static const struct cpu_operations *dt_supported_cpu_ops[] __initconst = {
34 &smp_spin_table_ops,
35 &cpu_psci_ops,
36 NULL,
37 };
38
39 static const struct cpu_operations *acpi_supported_cpu_ops[] __initconst = {
40 #ifdef CONFIG_ARM64_ACPI_PARKING_PROTOCOL
41 &acpi_parking_protocol_ops,
42 #endif
43 &cpu_psci_ops,
44 NULL,
45 };
46
cpu_get_ops(const char * name)47 static const struct cpu_operations * __init cpu_get_ops(const char *name)
48 {
49 const struct cpu_operations **ops;
50
51 ops = acpi_disabled ? dt_supported_cpu_ops : acpi_supported_cpu_ops;
52
53 while (*ops) {
54 if (!strcmp(name, (*ops)->name))
55 return *ops;
56
57 ops++;
58 }
59
60 return NULL;
61 }
62
cpu_read_enable_method(int cpu)63 static const char *__init cpu_read_enable_method(int cpu)
64 {
65 const char *enable_method;
66
67 if (acpi_disabled) {
68 struct device_node *dn = of_get_cpu_node(cpu, NULL);
69
70 if (!dn) {
71 if (!cpu)
72 pr_err("Failed to find device node for boot cpu\n");
73 return NULL;
74 }
75
76 enable_method = of_get_property(dn, "enable-method", NULL);
77 if (!enable_method) {
78 /*
79 * The boot CPU may not have an enable method (e.g.
80 * when spin-table is used for secondaries).
81 * Don't warn spuriously.
82 */
83 if (cpu != 0)
84 pr_err("%s: missing enable-method property\n",
85 dn->full_name);
86 }
87 of_node_put(dn);
88 } else {
89 enable_method = acpi_get_enable_method(cpu);
90 if (!enable_method) {
91 /*
92 * In ACPI systems the boot CPU does not require
93 * checking the enable method since for some
94 * boot protocol (ie parking protocol) it need not
95 * be initialized. Don't warn spuriously.
96 */
97 if (cpu != 0)
98 pr_err("Unsupported ACPI enable-method\n");
99 }
100 }
101
102 return enable_method;
103 }
104 /*
105 * Read a cpu's enable method and record it in cpu_ops.
106 */
cpu_read_ops(int cpu)107 int __init cpu_read_ops(int cpu)
108 {
109 const char *enable_method = cpu_read_enable_method(cpu);
110
111 if (!enable_method)
112 return -ENODEV;
113
114 cpu_ops[cpu] = cpu_get_ops(enable_method);
115 if (!cpu_ops[cpu]) {
116 pr_warn("Unsupported enable-method: %s\n", enable_method);
117 return -EOPNOTSUPP;
118 }
119
120 return 0;
121 }
122