1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * CPU kernel entry/exit control
4 *
5 * Copyright (C) 2013 ARM Ltd.
6 */
7
8 #include <linux/acpi.h>
9 #include <linux/cache.h>
10 #include <linux/errno.h>
11 #include <linux/of.h>
12 #include <linux/string.h>
13 #include <asm/acpi.h>
14 #include <asm/cpu_ops.h>
15 #include <asm/smp_plat.h>
16
17 extern const struct cpu_operations smp_spin_table_ops;
18 #ifdef CONFIG_ARM64_ACPI_PARKING_PROTOCOL
19 extern const struct cpu_operations acpi_parking_protocol_ops;
20 #endif
21 extern const struct cpu_operations cpu_psci_ops;
22
23 static const struct cpu_operations *cpu_ops[NR_CPUS] __ro_after_init;
24
25 static const struct cpu_operations *const dt_supported_cpu_ops[] __initconst = {
26 &smp_spin_table_ops,
27 &cpu_psci_ops,
28 NULL,
29 };
30
31 static const struct cpu_operations *const acpi_supported_cpu_ops[] __initconst = {
32 #ifdef CONFIG_ARM64_ACPI_PARKING_PROTOCOL
33 &acpi_parking_protocol_ops,
34 #endif
35 &cpu_psci_ops,
36 NULL,
37 };
38
39 static const struct cpu_operations * __init cpu_get_ops(const char *name)
40 {
41 const struct cpu_operations *const *ops;
42
43 ops = acpi_disabled ? dt_supported_cpu_ops : acpi_supported_cpu_ops;
44
45 while (*ops) {
46 if (!strcmp(name, (*ops)->name))
47 return *ops;
48
49 ops++;
50 }
51
52 return NULL;
53 }
54
55 static const char *__init cpu_read_enable_method(int cpu)
56 {
57 const char *enable_method;
58
59 if (acpi_disabled) {
60 struct device_node *dn = of_get_cpu_node(cpu, NULL);
61
62 if (!dn) {
63 if (!cpu)
64 pr_err("Failed to find device node for boot cpu\n");
65 return NULL;
66 }
67
68 enable_method = of_get_property(dn, "enable-method", NULL);
69 if (!enable_method) {
70 /*
71 * The boot CPU may not have an enable method (e.g.
72 * when spin-table is used for secondaries).
73 * Don't warn spuriously.
74 */
75 if (cpu != 0)
76 pr_err("%pOF: missing enable-method property\n",
77 dn);
78 }
79 of_node_put(dn);
80 } else {
81 enable_method = acpi_get_enable_method(cpu);
82 if (!enable_method) {
83 /*
84 * In ACPI systems the boot CPU does not require
85 * checking the enable method since for some
86 * boot protocol (ie parking protocol) it need not
87 * be initialized. Don't warn spuriously.
88 */
89 if (cpu != 0)
90 pr_err("Unsupported ACPI enable-method\n");
91 }
92 }
93
94 return enable_method;
95 }
96 /*
97 * Read a cpu's enable method and record it in cpu_ops.
98 */
99 int __init init_cpu_ops(int cpu)
100 {
101 const char *enable_method = cpu_read_enable_method(cpu);
102
103 if (!enable_method)
104 return -ENODEV;
105
106 cpu_ops[cpu] = cpu_get_ops(enable_method);
107 if (!cpu_ops[cpu]) {
108 pr_warn("Unsupported enable-method: %s\n", enable_method);
109 return -EOPNOTSUPP;
110 }
111
112 return 0;
113 }
114
115 const struct cpu_operations *get_cpu_ops(int cpu)
116 {
117 return cpu_ops[cpu];
118 }
119
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