LXR linux/arch/arm64/kernel/cpu

   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
  17extern const struct cpu_operations smp_spin_table_ops;
  18#ifdef CONFIG_ARM64_ACPI_PARKING_PROTOCOL
  19extern const struct cpu_operations acpi_parking_protocol_ops;
  20#endif
  21extern const struct cpu_operations cpu_psci_ops;
  22
  23static const struct cpu_operations *cpu_ops[NR_CPUS] __ro_after_init;
  24
  25static const struct cpu_operations *const dt_supported_cpu_ops[] __initconst = {
  26        &smp_spin_table_ops,
  27        &cpu_psci_ops,
  28        NULL,
  29};
  30
  31static 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
  39static 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
  55static 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 */
  99int __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
 115const struct cpu_operations *get_cpu_ops(int cpu)
 116{
 117        return cpu_ops[cpu];
 118}
 119