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