/* * CPU kernel entry/exit control * * Copyright (C) 2013 ARM Ltd. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program.  If not, see <http://www.gnu.org/licenses/>. */ #include <linux/acpi.h>#include <linux/cache.h>#include <linux/errno.h>#include <linux/of.h>#include <linux/string.h>#include <asm/acpi.h>#include <asm/cpu_ops.h>#include <asm/smp_plat.h> extern const struct cpu_operations smp_spin_table_ops;extern const struct cpu_operations acpi_parking_protocol_ops;extern const struct cpu_operations cpu_psci_ops; const struct cpu_operations *cpu_ops[NR_CPUS] __ro_after_init; static const struct cpu_operations *dt_supported_cpu_ops[] __initconst = {	&smp_spin_table_ops,	&cpu_psci_ops,	NULL,}; static const struct cpu_operations *acpi_supported_cpu_ops[] __initconst = {#ifdef CONFIG_ARM64_ACPI_PARKING_PROTOCOL	&acpi_parking_protocol_ops,#endif	&cpu_psci_ops,	NULL,}; static const struct cpu_operations * __init cpu_get_ops(const char *name){	const struct cpu_operations **ops; 	ops = acpi_disabled ? dt_supported_cpu_ops : acpi_supported_cpu_ops; 	while (*ops) {		if (!strcmp(name, (*ops)->name))			return *ops; 		ops++;	} 	return NULL;} static const char *__init cpu_read_enable_method(int cpu){	const char *enable_method; 	if (acpi_disabled) {		struct device_node *dn = of_get_cpu_node(cpu, NULL); 		if (!dn) {			if (!cpu)				pr_err("Failed to find device node for boot cpu\n");			return NULL;		} 		enable_method = of_get_property(dn, "enable-method", NULL);		if (!enable_method) {			/*			 * The boot CPU may not have an enable method (e.g.			 * when spin-table is used for secondaries).			 * Don't warn spuriously.			 */			if (cpu != 0)				pr_err("%pOF: missing enable-method property\n",					dn);		}	} else {		enable_method = acpi_get_enable_method(cpu);		if (!enable_method) {			/*			 * In ACPI systems the boot CPU does not require			 * checking the enable method since for some			 * boot protocol (ie parking protocol) it need not			 * be initialized. Don't warn spuriously.			 */			if (cpu != 0)				pr_err("Unsupported ACPI enable-method\n");		}	} 	return enable_method;}/* * Read a cpu's enable method and record it in cpu_ops. */int __init cpu_read_ops(int cpu){	const char *enable_method = cpu_read_enable_method(cpu); 	if (!enable_method)		return -ENODEV; 	cpu_ops[cpu] = cpu_get_ops(enable_method);	if (!cpu_ops[cpu]) {		pr_warn("Unsupported enable-method: %s\n", enable_method);		return -EOPNOTSUPP;	} 	return 0;}