// SPDX-License-Identifier: GPL-2.0-or-later/* * Copyright 2012 Linaro Ltd. */ #include <linux/cpuidle.h>#include <linux/of.h>#include <asm/cpuidle.h> extern struct of_cpuidle_method __cpuidle_method_of_table[]; static const struct of_cpuidle_method __cpuidle_method_of_table_sentinel	__used __section("__cpuidle_method_of_table_end"); static struct cpuidle_ops cpuidle_ops[NR_CPUS] __ro_after_init; /** * arm_cpuidle_simple_enter() - a wrapper to cpu_do_idle() * @dev: not used * @drv: not used * @index: not used * * A trivial wrapper to allow the cpu_do_idle function to be assigned as a * cpuidle callback by matching the function signature. * * Returns the index passed as parameter */__cpuidle int arm_cpuidle_simple_enter(struct cpuidle_device *dev, struct				       cpuidle_driver *drv, int index){	cpu_do_idle(); 	return index;} /** * arm_cpuidle_suspend() - function to enter low power idle states * @index: an integer used as an identifier for the low level PM callbacks * * This function calls the underlying arch specific low level PM code as * registered at the init time. * * Returns the result of the suspend callback. */int arm_cpuidle_suspend(int index){	int cpu = smp_processor_id(); 	return cpuidle_ops[cpu].suspend(index);} /** * arm_cpuidle_get_ops() - find a registered cpuidle_ops by name * @method: the method name * * Search in the __cpuidle_method_of_table array the cpuidle ops matching the * method name. * * Returns a struct cpuidle_ops pointer, NULL if not found. */static const struct cpuidle_ops *__init arm_cpuidle_get_ops(const char *method){	struct of_cpuidle_method *m = __cpuidle_method_of_table; 	for (; m->method; m++)		if (!strcmp(m->method, method))			return m->ops; 	return NULL;} /** * arm_cpuidle_read_ops() - Initialize the cpuidle ops with the device tree * @dn: a pointer to a struct device node corresponding to a cpu node * @cpu: the cpu identifier * * Get the method name defined in the 'enable-method' property, retrieve the * associated cpuidle_ops and do a struct copy. This copy is needed because all * cpuidle_ops are tagged __initconst and will be unloaded after the init * process. * * Return 0 on sucess, -ENOENT if no 'enable-method' is defined, -EOPNOTSUPP if * no cpuidle_ops is registered for the 'enable-method', or if either init or * suspend callback isn't defined. */static int __init arm_cpuidle_read_ops(struct device_node *dn, int cpu){	const char *enable_method;	const struct cpuidle_ops *ops; 	enable_method = of_get_property(dn, "enable-method", NULL);	if (!enable_method)		return -ENOENT; 	ops = arm_cpuidle_get_ops(enable_method);	if (!ops) {		pr_warn("%pOF: unsupported enable-method property: %s\n",			dn, enable_method);		return -EOPNOTSUPP;	} 	if (!ops->init || !ops->suspend) {		pr_warn("cpuidle_ops '%s': no init or suspend callback\n",			enable_method);		return -EOPNOTSUPP;	} 	cpuidle_ops[cpu] = *ops; /* structure copy */ 	pr_notice("cpuidle: enable-method property '%s'"		  " found operations\n", enable_method); 	return 0;} /** * arm_cpuidle_init() - Initialize cpuidle_ops for a specific cpu * @cpu: the cpu to be initialized * * Initialize the cpuidle ops with the device for the cpu and then call * the cpu's idle initialization callback. This may fail if the underlying HW * is not operational. * * Returns: *  0 on success, *  -ENODEV if it fails to find the cpu node in the device tree, *  -EOPNOTSUPP if it does not find a registered and valid cpuidle_ops for *  this cpu, *  -ENOENT if it fails to find an 'enable-method' property, *  -ENXIO if the HW reports a failure or a misconfiguration, *  -ENOMEM if the HW report an memory allocation failure  */int __init arm_cpuidle_init(int cpu){	struct device_node *cpu_node = of_cpu_device_node_get(cpu);	int ret; 	if (!cpu_node)		return -ENODEV; 	ret = arm_cpuidle_read_ops(cpu_node, cpu);	if (!ret)		ret = cpuidle_ops[cpu].init(cpu_node, cpu); 	of_node_put(cpu_node); 	return ret;}