// SPDX-License-Identifier: GPL-2.0
/*
 *  syscore.c - Execution of system core operations.
 *
 *  Copyright (C) 2011 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
 */

#include <linux/syscore_ops.h>
#include <linux/mutex.h>
#include <linux/module.h>
#include <linux/suspend.h>
#include <trace/events/power.h>

static LIST_HEAD(syscore_list);
static DEFINE_MUTEX(syscore_lock);

/**
 * register_syscore - Register a set of system core operations.
 * @syscore: System core operations to register.
 */
void register_syscore(struct syscore *syscore)
{
        mutex_lock(&syscore_lock);
        list_add_tail(&syscore->node, &syscore_list);
        mutex_unlock(&syscore_lock);
}
EXPORT_SYMBOL_GPL(register_syscore);

/**
 * unregister_syscore - Unregister a set of system core operations.
 * @syscore: System core operations to unregister.
 */
void unregister_syscore(struct syscore *syscore)
{
        mutex_lock(&syscore_lock);
        list_del(&syscore->node);
        mutex_unlock(&syscore_lock);
}
EXPORT_SYMBOL_GPL(unregister_syscore);

#ifdef CONFIG_PM_SLEEP
/**
 * syscore_suspend - Execute all the registered system core suspend callbacks.
 *
 * This function is executed with one CPU on-line and disabled interrupts.
 */
int syscore_suspend(void)
{
        struct syscore *syscore;
        int ret = 0;

        trace_suspend_resume(TPS("syscore_suspend"), 0, true);
        pm_pr_dbg("Checking wakeup interrupts\n");

        /* Return error code if there are any wakeup interrupts pending. */
        if (pm_wakeup_pending())
                return -EBUSY;

        WARN_ONCE(!irqs_disabled(),
                "Interrupts enabled before system core suspend.\n");

        list_for_each_entry_reverse(syscore, &syscore_list, node)
                if (syscore->ops->suspend) {
                        pm_pr_dbg("Calling %pS\n", syscore->ops->suspend);
                        ret = syscore->ops->suspend(syscore->data);
                        if (ret)
                                goto err_out;
                        WARN_ONCE(!irqs_disabled(),
                                "Interrupts enabled after %pS\n",
                                syscore->ops->suspend);
                }

        trace_suspend_resume(TPS("syscore_suspend"), 0, false);
        return 0;

 err_out:
        pr_err("PM: System core suspend callback %pS failed.\n",
               syscore->ops->suspend);

        list_for_each_entry_continue(syscore, &syscore_list, node)
                if (syscore->ops->resume)
                        syscore->ops->resume(syscore->data);

        return ret;
}
EXPORT_SYMBOL_GPL(syscore_suspend);

/**
 * syscore_resume - Execute all the registered system core resume callbacks.
 *
 * This function is executed with one CPU on-line and disabled interrupts.
 */
void syscore_resume(void)
{
        struct syscore *syscore;

        trace_suspend_resume(TPS("syscore_resume"), 0, true);
        WARN_ONCE(!irqs_disabled(),
                "Interrupts enabled before system core resume.\n");

        list_for_each_entry(syscore, &syscore_list, node)
                if (syscore->ops->resume) {
                        pm_pr_dbg("Calling %pS\n", syscore->ops->resume);
                        syscore->ops->resume(syscore->data);
                        WARN_ONCE(!irqs_disabled(),
                                "Interrupts enabled after %pS\n",
                                syscore->ops->resume);
                }
        trace_suspend_resume(TPS("syscore_resume"), 0, false);
}
EXPORT_SYMBOL_GPL(syscore_resume);
#endif /* CONFIG_PM_SLEEP */

/**
 * syscore_shutdown - Execute all the registered system core shutdown callbacks.
 */
void syscore_shutdown(void)
{
        struct syscore *syscore;

        mutex_lock(&syscore_lock);

        list_for_each_entry_reverse(syscore, &syscore_list, node)
                if (syscore->ops->shutdown) {
                        if (initcall_debug)
                                pr_info("PM: Calling %pS\n",
                                        syscore->ops->shutdown);
                        syscore->ops->shutdown(syscore->data);
                }

        mutex_unlock(&syscore_lock);
}