Quelle  syscore.c   Sprache: C

// 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_ops_list);
static DEFINE_MUTEX(syscore_ops_lock);

/**
 * register_syscore_ops - Register a set of system core operations.
 * @ops: System core operations to register.
 */
void register_syscore_ops(struct syscore_ops *ops)
{
 mutex_lock(&syscore_ops_lock);
 list_add_tail(&ops->node, &syscore_ops_list);
 mutex_unlock(&syscore_ops_lock);
}
EXPORT_SYMBOL_GPL(register_syscore_ops);

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

#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_ops *ops;
 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(ops, &syscore_ops_list, node)
  if (ops->suspend) {
   pm_pr_dbg("Calling %pS\n", ops->suspend);
   ret = ops->suspend();
   if (ret)
    goto err_out;
   WARN_ONCE(!irqs_disabled(),
    "Interrupts enabled after %pS\n", ops->suspend);
  }

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

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

 list_for_each_entry_continue(ops, &syscore_ops_list, node)
  if (ops->resume)
   ops->resume();

 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_ops *ops;

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

 list_for_each_entry(ops, &syscore_ops_list, node)
  if (ops->resume) {
   pm_pr_dbg("Calling %pS\n", ops->resume);
   ops->resume();
   WARN_ONCE(!irqs_disabled(),
    "Interrupts enabled after %pS\n", 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_ops *ops;

 mutex_lock(&syscore_ops_lock);

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

 mutex_unlock(&syscore_ops_lock);
}