// SPDX-License-Identifier: GPL-2.0

  /*

   * Copyright (C) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
   *
   * This file contains power management functions related to interrupts.
   */
  
  #include <linux/irq.h>
  #include <linux/module.h>
  #include <linux/interrupt.h>

  #include <linux/suspend.h>

  #include <linux/syscore_ops.h>

  
  #include "internals.h"

  bool irq_pm_check_wakeup(struct irq_desc *desc)
  {
  	if (irqd_is_wakeup_armed(&desc->irq_data)) {
  		irqd_clear(&desc->irq_data, IRQD_WAKEUP_ARMED);
  		desc->istate |= IRQS_SUSPENDED | IRQS_PENDING;
  		desc->depth++;
  		irq_disable(desc);

  		pm_system_irq_wakeup(irq_desc_get_irq(desc));

  		return true;
  	}
  	return false;
  }

  /*
   * Called from __setup_irq() with desc->lock held after @action has
   * been installed in the action chain.
   */
  void irq_pm_install_action(struct irq_desc *desc, struct irqaction *action)
  {
  	desc->nr_actions++;
  
  	if (action->flags & IRQF_FORCE_RESUME)
  		desc->force_resume_depth++;
  
  	WARN_ON_ONCE(desc->force_resume_depth &&
  		     desc->force_resume_depth != desc->nr_actions);
  
  	if (action->flags & IRQF_NO_SUSPEND)
  		desc->no_suspend_depth++;

  	else if (action->flags & IRQF_COND_SUSPEND)
  		desc->cond_suspend_depth++;

  
  	WARN_ON_ONCE(desc->no_suspend_depth &&

  		     (desc->no_suspend_depth +
  			desc->cond_suspend_depth) != desc->nr_actions);

  }
  
  /*
   * Called from __free_irq() with desc->lock held after @action has
   * been removed from the action chain.
   */
  void irq_pm_remove_action(struct irq_desc *desc, struct irqaction *action)
  {
  	desc->nr_actions--;
  
  	if (action->flags & IRQF_FORCE_RESUME)
  		desc->force_resume_depth--;
  
  	if (action->flags & IRQF_NO_SUSPEND)
  		desc->no_suspend_depth--;

  	else if (action->flags & IRQF_COND_SUSPEND)
  		desc->cond_suspend_depth--;

  }

  static bool suspend_device_irq(struct irq_desc *desc)

  {

  	unsigned long chipflags = irq_desc_get_chip(desc)->flags;
  	struct irq_data *irqd = &desc->irq_data;

  	if (!desc->action || irq_desc_is_chained(desc) ||
  	    desc->no_suspend_depth)

  		return false;

  	if (irqd_is_wakeup_set(irqd)) {
  		irqd_set(irqd, IRQD_WAKEUP_ARMED);
  
  		if ((chipflags & IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND) &&
  		     irqd_irq_disabled(irqd)) {
  			/*
  			 * Interrupt marked for wakeup is in disabled state.
  			 * Enable interrupt here to unmask/enable in irqchip
  			 * to be able to resume with such interrupts.
  			 */
  			__enable_irq(desc);
  			irqd_set(irqd, IRQD_IRQ_ENABLED_ON_SUSPEND);
  		}

  		/*
  		 * We return true here to force the caller to issue
  		 * synchronize_irq(). We need to make sure that the
  		 * IRQD_WAKEUP_ARMED is visible before we return from
  		 * suspend_device_irqs().
  		 */
  		return true;
  	}

  	desc->istate |= IRQS_SUSPENDED;

  	__disable_irq(desc);

  
  	/*
  	 * Hardware which has no wakeup source configuration facility
  	 * requires that the non wakeup interrupts are masked at the
  	 * chip level. The chip implementation indicates that with
  	 * IRQCHIP_MASK_ON_SUSPEND.
  	 */

  	if (chipflags & IRQCHIP_MASK_ON_SUSPEND)

  		mask_irq(desc);

  	return true;

  }

  /**
   * suspend_device_irqs - disable all currently enabled interrupt lines
   *

   * During system-wide suspend or hibernation device drivers need to be
   * prevented from receiving interrupts and this function is provided
   * for this purpose.
   *
   * So we disable all interrupts and mark them IRQS_SUSPENDED except

   * for those which are unused, those which are marked as not

   * suspendable via an interrupt request with the flag IRQF_NO_SUSPEND

   * set and those which are marked as active wakeup sources.
   *
   * The active wakeup sources are handled by the flow handler entry
   * code which checks for the IRQD_WAKEUP_ARMED flag, suspends the
   * interrupt and notifies the pm core about the wakeup.

   */
  void suspend_device_irqs(void)
  {
  	struct irq_desc *desc;
  	int irq;
  
  	for_each_irq_desc(irq, desc) {
  		unsigned long flags;

  		bool sync;

  		if (irq_settings_is_nested_thread(desc))
  			continue;

  		raw_spin_lock_irqsave(&desc->lock, flags);

  		sync = suspend_device_irq(desc);

  		raw_spin_unlock_irqrestore(&desc->lock, flags);

  		if (sync)

  			synchronize_irq(irq);

  	}

  }
  EXPORT_SYMBOL_GPL(suspend_device_irqs);

  static void resume_irq(struct irq_desc *desc)

  {

  	struct irq_data *irqd = &desc->irq_data;
  
  	irqd_clear(irqd, IRQD_WAKEUP_ARMED);
  
  	if (irqd_is_enabled_on_suspend(irqd)) {
  		/*
  		 * Interrupt marked for wakeup was enabled during suspend
  		 * entry. Disable such interrupts to restore them back to
  		 * original state.
  		 */
  		__disable_irq(desc);
  		irqd_clear(irqd, IRQD_IRQ_ENABLED_ON_SUSPEND);
  	}

  	if (desc->istate & IRQS_SUSPENDED)
  		goto resume;

  	/* Force resume the interrupt? */
  	if (!desc->force_resume_depth)

  		return;
  
  	/* Pretend that it got disabled ! */
  	desc->depth++;

  	irq_state_set_disabled(desc);
  	irq_state_set_masked(desc);

  resume:
  	desc->istate &= ~IRQS_SUSPENDED;

  	__enable_irq(desc);

  }

  static void resume_irqs(bool want_early)

  {
  	struct irq_desc *desc;
  	int irq;
  
  	for_each_irq_desc(irq, desc) {
  		unsigned long flags;

  		bool is_early = desc->action &&
  			desc->action->flags & IRQF_EARLY_RESUME;

  		if (!is_early && want_early)

  			continue;

  		if (irq_settings_is_nested_thread(desc))
  			continue;

  		raw_spin_lock_irqsave(&desc->lock, flags);

  		resume_irq(desc);

  		raw_spin_unlock_irqrestore(&desc->lock, flags);

  	}
  }

  
  /**

   * rearm_wake_irq - rearm a wakeup interrupt line after signaling wakeup
   * @irq: Interrupt to rearm
   */
  void rearm_wake_irq(unsigned int irq)
  {
  	unsigned long flags;
  	struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);

  	if (!desc)

  		return;

  	if (!(desc->istate & IRQS_SUSPENDED) ||
  	    !irqd_is_wakeup_set(&desc->irq_data))
  		goto unlock;

  	desc->istate &= ~IRQS_SUSPENDED;
  	irqd_set(&desc->irq_data, IRQD_WAKEUP_ARMED);
  	__enable_irq(desc);

  unlock:

  	irq_put_desc_busunlock(desc, flags);
  }
  
  /**

   * irq_pm_syscore_ops - enable interrupt lines early
   *
   * Enable all interrupt lines with %IRQF_EARLY_RESUME set.
   */
  static void irq_pm_syscore_resume(void)
  {
  	resume_irqs(true);
  }
  
  static struct syscore_ops irq_pm_syscore_ops = {
  	.resume		= irq_pm_syscore_resume,
  };
  
  static int __init irq_pm_init_ops(void)
  {
  	register_syscore_ops(&irq_pm_syscore_ops);
  	return 0;
  }
  
  device_initcall(irq_pm_init_ops);
  
  /**
   * resume_device_irqs - enable interrupt lines disabled by suspend_device_irqs()
   *
   * Enable all non-%IRQF_EARLY_RESUME interrupt lines previously
   * disabled by suspend_device_irqs() that have the IRQS_SUSPENDED flag
   * set as well as those with %IRQF_FORCE_RESUME.
   */
  void resume_device_irqs(void)
  {
  	resume_irqs(false);
  }

  EXPORT_SYMBOL_GPL(resume_device_irqs);