/*
   * linux/kernel/irq/resend.c
   *
   * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
   * Copyright (C) 2005-2006, Thomas Gleixner
   *
   * This file contains the IRQ-resend code
   *
   * If the interrupt is waiting to be processed, we try to re-run it.
   * We can't directly run it from here since the caller might be in an
   * interrupt-protected region. Not all irq controller chips can
   * retrigger interrupts at the hardware level, so in those cases
   * we allow the resending of IRQs via a tasklet.
   */
  
  #include <linux/irq.h>
  #include <linux/module.h>
  #include <linux/random.h>
  #include <linux/interrupt.h>
  
  #include "internals.h"
  
  #ifdef CONFIG_HARDIRQS_SW_RESEND
  
  /* Bitmap to handle software resend of interrupts: */

  static DECLARE_BITMAP(irqs_resend, IRQ_BITMAP_BITS);

  
  /*
   * Run software resends of IRQ's
   */
  static void resend_irqs(unsigned long arg)
  {
  	struct irq_desc *desc;
  	int irq;

  	while (!bitmap_empty(irqs_resend, nr_irqs)) {
  		irq = find_first_bit(irqs_resend, nr_irqs);

  		clear_bit(irq, irqs_resend);

  		desc = irq_to_desc(irq);

  		local_irq_disable();

  		desc->handle_irq(desc);

  		local_irq_enable();

  	}
  }
  
  /* Tasklet to handle resend: */
  static DECLARE_TASKLET(resend_tasklet, resend_irqs, 0);
  
  #endif
  
  /*
   * IRQ resend
   *
   * Is called with interrupts disabled and desc->lock held.
   */

  void check_irq_resend(struct irq_desc *desc)

  {

  	/*

  	 * We do not resend level type interrupts. Level type
  	 * interrupts are resent by hardware when they are still

  	 * active. Clear the pending bit so suspend/resume does not
  	 * get confused.

  	 */

  	if (irq_settings_is_level(desc)) {
  		desc->istate &= ~IRQS_PENDING;

  		return;

  	}

  	if (desc->istate & IRQS_REPLAY)
  		return;

  	if (desc->istate & IRQS_PENDING) {

  		desc->istate &= ~IRQS_PENDING;

  		desc->istate |= IRQS_REPLAY;

  		if (!desc->irq_data.chip->irq_retrigger ||
  		    !desc->irq_data.chip->irq_retrigger(&desc->irq_data)) {

  #ifdef CONFIG_HARDIRQS_SW_RESEND

  			unsigned int irq = irq_desc_get_irq(desc);

  			/*

  			 * If the interrupt is running in the thread
  			 * context of the parent irq we need to be
  			 * careful, because we cannot trigger it
  			 * directly.

  			 */

  			if (irq_settings_is_nested_thread(desc)) {
  				/*
  				 * If the parent_irq is valid, we
  				 * retrigger the parent, otherwise we
  				 * do nothing.
  				 */
  				if (!desc->parent_irq)
  					return;

  				irq = desc->parent_irq;

  			}

  			/* Set it pending and activate the softirq: */
  			set_bit(irq, irqs_resend);
  			tasklet_schedule(&resend_tasklet);
  #endif
  		}
  	}
  }