LXR linux/kernel/irq/resend.c

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * linux/kernel/irq/resend.c
   4 *
   5 * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
   6 * Copyright (C) 2005-2006, Thomas Gleixner
   7 *
   8 * This file contains the IRQ-resend code
   9 *
  10 * If the interrupt is waiting to be processed, we try to re-run it.
  11 * We can't directly run it from here since the caller might be in an
  12 * interrupt-protected region. Not all irq controller chips can
  13 * retrigger interrupts at the hardware level, so in those cases
  14 * we allow the resending of IRQs via a tasklet.
  15 */
  16
  17#include <linux/irq.h>
  18#include <linux/module.h>
  19#include <linux/random.h>
  20#include <linux/interrupt.h>
  21
  22#include "internals.h"
  23
  24#ifdef CONFIG_HARDIRQS_SW_RESEND
  25
  26/* Bitmap to handle software resend of interrupts: */
  27static DECLARE_BITMAP(irqs_resend, IRQ_BITMAP_BITS);
  28
  29/*
  30 * Run software resends of IRQ's
  31 */
  32static void resend_irqs(unsigned long arg)
  33{
  34        struct irq_desc *desc;
  35        int irq;
  36
  37        while (!bitmap_empty(irqs_resend, nr_irqs)) {
  38                irq = find_first_bit(irqs_resend, nr_irqs);
  39                clear_bit(irq, irqs_resend);
  40                desc = irq_to_desc(irq);
  41                local_irq_disable();
  42                desc->handle_irq(desc);
  43                local_irq_enable();
  44        }
  45}
  46
  47/* Tasklet to handle resend: */
  48static DECLARE_TASKLET(resend_tasklet, resend_irqs, 0);
  49
  50#endif
  51
  52/*
  53 * IRQ resend
  54 *
  55 * Is called with interrupts disabled and desc->lock held.
  56 */
  57void check_irq_resend(struct irq_desc *desc)
  58{
  59        /*
  60         * We do not resend level type interrupts. Level type
  61         * interrupts are resent by hardware when they are still
  62         * active. Clear the pending bit so suspend/resume does not
  63         * get confused.
  64         */
  65        if (irq_settings_is_level(desc)) {
  66                desc->istate &= ~IRQS_PENDING;
  67                return;
  68        }
  69        if (desc->istate & IRQS_REPLAY)
  70                return;
  71        if (desc->istate & IRQS_PENDING) {
  72                desc->istate &= ~IRQS_PENDING;
  73                desc->istate |= IRQS_REPLAY;
  74
  75                if (!desc->irq_data.chip->irq_retrigger ||
  76                    !desc->irq_data.chip->irq_retrigger(&desc->irq_data)) {
  77#ifdef CONFIG_HARDIRQS_SW_RESEND
  78                        unsigned int irq = irq_desc_get_irq(desc);
  79
  80                        /*
  81                         * If the interrupt is running in the thread
  82                         * context of the parent irq we need to be
  83                         * careful, because we cannot trigger it
  84                         * directly.
  85                         */
  86                        if (irq_settings_is_nested_thread(desc)) {
  87                                /*
  88                                 * If the parent_irq is valid, we
  89                                 * retrigger the parent, otherwise we
  90                                 * do nothing.
  91                                 */
  92                                if (!desc->parent_irq)
  93                                        return;
  94                                irq = desc->parent_irq;
  95                        }
  96                        /* Set it pending and activate the softirq: */
  97                        set_bit(irq, irqs_resend);
  98                        tasklet_schedule(&resend_tasklet);
  99#endif
 100                }
 101        }
 102}
 103