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: */
  27 static DECLARE_BITMAP(irqs_resend, IRQ_BITMAP_BITS);
  28
  29 /*
  30  * Run software resends of IRQ's
  31  */
  32 static 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: */
  48 static 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  */
  57 void 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 }