kernel/irq/resend.c

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