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 if (!desc)
40 continue;
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 }