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 */
resend_irqs(unsigned long arg)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 if (!desc)
42 continue;
43 local_irq_disable();
44 desc->handle_irq(desc);
45 local_irq_enable();
46 }
47 }
48
49 /* Tasklet to handle resend: */
50 static DECLARE_TASKLET(resend_tasklet, resend_irqs, 0);
51
52 #endif
53
54 /*
55 * IRQ resend
56 *
57 * Is called with interrupts disabled and desc->lock held.
58 */
check_irq_resend(struct irq_desc * desc)59 void check_irq_resend(struct irq_desc *desc)
60 {
61 /*
62 * We do not resend level type interrupts. Level type
63 * interrupts are resent by hardware when they are still
64 * active. Clear the pending bit so suspend/resume does not
65 * get confused.
66 */
67 if (irq_settings_is_level(desc)) {
68 desc->istate &= ~IRQS_PENDING;
69 return;
70 }
71 if (desc->istate & IRQS_REPLAY)
72 return;
73 if (desc->istate & IRQS_PENDING) {
74 desc->istate &= ~IRQS_PENDING;
75 desc->istate |= IRQS_REPLAY;
76
77 if (!desc->irq_data.chip->irq_retrigger ||
78 !desc->irq_data.chip->irq_retrigger(&desc->irq_data)) {
79 #ifdef CONFIG_HARDIRQS_SW_RESEND
80 unsigned int irq = irq_desc_get_irq(desc);
81
82 /*
83 * If the interrupt is running in the thread
84 * context of the parent irq we need to be
85 * careful, because we cannot trigger it
86 * directly.
87 */
88 if (irq_settings_is_nested_thread(desc)) {
89 /*
90 * If the parent_irq is valid, we
91 * retrigger the parent, otherwise we
92 * do nothing.
93 */
94 if (!desc->parent_irq)
95 return;
96 irq = desc->parent_irq;
97 }
98 /* Set it pending and activate the softirq: */
99 set_bit(irq, irqs_resend);
100 tasklet_schedule(&resend_tasklet);
101 #endif
102 }
103 }
104 }
105