1 /*
2 * linux/kernel/irq/resend.c
3 *
4 * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
5 * Copyright (C) 2005-2006, Thomas Gleixner
6 *
7 * This file contains the IRQ-resend code
8 *
9 * If the interrupt is waiting to be processed, we try to re-run it.
10 * We can't directly run it from here since the caller might be in an
11 * interrupt-protected region. Not all irq controller chips can
12 * retrigger interrupts at the hardware level, so in those cases
13 * we allow the resending of IRQs via a tasklet.
14 */
15
16 #include <linux/irq.h>
17 #include <linux/module.h>
18 #include <linux/random.h>
19 #include <linux/interrupt.h>
20
21 #include "internals.h"
22
23 #ifdef CONFIG_HARDIRQS_SW_RESEND
24
25 /* Bitmap to handle software resend of interrupts: */
26 static DECLARE_BITMAP(irqs_resend, NR_IRQS);
27
28 /*
29 * Run software resends of IRQ's
30 */
31 static void resend_irqs(unsigned long arg)
32 {
33 struct irq_desc *desc;
34 int irq;
35
36 while (!bitmap_empty(irqs_resend, nr_irqs)) {
37 irq = find_first_bit(irqs_resend, nr_irqs);
38 clear_bit(irq, irqs_resend);
39 desc = irq_to_desc(irq);
40 local_irq_disable();
41 desc->handle_irq(irq, desc);
42 local_irq_enable();
43 }
44 }
45
46 /* Tasklet to handle resend: */
47 static DECLARE_TASKLET(resend_tasklet, resend_irqs, 0);
48
49 #endif
50
51 /*
52 * IRQ resend
53 *
54 * Is called with interrupts disabled and desc->lock held.
55 */
56 void check_irq_resend(struct irq_desc *desc, unsigned int irq)
57 {
58 unsigned int status = desc->status;
59
60 /*
61 * Make sure the interrupt is enabled, before resending it:
62 */
63 desc->chip->enable(irq);
64
65 /*
66 * We do not resend level type interrupts. Level type
67 * interrupts are resent by hardware when they are still
68 * active.
69 */
70 if ((status & (IRQ_LEVEL | IRQ_PENDING | IRQ_REPLAY)) == IRQ_PENDING) {
71 desc->status = (status & ~IRQ_PENDING) | IRQ_REPLAY;
72
73 if (!desc->chip || !desc->chip->retrigger ||
74 !desc->chip->retrigger(irq)) {
75 #ifdef CONFIG_HARDIRQS_SW_RESEND
76 /* Set it pending and activate the softirq: */
77 set_bit(irq, irqs_resend);
78 tasklet_schedule(&resend_tasklet);
79 #endif
80 }
81 }
82 }
83
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