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, IRQ_BITMAP_BITS);
27
28 /*
29 * Run software resends of IRQ's
30 */
resend_irqs(unsigned long arg)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 */
check_irq_resend(struct irq_desc * desc,unsigned int irq)56 void check_irq_resend(struct irq_desc *desc, unsigned int irq)
57 {
58 /*
59 * We do not resend level type interrupts. Level type
60 * interrupts are resent by hardware when they are still
61 * active.
62 */
63 if (irq_settings_is_level(desc))
64 return;
65 if (desc->istate & IRQS_REPLAY)
66 return;
67 if (desc->istate & IRQS_PENDING) {
68 desc->istate &= ~IRQS_PENDING;
69 desc->istate |= IRQS_REPLAY;
70
71 if (!desc->irq_data.chip->irq_retrigger ||
72 !desc->irq_data.chip->irq_retrigger(&desc->irq_data)) {
73 #ifdef CONFIG_HARDIRQS_SW_RESEND
74 /* Set it pending and activate the softirq: */
75 set_bit(irq, irqs_resend);
76 tasklet_schedule(&resend_tasklet);
77 #endif
78 }
79 }
80 }
81