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authorThomas Gleixner <tglx@linutronix.de>2006-06-29 05:24:48 -0400
committerLinus Torvalds <torvalds@g5.osdl.org>2006-06-29 13:26:23 -0400
commita4633adcdbc15ac51afcd0e1395de58cee27cf92 (patch)
tree5ab714eba77aec7546e862ac6d63a22010819efe /kernel/irq/resend.c
parent11c869eaf1a9c97ef273f824a697fac017d68286 (diff)
[PATCH] genirq: add genirq sw IRQ-retrigger
Enable platforms that do not have a hardware-assisted hardirq-resend mechanism to resend them via a softirq-driven IRQ emulation mechanism. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel/irq/resend.c')
-rw-r--r--kernel/irq/resend.c78
1 files changed, 78 insertions, 0 deletions
diff --git a/kernel/irq/resend.c b/kernel/irq/resend.c
new file mode 100644
index 000000000000..096b102fb392
--- /dev/null
+++ b/kernel/irq/resend.c
@@ -0,0 +1,78 @@
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: */
26static DECLARE_BITMAP(irqs_resend, NR_IRQS);
27
28/*
29 * Run software resends of IRQ's
30 */
31static 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_desc + irq;
40 spin_lock_irqsave(&desc->lock, flags);
41 desc->handle_irq(irq, desc, NULL);
42 spin_unlock_irqrestore(&desc->lock, flags);
43 }
44}
45
46/* Tasklet to handle resend: */
47static 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 */
56void 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 if ((status & (IRQ_PENDING | IRQ_REPLAY)) == IRQ_PENDING) {
66 desc->status &= ~IRQ_PENDING;
67 desc->status = status | IRQ_REPLAY;
68
69 if (!desc->chip || !desc->chip->retrigger ||
70 !desc->chip->retrigger(irq)) {
71#ifdef CONFIG_HARDIRQS_SW_RESEND
72 /* Set it pending and activate the softirq: */
73 set_bit(irq, irqs_resend);
74 tasklet_schedule(&resend_tasklet);
75#endif
76 }
77 }
78}