ia64/linux-2.6.18-xen.hg

view kernel/irq/resend.c @ 912:dd42cdb0ab89

[IA64] Build blktap2 driver by default in x86 builds.

add CONFIG_XEN_BLKDEV_TAP2=y to buildconfigs/linux-defconfig_xen_ia64.

Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>
author Isaku Yamahata <yamahata@valinux.co.jp>
date Mon Jun 29 12:09:16 2009 +0900 (2009-06-29)
parents 831230e53067
children
line source
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 */
16 #include <linux/irq.h>
17 #include <linux/module.h>
18 #include <linux/random.h>
19 #include <linux/interrupt.h>
21 #include "internals.h"
23 #ifdef CONFIG_HARDIRQS_SW_RESEND
25 /* Bitmap to handle software resend of interrupts: */
26 static DECLARE_BITMAP(irqs_resend, NR_IRQS);
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;
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 local_irq_disable();
41 desc->handle_irq(irq, desc, NULL);
42 local_irq_enable();
43 }
44 }
46 /* Tasklet to handle resend: */
47 static DECLARE_TASKLET(resend_tasklet, resend_irqs, 0);
49 #endif
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;
60 /*
61 * Make sure the interrupt is enabled, before resending it:
62 */
63 desc->chip->enable(irq);
65 if ((status & (IRQ_PENDING | IRQ_REPLAY)) == IRQ_PENDING) {
66 desc->status = (status & ~IRQ_PENDING) | IRQ_REPLAY;
68 if (!desc->chip || !desc->chip->retrigger ||
69 !desc->chip->retrigger(irq)) {
70 #ifdef CONFIG_HARDIRQS_SW_RESEND
71 /* Set it pending and activate the softirq: */
72 set_bit(irq, irqs_resend);
73 tasklet_schedule(&resend_tasklet);
74 #endif
75 }
76 }
77 }