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[PATCH] genirq: add genirq sw IRQ-retrigger

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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>
This commit is contained in:
Thomas Gleixner 2006-06-29 02:24:48 -07:00 committed by Linus Torvalds
parent 11c869eaf1
commit a4633adcdb
4 changed files with 83 additions and 10 deletions
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3
include/linux/irq.h
View file

@ -246,6 +246,9 @@ extern void note_interrupt(unsigned int irq, struct irq_desc *desc,
int action_ret, struct pt_regs *regs);
extern int can_request_irq(unsigned int irq, unsigned long irqflags);
/* Resending of interrupts :*/
void check_irq_resend(struct irq_desc *desc, unsigned int irq);
extern void init_irq_proc(void);
#endif /* CONFIG_GENERIC_HARDIRQS */

2
kernel/irq/Makefile
View file

@ -1,5 +1,5 @@
obj-y := handle.o manage.o spurious.o
obj-y := handle.o manage.o spurious.o resend.o
obj-$(CONFIG_GENERIC_IRQ_PROBE) += autoprobe.o
obj-$(CONFIG_PROC_FS) += proc.o
obj-$(CONFIG_GENERIC_PENDING_IRQ) += migration.o

10
kernel/irq/manage.c
View file

@ -118,15 +118,7 @@ void enable_irq(unsigned int irq)
WARN_ON(1);
break;
case 1: {
unsigned int status = desc->status & ~IRQ_DISABLED;
desc->status = status;
if ((status & (IRQ_PENDING | IRQ_REPLAY)) == IRQ_PENDING) {
desc->status = status | IRQ_REPLAY;
if (desc->chip && desc->chip->retrigger)
desc->chip->retrigger(irq);
}
desc->chip->enable(irq);
check_irq_resend(desc, irq);
/* fall-through */
}
default:

78
kernel/irq/resend.c Normal file
View file

@ -0,0 +1,78 @@
/*
* linux/kernel/irq/resend.c
*
* Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
* Copyright (C) 2005-2006, Thomas Gleixner
*
* This file contains the IRQ-resend code
*
* If the interrupt is waiting to be processed, we try to re-run it.
* We can't directly run it from here since the caller might be in an
* interrupt-protected region. Not all irq controller chips can
* retrigger interrupts at the hardware level, so in those cases
* we allow the resending of IRQs via a tasklet.
*/
#include <linux/irq.h>
#include <linux/module.h>
#include <linux/random.h>
#include <linux/interrupt.h>
#include "internals.h"
#ifdef CONFIG_HARDIRQS_SW_RESEND
/* Bitmap to handle software resend of interrupts: */
static DECLARE_BITMAP(irqs_resend, NR_IRQS);
/*
* Run software resends of IRQ's
*/
static void resend_irqs(unsigned long arg)
{
struct irq_desc *desc;
int irq;
while (!bitmap_empty(irqs_resend, NR_IRQS)) {
irq = find_first_bit(irqs_resend, NR_IRQS);
clear_bit(irq, irqs_resend);
desc = irq_desc + irq;
spin_lock_irqsave(&desc->lock, flags);
desc->handle_irq(irq, desc, NULL);
spin_unlock_irqrestore(&desc->lock, flags);
}
}
/* Tasklet to handle resend: */
static DECLARE_TASKLET(resend_tasklet, resend_irqs, 0);
#endif
/*
* IRQ resend
*
* Is called with interrupts disabled and desc->lock held.
*/
void check_irq_resend(struct irq_desc *desc, unsigned int irq)
{
unsigned int status = desc->status;
/*
* Make sure the interrupt is enabled, before resending it:
*/
desc->chip->enable(irq);
if ((status & (IRQ_PENDING | IRQ_REPLAY)) == IRQ_PENDING) {
desc->status &= ~IRQ_PENDING;
desc->status = status | IRQ_REPLAY;
if (!desc->chip || !desc->chip->retrigger ||
!desc->chip->retrigger(irq)) {
#ifdef CONFIG_HARDIRQS_SW_RESEND
/* Set it pending and activate the softirq: */
set_bit(irq, irqs_resend);
tasklet_schedule(&resend_tasklet);
#endif
}
}
}