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Commit a4633adc authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Linus Torvalds
Browse files

[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: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 11c869ea

include/linux/irq.h

+3 −0
Original line number Diff line number Diff line
@@ -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 */

kernel/irq/Makefile

+1 −1
Original line number Diff line number Diff line 


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

kernel/irq/manage.c

+1 −9
Original line number Diff line number Diff line
@@ -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:

kernel/irq/resend.c

0 → 100644
+78 −0
Original line number Diff line number Diff line 
/*

 * 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

		}

	}

}