Messages in this thread Patch in this message | | | Date | Wed, 17 May 2006 02:16:28 +0200 | From | Ingo Molnar <> | Subject | [patch 16/50] genirq: add genirq sw IRQ-retrigger |
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From: Thomas Gleixner <tglx@linutronix.de>
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> --- include/linux/irq.h | 3 + kernel/irq/Makefile | 2 - kernel/irq/manage.c | 10 ------ kernel/irq/resend.c | 79 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 84 insertions(+), 10 deletions(-)
Index: linux-genirq.q/include/linux/irq.h =================================================================== --- linux-genirq.q.orig/include/linux/irq.h +++ linux-genirq.q/include/linux/irq.h @@ -242,6 +242,9 @@ extern void note_interrupt(unsigned int 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 */ Index: linux-genirq.q/kernel/irq/Makefile =================================================================== --- linux-genirq.q.orig/kernel/irq/Makefile +++ linux-genirq.q/kernel/irq/Makefile @@ -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 Index: linux-genirq.q/kernel/irq/manage.c =================================================================== --- linux-genirq.q.orig/kernel/irq/manage.c +++ linux-genirq.q/kernel/irq/manage.c @@ -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->handler && desc->handler->retrigger) - desc->handler->retrigger(irq); - } - desc->handler->enable(irq); + check_irq_resend(desc, irq); /* fall-through */ } default: Index: linux-genirq.q/kernel/irq/resend.c =================================================================== --- /dev/null +++ linux-genirq.q/kernel/irq/resend.c @@ -0,0 +1,79 @@ +/* + * 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; + unsigned long flags; + 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, 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->handler->enable(irq); + + if ((status & (IRQ_PENDING | IRQ_REPLAY)) == IRQ_PENDING) { + desc->status &= ~IRQ_PENDING; + desc->status = status | IRQ_REPLAY; + + if (!desc->handler || !desc->handler->retrigger || + !desc->handler->retrigger(irq)) { +#ifdef CONFIG_HARDIRQS_SW_RESEND + /* Set it pending and activate the softirq: */ + set_bit(irq, irqs_resend); + tasklet_schedule(&resend_tasklet); +#endif + } + } +} - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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