From a4633adcdbc15ac51afcd0e1395de58cee27cf92 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 29 Jun 2006 02:24:48 -0700 Subject: [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 Signed-off-by: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/irq/resend.c | 78 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 78 insertions(+) create mode 100644 kernel/irq/resend.c (limited to 'kernel/irq/resend.c') diff --git a/kernel/irq/resend.c b/kernel/irq/resend.c new file mode 100644 index 00000000000..096b102fb39 --- /dev/null +++ b/kernel/irq/resend.c @@ -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 +#include +#include +#include + +#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 + } + } +} -- cgit v1.2.3