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arm: Ns9xxx: Remove private irq flow handler

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handle_prio_irq is almost identical with handle_fasteoi_irq. The
subtle differences are

1) The handler checks for IRQ_DISABLED after the device handler has
   been called. In case it's set it masks the interrupt.

2) When the handler sees IRQ_DISABLED on entry it masks the interupt
   in the same way as handle_fastoei_irq, but does not set the
   IRQ_PENDING flag.

3) Instead of gracefully handling a recursive interrupt it crashes the
   kernel.

#1 is just relevant when a device handler calls disable_irq_nosync()
   and it does not matter whether we mask the interrupt right away or
   not. We handle lazy masking for disable_irq anyway, so there is no
   real reason to have this extra mask in place.

#2 will prevent the resend of a pending interrupt, which can result in
   lost interrupts for edge type interrupts. For level type interrupts
   the resend is a noop in the generic code. According to the
   datasheet all interrupts are level type, so marking them as such
   will result in the exact same behaviour as the private
   handle_prio_irq implementation.

#3 is just stupid. Crashing the kernel instead of handling a problem
   gracefully is just wrong. With the current semantics- all handlers
   run with interrupts disabled - this is even more wrong.

Rename ack to eoi, remove the unused mask_ack, switch to
handle_fasteoi_irq and remove the private function.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Acked-by: Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>
Cc: linux-arm-kernel@lists.infradead.org
LKML-Reference: <20110202212552.299898447@linutronix.de>
This commit is contained in:
Thomas Gleixner 2011-02-02 21:41:27 +00:00
parent f9ba4475f9
commit 6829310548
1 changed files with 4 additions and 54 deletions
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58
arch/arm/mach-ns9xxx/irq.c
View file

@ -31,17 +31,11 @@ static void ns9xxx_mask_irq(struct irq_data *d)
__raw_writel(ic, SYS_IC(prio / 4));
}
static void ns9xxx_ack_irq(struct irq_data *d)
static void ns9xxx_eoi_irq(struct irq_data *d)
{
__raw_writel(0, SYS_ISRADDR);
}
static void ns9xxx_maskack_irq(struct irq_data *d)
{
ns9xxx_mask_irq(d);
ns9xxx_ack_irq(d);
}
static void ns9xxx_unmask_irq(struct irq_data *d)
{
/* XXX: better use cpp symbols */
@ -52,56 +46,11 @@ static void ns9xxx_unmask_irq(struct irq_data *d)
}
static struct irq_chip ns9xxx_chip = {
.irq_ack = ns9xxx_ack_irq,
.irq_eoi = ns9xxx_eoi_irq,
.irq_mask = ns9xxx_mask_irq,
.irq_mask_ack = ns9xxx_maskack_irq,
.irq_unmask = ns9xxx_unmask_irq,
};
#if 0
#define handle_irq handle_level_irq
#else
static void handle_prio_irq(unsigned int irq, struct irq_desc *desc)
{
struct irqaction *action;
irqreturn_t action_ret;
raw_spin_lock(&desc->lock);
BUG_ON(desc->status & IRQ_INPROGRESS);
desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
kstat_incr_irqs_this_cpu(irq, desc);
action = desc->action;
if (unlikely(!action || (desc->status & IRQ_DISABLED)))
goto out_mask;
desc->status |= IRQ_INPROGRESS;
raw_spin_unlock(&desc->lock);
action_ret = handle_IRQ_event(irq, action);
/* XXX: There is no direct way to access noirqdebug, so check
* unconditionally for spurious irqs...
* Maybe this function should go to kernel/irq/chip.c? */
note_interrupt(irq, desc, action_ret);
raw_spin_lock(&desc->lock);
desc->status &= ~IRQ_INPROGRESS;
if (desc->status & IRQ_DISABLED)
out_mask:
desc->irq_data.chip->irq_mask(&desc->irq_data);
/* ack unconditionally to unmask lower prio irqs */
desc->irq_data.chip->irq_ack(&desc->irq_data);
raw_spin_unlock(&desc->lock);
}
#define handle_irq handle_prio_irq
#endif
void __init ns9xxx_init_irq(void)
{
int i;
@ -119,7 +68,8 @@ void __init ns9xxx_init_irq(void)
for (i = 0; i <= 31; ++i) {
set_irq_chip(i, &ns9xxx_chip);
set_irq_handler(i, handle_irq);
set_irq_handler(i, handle_fasteoi_irq);
set_irq_flags(i, IRQF_VALID);
irq_set_status_flags(i, IRQ_LEVEL);
}
}