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irqchip: sun4i: Fix irq 0 not working

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SUN4I_IRQ_VECTOR_REG containing 0 can mean one of 3 things:

1) no more irqs pending
2) irq 0 pending
3) spurious irq

So if we immediately get a reading of 0, check the irq-pending reg
to differentiate between 2 and 3. We only do this once to avoid
the extra check in the common case of 1) hapening after having
read the vector-reg once.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-sunxi@googlegroups.com
Link: http://lkml.kernel.org/r/1394733834-26839-3-git-send-email-hdegoede@redhat.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Hans de Goede 2014-03-13 19:03:52 +01:00 committed by Thomas Gleixner
parent 328a4978df
commit 56af0416b0
1 changed files with 16 additions and 2 deletions
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18
drivers/irqchip/irq-sun4i.c
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@ -140,10 +140,24 @@ static void __exception_irq_entry sun4i_handle_irq(struct pt_regs *regs)
{
u32 irq, hwirq;
/*
* hwirq == 0 can mean one of 3 things:
* 1) no more irqs pending
* 2) irq 0 pending
* 3) spurious irq
* So if we immediately get a reading of 0, check the irq-pending reg
* to differentiate between 2 and 3. We only do this once to avoid
* the extra check in the common case of 1 hapening after having
* read the vector-reg once.
*/
hwirq = readl(sun4i_irq_base + SUN4I_IRQ_VECTOR_REG) >> 2;
while (hwirq != 0) {
if (hwirq == 0 &&
!(readl(sun4i_irq_base + SUN4I_IRQ_PENDING_REG(0)) & BIT(0)))
return;
do {
irq = irq_find_mapping(sun4i_irq_domain, hwirq);
handle_IRQ(irq, regs);
hwirq = readl(sun4i_irq_base + SUN4I_IRQ_VECTOR_REG) >> 2;
}
} while (hwirq != 0);
}