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-rw-r--r--arch/arm/mach-dove/irq.c14
1 files changed, 13 insertions, 1 deletions
diff --git a/arch/arm/mach-dove/irq.c b/arch/arm/mach-dove/irq.c
index 087711524e8..bc4344aa100 100644
--- a/arch/arm/mach-dove/irq.c
+++ b/arch/arm/mach-dove/irq.c
@@ -46,8 +46,20 @@ static void pmu_irq_ack(struct irq_data *d)
int pin = irq_to_pmu(d->irq);
u32 u;
+ /*
+ * The PMU mask register is not RW0C: it is RW. This means that
+ * the bits take whatever value is written to them; if you write
+ * a '1', you will set the interrupt.
+ *
+ * Unfortunately this means there is NO race free way to clear
+ * these interrupts.
+ *
+ * So, let's structure the code so that the window is as small as
+ * possible.
+ */
u = ~(1 << (pin & 31));
- writel(u, PMU_INTERRUPT_CAUSE);
+ u &= readl_relaxed(PMU_INTERRUPT_CAUSE);
+ writel_relaxed(u, PMU_INTERRUPT_CAUSE);
}
static struct irq_chip pmu_irq_chip = {