[PATCH] irq-bcm2836: Prevent spurious interrupts, and trap them early

[Phil Elwell]

From: Phil Elwell <phil at raspberrypi.org>

The old arch-specific IRQ macros included a dsb to ensure the
write to clear the mailbox interrupt completed before returning
from the interrupt. The BCM2836 irqchip driver needs the same
precaution to avoid spurious interrupts.

Signed-off-by: Phil Elwell <phil at raspberrypi.org>
---
 drivers/irqchip/irq-bcm2836.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/irqchip/irq-bcm2836.c b/drivers/irqchip/irq-bcm2836.c
index d96b2c9..93e3f76 100644
--- a/drivers/irqchip/irq-bcm2836.c
+++ b/drivers/irqchip/irq-bcm2836.c
@@ -175,6 +175,7 @@ __exception_irq_entry
bcm2836_arm_irqchip_handle_irq(struct pt_regs *regs)
         u32 ipi = ffs(mbox_val) - 1;
 
         writel(1 << ipi, mailbox0);
+        dsb(sy);
         handle_IPI(ipi, regs);
 #endif
     } else if (stat) {
-- 
1.9.1