openwrtv4/target/linux/brcm2708/patches-4.4/0005-irq-bcm2836-Prevent-spurious-interrupts-and-trap-the.patch
Álvaro Fernández Rojas 20402106a3 brcm2708: update linux 4.4 patches to latest version
As usual these patches were extracted and rebased from the raspberry pi repo:
https://github.com/raspberrypi/linux/tree/rpi-4.4.y

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
2016-07-09 16:29:18 +02:00

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From 8ec469e6ed6a5dd357c04322dfc4e2ddbfcc040b Mon Sep 17 00:00:00 2001
From: Phil Elwell <phil@raspberrypi.org>
Date: Fri, 4 Dec 2015 17:41:50 +0000
Subject: [PATCH 005/423] irq-bcm2836: Prevent spurious interrupts, and trap
them early
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.
Spurious interrupts are still possible for other reasons,
though, so trap them early.
---
drivers/irqchip/irq-bcm2836.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/drivers/irqchip/irq-bcm2836.c
+++ b/drivers/irqchip/irq-bcm2836.c
@@ -170,9 +170,10 @@ __exception_irq_entry bcm2836_arm_irqchi
u32 ipi = ffs(mbox_val) - 1;
writel(1 << ipi, mailbox0);
+ dsb();
handle_IPI(ipi, regs);
#endif
- } else {
+ } else if (stat) {
u32 hwirq = ffs(stat) - 1;
handle_IRQ(irq_linear_revmap(intc.domain, hwirq), regs);