releases/3.13.6/irqchip-orion-clear-stale-interrupts-in-irq_startup.patch

From e0318ec3bf3f1502cd11b21b1eb00aa355b40b67 Mon Sep 17 00:00:00 2001
From: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Date: Fri, 24 Jan 2014 00:10:32 +0100
Subject: irqchip: orion: clear stale interrupts in irq_startup

From: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>

commit e0318ec3bf3f1502cd11b21b1eb00aa355b40b67 upstream.

Bridge IRQ_CAUSE bits are asserted regardless of the corresponding bit in
IRQ_MASK register. To avoid interrupt events on stale irqs, we have to clear
them before unmask. This installs an .irq_startup callback to ensure stale
irqs are cleared before initial unmask.

Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Tested-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/irqchip/irq-orion.c |   14 ++++++++++++++
 1 file changed, 14 insertions(+)

--- a/drivers/irqchip/irq-orion.c
+++ b/drivers/irqchip/irq-orion.c
@@ -123,6 +123,19 @@ static void orion_bridge_irq_handler(uns
 	}
 }
 
+/*
+ * Bridge IRQ_CAUSE is asserted regardless of IRQ_MASK register.
+ * To avoid interrupt events on stale irqs, we clear them before unmask.
+ */
+static unsigned int orion_bridge_irq_startup(struct irq_data *d)
+{
+	struct irq_chip_type *ct = irq_data_get_chip_type(d);
+
+	ct->chip.irq_ack(d);
+	ct->chip.irq_unmask(d);
+	return 0;
+}
+
 static int __init orion_bridge_irq_init(struct device_node *np,
 					struct device_node *parent)
 {
@@ -176,6 +189,7 @@ static int __init orion_bridge_irq_init(
 
 	gc->chip_types[0].regs.ack = ORION_BRIDGE_IRQ_CAUSE;
 	gc->chip_types[0].regs.mask = ORION_BRIDGE_IRQ_MASK;
+	gc->chip_types[0].chip.irq_startup = orion_bridge_irq_startup;
 	gc->chip_types[0].chip.irq_ack = irq_gc_ack_clr_bit;
 	gc->chip_types[0].chip.irq_mask = irq_gc_mask_clr_bit;
 	gc->chip_types[0].chip.irq_unmask = irq_gc_mask_set_bit;