releases/4.9.9/pinctrl-baytrail-add-missing-spinlock-usage-in-byt_gpio_irq_handler.patch

From cdca06e4e85974d8a3503ab15709dbbaf90d3dd1 Mon Sep 17 00:00:00 2001
From: Alexander Stein <alexander.stein@systec-electronic.com>
Date: Mon, 30 Jan 2017 12:35:28 +0100
Subject: pinctrl: baytrail: Add missing spinlock usage in byt_gpio_irq_handler

From: Alexander Stein <alexander.stein@systec-electronic.com>

commit cdca06e4e85974d8a3503ab15709dbbaf90d3dd1 upstream.

According to VLI64 Intel Atom E3800 Specification Update (#329901)
concurrent read accesses may result in returning 0xffffffff and write
accesses may be dropped silently.
To workaround all accesses must be protected by locks.

Signed-off-by: Alexander Stein <alexander.stein@systec-electronic.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/pinctrl/intel/pinctrl-baytrail.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/pinctrl/intel/pinctrl-baytrail.c
+++ b/drivers/pinctrl/intel/pinctrl-baytrail.c
@@ -1612,7 +1612,9 @@ static void byt_gpio_irq_handler(struct
 			continue;
 		}
 
+		raw_spin_lock(&vg->lock);
 		pending = readl(reg);
+		raw_spin_unlock(&vg->lock);
 		for_each_set_bit(pin, &pending, 32) {
 			virq = irq_find_mapping(vg->chip.irqdomain, base + pin);
 			generic_handle_irq(virq);