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From: Greg KH on 6 Aug 2010 15:40
2.6.34-stable review patch. If anyone has any objections, please let us know.

------------------

From: Baruch Siach <baruch(a)tkos.co.il>

commit 14cb0deb66fcfca8fdbef75da8c84b5405a8c767 upstream.

The GPIO registers need protection from concurrent access for operations that
are not atomic.

Cc: Juergen Beisert <j.beisert(a)pengutronix.de>
Cc: Daniel Mack <daniel(a)caiaq.de>
Reported-by: rpkamiak(a)rockwellcollins.com
Signed-off-by: Baruch Siach <baruch(a)tkos.co.il>
Signed-off-by: Sascha Hauer <s.hauer(a)pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh(a)suse.de>

---
arch/arm/plat-mxc/gpio.c | 8 ++++++++
arch/arm/plat-mxc/include/mach/gpio.h | 1 +
2 files changed, 9 insertions(+)

--- a/arch/arm/plat-mxc/gpio.c
+++ b/arch/arm/plat-mxc/gpio.c
@@ -215,13 +215,16 @@ static void _set_gpio_direction(struct g
struct mxc_gpio_port *port =
container_of(chip, struct mxc_gpio_port, chip);
u32 l;
+ unsigned long flags;

+ spin_lock_irqsave(&port->lock, flags);
l = __raw_readl(port->base + GPIO_GDIR);
if (dir)
l |= 1 << offset;
else
l &= ~(1 << offset);
__raw_writel(l, port->base + GPIO_GDIR);
+ spin_unlock_irqrestore(&port->lock, flags);
}

static void mxc_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
@@ -230,9 +233,12 @@ static void mxc_gpio_set(struct gpio_chi
container_of(chip, struct mxc_gpio_port, chip);
void __iomem *reg = port->base + GPIO_DR;
u32 l;
+ unsigned long flags;

+ spin_lock_irqsave(&port->lock, flags);
l = (__raw_readl(reg) & (~(1 << offset))) | (value << offset);
__raw_writel(l, reg);
+ spin_unlock_irqrestore(&port->lock, flags);
}

static int mxc_gpio_get(struct gpio_chip *chip, unsigned offset)
@@ -286,6 +292,8 @@ int __init mxc_gpio_init(struct mxc_gpio
port[i].chip.base = i * 32;
port[i].chip.ngpio = 32;

+ spin_lock_init(&port[i].lock);
+
/* its a serious configuration bug when it fails */
BUG_ON( gpiochip_add(&port[i].chip) < 0 );

--- a/arch/arm/plat-mxc/include/mach/gpio.h
+++ b/arch/arm/plat-mxc/include/mach/gpio.h
@@ -36,6 +36,7 @@ struct mxc_gpio_port {
int virtual_irq_start;
struct gpio_chip chip;
u32 both_edges;
+ spinlock_t lock;
};

int mxc_gpio_init(struct mxc_gpio_port*, int);


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