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gpio: merrifield: Protect irq_ack() and gpio_set() by lock 

There is a potential race when two threads do the writes to the same register
in parallel.

Prevent out of order in such case by protecting I/O access by spin lock.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
Andy Shevchenko 2016-07-11 13:06:26 +03:00 committed by Linus Walleij
parent ccf6fd6dcc
commit fcce9f14f0
1 changed files with 11 additions and 0 deletions
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11
drivers/gpio/gpio-merrifield.c
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@ -105,7 +105,11 @@ static int mrfld_gpio_get(struct gpio_chip *chip, unsigned int offset)
static void mrfld_gpio_set(struct gpio_chip *chip, unsigned int offset,
int value)
{
struct mrfld_gpio *priv = gpiochip_get_data(chip);
void __iomem *gpsr, *gpcr;
unsigned long flags;
raw_spin_lock_irqsave(&priv->lock, flags);
if (value) {
gpsr = gpio_reg(chip, offset, GPSR);
@ -114,6 +118,8 @@ static void mrfld_gpio_set(struct gpio_chip *chip, unsigned int offset,
gpcr = gpio_reg(chip, offset, GPCR);
writel(BIT(offset % 32), gpcr);
}
raw_spin_unlock_irqrestore(&priv->lock, flags);
}
static int mrfld_gpio_direction_input(struct gpio_chip *chip,
@ -160,8 +166,13 @@ static void mrfld_irq_ack(struct irq_data *d)
struct mrfld_gpio *priv = irq_data_get_irq_chip_data(d);
u32 gpio = irqd_to_hwirq(d);
void __iomem *gisr = gpio_reg(&priv->chip, gpio, GISR);
unsigned long flags;
raw_spin_lock_irqsave(&priv->lock, flags);
writel(BIT(gpio % 32), gisr);
raw_spin_unlock_irqrestore(&priv->lock, flags);
}
static void mrfld_irq_unmask_mask(struct irq_data *d, bool unmask)