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arm/imx/gpio: add spinlock protection

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

Cc: stable@kernel.org
Cc: Juergen Beisert <j.beisert@pengutronix.de>
Cc: Daniel Mack <daniel@caiaq.de>
Reported-by: rpkamiak@rockwellcollins.com
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
This commit is contained in:
Baruch Siach 2010-07-06 14:03:22 +03:00 • committed by Sascha Hauer
commit 14cb0deb66
2 changed files with 9 additions and 0 deletions
Download patch file Download diff file Expand all files Collapse all files

8
arch/arm/plat-mxc/gpio.c
View file

@ -214,13 +214,16 @@ static void _set_gpio_direction(struct gpio_chip *chip, unsigned offset,
struct mxc_gpio_port *port = struct mxc_gpio_port *port =
container_of(chip, struct mxc_gpio_port, chip); container_of(chip, struct mxc_gpio_port, chip);
u32 l; u32 l;
unsigned long flags;
spin_lock_irqsave(&port->lock, flags);
l = __raw_readl(port->base + GPIO_GDIR); l = __raw_readl(port->base + GPIO_GDIR);
if (dir) if (dir)
l |= 1 << offset; l |= 1 << offset;
else else
l &= ~(1 << offset); l &= ~(1 << offset);
__raw_writel(l, port->base + GPIO_GDIR); __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) static void mxc_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
@ -229,9 +232,12 @@ static void mxc_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
container_of(chip, struct mxc_gpio_port, chip); container_of(chip, struct mxc_gpio_port, chip);
void __iomem *reg = port->base + GPIO_DR; void __iomem *reg = port->base + GPIO_DR;
u32 l; u32 l;
unsigned long flags;
spin_lock_irqsave(&port->lock, flags);
l = (__raw_readl(reg) & (~(1 << offset))) | (value << offset); l = (__raw_readl(reg) & (~(1 << offset))) | (value << offset);
__raw_writel(l, reg); __raw_writel(l, reg);
spin_unlock_irqrestore(&port->lock, flags);
} }
static int mxc_gpio_get(struct gpio_chip *chip, unsigned offset) static int mxc_gpio_get(struct gpio_chip *chip, unsigned offset)
@ -285,6 +291,8 @@ int __init mxc_gpio_init(struct mxc_gpio_port *port, int cnt)
port[i].chip.base = i * 32; port[i].chip.base = i * 32;
port[i].chip.ngpio = 32; port[i].chip.ngpio = 32;
spin_lock_init(&port[i].lock);
/* its a serious configuration bug when it fails */ /* its a serious configuration bug when it fails */
BUG_ON( gpiochip_add(&port[i].chip) < 0 ); BUG_ON( gpiochip_add(&port[i].chip) < 0 );

1
arch/arm/plat-mxc/include/mach/gpio.h
View file

@ -37,6 +37,7 @@ struct mxc_gpio_port {
int virtual_irq_start; int virtual_irq_start;
struct gpio_chip chip; struct gpio_chip chip;
u32 both_edges; u32 both_edges;
spinlock_t lock;
}; };
int mxc_gpio_init(struct mxc_gpio_port*, int); int mxc_gpio_init(struct mxc_gpio_port*, int);