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ARM: SAMSUNG: Add spinlock locking to GPIO banks

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Add locking to each GPIO bank to allow for SMP capable code
to use the gpiolib functions. See the gpio-core.h header file
for more information.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
This commit is contained in:
Ben Dooks 2010-05-06 15:42:23 +09:00
parent 1d3ef014b5
commit fcef85c0c1
3 changed files with 29 additions and 12 deletions
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12
arch/arm/plat-samsung/gpio-config.c
View File

@ -33,9 +33,9 @@ int s3c_gpio_cfgpin(unsigned int pin, unsigned int config)
offset = pin - chip->chip.base;
local_irq_save(flags);
s3c_gpio_lock(chip, flags);
ret = s3c_gpio_do_setcfg(chip, offset, config);
local_irq_restore(flags);
s3c_gpio_unlock(chip, flags);
return ret;
}
@ -51,9 +51,9 @@ unsigned s3c_gpio_getcfg(unsigned int pin)
if (chip) {
offset = pin - chip->chip.base;
local_irq_save(flags);
s3c_gpio_lock(chip, flags);
ret = s3c_gpio_do_getcfg(chip, offset);
local_irq_restore(flags);
s3c_gpio_unlock(chip, flags);
}
return ret;
@ -72,9 +72,9 @@ int s3c_gpio_setpull(unsigned int pin, s3c_gpio_pull_t pull)
offset = pin - chip->chip.base;
local_irq_save(flags);
s3c_gpio_lock(chip, flags);
ret = s3c_gpio_do_setpull(chip, offset, pull);
local_irq_restore(flags);
s3c_gpio_unlock(chip, flags);
return ret;
}

15
arch/arm/plat-samsung/gpio.c
View File

@ -15,6 +15,7 @@
#include <linux/init.h>
#include <linux/io.h>
#include <linux/gpio.h>
#include <linux/spinlock.h>
#include <plat/gpio-core.h>
@ -52,14 +53,14 @@ static int s3c_gpiolib_input(struct gpio_chip *chip, unsigned offset)
unsigned long flags;
unsigned long con;
local_irq_save(flags);
s3c_gpio_lock(ourchip, flags);
con = __raw_readl(base + 0x00);
con &= ~(3 << (offset * 2));
__raw_writel(con, base + 0x00);
local_irq_restore(flags);
s3c_gpio_unlock(ourchip, flags);
return 0;
}
@ -72,7 +73,7 @@ static int s3c_gpiolib_output(struct gpio_chip *chip,
unsigned long dat;
unsigned long con;
local_irq_save(flags);
s3c_gpio_lock(ourchip, flags);
dat = __raw_readl(base + 0x04);
dat &= ~(1 << offset);
@ -87,7 +88,7 @@ static int s3c_gpiolib_output(struct gpio_chip *chip,
__raw_writel(con, base + 0x00);
__raw_writel(dat, base + 0x04);
local_irq_restore(flags);
s3c_gpio_unlock(ourchip, flags);
return 0;
}
@ -99,7 +100,7 @@ static void s3c_gpiolib_set(struct gpio_chip *chip,
unsigned long flags;
unsigned long dat;
local_irq_save(flags);
s3c_gpio_lock(ourchip, flags);
dat = __raw_readl(base + 0x04);
dat &= ~(1 << offset);
@ -107,7 +108,7 @@ static void s3c_gpiolib_set(struct gpio_chip *chip,
dat |= 1 << offset;
__raw_writel(dat, base + 0x04);
local_irq_restore(flags);
s3c_gpio_unlock(ourchip, flags);
}
static int s3c_gpiolib_get(struct gpio_chip *chip, unsigned offset)
@ -131,6 +132,8 @@ __init void s3c_gpiolib_add(struct s3c_gpio_chip *chip)
BUG_ON(!gc->label);
BUG_ON(!gc->ngpio);
spin_lock_init(&chip->lock);
if (!gc->direction_input)
gc->direction_input = s3c_gpiolib_input;
if (!gc->direction_output)

14
arch/arm/plat-samsung/include/plat/gpio-core.h
View File

@ -44,16 +44,26 @@ struct s3c_gpio_cfg;
* @chip: The chip structure to be exported via gpiolib.
* @base: The base pointer to the gpio configuration registers.
* @config: special function and pull-resistor control information.
* @lock: Lock for exclusive access to this gpio bank.
* @pm_save: Save information for suspend/resume support.
*
* This wrapper provides the necessary information for the Samsung
* specific gpios being registered with gpiolib.
*
* The lock protects each gpio bank from multiple access of the shared
* configuration registers, or from reading of data whilst another thread
* is writing to the register set.
*
* Each chip has its own lock to avoid any contention between different
* CPU cores trying to get one lock for different GPIO banks, where each
* bank of GPIO has its own register space and configuration registers.
*/
struct s3c_gpio_chip {
struct gpio_chip chip;
struct s3c_gpio_cfg *config;
struct s3c_gpio_pm *pm;
void __iomem *base;
spinlock_t lock;
#ifdef CONFIG_PM
u32 pm_save[4];
#endif
@ -138,3 +148,7 @@ extern struct s3c_gpio_pm s3c_gpio_pm_4bit;
#define __gpio_pm(x) NULL
#endif /* CONFIG_PM */
/* locking wrappers to deal with multiple access to the same gpio bank */
#define s3c_gpio_lock(_oc, _fl) spin_lock_irqsave(&(_oc)->lock, _fl)
#define s3c_gpio_unlock(_oc, _fl) spin_unlock_irqrestore(&(_oc)->lock, _fl)