From fcef85c0c122f90f57f2f3ef0caeaf6404d6e8f3 Mon Sep 17 00:00:00 2001 From: Ben Dooks Date: Thu, 6 May 2010 15:42:23 +0900 Subject: [PATCH] ARM: SAMSUNG: Add spinlock locking to GPIO banks 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 --- arch/arm/plat-samsung/gpio-config.c | 12 ++++++------ arch/arm/plat-samsung/gpio.c | 15 +++++++++------ arch/arm/plat-samsung/include/plat/gpio-core.h | 14 ++++++++++++++ 3 files changed, 29 insertions(+), 12 deletions(-) diff --git a/arch/arm/plat-samsung/gpio-config.c b/arch/arm/plat-samsung/gpio-config.c index 3282db360fa8..a76eef533392 100644 --- a/arch/arm/plat-samsung/gpio-config.c +++ b/arch/arm/plat-samsung/gpio-config.c @@ -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; } diff --git a/arch/arm/plat-samsung/gpio.c b/arch/arm/plat-samsung/gpio.c index 28d2ab8a08db..b83a83351cea 100644 --- a/arch/arm/plat-samsung/gpio.c +++ b/arch/arm/plat-samsung/gpio.c @@ -15,6 +15,7 @@ #include #include #include +#include #include @@ -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) diff --git a/arch/arm/plat-samsung/include/plat/gpio-core.h b/arch/arm/plat-samsung/include/plat/gpio-core.h index f0584f26d493..f3a68d1a07b9 100644 --- a/arch/arm/plat-samsung/include/plat/gpio-core.h +++ b/arch/arm/plat-samsung/include/plat/gpio-core.h @@ -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)