diff options
Diffstat (limited to 'drivers/gpio/gpiolib.h')
| -rw-r--r-- | drivers/gpio/gpiolib.h | 92 |
1 files changed, 60 insertions, 32 deletions
diff --git a/drivers/gpio/gpiolib.h b/drivers/gpio/gpiolib.h index c6e5fb9aa..8e0e211eb 100644 --- a/drivers/gpio/gpiolib.h +++ b/drivers/gpio/gpiolib.h @@ -16,7 +16,7 @@ #include <linux/gpio/driver.h> #include <linux/module.h> #include <linux/notifier.h> -#include <linux/rwsem.h> +#include <linux/srcu.h> #define GPIOCHIP_NAME "gpiochip" @@ -31,8 +31,11 @@ * @chip: pointer to the corresponding gpiochip, holding static * data for this device * @descs: array of ngpio descriptors. + * @desc_srcu: ensures consistent state of GPIO descriptors exposed to users * @ngpio: the number of GPIO lines on this GPIO device, equal to the size * of the @descs array. + * @can_sleep: indicate whether the GPIO chip driver's callbacks can sleep + * implying that they cannot be used from atomic context * @base: GPIO base in the DEPRECATED global Linux GPIO numberspace, assigned * at device creation time. * @label: a descriptive name for the GPIO device, such as the part number @@ -43,9 +46,7 @@ * requested, released or reconfigured * @device_notifier: used to notify character device wait queues about the GPIO * device being unregistered - * @sem: protects the structure from a NULL-pointer dereference of @chip by - * user-space operations when the device gets unregistered during - * a hot-unplug event + * @srcu: protects the pointer to the underlying GPIO chip * @pin_ranges: range of pins served by the GPIO driver * * This state container holds most of the runtime variable data @@ -59,16 +60,18 @@ struct gpio_device { int id; struct device *mockdev; struct module *owner; - struct gpio_chip *chip; + struct gpio_chip __rcu *chip; struct gpio_desc *descs; + struct srcu_struct desc_srcu; int base; u16 ngpio; + bool can_sleep; const char *label; void *data; struct list_head list; struct blocking_notifier_head line_state_notifier; struct blocking_notifier_head device_notifier; - struct rw_semaphore sem; + struct srcu_struct srcu; #ifdef CONFIG_PINCTRL /* @@ -134,11 +137,13 @@ int gpiod_set_array_value_complex(bool raw, bool can_sleep, int gpiod_set_transitory(struct gpio_desc *desc, bool transitory); -extern spinlock_t gpio_lock; -extern struct list_head gpio_devices; - void gpiod_line_state_notify(struct gpio_desc *desc, unsigned long action); +struct gpio_desc_label { + struct rcu_head rh; + char str[]; +}; + /** * struct gpio_desc - Opaque descriptor for a GPIO * @@ -178,7 +183,7 @@ struct gpio_desc { #define FLAG_EVENT_CLOCK_HTE 19 /* GPIO CDEV reports hardware timestamps in events */ /* Connection label */ - const char *label; + struct gpio_desc_label __rcu *label; /* Name of the GPIO */ const char *name; #ifdef CONFIG_OF_DYNAMIC @@ -188,6 +193,27 @@ struct gpio_desc { #define gpiod_not_found(desc) (IS_ERR(desc) && PTR_ERR(desc) == -ENOENT) +struct gpio_chip_guard { + struct gpio_device *gdev; + struct gpio_chip *gc; + int idx; +}; + +DEFINE_CLASS(gpio_chip_guard, + struct gpio_chip_guard, + srcu_read_unlock(&_T.gdev->srcu, _T.idx), + ({ + struct gpio_chip_guard _guard; + + _guard.gdev = desc->gdev; + _guard.idx = srcu_read_lock(&_guard.gdev->srcu); + _guard.gc = srcu_dereference(_guard.gdev->chip, + &_guard.gdev->srcu); + + _guard; + }), + struct gpio_desc *desc) + int gpiod_request(struct gpio_desc *desc, const char *label); void gpiod_free(struct gpio_desc *desc); @@ -216,6 +242,7 @@ int gpio_set_debounce_timeout(struct gpio_desc *desc, unsigned int debounce); int gpiod_hog(struct gpio_desc *desc, const char *name, unsigned long lflags, enum gpiod_flags dflags); int gpiochip_get_ngpios(struct gpio_chip *gc, struct device *dev); +const char *gpiod_get_label(struct gpio_desc *desc); /* * Return the GPIO number of the passed descriptor relative to its chip @@ -227,31 +254,32 @@ static inline int gpio_chip_hwgpio(const struct gpio_desc *desc) /* With descriptor prefix */ -#define gpiod_emerg(desc, fmt, ...) \ - pr_emerg("gpio-%d (%s): " fmt, desc_to_gpio(desc), desc->label ? : "?",\ - ##__VA_ARGS__) -#define gpiod_crit(desc, fmt, ...) \ - pr_crit("gpio-%d (%s): " fmt, desc_to_gpio(desc), desc->label ? : "?", \ - ##__VA_ARGS__) -#define gpiod_err(desc, fmt, ...) \ - pr_err("gpio-%d (%s): " fmt, desc_to_gpio(desc), desc->label ? : "?", \ - ##__VA_ARGS__) -#define gpiod_warn(desc, fmt, ...) \ - pr_warn("gpio-%d (%s): " fmt, desc_to_gpio(desc), desc->label ? : "?", \ - ##__VA_ARGS__) -#define gpiod_info(desc, fmt, ...) \ - pr_info("gpio-%d (%s): " fmt, desc_to_gpio(desc), desc->label ? : "?", \ - ##__VA_ARGS__) -#define gpiod_dbg(desc, fmt, ...) \ - pr_debug("gpio-%d (%s): " fmt, desc_to_gpio(desc), desc->label ? : "?",\ - ##__VA_ARGS__) +#define gpiod_err(desc, fmt, ...) \ +do { \ + scoped_guard(srcu, &desc->gdev->desc_srcu) { \ + pr_err("gpio-%d (%s): " fmt, desc_to_gpio(desc), \ + gpiod_get_label(desc) ? : "?", ##__VA_ARGS__); \ + } \ +} while (0) + +#define gpiod_warn(desc, fmt, ...) \ +do { \ + scoped_guard(srcu, &desc->gdev->desc_srcu) { \ + pr_warn("gpio-%d (%s): " fmt, desc_to_gpio(desc), \ + gpiod_get_label(desc) ? : "?", ##__VA_ARGS__); \ + } \ +} while (0) + +#define gpiod_dbg(desc, fmt, ...) \ +do { \ + scoped_guard(srcu, &desc->gdev->desc_srcu) { \ + pr_debug("gpio-%d (%s): " fmt, desc_to_gpio(desc), \ + gpiod_get_label(desc) ? : "?", ##__VA_ARGS__); \ + } \ +} while (0) /* With chip prefix */ -#define chip_emerg(gc, fmt, ...) \ - dev_emerg(&gc->gpiodev->dev, "(%s): " fmt, gc->label, ##__VA_ARGS__) -#define chip_crit(gc, fmt, ...) \ - dev_crit(&gc->gpiodev->dev, "(%s): " fmt, gc->label, ##__VA_ARGS__) #define chip_err(gc, fmt, ...) \ dev_err(&gc->gpiodev->dev, "(%s): " fmt, gc->label, ##__VA_ARGS__) #define chip_warn(gc, fmt, ...) \ |