diff options
Diffstat (limited to 'drivers/gpio/gpiolib.c')
| -rw-r--r-- | drivers/gpio/gpiolib.c | 973 |
1 files changed, 528 insertions, 445 deletions
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index d9da0331e..fa50db0c3 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -2,6 +2,7 @@ #include <linux/acpi.h> #include <linux/bitmap.h> +#include <linux/cleanup.h> #include <linux/compat.h> #include <linux/debugfs.h> #include <linux/device.h> @@ -14,12 +15,14 @@ #include <linux/irq.h> #include <linux/kernel.h> #include <linux/list.h> +#include <linux/lockdep.h> #include <linux/module.h> #include <linux/of.h> #include <linux/pinctrl/consumer.h> #include <linux/seq_file.h> #include <linux/slab.h> #include <linux/spinlock.h> +#include <linux/srcu.h> #include <linux/string.h> #include <linux/gpio.h> @@ -63,7 +66,7 @@ static int gpio_bus_match(struct device *dev, struct device_driver *drv) return 1; } -static struct bus_type gpio_bus_type = { +static const struct bus_type gpio_bus_type = { .name = "gpio", .match = gpio_bus_match, }; @@ -73,15 +76,14 @@ static struct bus_type gpio_bus_type = { */ #define FASTPATH_NGPIO CONFIG_GPIOLIB_FASTPATH_LIMIT -/* gpio_lock prevents conflicts during gpio_desc[] table updates. - * While any GPIO is requested, its gpio_chip is not removable; - * each GPIO's "requested" flag serves as a lock and refcount. - */ -DEFINE_SPINLOCK(gpio_lock); - static DEFINE_MUTEX(gpio_lookup_lock); static LIST_HEAD(gpio_lookup_list); -LIST_HEAD(gpio_devices); + +static LIST_HEAD(gpio_devices); +/* Protects the GPIO device list against concurrent modifications. */ +static DEFINE_MUTEX(gpio_devices_lock); +/* Ensures coherence during read-only accesses to the list of GPIO devices. */ +DEFINE_STATIC_SRCU(gpio_devices_srcu); static DEFINE_MUTEX(gpio_machine_hogs_mutex); static LIST_HEAD(gpio_machine_hogs); @@ -97,9 +99,48 @@ static void gpiochip_irqchip_free_valid_mask(struct gpio_chip *gc); static bool gpiolib_initialized; -static inline void desc_set_label(struct gpio_desc *d, const char *label) +const char *gpiod_get_label(struct gpio_desc *desc) { - d->label = label; + struct gpio_desc_label *label; + unsigned long flags; + + flags = READ_ONCE(desc->flags); + if (test_bit(FLAG_USED_AS_IRQ, &flags) && + !test_bit(FLAG_REQUESTED, &flags)) + return "interrupt"; + + if (!test_bit(FLAG_REQUESTED, &flags)) + return NULL; + + label = srcu_dereference_check(desc->label, &desc->gdev->desc_srcu, + srcu_read_lock_held(&desc->gdev->desc_srcu)); + + return label->str; +} + +static void desc_free_label(struct rcu_head *rh) +{ + kfree(container_of(rh, struct gpio_desc_label, rh)); +} + +static int desc_set_label(struct gpio_desc *desc, const char *label) +{ + struct gpio_desc_label *new = NULL, *old; + + if (label) { + new = kzalloc(struct_size(new, str, strlen(label) + 1), + GFP_KERNEL); + if (!new) + return -ENOMEM; + + strcpy(new->str, label); + } + + old = rcu_replace_pointer(desc->label, new, 1); + if (old) + call_srcu(&desc->gdev->desc_srcu, &old->rh, desc_free_label); + + return 0; } /** @@ -113,20 +154,16 @@ static inline void desc_set_label(struct gpio_desc *d, const char *label) struct gpio_desc *gpio_to_desc(unsigned gpio) { struct gpio_device *gdev; - unsigned long flags; - spin_lock_irqsave(&gpio_lock, flags); - - list_for_each_entry(gdev, &gpio_devices, list) { - if (gdev->base <= gpio && - gdev->base + gdev->ngpio > gpio) { - spin_unlock_irqrestore(&gpio_lock, flags); - return &gdev->descs[gpio - gdev->base]; + scoped_guard(srcu, &gpio_devices_srcu) { + list_for_each_entry_srcu(gdev, &gpio_devices, list, + srcu_read_lock_held(&gpio_devices_srcu)) { + if (gdev->base <= gpio && + gdev->base + gdev->ngpio > gpio) + return &gdev->descs[gpio - gdev->base]; } } - spin_unlock_irqrestore(&gpio_lock, flags); - if (!gpio_is_valid(gpio)) pr_warn("invalid GPIO %d\n", gpio); @@ -161,16 +198,6 @@ EXPORT_SYMBOL_GPL(gpiochip_get_desc); struct gpio_desc * gpio_device_get_desc(struct gpio_device *gdev, unsigned int hwnum) { - struct gpio_chip *gc; - - /* - * FIXME: This will be locked once we protect gdev->chip everywhere - * with SRCU. - */ - gc = gdev->chip; - if (!gc) - return ERR_PTR(-ENODEV); - if (hwnum >= gdev->ngpio) return ERR_PTR(-EINVAL); @@ -198,12 +225,18 @@ EXPORT_SYMBOL_GPL(desc_to_gpio); /** * gpiod_to_chip - Return the GPIO chip to which a GPIO descriptor belongs * @desc: descriptor to return the chip of + * + * *DEPRECATED* + * This function is unsafe and should not be used. Using the chip address + * without taking the SRCU read lock may result in dereferencing a dangling + * pointer. */ struct gpio_chip *gpiod_to_chip(const struct gpio_desc *desc) { - if (!desc || !desc->gdev) + if (!desc) return NULL; - return desc->gdev->chip; + + return gpio_device_get_chip(desc->gdev); } EXPORT_SYMBOL_GPL(gpiod_to_chip); @@ -262,6 +295,7 @@ EXPORT_SYMBOL(gpio_device_get_label); * Returns: * Address of the GPIO chip backing this device. * + * *DEPRECATED* * Until we can get rid of all non-driver users of struct gpio_chip, we must * provide a way of retrieving the pointer to it from struct gpio_device. This * is *NOT* safe as the GPIO API is considered to be hot-unpluggable and the @@ -272,7 +306,7 @@ EXPORT_SYMBOL(gpio_device_get_label); */ struct gpio_chip *gpio_device_get_chip(struct gpio_device *gdev) { - return gdev->chip; + return rcu_dereference_check(gdev->chip, 1); } EXPORT_SYMBOL_GPL(gpio_device_get_chip); @@ -282,7 +316,8 @@ static int gpiochip_find_base_unlocked(int ngpio) struct gpio_device *gdev; int base = GPIO_DYNAMIC_BASE; - list_for_each_entry(gdev, &gpio_devices, list) { + list_for_each_entry_srcu(gdev, &gpio_devices, list, + lockdep_is_held(&gpio_devices_lock)) { /* found a free space? */ if (gdev->base >= base + ngpio) break; @@ -311,25 +346,36 @@ static int gpiochip_find_base_unlocked(int ngpio) */ int gpiod_get_direction(struct gpio_desc *desc) { - struct gpio_chip *gc; + unsigned long flags; unsigned int offset; int ret; - gc = gpiod_to_chip(desc); + /* + * We cannot use VALIDATE_DESC() as we must not return 0 for a NULL + * descriptor like we usually do. + */ + if (!desc || IS_ERR(desc)) + return -EINVAL; + + CLASS(gpio_chip_guard, guard)(desc); + if (!guard.gc) + return -ENODEV; + offset = gpio_chip_hwgpio(desc); + flags = READ_ONCE(desc->flags); /* * Open drain emulation using input mode may incorrectly report * input here, fix that up. */ - if (test_bit(FLAG_OPEN_DRAIN, &desc->flags) && - test_bit(FLAG_IS_OUT, &desc->flags)) + if (test_bit(FLAG_OPEN_DRAIN, &flags) && + test_bit(FLAG_IS_OUT, &flags)) return 0; - if (!gc->get_direction) + if (!guard.gc->get_direction) return -ENOTSUPP; - ret = gc->get_direction(gc, offset); + ret = guard.gc->get_direction(guard.gc, offset); if (ret < 0) return ret; @@ -337,7 +383,8 @@ int gpiod_get_direction(struct gpio_desc *desc) if (ret > 0) ret = 1; - assign_bit(FLAG_IS_OUT, &desc->flags, !ret); + assign_bit(FLAG_IS_OUT, &flags, !ret); + WRITE_ONCE(desc->flags, flags); return ret; } @@ -354,23 +401,25 @@ static int gpiodev_add_to_list_unlocked(struct gpio_device *gdev) { struct gpio_device *prev, *next; + lockdep_assert_held(&gpio_devices_lock); + if (list_empty(&gpio_devices)) { /* initial entry in list */ - list_add_tail(&gdev->list, &gpio_devices); + list_add_tail_rcu(&gdev->list, &gpio_devices); return 0; } next = list_first_entry(&gpio_devices, struct gpio_device, list); if (gdev->base + gdev->ngpio <= next->base) { /* add before first entry */ - list_add(&gdev->list, &gpio_devices); + list_add_rcu(&gdev->list, &gpio_devices); return 0; } prev = list_last_entry(&gpio_devices, struct gpio_device, list); if (prev->base + prev->ngpio <= gdev->base) { /* add behind last entry */ - list_add_tail(&gdev->list, &gpio_devices); + list_add_tail_rcu(&gdev->list, &gpio_devices); return 0; } @@ -382,11 +431,13 @@ static int gpiodev_add_to_list_unlocked(struct gpio_device *gdev) /* add between prev and next */ if (prev->base + prev->ngpio <= gdev->base && gdev->base + gdev->ngpio <= next->base) { - list_add(&gdev->list, &prev->list); + list_add_rcu(&gdev->list, &prev->list); return 0; } } + synchronize_srcu(&gpio_devices_srcu); + return -EBUSY; } @@ -399,26 +450,28 @@ static int gpiodev_add_to_list_unlocked(struct gpio_device *gdev) static struct gpio_desc *gpio_name_to_desc(const char * const name) { struct gpio_device *gdev; - unsigned long flags; + struct gpio_desc *desc; + struct gpio_chip *gc; if (!name) return NULL; - spin_lock_irqsave(&gpio_lock, flags); + guard(srcu)(&gpio_devices_srcu); - list_for_each_entry(gdev, &gpio_devices, list) { - struct gpio_desc *desc; + list_for_each_entry_srcu(gdev, &gpio_devices, list, + srcu_read_lock_held(&gpio_devices_srcu)) { + guard(srcu)(&gdev->srcu); - for_each_gpio_desc(gdev->chip, desc) { - if (desc->name && !strcmp(desc->name, name)) { - spin_unlock_irqrestore(&gpio_lock, flags); + gc = srcu_dereference(gdev->chip, &gdev->srcu); + if (!gc) + continue; + + for_each_gpio_desc(gc, desc) { + if (desc->name && !strcmp(desc->name, name)) return desc; - } } } - spin_unlock_irqrestore(&gpio_lock, flags); - return NULL; } @@ -657,12 +710,22 @@ static void gpiodev_release(struct device *dev) { struct gpio_device *gdev = to_gpio_device(dev); + /* Call pending kfree()s for descriptor labels. */ + synchronize_srcu(&gdev->desc_srcu); + cleanup_srcu_struct(&gdev->desc_srcu); + ida_free(&gpio_ida, gdev->id); kfree_const(gdev->label); kfree(gdev->descs); + cleanup_srcu_struct(&gdev->srcu); kfree(gdev); } +static const struct device_type gpio_dev_type = { + .name = "gpio_chip", + .release = gpiodev_release, +}; + #ifdef CONFIG_GPIO_CDEV #define gcdev_register(gdev, devt) gpiolib_cdev_register((gdev), (devt)) #define gcdev_unregister(gdev) gpiolib_cdev_unregister((gdev)) @@ -680,6 +743,8 @@ static int gpiochip_setup_dev(struct gpio_device *gdev) struct fwnode_handle *fwnode = dev_fwnode(&gdev->dev); int ret; + device_initialize(&gdev->dev); + /* * If fwnode doesn't belong to another device, it's safe to clear its * initialized flag. @@ -691,15 +756,12 @@ static int gpiochip_setup_dev(struct gpio_device *gdev) if (ret) return ret; - /* From this point, the .release() function cleans up gpio_device */ - gdev->dev.release = gpiodev_release; - ret = gpiochip_sysfs_register(gdev); if (ret) goto err_remove_device; dev_dbg(&gdev->dev, "registered GPIOs %d to %d on %s\n", gdev->base, - gdev->base + gdev->ngpio - 1, gdev->chip->label ? : "generic"); + gdev->base + gdev->ngpio - 1, gdev->label); return 0; @@ -720,9 +782,6 @@ static void gpiochip_machine_hog(struct gpio_chip *gc, struct gpiod_hog *hog) return; } - if (test_bit(FLAG_IS_HOGGED, &desc->flags)) - return; - rv = gpiod_hog(desc, hog->line_name, hog->lflags, hog->dflags); if (rv) gpiod_err(desc, "%s: unable to hog GPIO line (%s:%u): %d\n", @@ -748,7 +807,10 @@ static void gpiochip_setup_devs(void) struct gpio_device *gdev; int ret; - list_for_each_entry(gdev, &gpio_devices, list) { + guard(srcu)(&gpio_devices_srcu); + + list_for_each_entry_srcu(gdev, &gpio_devices, list, + srcu_read_lock_held(&gpio_devices_srcu)) { ret = gpiochip_setup_dev(gdev); if (ret) dev_err(&gdev->dev, @@ -813,8 +875,7 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data, struct lock_class_key *request_key) { struct gpio_device *gdev; - unsigned long flags; - unsigned int i; + unsigned int desc_index; int base = 0; int ret = 0; @@ -825,9 +886,11 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data, gdev = kzalloc(sizeof(*gdev), GFP_KERNEL); if (!gdev) return -ENOMEM; + + gdev->dev.type = &gpio_dev_type; gdev->dev.bus = &gpio_bus_type; gdev->dev.parent = gc->parent; - gdev->chip = gc; + rcu_assign_pointer(gdev->chip, gc); gc->gpiodev = gdev; gpiochip_set_data(gc, data); @@ -851,7 +914,6 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data, if (ret) goto err_free_ida; - device_initialize(&gdev->dev); if (gc->parent && gc->parent->driver) gdev->owner = gc->parent->driver->owner; else if (gc->owner) @@ -877,53 +939,59 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data, } gdev->ngpio = gc->ngpio; + gdev->can_sleep = gc->can_sleep; - spin_lock_irqsave(&gpio_lock, flags); - - /* - * TODO: this allocates a Linux GPIO number base in the global - * GPIO numberspace for this chip. In the long run we want to - * get *rid* of this numberspace and use only descriptors, but - * it may be a pipe dream. It will not happen before we get rid - * of the sysfs interface anyways. - */ - base = gc->base; - if (base < 0) { - base = gpiochip_find_base_unlocked(gc->ngpio); - if (base < 0) { - spin_unlock_irqrestore(&gpio_lock, flags); - ret = base; - base = 0; - goto err_free_label; - } + scoped_guard(mutex, &gpio_devices_lock) { /* - * TODO: it should not be necessary to reflect the assigned - * base outside of the GPIO subsystem. Go over drivers and - * see if anyone makes use of this, else drop this and assign - * a poison instead. + * TODO: this allocates a Linux GPIO number base in the global + * GPIO numberspace for this chip. In the long run we want to + * get *rid* of this numberspace and use only descriptors, but + * it may be a pipe dream. It will not happen before we get rid + * of the sysfs interface anyways. */ - gc->base = base; - } else { - dev_warn(&gdev->dev, - "Static allocation of GPIO base is deprecated, use dynamic allocation.\n"); - } - gdev->base = base; + base = gc->base; + if (base < 0) { + base = gpiochip_find_base_unlocked(gc->ngpio); + if (base < 0) { + ret = base; + base = 0; + goto err_free_label; + } - ret = gpiodev_add_to_list_unlocked(gdev); - if (ret) { - spin_unlock_irqrestore(&gpio_lock, flags); - chip_err(gc, "GPIO integer space overlap, cannot add chip\n"); - goto err_free_label; - } + /* + * TODO: it should not be necessary to reflect the + * assigned base outside of the GPIO subsystem. Go over + * drivers and see if anyone makes use of this, else + * drop this and assign a poison instead. + */ + gc->base = base; + } else { + dev_warn(&gdev->dev, + "Static allocation of GPIO base is deprecated, use dynamic allocation.\n"); + } - for (i = 0; i < gc->ngpio; i++) - gdev->descs[i].gdev = gdev; + gdev->base = base; - spin_unlock_irqrestore(&gpio_lock, flags); + ret = gpiodev_add_to_list_unlocked(gdev); + if (ret) { + chip_err(gc, "GPIO integer space overlap, cannot add chip\n"); + goto err_free_label; + } + } + + for (desc_index = 0; desc_index < gc->ngpio; desc_index++) + gdev->descs[desc_index].gdev = gdev; BLOCKING_INIT_NOTIFIER_HEAD(&gdev->line_state_notifier); BLOCKING_INIT_NOTIFIER_HEAD(&gdev->device_notifier); - init_rwsem(&gdev->sem); + + ret = init_srcu_struct(&gdev->srcu); + if (ret) + goto err_remove_from_list; + + ret = init_srcu_struct(&gdev->desc_srcu); + if (ret) + goto err_cleanup_gdev_srcu; #ifdef CONFIG_PINCTRL INIT_LIST_HEAD(&gdev->pin_ranges); @@ -932,32 +1000,32 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data, if (gc->names) { ret = gpiochip_set_desc_names(gc); if (ret) - goto err_remove_from_list; + goto err_cleanup_desc_srcu; } ret = gpiochip_set_names(gc); if (ret) - goto err_remove_from_list; + goto err_cleanup_desc_srcu; ret = gpiochip_init_valid_mask(gc); if (ret) - goto err_remove_from_list; + goto err_cleanup_desc_srcu; - ret = of_gpiochip_add(gc); - if (ret) - goto err_free_gpiochip_mask; - - for (i = 0; i < gc->ngpio; i++) { - struct gpio_desc *desc = &gdev->descs[i]; + for (desc_index = 0; desc_index < gc->ngpio; desc_index++) { + struct gpio_desc *desc = &gdev->descs[desc_index]; - if (gc->get_direction && gpiochip_line_is_valid(gc, i)) { + if (gc->get_direction && gpiochip_line_is_valid(gc, desc_index)) { assign_bit(FLAG_IS_OUT, - &desc->flags, !gc->get_direction(gc, i)); + &desc->flags, !gc->get_direction(gc, desc_index)); } else { assign_bit(FLAG_IS_OUT, &desc->flags, !gc->direction_input); } } + ret = of_gpiochip_add(gc); + if (ret) + goto err_free_valid_mask; + ret = gpiochip_add_pin_ranges(gc); if (ret) goto err_remove_of_chip; @@ -1003,12 +1071,16 @@ err_free_hogs: gpiochip_remove_pin_ranges(gc); err_remove_of_chip: of_gpiochip_remove(gc); -err_free_gpiochip_mask: +err_free_valid_mask: gpiochip_free_valid_mask(gc); +err_cleanup_desc_srcu: + cleanup_srcu_struct(&gdev->desc_srcu); +err_cleanup_gdev_srcu: + cleanup_srcu_struct(&gdev->srcu); err_remove_from_list: - spin_lock_irqsave(&gpio_lock, flags); - list_del(&gdev->list); - spin_unlock_irqrestore(&gpio_lock, flags); + scoped_guard(mutex, &gpio_devices_lock) + list_del_rcu(&gdev->list); + synchronize_srcu(&gpio_devices_srcu); if (gdev->dev.release) { /* release() has been registered by gpiochip_setup_dev() */ gpio_device_put(gdev); @@ -1044,16 +1116,18 @@ EXPORT_SYMBOL_GPL(gpiochip_add_data_with_key); void gpiochip_remove(struct gpio_chip *gc) { struct gpio_device *gdev = gc->gpiodev; - unsigned long flags; - unsigned int i; - - down_write(&gdev->sem); /* FIXME: should the legacy sysfs handling be moved to gpio_device? */ gpiochip_sysfs_unregister(gdev); gpiochip_free_hogs(gc); + + scoped_guard(mutex, &gpio_devices_lock) + list_del_rcu(&gdev->list); + synchronize_srcu(&gpio_devices_srcu); + /* Numb the device, cancelling all outstanding operations */ - gdev->chip = NULL; + rcu_assign_pointer(gdev->chip, NULL); + synchronize_srcu(&gdev->srcu); gpiochip_irqchip_remove(gc); acpi_gpiochip_remove(gc); of_gpiochip_remove(gc); @@ -1065,20 +1139,6 @@ void gpiochip_remove(struct gpio_chip *gc) */ gpiochip_set_data(gc, NULL); - spin_lock_irqsave(&gpio_lock, flags); - for (i = 0; i < gdev->ngpio; i++) { - if (test_bit(FLAG_REQUESTED, &gdev->descs[i].flags)) - break; - } - spin_unlock_irqrestore(&gpio_lock, flags); - - if (i != gdev->ngpio) - dev_crit(&gdev->dev, - "REMOVING GPIOCHIP WITH GPIOS STILL REQUESTED\n"); - - scoped_guard(spinlock_irqsave, &gpio_lock) - list_del(&gdev->list); - /* * The gpiochip side puts its use of the device to rest here: * if there are no userspace clients, the chardev and device will @@ -1086,7 +1146,6 @@ void gpiochip_remove(struct gpio_chip *gc) * gone. */ gcdev_unregister(gdev); - up_write(&gdev->sem); gpio_device_put(gdev); } EXPORT_SYMBOL_GPL(gpiochip_remove); @@ -1112,11 +1171,12 @@ EXPORT_SYMBOL_GPL(gpiochip_remove); * If the function returns non-NULL, the returned reference must be freed by * the caller using gpio_device_put(). */ -struct gpio_device *gpio_device_find(void *data, +struct gpio_device *gpio_device_find(const void *data, int (*match)(struct gpio_chip *gc, - void *data)) + const void *data)) { struct gpio_device *gdev; + struct gpio_chip *gc; /* * Not yet but in the future the spinlock below will become a mutex. @@ -1125,10 +1185,18 @@ struct gpio_device *gpio_device_find(void *data, */ might_sleep(); - guard(spinlock_irqsave)(&gpio_lock); + guard(srcu)(&gpio_devices_srcu); - list_for_each_entry(gdev, &gpio_devices, list) { - if (gdev->chip && match(gdev->chip, data)) + list_for_each_entry_srcu(gdev, &gpio_devices, list, + srcu_read_lock_held(&gpio_devices_srcu)) { + if (!device_is_registered(&gdev->dev)) + continue; + + guard(srcu)(&gdev->srcu); + + gc = srcu_dereference(gdev->chip, &gdev->srcu); + + if (gc && match(gc, data)) return gpio_device_get(gdev); } @@ -1136,7 +1204,7 @@ struct gpio_device *gpio_device_find(void *data, } EXPORT_SYMBOL_GPL(gpio_device_find); -static int gpio_chip_match_by_label(struct gpio_chip *gc, void *label) +static int gpio_chip_match_by_label(struct gpio_chip *gc, const void *label) { return gc->label && !strcmp(gc->label, label); } @@ -1156,7 +1224,7 @@ struct gpio_device *gpio_device_find_by_label(const char *label) } EXPORT_SYMBOL_GPL(gpio_device_find_by_label); -static int gpio_chip_match_by_fwnode(struct gpio_chip *gc, void *fwnode) +static int gpio_chip_match_by_fwnode(struct gpio_chip *gc, const void *fwnode) { return device_match_fwnode(&gc->gpiodev->dev, fwnode); } @@ -1254,8 +1322,8 @@ static void gpiochip_irqchip_free_valid_mask(struct gpio_chip *gc) gpiochip_free_mask(&gc->irq.valid_mask); } -bool gpiochip_irqchip_irq_valid(const struct gpio_chip *gc, - unsigned int offset) +static bool gpiochip_irqchip_irq_valid(const struct gpio_chip *gc, + unsigned int offset) { if (!gpiochip_line_is_valid(gc, offset)) return false; @@ -1264,7 +1332,6 @@ bool gpiochip_irqchip_irq_valid(const struct gpio_chip *gc, return true; return test_bit(offset, gc->irq.valid_mask); } -EXPORT_SYMBOL_GPL(gpiochip_irqchip_irq_valid); #ifdef CONFIG_IRQ_DOMAIN_HIERARCHY @@ -1439,6 +1506,43 @@ static unsigned int gpiochip_child_offset_to_irq_noop(struct gpio_chip *gc, return offset; } +/** + * gpiochip_irq_domain_activate() - Lock a GPIO to be used as an IRQ + * @domain: The IRQ domain used by this IRQ chip + * @data: Outermost irq_data associated with the IRQ + * @reserve: If set, only reserve an interrupt vector instead of assigning one + * + * This function is a wrapper that calls gpiochip_lock_as_irq() and is to be + * used as the activate function for the &struct irq_domain_ops. The host_data + * for the IRQ domain must be the &struct gpio_chip. + */ +static int gpiochip_irq_domain_activate(struct irq_domain *domain, + struct irq_data *data, bool reserve) +{ + struct gpio_chip *gc = domain->host_data; + unsigned int hwirq = irqd_to_hwirq(data); + + return gpiochip_lock_as_irq(gc, hwirq); +} + +/** + * gpiochip_irq_domain_deactivate() - Unlock a GPIO used as an IRQ + * @domain: The IRQ domain used by this IRQ chip + * @data: Outermost irq_data associated with the IRQ + * + * This function is a wrapper that will call gpiochip_unlock_as_irq() and is to + * be used as the deactivate function for the &struct irq_domain_ops. The + * host_data for the IRQ domain must be the &struct gpio_chip. + */ +static void gpiochip_irq_domain_deactivate(struct irq_domain *domain, + struct irq_data *data) +{ + struct gpio_chip *gc = domain->host_data; + unsigned int hwirq = irqd_to_hwirq(data); + + return gpiochip_unlock_as_irq(gc, hwirq); +} + static void gpiochip_hierarchy_setup_domain_ops(struct irq_domain_ops *ops) { ops->activate = gpiochip_irq_domain_activate; @@ -1556,7 +1660,8 @@ static bool gpiochip_hierarchy_is_hierarchical(struct gpio_chip *gc) * gpiochip by assigning the gpiochip as chip data, and using the irqchip * stored inside the gpiochip. */ -int gpiochip_irq_map(struct irq_domain *d, unsigned int irq, irq_hw_number_t hwirq) +static int gpiochip_irq_map(struct irq_domain *d, unsigned int irq, + irq_hw_number_t hwirq) { struct gpio_chip *gc = d->host_data; int ret = 0; @@ -1593,9 +1698,8 @@ int gpiochip_irq_map(struct irq_domain *d, unsigned int irq, irq_hw_number_t hwi return 0; } -EXPORT_SYMBOL_GPL(gpiochip_irq_map); -void gpiochip_irq_unmap(struct irq_domain *d, unsigned int irq) +static void gpiochip_irq_unmap(struct irq_domain *d, unsigned int irq) { struct gpio_chip *gc = d->host_data; @@ -1604,7 +1708,6 @@ void gpiochip_irq_unmap(struct irq_domain *d, unsigned int irq) irq_set_chip_and_handler(irq, NULL, NULL); irq_set_chip_data(irq, NULL); } -EXPORT_SYMBOL_GPL(gpiochip_irq_unmap); static const struct irq_domain_ops gpiochip_domain_ops = { .map = gpiochip_irq_map, @@ -1626,50 +1729,6 @@ static struct irq_domain *gpiochip_simple_create_domain(struct gpio_chip *gc) return domain; } -/* - * TODO: move these activate/deactivate in under the hierarchicial - * irqchip implementation as static once SPMI and SSBI (all external - * users) are phased over. - */ -/** - * gpiochip_irq_domain_activate() - Lock a GPIO to be used as an IRQ - * @domain: The IRQ domain used by this IRQ chip - * @data: Outermost irq_data associated with the IRQ - * @reserve: If set, only reserve an interrupt vector instead of assigning one - * - * This function is a wrapper that calls gpiochip_lock_as_irq() and is to be - * used as the activate function for the &struct irq_domain_ops. The host_data - * for the IRQ domain must be the &struct gpio_chip. - */ -int gpiochip_irq_domain_activate(struct irq_domain *domain, - struct irq_data *data, bool reserve) -{ - struct gpio_chip *gc = domain->host_data; - unsigned int hwirq = irqd_to_hwirq(data); - - return gpiochip_lock_as_irq(gc, hwirq); -} -EXPORT_SYMBOL_GPL(gpiochip_irq_domain_activate); - -/** - * gpiochip_irq_domain_deactivate() - Unlock a GPIO used as an IRQ - * @domain: The IRQ domain used by this IRQ chip - * @data: Outermost irq_data associated with the IRQ - * - * This function is a wrapper that will call gpiochip_unlock_as_irq() and is to - * be used as the deactivate function for the &struct irq_domain_ops. The - * host_data for the IRQ domain must be the &struct gpio_chip. - */ -void gpiochip_irq_domain_deactivate(struct irq_domain *domain, - struct irq_data *data) -{ - struct gpio_chip *gc = domain->host_data; - unsigned int hwirq = irqd_to_hwirq(data); - - return gpiochip_unlock_as_irq(gc, hwirq); -} -EXPORT_SYMBOL_GPL(gpiochip_irq_domain_deactivate); - static int gpiochip_to_irq(struct gpio_chip *gc, unsigned int offset) { struct irq_domain *domain = gc->irq.domain; @@ -2189,58 +2248,41 @@ EXPORT_SYMBOL_GPL(gpiochip_remove_pin_ranges); */ static int gpiod_request_commit(struct gpio_desc *desc, const char *label) { - struct gpio_chip *gc = desc->gdev->chip; - unsigned long flags; unsigned int offset; int ret; - if (label) { - label = kstrdup_const(label, GFP_KERNEL); - if (!label) - return -ENOMEM; - } + CLASS(gpio_chip_guard, guard)(desc); + if (!guard.gc) + return -ENODEV; - spin_lock_irqsave(&gpio_lock, flags); + if (test_and_set_bit(FLAG_REQUESTED, &desc->flags)) + return -EBUSY; /* NOTE: gpio_request() can be called in early boot, * before IRQs are enabled, for non-sleeping (SOC) GPIOs. */ - if (test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0) { - desc_set_label(desc, label ? : "?"); - } else { - ret = -EBUSY; - goto out_free_unlock; - } - - if (gc->request) { - /* gc->request may sleep */ - spin_unlock_irqrestore(&gpio_lock, flags); + if (guard.gc->request) { offset = gpio_chip_hwgpio(desc); - if (gpiochip_line_is_valid(gc, offset)) - ret = gc->request(gc, offset); + if (gpiochip_line_is_valid(guard.gc, offset)) + ret = guard.gc->request(guard.gc, offset); else ret = -EINVAL; - spin_lock_irqsave(&gpio_lock, flags); - - if (ret) { - desc_set_label(desc, NULL); - clear_bit(FLAG_REQUESTED, &desc->flags); - goto out_free_unlock; - } + if (ret) + goto out_clear_bit; } - if (gc->get_direction) { - /* gc->get_direction may sleep */ - spin_unlock_irqrestore(&gpio_lock, flags); + + if (guard.gc->get_direction) gpiod_get_direction(desc); - spin_lock_irqsave(&gpio_lock, flags); - } - spin_unlock_irqrestore(&gpio_lock, flags); + + ret = desc_set_label(desc, label ? : "?"); + if (ret) + goto out_clear_bit; + return 0; -out_free_unlock: - spin_unlock_irqrestore(&gpio_lock, flags); - kfree_const(label); +out_clear_bit: + clear_bit(FLAG_REQUESTED, &desc->flags); return ret; } @@ -2254,19 +2296,12 @@ static int validate_desc(const struct gpio_desc *desc, const char *func) { if (!desc) return 0; + if (IS_ERR(desc)) { pr_warn("%s: invalid GPIO (errorpointer)\n", func); return PTR_ERR(desc); } - if (!desc->gdev) { - pr_warn("%s: invalid GPIO (no device)\n", func); - return -EINVAL; - } - if (!desc->gdev->chip) { - dev_warn(&desc->gdev->dev, - "%s: backing chip is gone\n", func); - return 0; - } + return 1; } @@ -2302,60 +2337,45 @@ int gpiod_request(struct gpio_desc *desc, const char *label) return ret; } -static bool gpiod_free_commit(struct gpio_desc *desc) +static void gpiod_free_commit(struct gpio_desc *desc) { - struct gpio_chip *gc; unsigned long flags; - bool ret = false; might_sleep(); - spin_lock_irqsave(&gpio_lock, flags); + CLASS(gpio_chip_guard, guard)(desc); - gc = desc->gdev->chip; - if (gc && test_bit(FLAG_REQUESTED, &desc->flags)) { - if (gc->free) { - spin_unlock_irqrestore(&gpio_lock, flags); - might_sleep_if(gc->can_sleep); - gc->free(gc, gpio_chip_hwgpio(desc)); - spin_lock_irqsave(&gpio_lock, flags); - } - kfree_const(desc->label); - desc_set_label(desc, NULL); - clear_bit(FLAG_ACTIVE_LOW, &desc->flags); - clear_bit(FLAG_REQUESTED, &desc->flags); - clear_bit(FLAG_OPEN_DRAIN, &desc->flags); - clear_bit(FLAG_OPEN_SOURCE, &desc->flags); - clear_bit(FLAG_PULL_UP, &desc->flags); - clear_bit(FLAG_PULL_DOWN, &desc->flags); - clear_bit(FLAG_BIAS_DISABLE, &desc->flags); - clear_bit(FLAG_EDGE_RISING, &desc->flags); - clear_bit(FLAG_EDGE_FALLING, &desc->flags); - clear_bit(FLAG_IS_HOGGED, &desc->flags); + flags = READ_ONCE(desc->flags); + + if (guard.gc && test_bit(FLAG_REQUESTED, &flags)) { + if (guard.gc->free) + guard.gc->free(guard.gc, gpio_chip_hwgpio(desc)); + + clear_bit(FLAG_ACTIVE_LOW, &flags); + clear_bit(FLAG_REQUESTED, &flags); + clear_bit(FLAG_OPEN_DRAIN, &flags); + clear_bit(FLAG_OPEN_SOURCE, &flags); + clear_bit(FLAG_PULL_UP, &flags); + clear_bit(FLAG_PULL_DOWN, &flags); + clear_bit(FLAG_BIAS_DISABLE, &flags); + clear_bit(FLAG_EDGE_RISING, &flags); + clear_bit(FLAG_EDGE_FALLING, &flags); + clear_bit(FLAG_IS_HOGGED, &flags); #ifdef CONFIG_OF_DYNAMIC - desc->hog = NULL; + WRITE_ONCE(desc->hog, NULL); #endif - ret = true; - } - - spin_unlock_irqrestore(&gpio_lock, flags); - gpiod_line_state_notify(desc, GPIOLINE_CHANGED_RELEASED); + desc_set_label(desc, NULL); + WRITE_ONCE(desc->flags, flags); - return ret; + gpiod_line_state_notify(desc, GPIOLINE_CHANGED_RELEASED); + } } void gpiod_free(struct gpio_desc *desc) { - /* - * We must not use VALIDATE_DESC_VOID() as the underlying gdev->chip - * may already be NULL but we still want to put the references. - */ - if (!desc) - return; - - if (!gpiod_free_commit(desc)) - WARN_ON(1); + VALIDATE_DESC_VOID(desc); + gpiod_free_commit(desc); module_put(desc->gdev->owner); gpio_device_put(desc->gdev); } @@ -2381,20 +2401,12 @@ char *gpiochip_dup_line_label(struct gpio_chip *gc, unsigned int offset) if (IS_ERR(desc)) return NULL; - guard(spinlock_irqsave)(&gpio_lock); - if (!test_bit(FLAG_REQUESTED, &desc->flags)) return NULL; - /* - * FIXME: Once we mark gpiod_direction_input/output() and - * gpiod_get_direction() with might_sleep(), we'll be able to protect - * the GPIO descriptors with mutex (while value setting operations will - * become lockless). - * - * Until this happens, this allocation needs to be atomic. - */ - label = kstrdup(desc->label, GFP_ATOMIC); + guard(srcu)(&desc->gdev->desc_srcu); + + label = kstrdup(gpiod_get_label(desc), GFP_KERNEL); if (!label) return ERR_PTR(-ENOMEM); @@ -2495,11 +2507,14 @@ static int gpio_set_config_with_argument(struct gpio_desc *desc, enum pin_config_param mode, u32 argument) { - struct gpio_chip *gc = desc->gdev->chip; unsigned long config; + CLASS(gpio_chip_guard, guard)(desc); + if (!guard.gc) + return -ENODEV; + config = pinconf_to_config_packed(mode, argument); - return gpio_do_set_config(gc, gpio_chip_hwgpio(desc), config); + return gpio_do_set_config(guard.gc, gpio_chip_hwgpio(desc), config); } static int gpio_set_config_with_argument_optional(struct gpio_desc *desc, @@ -2533,13 +2548,16 @@ static int gpio_set_config(struct gpio_desc *desc, enum pin_config_param mode) static int gpio_set_bias(struct gpio_desc *desc) { enum pin_config_param bias; + unsigned long flags; unsigned int arg; - if (test_bit(FLAG_BIAS_DISABLE, &desc->flags)) + flags = READ_ONCE(desc->flags); + + if (test_bit(FLAG_BIAS_DISABLE, &flags)) bias = PIN_CONFIG_BIAS_DISABLE; - else if (test_bit(FLAG_PULL_UP, &desc->flags)) + else if (test_bit(FLAG_PULL_UP, &flags)) bias = PIN_CONFIG_BIAS_PULL_UP; - else if (test_bit(FLAG_PULL_DOWN, &desc->flags)) + else if (test_bit(FLAG_PULL_DOWN, &flags)) bias = PIN_CONFIG_BIAS_PULL_DOWN; else return 0; @@ -2586,18 +2604,20 @@ int gpio_set_debounce_timeout(struct gpio_desc *desc, unsigned int debounce) */ int gpiod_direction_input(struct gpio_desc *desc) { - struct gpio_chip *gc; int ret = 0; VALIDATE_DESC(desc); - gc = desc->gdev->chip; + + CLASS(gpio_chip_guard, guard)(desc); + if (!guard.gc) + return -ENODEV; /* * It is legal to have no .get() and .direction_input() specified if * the chip is output-only, but you can't specify .direction_input() * and not support the .get() operation, that doesn't make sense. */ - if (!gc->get && gc->direction_input) { + if (!guard.gc->get && guard.gc->direction_input) { gpiod_warn(desc, "%s: missing get() but have direction_input()\n", __func__); @@ -2610,10 +2630,12 @@ int gpiod_direction_input(struct gpio_desc *desc) * direction (if .get_direction() is supported) else we silently * assume we are in input mode after this. */ - if (gc->direction_input) { - ret = gc->direction_input(gc, gpio_chip_hwgpio(desc)); - } else if (gc->get_direction && - (gc->get_direction(gc, gpio_chip_hwgpio(desc)) != 1)) { + if (guard.gc->direction_input) { + ret = guard.gc->direction_input(guard.gc, + gpio_chip_hwgpio(desc)); + } else if (guard.gc->get_direction && + (guard.gc->get_direction(guard.gc, + gpio_chip_hwgpio(desc)) != 1)) { gpiod_warn(desc, "%s: missing direction_input() operation and line is output\n", __func__); @@ -2632,28 +2654,31 @@ EXPORT_SYMBOL_GPL(gpiod_direction_input); static int gpiod_direction_output_raw_commit(struct gpio_desc *desc, int value) { - struct gpio_chip *gc = desc->gdev->chip; - int val = !!value; - int ret = 0; + int val = !!value, ret = 0; + + CLASS(gpio_chip_guard, guard)(desc); + if (!guard.gc) + return -ENODEV; /* * It's OK not to specify .direction_output() if the gpiochip is * output-only, but if there is then not even a .set() operation it * is pretty tricky to drive the output line. */ - if (!gc->set && !gc->direction_output) { + if (!guard.gc->set && !guard.gc->direction_output) { gpiod_warn(desc, "%s: missing set() and direction_output() operations\n", __func__); return -EIO; } - if (gc->direction_output) { - ret = gc->direction_output(gc, gpio_chip_hwgpio(desc), val); + if (guard.gc->direction_output) { + ret = guard.gc->direction_output(guard.gc, + gpio_chip_hwgpio(desc), val); } else { /* Check that we are in output mode if we can */ - if (gc->get_direction && - gc->get_direction(gc, gpio_chip_hwgpio(desc))) { + if (guard.gc->get_direction && + guard.gc->get_direction(guard.gc, gpio_chip_hwgpio(desc))) { gpiod_warn(desc, "%s: missing direction_output() operation\n", __func__); @@ -2663,7 +2688,7 @@ static int gpiod_direction_output_raw_commit(struct gpio_desc *desc, int value) * If we can't actively set the direction, we are some * output-only chip, so just drive the output as desired. */ - gc->set(gc, gpio_chip_hwgpio(desc), val); + guard.gc->set(guard.gc, gpio_chip_hwgpio(desc), val); } if (!ret) @@ -2705,24 +2730,28 @@ EXPORT_SYMBOL_GPL(gpiod_direction_output_raw); */ int gpiod_direction_output(struct gpio_desc *desc, int value) { + unsigned long flags; int ret; VALIDATE_DESC(desc); - if (test_bit(FLAG_ACTIVE_LOW, &desc->flags)) + + flags = READ_ONCE(desc->flags); + + if (test_bit(FLAG_ACTIVE_LOW, &flags)) value = !value; else value = !!value; /* GPIOs used for enabled IRQs shall not be set as output */ - if (test_bit(FLAG_USED_AS_IRQ, &desc->flags) && - test_bit(FLAG_IRQ_IS_ENABLED, &desc->flags)) { + if (test_bit(FLAG_USED_AS_IRQ, &flags) && + test_bit(FLAG_IRQ_IS_ENABLED, &flags)) { gpiod_err(desc, "%s: tried to set a GPIO tied to an IRQ as output\n", __func__); return -EIO; } - if (test_bit(FLAG_OPEN_DRAIN, &desc->flags)) { + if (test_bit(FLAG_OPEN_DRAIN, &flags)) { /* First see if we can enable open drain in hardware */ ret = gpio_set_config(desc, PIN_CONFIG_DRIVE_OPEN_DRAIN); if (!ret) @@ -2732,7 +2761,7 @@ int gpiod_direction_output(struct gpio_desc *desc, int value) ret = gpiod_direction_input(desc); goto set_output_flag; } - } else if (test_bit(FLAG_OPEN_SOURCE, &desc->flags)) { + } else if (test_bit(FLAG_OPEN_SOURCE, &flags)) { ret = gpio_set_config(desc, PIN_CONFIG_DRIVE_OPEN_SOURCE); if (!ret) goto set_output_value; @@ -2775,17 +2804,20 @@ EXPORT_SYMBOL_GPL(gpiod_direction_output); int gpiod_enable_hw_timestamp_ns(struct gpio_desc *desc, unsigned long flags) { int ret = 0; - struct gpio_chip *gc; VALIDATE_DESC(desc); - gc = desc->gdev->chip; - if (!gc->en_hw_timestamp) { + CLASS(gpio_chip_guard, guard)(desc); + if (!guard.gc) + return -ENODEV; + + if (!guard.gc->en_hw_timestamp) { gpiod_warn(desc, "%s: hw ts not supported\n", __func__); return -ENOTSUPP; } - ret = gc->en_hw_timestamp(gc, gpio_chip_hwgpio(desc), flags); + ret = guard.gc->en_hw_timestamp(guard.gc, + gpio_chip_hwgpio(desc), flags); if (ret) gpiod_warn(desc, "%s: hw ts request failed\n", __func__); @@ -2804,17 +2836,20 @@ EXPORT_SYMBOL_GPL(gpiod_enable_hw_timestamp_ns); int gpiod_disable_hw_timestamp_ns(struct gpio_desc *desc, unsigned long flags) { int ret = 0; - struct gpio_chip *gc; VALIDATE_DESC(desc); - gc = desc->gdev->chip; - if (!gc->dis_hw_timestamp) { + CLASS(gpio_chip_guard, guard)(desc); + if (!guard.gc) + return -ENODEV; + + if (!guard.gc->dis_hw_timestamp) { gpiod_warn(desc, "%s: hw ts not supported\n", __func__); return -ENOTSUPP; } - ret = gc->dis_hw_timestamp(gc, gpio_chip_hwgpio(desc), flags); + ret = guard.gc->dis_hw_timestamp(guard.gc, gpio_chip_hwgpio(desc), + flags); if (ret) gpiod_warn(desc, "%s: hw ts release failed\n", __func__); @@ -2833,12 +2868,13 @@ EXPORT_SYMBOL_GPL(gpiod_disable_hw_timestamp_ns); */ int gpiod_set_config(struct gpio_desc *desc, unsigned long config) { - struct gpio_chip *gc; - VALIDATE_DESC(desc); - gc = desc->gdev->chip; - return gpio_do_set_config(gc, gpio_chip_hwgpio(desc), config); + CLASS(gpio_chip_guard, guard)(desc); + if (!guard.gc) + return -ENODEV; + + return gpio_do_set_config(guard.gc, gpio_chip_hwgpio(desc), config); } EXPORT_SYMBOL_GPL(gpiod_set_config); @@ -2936,10 +2972,19 @@ static int gpio_chip_get_value(struct gpio_chip *gc, const struct gpio_desc *des static int gpiod_get_raw_value_commit(const struct gpio_desc *desc) { + struct gpio_device *gdev; struct gpio_chip *gc; int value; - gc = desc->gdev->chip; + /* FIXME Unable to use gpio_chip_guard due to const desc. */ + gdev = desc->gdev; + + guard(srcu)(&gdev->srcu); + + gc = srcu_dereference(gdev->chip, &gdev->srcu); + if (!gc) + return -ENODEV; + value = gpio_chip_get_value(gc, desc); value = value < 0 ? value : !!value; trace_gpio_value(desc_to_gpio(desc), 1, value); @@ -2965,6 +3010,14 @@ static int gpio_chip_get_multiple(struct gpio_chip *gc, return -EIO; } +/* The 'other' chip must be protected with its GPIO device's SRCU. */ +static bool gpio_device_chip_cmp(struct gpio_device *gdev, struct gpio_chip *gc) +{ + guard(srcu)(&gdev->srcu); + + return gc == srcu_dereference(gdev->chip, &gdev->srcu); +} + int gpiod_get_array_value_complex(bool raw, bool can_sleep, unsigned int array_size, struct gpio_desc **desc_array, @@ -3002,33 +3055,36 @@ int gpiod_get_array_value_complex(bool raw, bool can_sleep, } while (i < array_size) { - struct gpio_chip *gc = desc_array[i]->gdev->chip; DECLARE_BITMAP(fastpath_mask, FASTPATH_NGPIO); DECLARE_BITMAP(fastpath_bits, FASTPATH_NGPIO); unsigned long *mask, *bits; int first, j; - if (likely(gc->ngpio <= FASTPATH_NGPIO)) { + CLASS(gpio_chip_guard, guard)(desc_array[i]); + if (!guard.gc) + return -ENODEV; + + if (likely(guard.gc->ngpio <= FASTPATH_NGPIO)) { mask = fastpath_mask; bits = fastpath_bits; } else { gfp_t flags = can_sleep ? GFP_KERNEL : GFP_ATOMIC; - mask = bitmap_alloc(gc->ngpio, flags); + mask = bitmap_alloc(guard.gc->ngpio, flags); if (!mask) return -ENOMEM; - bits = bitmap_alloc(gc->ngpio, flags); + bits = bitmap_alloc(guard.gc->ngpio, flags); if (!bits) { bitmap_free(mask); return -ENOMEM; } } - bitmap_zero(mask, gc->ngpio); + bitmap_zero(mask, guard.gc->ngpio); if (!can_sleep) - WARN_ON(gc->can_sleep); + WARN_ON(guard.gc->can_sleep); /* collect all inputs belonging to the same chip */ first = i; @@ -3043,9 +3099,9 @@ int gpiod_get_array_value_complex(bool raw, bool can_sleep, i = find_next_zero_bit(array_info->get_mask, array_size, i); } while ((i < array_size) && - (desc_array[i]->gdev->chip == gc)); + gpio_device_chip_cmp(desc_array[i]->gdev, guard.gc)); - ret = gpio_chip_get_multiple(gc, mask, bits); + ret = gpio_chip_get_multiple(guard.gc, mask, bits); if (ret) { if (mask != fastpath_mask) bitmap_free(mask); @@ -3092,7 +3148,7 @@ int gpiod_get_raw_value(const struct gpio_desc *desc) { VALIDATE_DESC(desc); /* Should be using gpiod_get_raw_value_cansleep() */ - WARN_ON(desc->gdev->chip->can_sleep); + WARN_ON(desc->gdev->can_sleep); return gpiod_get_raw_value_commit(desc); } EXPORT_SYMBOL_GPL(gpiod_get_raw_value); @@ -3113,7 +3169,7 @@ int gpiod_get_value(const struct gpio_desc *desc) VALIDATE_DESC(desc); /* Should be using gpiod_get_value_cansleep() */ - WARN_ON(desc->gdev->chip->can_sleep); + WARN_ON(desc->gdev->can_sleep); value = gpiod_get_raw_value_commit(desc); if (value < 0) @@ -3186,14 +3242,16 @@ EXPORT_SYMBOL_GPL(gpiod_get_array_value); */ static void gpio_set_open_drain_value_commit(struct gpio_desc *desc, bool value) { - int ret = 0; - struct gpio_chip *gc = desc->gdev->chip; - int offset = gpio_chip_hwgpio(desc); + int ret = 0, offset = gpio_chip_hwgpio(desc); + + CLASS(gpio_chip_guard, guard)(desc); + if (!guard.gc) + return; if (value) { - ret = gc->direction_input(gc, offset); + ret = guard.gc->direction_input(guard.gc, offset); } else { - ret = gc->direction_output(gc, offset, 0); + ret = guard.gc->direction_output(guard.gc, offset, 0); if (!ret) set_bit(FLAG_IS_OUT, &desc->flags); } @@ -3211,16 +3269,18 @@ static void gpio_set_open_drain_value_commit(struct gpio_desc *desc, bool value) */ static void gpio_set_open_source_value_commit(struct gpio_desc *desc, bool value) { - int ret = 0; - struct gpio_chip *gc = desc->gdev->chip; - int offset = gpio_chip_hwgpio(desc); + int ret = 0, offset = gpio_chip_hwgpio(desc); + + CLASS(gpio_chip_guard, guard)(desc); + if (!guard.gc) + return; if (value) { - ret = gc->direction_output(gc, offset, 1); + ret = guard.gc->direction_output(guard.gc, offset, 1); if (!ret) set_bit(FLAG_IS_OUT, &desc->flags); } else { - ret = gc->direction_input(gc, offset); + ret = guard.gc->direction_input(guard.gc, offset); } trace_gpio_direction(desc_to_gpio(desc), !value, ret); if (ret < 0) @@ -3231,11 +3291,12 @@ static void gpio_set_open_source_value_commit(struct gpio_desc *desc, bool value static void gpiod_set_raw_value_commit(struct gpio_desc *desc, bool value) { - struct gpio_chip *gc; + CLASS(gpio_chip_guard, guard)(desc); + if (!guard.gc) + return; - gc = desc->gdev->chip; trace_gpio_value(desc_to_gpio(desc), 0, value); - gc->set(gc, gpio_chip_hwgpio(desc), value); + guard.gc->set(guard.gc, gpio_chip_hwgpio(desc), value); } /* @@ -3296,33 +3357,36 @@ int gpiod_set_array_value_complex(bool raw, bool can_sleep, } while (i < array_size) { - struct gpio_chip *gc = desc_array[i]->gdev->chip; DECLARE_BITMAP(fastpath_mask, FASTPATH_NGPIO); DECLARE_BITMAP(fastpath_bits, FASTPATH_NGPIO); unsigned long *mask, *bits; int count = 0; - if (likely(gc->ngpio <= FASTPATH_NGPIO)) { + CLASS(gpio_chip_guard, guard)(desc_array[i]); + if (!guard.gc) + return -ENODEV; + + if (likely(guard.gc->ngpio <= FASTPATH_NGPIO)) { mask = fastpath_mask; bits = fastpath_bits; } else { gfp_t flags = can_sleep ? GFP_KERNEL : GFP_ATOMIC; - mask = bitmap_alloc(gc->ngpio, flags); + mask = bitmap_alloc(guard.gc->ngpio, flags); if (!mask) return -ENOMEM; - bits = bitmap_alloc(gc->ngpio, flags); + bits = bitmap_alloc(guard.gc->ngpio, flags); if (!bits) { bitmap_free(mask); return -ENOMEM; } } - bitmap_zero(mask, gc->ngpio); + bitmap_zero(mask, guard.gc->ngpio); if (!can_sleep) - WARN_ON(gc->can_sleep); + WARN_ON(guard.gc->can_sleep); do { struct gpio_desc *desc = desc_array[i]; @@ -3358,10 +3422,10 @@ int gpiod_set_array_value_complex(bool raw, bool can_sleep, i = find_next_zero_bit(array_info->set_mask, array_size, i); } while ((i < array_size) && - (desc_array[i]->gdev->chip == gc)); + gpio_device_chip_cmp(desc_array[i]->gdev, guard.gc)); /* push collected bits to outputs */ if (count != 0) - gpio_chip_set_multiple(gc, mask, bits); + gpio_chip_set_multiple(guard.gc, mask, bits); if (mask != fastpath_mask) bitmap_free(mask); @@ -3386,7 +3450,7 @@ void gpiod_set_raw_value(struct gpio_desc *desc, int value) { VALIDATE_DESC_VOID(desc); /* Should be using gpiod_set_raw_value_cansleep() */ - WARN_ON(desc->gdev->chip->can_sleep); + WARN_ON(desc->gdev->can_sleep); gpiod_set_raw_value_commit(desc, value); } EXPORT_SYMBOL_GPL(gpiod_set_raw_value); @@ -3427,7 +3491,7 @@ void gpiod_set_value(struct gpio_desc *desc, int value) { VALIDATE_DESC_VOID(desc); /* Should be using gpiod_set_value_cansleep() */ - WARN_ON(desc->gdev->chip->can_sleep); + WARN_ON(desc->gdev->can_sleep); gpiod_set_value_nocheck(desc, value); } EXPORT_SYMBOL_GPL(gpiod_set_value); @@ -3491,7 +3555,7 @@ EXPORT_SYMBOL_GPL(gpiod_set_array_value); int gpiod_cansleep(const struct gpio_desc *desc) { VALIDATE_DESC(desc); - return desc->gdev->chip->can_sleep; + return desc->gdev->can_sleep; } EXPORT_SYMBOL_GPL(gpiod_cansleep); @@ -3503,16 +3567,8 @@ EXPORT_SYMBOL_GPL(gpiod_cansleep); int gpiod_set_consumer_name(struct gpio_desc *desc, const char *name) { VALIDATE_DESC(desc); - if (name) { - name = kstrdup_const(name, GFP_KERNEL); - if (!name) - return -ENOMEM; - } - kfree_const(desc->label); - desc_set_label(desc, name); - - return 0; + return desc_set_label(desc, name); } EXPORT_SYMBOL_GPL(gpiod_set_consumer_name); @@ -3525,6 +3581,7 @@ EXPORT_SYMBOL_GPL(gpiod_set_consumer_name); */ int gpiod_to_irq(const struct gpio_desc *desc) { + struct gpio_device *gdev; struct gpio_chip *gc; int offset; @@ -3533,10 +3590,16 @@ int gpiod_to_irq(const struct gpio_desc *desc) * requires this function to not return zero on an invalid descriptor * but rather a negative error number. */ - if (!desc || IS_ERR(desc) || !desc->gdev || !desc->gdev->chip) + if (!desc || IS_ERR(desc)) return -EINVAL; - gc = desc->gdev->chip; + gdev = desc->gdev; + /* FIXME Cannot use gpio_chip_guard due to const desc. */ + guard(srcu)(&gdev->srcu); + gc = srcu_dereference(gdev->chip, &gdev->srcu); + if (!gc) + return -ENODEV; + offset = gpio_chip_hwgpio(desc); if (gc->to_irq) { int retirq = gc->to_irq(gc, offset); @@ -3603,14 +3666,6 @@ int gpiochip_lock_as_irq(struct gpio_chip *gc, unsigned int offset) set_bit(FLAG_USED_AS_IRQ, &desc->flags); set_bit(FLAG_IRQ_IS_ENABLED, &desc->flags); - /* - * If the consumer has not set up a label (such as when the - * IRQ is referenced from .to_irq()) we set up a label here - * so it is clear this is used as an interrupt. - */ - if (!desc->label) - desc_set_label(desc, "interrupt"); - return 0; } EXPORT_SYMBOL_GPL(gpiochip_lock_as_irq); @@ -3633,10 +3688,6 @@ void gpiochip_unlock_as_irq(struct gpio_chip *gc, unsigned int offset) clear_bit(FLAG_USED_AS_IRQ, &desc->flags); clear_bit(FLAG_IRQ_IS_ENABLED, &desc->flags); - - /* If we only had this marking, erase it */ - if (desc->label && !strcmp(desc->label, "interrupt")) - desc_set_label(desc, NULL); } EXPORT_SYMBOL_GPL(gpiochip_unlock_as_irq); @@ -4152,30 +4203,38 @@ struct gpio_desc *gpiod_find_and_request(struct device *consumer, { unsigned long lookupflags = GPIO_LOOKUP_FLAGS_DEFAULT; const char *name = function_name_or_default(con_id); - struct gpio_desc *desc; - int ret; + /* + * scoped_guard() is implemented as a for loop, meaning static + * analyzers will complain about these two not being initialized. + */ + struct gpio_desc *desc = NULL; + int ret = 0; + + scoped_guard(srcu, &gpio_devices_srcu) { + desc = gpiod_find_by_fwnode(fwnode, consumer, con_id, idx, + &flags, &lookupflags); + if (gpiod_not_found(desc) && platform_lookup_allowed) { + /* + * Either we are not using DT or ACPI, or their lookup + * did not return a result. In that case, use platform + * lookup as a fallback. + */ + dev_dbg(consumer, + "using lookup tables for GPIO lookup\n"); + desc = gpiod_find(consumer, con_id, idx, &lookupflags); + } + + if (IS_ERR(desc)) { + dev_dbg(consumer, "No GPIO consumer %s found\n", name); + return desc; + } - desc = gpiod_find_by_fwnode(fwnode, consumer, con_id, idx, &flags, &lookupflags); - if (gpiod_not_found(desc) && platform_lookup_allowed) { /* - * Either we are not using DT or ACPI, or their lookup did not - * return a result. In that case, use platform lookup as a - * fallback. + * If a connection label was passed use that, else attempt to use + * the device name as label */ - dev_dbg(consumer, "using lookup tables for GPIO lookup\n"); - desc = gpiod_find(consumer, con_id, idx, &lookupflags); + ret = gpiod_request(desc, label); } - - if (IS_ERR(desc)) { - dev_dbg(consumer, "No GPIO consumer %s found\n", name); - return desc; - } - - /* - * If a connection label was passed use that, else attempt to use - * the device name as label - */ - ret = gpiod_request(desc, label); if (ret) { if (!(ret == -EBUSY && flags & GPIOD_FLAGS_BIT_NONEXCLUSIVE)) return ERR_PTR(ret); @@ -4247,9 +4306,9 @@ int gpiod_count(struct device *dev, const char *con_id) int count = -ENOENT; if (is_of_node(fwnode)) - count = of_gpio_get_count(dev, con_id); + count = of_gpio_count(fwnode, con_id); else if (is_acpi_node(fwnode)) - count = acpi_gpio_count(dev, con_id); + count = acpi_gpio_count(fwnode, con_id); else if (is_software_node(fwnode)) count = swnode_gpio_count(fwnode, con_id); @@ -4434,26 +4493,30 @@ EXPORT_SYMBOL_GPL(gpiod_get_index_optional); int gpiod_hog(struct gpio_desc *desc, const char *name, unsigned long lflags, enum gpiod_flags dflags) { - struct gpio_chip *gc; + struct gpio_device *gdev = desc->gdev; struct gpio_desc *local_desc; int hwnum; int ret; - gc = gpiod_to_chip(desc); + CLASS(gpio_chip_guard, guard)(desc); + if (!guard.gc) + return -ENODEV; + + if (test_and_set_bit(FLAG_IS_HOGGED, &desc->flags)) + return 0; + hwnum = gpio_chip_hwgpio(desc); - local_desc = gpiochip_request_own_desc(gc, hwnum, name, + local_desc = gpiochip_request_own_desc(guard.gc, hwnum, name, lflags, dflags); if (IS_ERR(local_desc)) { + clear_bit(FLAG_IS_HOGGED, &desc->flags); ret = PTR_ERR(local_desc); pr_err("requesting hog GPIO %s (chip %s, offset %d) failed, %d\n", - name, gc->label, hwnum, ret); + name, gdev->label, hwnum, ret); return ret; } - /* Mark GPIO as hogged so it can be identified and removed later */ - set_bit(FLAG_IS_HOGGED, &desc->flags); - gpiod_dbg(desc, "hogged as %s%s\n", (dflags & GPIOD_FLAGS_BIT_DIR_OUT) ? "output" : "input", (dflags & GPIOD_FLAGS_BIT_DIR_OUT) ? @@ -4717,13 +4780,22 @@ core_initcall(gpiolib_dev_init); static void gpiolib_dbg_show(struct seq_file *s, struct gpio_device *gdev) { - struct gpio_chip *gc = gdev->chip; bool active_low, is_irq, is_out; unsigned int gpio = gdev->base; struct gpio_desc *desc; + struct gpio_chip *gc; int value; + guard(srcu)(&gdev->srcu); + + gc = srcu_dereference(gdev->chip, &gdev->srcu); + if (!gc) { + seq_puts(s, "Underlying GPIO chip is gone\n"); + return; + } + for_each_gpio_desc(gc, desc) { + guard(srcu)(&desc->gdev->desc_srcu); if (test_bit(FLAG_REQUESTED, &desc->flags)) { gpiod_get_direction(desc); is_out = test_bit(FLAG_IS_OUT, &desc->flags); @@ -4731,7 +4803,7 @@ static void gpiolib_dbg_show(struct seq_file *s, struct gpio_device *gdev) is_irq = test_bit(FLAG_USED_AS_IRQ, &desc->flags); active_low = test_bit(FLAG_ACTIVE_LOW, &desc->flags); seq_printf(s, " gpio-%-3d (%-20.20s|%-20.20s) %s %s %s%s\n", - gpio, desc->name ?: "", desc->label, + gpio, desc->name ?: "", gpiod_get_label(desc), is_out ? "out" : "in ", value >= 0 ? (value ? "hi" : "lo") : "? ", is_irq ? "IRQ " : "", @@ -4744,61 +4816,72 @@ static void gpiolib_dbg_show(struct seq_file *s, struct gpio_device *gdev) } } +struct gpiolib_seq_priv { + bool newline; + int idx; +}; + static void *gpiolib_seq_start(struct seq_file *s, loff_t *pos) { - unsigned long flags; - struct gpio_device *gdev = NULL; + struct gpiolib_seq_priv *priv; + struct gpio_device *gdev; loff_t index = *pos; - s->private = ""; + priv = kzalloc(sizeof(*priv), GFP_KERNEL); + if (!priv) + return NULL; + + s->private = priv; + priv->idx = srcu_read_lock(&gpio_devices_srcu); - spin_lock_irqsave(&gpio_lock, flags); - list_for_each_entry(gdev, &gpio_devices, list) - if (index-- == 0) { - spin_unlock_irqrestore(&gpio_lock, flags); + list_for_each_entry_srcu(gdev, &gpio_devices, list, + srcu_read_lock_held(&gpio_devices_srcu)) { + if (index-- == 0) return gdev; - } - spin_unlock_irqrestore(&gpio_lock, flags); + } return NULL; } static void *gpiolib_seq_next(struct seq_file *s, void *v, loff_t *pos) { - unsigned long flags; - struct gpio_device *gdev = v; - void *ret = NULL; - - spin_lock_irqsave(&gpio_lock, flags); - if (list_is_last(&gdev->list, &gpio_devices)) - ret = NULL; - else - ret = list_first_entry(&gdev->list, struct gpio_device, list); - spin_unlock_irqrestore(&gpio_lock, flags); + struct gpiolib_seq_priv *priv = s->private; + struct gpio_device *gdev = v, *next; - s->private = "\n"; + next = list_entry_rcu(gdev->list.next, struct gpio_device, list); + gdev = &next->list == &gpio_devices ? NULL : next; + priv->newline = true; ++*pos; - return ret; + return gdev; } static void gpiolib_seq_stop(struct seq_file *s, void *v) { + struct gpiolib_seq_priv *priv = s->private; + + srcu_read_unlock(&gpio_devices_srcu, priv->idx); + kfree(priv); } static int gpiolib_seq_show(struct seq_file *s, void *v) { + struct gpiolib_seq_priv *priv = s->private; struct gpio_device *gdev = v; - struct gpio_chip *gc = gdev->chip; + struct gpio_chip *gc; struct device *parent; + guard(srcu)(&gdev->srcu); + + gc = srcu_dereference(gdev->chip, &gdev->srcu); if (!gc) { - seq_printf(s, "%s%s: (dangling chip)", (char *)s->private, + seq_printf(s, "%s%s: (dangling chip)", + priv->newline ? "\n" : "", dev_name(&gdev->dev)); return 0; } - seq_printf(s, "%s%s: GPIOs %d-%d", (char *)s->private, + seq_printf(s, "%s%s: GPIOs %d-%d", priv->newline ? "\n" : "", dev_name(&gdev->dev), gdev->base, gdev->base + gdev->ngpio - 1); parent = gc->parent; |