diff options
Diffstat (limited to 'drivers/base/core.c')
| -rw-r--r-- | drivers/base/core.c | 3410 |
1 files changed, 3410 insertions, 0 deletions
diff --git a/drivers/base/core.c b/drivers/base/core.c new file mode 100644 index 000000000..6e380ad9d --- /dev/null +++ b/drivers/base/core.c @@ -0,0 +1,3410 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * drivers/base/core.c - core driver model code (device registration, etc) + * + * Copyright (c) 2002-3 Patrick Mochel + * Copyright (c) 2002-3 Open Source Development Labs + * Copyright (c) 2006 Greg Kroah-Hartman <gregkh@suse.de> + * Copyright (c) 2006 Novell, Inc. + */ + +#include <linux/cpufreq.h> +#include <linux/device.h> +#include <linux/err.h> +#include <linux/fwnode.h> +#include <linux/init.h> +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/string.h> +#include <linux/kdev_t.h> +#include <linux/notifier.h> +#include <linux/of.h> +#include <linux/of_device.h> +#include <linux/genhd.h> +#include <linux/mutex.h> +#include <linux/pm_runtime.h> +#include <linux/netdevice.h> +#include <linux/sched/signal.h> +#include <linux/sysfs.h> + +#include "base.h" +#include "power/power.h" + +#ifdef CONFIG_SYSFS_DEPRECATED +#ifdef CONFIG_SYSFS_DEPRECATED_V2 +long sysfs_deprecated = 1; +#else +long sysfs_deprecated = 0; +#endif +static int __init sysfs_deprecated_setup(char *arg) +{ + return kstrtol(arg, 10, &sysfs_deprecated); +} +early_param("sysfs.deprecated", sysfs_deprecated_setup); +#endif + +/* Device links support. */ + +#ifdef CONFIG_SRCU +static DEFINE_MUTEX(device_links_lock); +DEFINE_STATIC_SRCU(device_links_srcu); + +static inline void device_links_write_lock(void) +{ + mutex_lock(&device_links_lock); +} + +static inline void device_links_write_unlock(void) +{ + mutex_unlock(&device_links_lock); +} + +int device_links_read_lock(void) +{ + return srcu_read_lock(&device_links_srcu); +} + +void device_links_read_unlock(int idx) +{ + srcu_read_unlock(&device_links_srcu, idx); +} +#else /* !CONFIG_SRCU */ +static DECLARE_RWSEM(device_links_lock); + +static inline void device_links_write_lock(void) +{ + down_write(&device_links_lock); +} + +static inline void device_links_write_unlock(void) +{ + up_write(&device_links_lock); +} + +int device_links_read_lock(void) +{ + down_read(&device_links_lock); + return 0; +} + +void device_links_read_unlock(int not_used) +{ + up_read(&device_links_lock); +} +#endif /* !CONFIG_SRCU */ + +static bool device_is_ancestor(struct device *dev, struct device *target) +{ + while (target->parent) { + target = target->parent; + if (dev == target) + return true; + } + return false; +} + +/** + * device_is_dependent - Check if one device depends on another one + * @dev: Device to check dependencies for. + * @target: Device to check against. + * + * Check if @target depends on @dev or any device dependent on it (its child or + * its consumer etc). Return 1 if that is the case or 0 otherwise. + */ +static int device_is_dependent(struct device *dev, void *target) +{ + struct device_link *link; + int ret; + + /* + * The "ancestors" check is needed to catch the case when the target + * device has not been completely initialized yet and it is still + * missing from the list of children of its parent device. + */ + if (dev == target || device_is_ancestor(dev, target)) + return 1; + + ret = device_for_each_child(dev, target, device_is_dependent); + if (ret) + return ret; + + list_for_each_entry(link, &dev->links.consumers, s_node) { + if (link->consumer == target) + return 1; + + ret = device_is_dependent(link->consumer, target); + if (ret) + break; + } + return ret; +} + +static void device_link_init_status(struct device_link *link, + struct device *consumer, + struct device *supplier) +{ + switch (supplier->links.status) { + case DL_DEV_PROBING: + switch (consumer->links.status) { + case DL_DEV_PROBING: + /* + * A consumer driver can create a link to a supplier + * that has not completed its probing yet as long as it + * knows that the supplier is already functional (for + * example, it has just acquired some resources from the + * supplier). + */ + link->status = DL_STATE_CONSUMER_PROBE; + break; + default: + link->status = DL_STATE_DORMANT; + break; + } + break; + case DL_DEV_DRIVER_BOUND: + switch (consumer->links.status) { + case DL_DEV_PROBING: + link->status = DL_STATE_CONSUMER_PROBE; + break; + case DL_DEV_DRIVER_BOUND: + link->status = DL_STATE_ACTIVE; + break; + default: + link->status = DL_STATE_AVAILABLE; + break; + } + break; + case DL_DEV_UNBINDING: + link->status = DL_STATE_SUPPLIER_UNBIND; + break; + default: + link->status = DL_STATE_DORMANT; + break; + } +} + +static int device_reorder_to_tail(struct device *dev, void *not_used) +{ + struct device_link *link; + + /* + * Devices that have not been registered yet will be put to the ends + * of the lists during the registration, so skip them here. + */ + if (device_is_registered(dev)) + devices_kset_move_last(dev); + + if (device_pm_initialized(dev)) + device_pm_move_last(dev); + + device_for_each_child(dev, NULL, device_reorder_to_tail); + list_for_each_entry(link, &dev->links.consumers, s_node) + device_reorder_to_tail(link->consumer, NULL); + + return 0; +} + +/** + * device_pm_move_to_tail - Move set of devices to the end of device lists + * @dev: Device to move + * + * This is a device_reorder_to_tail() wrapper taking the requisite locks. + * + * It moves the @dev along with all of its children and all of its consumers + * to the ends of the device_kset and dpm_list, recursively. + */ +void device_pm_move_to_tail(struct device *dev) +{ + int idx; + + idx = device_links_read_lock(); + device_pm_lock(); + device_reorder_to_tail(dev, NULL); + device_pm_unlock(); + device_links_read_unlock(idx); +} + +#define DL_MANAGED_LINK_FLAGS (DL_FLAG_AUTOREMOVE_CONSUMER | \ + DL_FLAG_AUTOREMOVE_SUPPLIER | \ + DL_FLAG_AUTOPROBE_CONSUMER) + +#define DL_ADD_VALID_FLAGS (DL_MANAGED_LINK_FLAGS | DL_FLAG_STATELESS | \ + DL_FLAG_PM_RUNTIME | DL_FLAG_RPM_ACTIVE) + +/** + * device_link_add - Create a link between two devices. + * @consumer: Consumer end of the link. + * @supplier: Supplier end of the link. + * @flags: Link flags. + * + * The caller is responsible for the proper synchronization of the link creation + * with runtime PM. First, setting the DL_FLAG_PM_RUNTIME flag will cause the + * runtime PM framework to take the link into account. Second, if the + * DL_FLAG_RPM_ACTIVE flag is set in addition to it, the supplier devices will + * be forced into the active metastate and reference-counted upon the creation + * of the link. If DL_FLAG_PM_RUNTIME is not set, DL_FLAG_RPM_ACTIVE will be + * ignored. + * + * If DL_FLAG_STATELESS is set in @flags, the caller of this function is + * expected to release the link returned by it directly with the help of either + * device_link_del() or device_link_remove(). + * + * If that flag is not set, however, the caller of this function is handing the + * management of the link over to the driver core entirely and its return value + * can only be used to check whether or not the link is present. In that case, + * the DL_FLAG_AUTOREMOVE_CONSUMER and DL_FLAG_AUTOREMOVE_SUPPLIER device link + * flags can be used to indicate to the driver core when the link can be safely + * deleted. Namely, setting one of them in @flags indicates to the driver core + * that the link is not going to be used (by the given caller of this function) + * after unbinding the consumer or supplier driver, respectively, from its + * device, so the link can be deleted at that point. If none of them is set, + * the link will be maintained until one of the devices pointed to by it (either + * the consumer or the supplier) is unregistered. + * + * Also, if DL_FLAG_STATELESS, DL_FLAG_AUTOREMOVE_CONSUMER and + * DL_FLAG_AUTOREMOVE_SUPPLIER are not set in @flags (that is, a persistent + * managed device link is being added), the DL_FLAG_AUTOPROBE_CONSUMER flag can + * be used to request the driver core to automaticall probe for a consmer + * driver after successfully binding a driver to the supplier device. + * + * The combination of DL_FLAG_STATELESS and one of DL_FLAG_AUTOREMOVE_CONSUMER, + * DL_FLAG_AUTOREMOVE_SUPPLIER, or DL_FLAG_AUTOPROBE_CONSUMER set in @flags at + * the same time is invalid and will cause NULL to be returned upfront. + * However, if a device link between the given @consumer and @supplier pair + * exists already when this function is called for them, the existing link will + * be returned regardless of its current type and status (the link's flags may + * be modified then). The caller of this function is then expected to treat + * the link as though it has just been created, so (in particular) if + * DL_FLAG_STATELESS was passed in @flags, the link needs to be released + * explicitly when not needed any more (as stated above). + * + * A side effect of the link creation is re-ordering of dpm_list and the + * devices_kset list by moving the consumer device and all devices depending + * on it to the ends of these lists (that does not happen to devices that have + * not been registered when this function is called). + * + * The supplier device is required to be registered when this function is called + * and NULL will be returned if that is not the case. The consumer device need + * not be registered, however. + */ +struct device_link *device_link_add(struct device *consumer, + struct device *supplier, u32 flags) +{ + struct device_link *link; + + if (!consumer || !supplier || flags & ~DL_ADD_VALID_FLAGS || + (flags & DL_FLAG_STATELESS && flags & DL_MANAGED_LINK_FLAGS) || + (flags & DL_FLAG_AUTOPROBE_CONSUMER && + flags & (DL_FLAG_AUTOREMOVE_CONSUMER | + DL_FLAG_AUTOREMOVE_SUPPLIER))) + return NULL; + + if (flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) { + if (pm_runtime_get_sync(supplier) < 0) { + pm_runtime_put_noidle(supplier); + return NULL; + } + } + + if (!(flags & DL_FLAG_STATELESS)) + flags |= DL_FLAG_MANAGED; + + device_links_write_lock(); + device_pm_lock(); + + /* + * If the supplier has not been fully registered yet or there is a + * reverse dependency between the consumer and the supplier already in + * the graph, return NULL. + */ + if (!device_pm_initialized(supplier) + || device_is_dependent(consumer, supplier)) { + link = NULL; + goto out; + } + + /* + * DL_FLAG_AUTOREMOVE_SUPPLIER indicates that the link will be needed + * longer than for DL_FLAG_AUTOREMOVE_CONSUMER and setting them both + * together doesn't make sense, so prefer DL_FLAG_AUTOREMOVE_SUPPLIER. + */ + if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER) + flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER; + + list_for_each_entry(link, &supplier->links.consumers, s_node) { + if (link->consumer != consumer) + continue; + + if (flags & DL_FLAG_PM_RUNTIME) { + if (!(link->flags & DL_FLAG_PM_RUNTIME)) { + pm_runtime_new_link(consumer); + link->flags |= DL_FLAG_PM_RUNTIME; + } + if (flags & DL_FLAG_RPM_ACTIVE) + refcount_inc(&link->rpm_active); + } + + if (flags & DL_FLAG_STATELESS) { + link->flags |= DL_FLAG_STATELESS; + kref_get(&link->kref); + goto out; + } + + /* + * If the life time of the link following from the new flags is + * longer than indicated by the flags of the existing link, + * update the existing link to stay around longer. + */ + if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER) { + if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) { + link->flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER; + link->flags |= DL_FLAG_AUTOREMOVE_SUPPLIER; + } + } else if (!(flags & DL_FLAG_AUTOREMOVE_CONSUMER)) { + link->flags &= ~(DL_FLAG_AUTOREMOVE_CONSUMER | + DL_FLAG_AUTOREMOVE_SUPPLIER); + } + if (!(link->flags & DL_FLAG_MANAGED)) { + kref_get(&link->kref); + link->flags |= DL_FLAG_MANAGED; + device_link_init_status(link, consumer, supplier); + } + goto out; + } + + link = kzalloc(sizeof(*link), GFP_KERNEL); + if (!link) + goto out; + + refcount_set(&link->rpm_active, 1); + + if (flags & DL_FLAG_PM_RUNTIME) { + if (flags & DL_FLAG_RPM_ACTIVE) + refcount_inc(&link->rpm_active); + + pm_runtime_new_link(consumer); + } + + get_device(supplier); + link->supplier = supplier; + INIT_LIST_HEAD(&link->s_node); + get_device(consumer); + link->consumer = consumer; + INIT_LIST_HEAD(&link->c_node); + link->flags = flags; + kref_init(&link->kref); + + /* Determine the initial link state. */ + if (flags & DL_FLAG_STATELESS) + link->status = DL_STATE_NONE; + else + device_link_init_status(link, consumer, supplier); + + /* + * Some callers expect the link creation during consumer driver probe to + * resume the supplier even without DL_FLAG_RPM_ACTIVE. + */ + if (link->status == DL_STATE_CONSUMER_PROBE && + flags & DL_FLAG_PM_RUNTIME) + pm_runtime_resume(supplier); + + /* + * Move the consumer and all of the devices depending on it to the end + * of dpm_list and the devices_kset list. + * + * It is necessary to hold dpm_list locked throughout all that or else + * we may end up suspending with a wrong ordering of it. + */ + device_reorder_to_tail(consumer, NULL); + + list_add_tail_rcu(&link->s_node, &supplier->links.consumers); + list_add_tail_rcu(&link->c_node, &consumer->links.suppliers); + + dev_info(consumer, "Linked as a consumer to %s\n", dev_name(supplier)); + + out: + device_pm_unlock(); + device_links_write_unlock(); + + if ((flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) && !link) + pm_runtime_put(supplier); + + return link; +} +EXPORT_SYMBOL_GPL(device_link_add); + +static void device_link_free(struct device_link *link) +{ + while (refcount_dec_not_one(&link->rpm_active)) + pm_runtime_put(link->supplier); + + put_device(link->consumer); + put_device(link->supplier); + kfree(link); +} + +#ifdef CONFIG_SRCU +static void __device_link_free_srcu(struct rcu_head *rhead) +{ + device_link_free(container_of(rhead, struct device_link, rcu_head)); +} + +static void __device_link_del(struct kref *kref) +{ + struct device_link *link = container_of(kref, struct device_link, kref); + + dev_info(link->consumer, "Dropping the link to %s\n", + dev_name(link->supplier)); + + if (link->flags & DL_FLAG_PM_RUNTIME) + pm_runtime_drop_link(link->consumer); + + list_del_rcu(&link->s_node); + list_del_rcu(&link->c_node); + call_srcu(&device_links_srcu, &link->rcu_head, __device_link_free_srcu); +} +#else /* !CONFIG_SRCU */ +static void __device_link_del(struct kref *kref) +{ + struct device_link *link = container_of(kref, struct device_link, kref); + + dev_info(link->consumer, "Dropping the link to %s\n", + dev_name(link->supplier)); + + if (link->flags & DL_FLAG_PM_RUNTIME) + pm_runtime_drop_link(link->consumer); + + list_del(&link->s_node); + list_del(&link->c_node); + device_link_free(link); +} +#endif /* !CONFIG_SRCU */ + +static void device_link_put_kref(struct device_link *link) +{ + if (link->flags & DL_FLAG_STATELESS) + kref_put(&link->kref, __device_link_del); + else + WARN(1, "Unable to drop a managed device link reference\n"); +} + +/** + * device_link_del - Delete a stateless link between two devices. + * @link: Device link to delete. + * + * The caller must ensure proper synchronization of this function with runtime + * PM. If the link was added multiple times, it needs to be deleted as often. + * Care is required for hotplugged devices: Their links are purged on removal + * and calling device_link_del() is then no longer allowed. + */ +void device_link_del(struct device_link *link) +{ + device_links_write_lock(); + device_pm_lock(); + device_link_put_kref(link); + device_pm_unlock(); + device_links_write_unlock(); +} +EXPORT_SYMBOL_GPL(device_link_del); + +/** + * device_link_remove - Delete a stateless link between two devices. + * @consumer: Consumer end of the link. + * @supplier: Supplier end of the link. + * + * The caller must ensure proper synchronization of this function with runtime + * PM. + */ +void device_link_remove(void *consumer, struct device *supplier) +{ + struct device_link *link; + + if (WARN_ON(consumer == supplier)) + return; + + device_links_write_lock(); + device_pm_lock(); + + list_for_each_entry(link, &supplier->links.consumers, s_node) { + if (link->consumer == consumer) { + device_link_put_kref(link); + break; + } + } + + device_pm_unlock(); + device_links_write_unlock(); +} +EXPORT_SYMBOL_GPL(device_link_remove); + +static void device_links_missing_supplier(struct device *dev) +{ + struct device_link *link; + + list_for_each_entry(link, &dev->links.suppliers, c_node) + if (link->status == DL_STATE_CONSUMER_PROBE) + WRITE_ONCE(link->status, DL_STATE_AVAILABLE); +} + +/** + * device_links_check_suppliers - Check presence of supplier drivers. + * @dev: Consumer device. + * + * Check links from this device to any suppliers. Walk the list of the device's + * links to suppliers and see if all of them are available. If not, simply + * return -EPROBE_DEFER. + * + * We need to guarantee that the supplier will not go away after the check has + * been positive here. It only can go away in __device_release_driver() and + * that function checks the device's links to consumers. This means we need to + * mark the link as "consumer probe in progress" to make the supplier removal + * wait for us to complete (or bad things may happen). + * + * Links without the DL_FLAG_MANAGED flag set are ignored. + */ +int device_links_check_suppliers(struct device *dev) +{ + struct device_link *link; + int ret = 0; + + device_links_write_lock(); + + list_for_each_entry(link, &dev->links.suppliers, c_node) { + if (!(link->flags & DL_FLAG_MANAGED)) + continue; + + if (link->status != DL_STATE_AVAILABLE) { + device_links_missing_supplier(dev); + ret = -EPROBE_DEFER; + break; + } + WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE); + } + dev->links.status = DL_DEV_PROBING; + + device_links_write_unlock(); + return ret; +} + +/** + * device_links_driver_bound - Update device links after probing its driver. + * @dev: Device to update the links for. + * + * The probe has been successful, so update links from this device to any + * consumers by changing their status to "available". + * + * Also change the status of @dev's links to suppliers to "active". + * + * Links without the DL_FLAG_MANAGED flag set are ignored. + */ +void device_links_driver_bound(struct device *dev) +{ + struct device_link *link; + + device_links_write_lock(); + + list_for_each_entry(link, &dev->links.consumers, s_node) { + if (!(link->flags & DL_FLAG_MANAGED)) + continue; + + /* + * Links created during consumer probe may be in the "consumer + * probe" state to start with if the supplier is still probing + * when they are created and they may become "active" if the + * consumer probe returns first. Skip them here. + */ + if (link->status == DL_STATE_CONSUMER_PROBE || + link->status == DL_STATE_ACTIVE) + continue; + + WARN_ON(link->status != DL_STATE_DORMANT); + WRITE_ONCE(link->status, DL_STATE_AVAILABLE); + + if (link->flags & DL_FLAG_AUTOPROBE_CONSUMER) + driver_deferred_probe_add(link->consumer); + } + + list_for_each_entry(link, &dev->links.suppliers, c_node) { + if (!(link->flags & DL_FLAG_MANAGED)) + continue; + + WARN_ON(link->status != DL_STATE_CONSUMER_PROBE); + WRITE_ONCE(link->status, DL_STATE_ACTIVE); + } + + dev->links.status = DL_DEV_DRIVER_BOUND; + + device_links_write_unlock(); +} + +static void device_link_drop_managed(struct device_link *link) +{ + link->flags &= ~DL_FLAG_MANAGED; + WRITE_ONCE(link->status, DL_STATE_NONE); + kref_put(&link->kref, __device_link_del); +} + +/** + * __device_links_no_driver - Update links of a device without a driver. + * @dev: Device without a drvier. + * + * Delete all non-persistent links from this device to any suppliers. + * + * Persistent links stay around, but their status is changed to "available", + * unless they already are in the "supplier unbind in progress" state in which + * case they need not be updated. + * + * Links without the DL_FLAG_MANAGED flag set are ignored. + */ +static void __device_links_no_driver(struct device *dev) +{ + struct device_link *link, *ln; + + list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) { + if (!(link->flags & DL_FLAG_MANAGED)) + continue; + + if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) + device_link_drop_managed(link); + else if (link->status == DL_STATE_CONSUMER_PROBE || + link->status == DL_STATE_ACTIVE) + WRITE_ONCE(link->status, DL_STATE_AVAILABLE); + } + + dev->links.status = DL_DEV_NO_DRIVER; +} + +/** + * device_links_no_driver - Update links after failing driver probe. + * @dev: Device whose driver has just failed to probe. + * + * Clean up leftover links to consumers for @dev and invoke + * %__device_links_no_driver() to update links to suppliers for it as + * appropriate. + * + * Links without the DL_FLAG_MANAGED flag set are ignored. + */ +void device_links_no_driver(struct device *dev) +{ + struct device_link *link; + + device_links_write_lock(); + + list_for_each_entry(link, &dev->links.consumers, s_node) { + if (!(link->flags & DL_FLAG_MANAGED)) + continue; + + /* + * The probe has failed, so if the status of the link is + * "consumer probe" or "active", it must have been added by + * a probing consumer while this device was still probing. + * Change its state to "dormant", as it represents a valid + * relationship, but it is not functionally meaningful. + */ + if (link->status == DL_STATE_CONSUMER_PROBE || + link->status == DL_STATE_ACTIVE) + WRITE_ONCE(link->status, DL_STATE_DORMANT); + } + + __device_links_no_driver(dev); + + device_links_write_unlock(); +} + +/** + * device_links_driver_cleanup - Update links after driver removal. + * @dev: Device whose driver has just gone away. + * + * Update links to consumers for @dev by changing their status to "dormant" and + * invoke %__device_links_no_driver() to update links to suppliers for it as + * appropriate. + * + * Links without the DL_FLAG_MANAGED flag set are ignored. + */ +void device_links_driver_cleanup(struct device *dev) +{ + struct device_link *link, *ln; + + device_links_write_lock(); + + list_for_each_entry_safe(link, ln, &dev->links.consumers, s_node) { + if (!(link->flags & DL_FLAG_MANAGED)) + continue; + + WARN_ON(link->flags & DL_FLAG_AUTOREMOVE_CONSUMER); + WARN_ON(link->status != DL_STATE_SUPPLIER_UNBIND); + + /* + * autoremove the links between this @dev and its consumer + * devices that are not active, i.e. where the link state + * has moved to DL_STATE_SUPPLIER_UNBIND. + */ + if (link->status == DL_STATE_SUPPLIER_UNBIND && + link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER) + device_link_drop_managed(link); + + WRITE_ONCE(link->status, DL_STATE_DORMANT); + } + + __device_links_no_driver(dev); + + device_links_write_unlock(); +} + +/** + * device_links_busy - Check if there are any busy links to consumers. + * @dev: Device to check. + * + * Check each consumer of the device and return 'true' if its link's status + * is one of "consumer probe" or "active" (meaning that the given consumer is + * probing right now or its driver is present). Otherwise, change the link + * state to "supplier unbind" to prevent the consumer from being probed + * successfully going forward. + * + * Return 'false' if there are no probing or active consumers. + * + * Links without the DL_FLAG_MANAGED flag set are ignored. + */ +bool device_links_busy(struct device *dev) +{ + struct device_link *link; + bool ret = false; + + device_links_write_lock(); + + list_for_each_entry(link, &dev->links.consumers, s_node) { + if (!(link->flags & DL_FLAG_MANAGED)) + continue; + + if (link->status == DL_STATE_CONSUMER_PROBE + || link->status == DL_STATE_ACTIVE) { + ret = true; + break; + } + WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND); + } + + dev->links.status = DL_DEV_UNBINDING; + + device_links_write_unlock(); + return ret; +} + +/** + * device_links_unbind_consumers - Force unbind consumers of the given device. + * @dev: Device to unbind the consumers of. + * + * Walk the list of links to consumers for @dev and if any of them is in the + * "consumer probe" state, wait for all device probes in progress to complete + * and start over. + * + * If that's not the case, change the status of the link to "supplier unbind" + * and check if the link was in the "active" state. If so, force the consumer + * driver to unbind and start over (the consumer will not re-probe as we have + * changed the state of the link already). + * + * Links without the DL_FLAG_MANAGED flag set are ignored. + */ +void device_links_unbind_consumers(struct device *dev) +{ + struct device_link *link; + + start: + device_links_write_lock(); + + list_for_each_entry(link, &dev->links.consumers, s_node) { + enum device_link_state status; + + if (!(link->flags & DL_FLAG_MANAGED)) + continue; + + status = link->status; + if (status == DL_STATE_CONSUMER_PROBE) { + device_links_write_unlock(); + + wait_for_device_probe(); + goto start; + } + WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND); + if (status == DL_STATE_ACTIVE) { + struct device *consumer = link->consumer; + + get_device(consumer); + + device_links_write_unlock(); + + device_release_driver_internal(consumer, NULL, + consumer->parent); + put_device(consumer); + goto start; + } + } + + device_links_write_unlock(); +} + +/** + * device_links_purge - Delete existing links to other devices. + * @dev: Target device. + */ +static void device_links_purge(struct device *dev) +{ + struct device_link *link, *ln; + + /* + * Delete all of the remaining links from this device to any other + * devices (either consumers or suppliers). + */ + device_links_write_lock(); + + list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) { + WARN_ON(link->status == DL_STATE_ACTIVE); + __device_link_del(&link->kref); + } + + list_for_each_entry_safe_reverse(link, ln, &dev->links.consumers, s_node) { + WARN_ON(link->status != DL_STATE_DORMANT && + link->status != DL_STATE_NONE); + __device_link_del(&link->kref); + } + + device_links_write_unlock(); +} + +/* Device links support end. */ + +int (*platform_notify)(struct device *dev) = NULL; +int (*platform_notify_remove)(struct device *dev) = NULL; +static struct kobject *dev_kobj; +struct kobject *sysfs_dev_char_kobj; +struct kobject *sysfs_dev_block_kobj; + +static DEFINE_MUTEX(device_hotplug_lock); + +void lock_device_hotplug(void) +{ + mutex_lock(&device_hotplug_lock); +} + +void unlock_device_hotplug(void) +{ + mutex_unlock(&device_hotplug_lock); +} + +int lock_device_hotplug_sysfs(void) +{ + if (mutex_trylock(&device_hotplug_lock)) + return 0; + + /* Avoid busy looping (5 ms of sleep should do). */ + msleep(5); + return restart_syscall(); +} + +#ifdef CONFIG_BLOCK +static inline int device_is_not_partition(struct device *dev) +{ + return !(dev->type == &part_type); +} +#else +static inline int device_is_not_partition(struct device *dev) +{ + return 1; +} +#endif + +/** + * dev_driver_string - Return a device's driver name, if at all possible + * @dev: struct device to get the name of + * + * Will return the device's driver's name if it is bound to a device. If + * the device is not bound to a driver, it will return the name of the bus + * it is attached to. If it is not attached to a bus either, an empty + * string will be returned. + */ +const char *dev_driver_string(const struct device *dev) +{ + struct device_driver *drv; + + /* dev->driver can change to NULL underneath us because of unbinding, + * so be careful about accessing it. dev->bus and dev->class should + * never change once they are set, so they don't need special care. + */ + drv = READ_ONCE(dev->driver); + return drv ? drv->name : + (dev->bus ? dev->bus->name : + (dev->class ? dev->class->name : "")); +} +EXPORT_SYMBOL(dev_driver_string); + +#define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr) + +static ssize_t dev_attr_show(struct kobject *kobj, struct attribute *attr, + char *buf) +{ + struct device_attribute *dev_attr = to_dev_attr(attr); + struct device *dev = kobj_to_dev(kobj); + ssize_t ret = -EIO; + + if (dev_attr->show) + ret = dev_attr->show(dev, dev_attr, buf); + if (ret >= (ssize_t)PAGE_SIZE) { + printk("dev_attr_show: %pS returned bad count\n", + dev_attr->show); + } + return ret; +} + +static ssize_t dev_attr_store(struct kobject *kobj, struct attribute *attr, + const char *buf, size_t count) +{ + struct device_attribute *dev_attr = to_dev_attr(attr); + struct device *dev = kobj_to_dev(kobj); + ssize_t ret = -EIO; + + if (dev_attr->store) + ret = dev_attr->store(dev, dev_attr, buf, count); + return ret; +} + +static const struct sysfs_ops dev_sysfs_ops = { + .show = dev_attr_show, + .store = dev_attr_store, +}; + +#define to_ext_attr(x) container_of(x, struct dev_ext_attribute, attr) + +ssize_t device_store_ulong(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t size) +{ + struct dev_ext_attribute *ea = to_ext_attr(attr); + char *end; + unsigned long new = simple_strtoul(buf, &end, 0); + if (end == buf) + return -EINVAL; + *(unsigned long *)(ea->var) = new; + /* Always return full write size even if we didn't consume all */ + return size; +} +EXPORT_SYMBOL_GPL(device_store_ulong); + +ssize_t device_show_ulong(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct dev_ext_attribute *ea = to_ext_attr(attr); + return snprintf(buf, PAGE_SIZE, "%lx\n", *(unsigned long *)(ea->var)); +} +EXPORT_SYMBOL_GPL(device_show_ulong); + +ssize_t device_store_int(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t size) +{ + struct dev_ext_attribute *ea = to_ext_attr(attr); + char *end; + long new = simple_strtol(buf, &end, 0); + if (end == buf || new > INT_MAX || new < INT_MIN) + return -EINVAL; + *(int *)(ea->var) = new; + /* Always return full write size even if we didn't consume all */ + return size; +} +EXPORT_SYMBOL_GPL(device_store_int); + +ssize_t device_show_int(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct dev_ext_attribute *ea = to_ext_attr(attr); + + return snprintf(buf, PAGE_SIZE, "%d\n", *(int *)(ea->var)); +} +EXPORT_SYMBOL_GPL(device_show_int); + +ssize_t device_store_bool(struct device *dev, struct device_attribute *attr, + const char *buf, size_t size) +{ + struct dev_ext_attribute *ea = to_ext_attr(attr); + + if (strtobool(buf, ea->var) < 0) + return -EINVAL; + + return size; +} +EXPORT_SYMBOL_GPL(device_store_bool); + +ssize_t device_show_bool(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct dev_ext_attribute *ea = to_ext_attr(attr); + + return snprintf(buf, PAGE_SIZE, "%d\n", *(bool *)(ea->var)); +} +EXPORT_SYMBOL_GPL(device_show_bool); + +/** + * device_release - free device structure. + * @kobj: device's kobject. + * + * This is called once the reference count for the object + * reaches 0. We forward the call to the device's release + * method, which should handle actually freeing the structure. + */ +static void device_release(struct kobject *kobj) +{ + struct device *dev = kobj_to_dev(kobj); + struct device_private *p = dev->p; + + /* + * Some platform devices are driven without driver attached + * and managed resources may have been acquired. Make sure + * all resources are released. + * + * Drivers still can add resources into device after device + * is deleted but alive, so release devres here to avoid + * possible memory leak. + */ + devres_release_all(dev); + + if (dev->release) + dev->release(dev); + else if (dev->type && dev->type->release) + dev->type->release(dev); + else if (dev->class && dev->class->dev_release) + dev->class->dev_release(dev); + else + WARN(1, KERN_ERR "Device '%s' does not have a release() " + "function, it is broken and must be fixed.\n", + dev_name(dev)); + kfree(p); +} + +static const void *device_namespace(struct kobject *kobj) +{ + struct device *dev = kobj_to_dev(kobj); + const void *ns = NULL; + + if (dev->class && dev->class->ns_type) + ns = dev->class->namespace(dev); + + return ns; +} + +static void device_get_ownership(struct kobject *kobj, kuid_t *uid, kgid_t *gid) +{ + struct device *dev = kobj_to_dev(kobj); + + if (dev->class && dev->class->get_ownership) + dev->class->get_ownership(dev, uid, gid); +} + +static struct kobj_type device_ktype = { + .release = device_release, + .sysfs_ops = &dev_sysfs_ops, + .namespace = device_namespace, + .get_ownership = device_get_ownership, +}; + + +static int dev_uevent_filter(struct kset *kset, struct kobject *kobj) +{ + struct kobj_type *ktype = get_ktype(kobj); + + if (ktype == &device_ktype) { + struct device *dev = kobj_to_dev(kobj); + if (dev->bus) + return 1; + if (dev->class) + return 1; + } + return 0; +} + +static const char *dev_uevent_name(struct kset *kset, struct kobject *kobj) +{ + struct device *dev = kobj_to_dev(kobj); + + if (dev->bus) + return dev->bus->name; + if (dev->class) + return dev->class->name; + return NULL; +} + +static int dev_uevent(struct kset *kset, struct kobject *kobj, + struct kobj_uevent_env *env) +{ + struct device *dev = kobj_to_dev(kobj); + int retval = 0; + + /* add device node properties if present */ + if (MAJOR(dev->devt)) { + const char *tmp; + const char *name; + umode_t mode = 0; + kuid_t uid = GLOBAL_ROOT_UID; + kgid_t gid = GLOBAL_ROOT_GID; + + add_uevent_var(env, "MAJOR=%u", MAJOR(dev->devt)); + add_uevent_var(env, "MINOR=%u", MINOR(dev->devt)); + name = device_get_devnode(dev, &mode, &uid, &gid, &tmp); + if (name) { + add_uevent_var(env, "DEVNAME=%s", name); + if (mode) + add_uevent_var(env, "DEVMODE=%#o", mode & 0777); + if (!uid_eq(uid, GLOBAL_ROOT_UID)) + add_uevent_var(env, "DEVUID=%u", from_kuid(&init_user_ns, uid)); + if (!gid_eq(gid, GLOBAL_ROOT_GID)) + add_uevent_var(env, "DEVGID=%u", from_kgid(&init_user_ns, gid)); + kfree(tmp); + } + } + + if (dev->type && dev->type->name) + add_uevent_var(env, "DEVTYPE=%s", dev->type->name); + + if (dev->driver) + add_uevent_var(env, "DRIVER=%s", dev->driver->name); + + /* Add common DT information about the device */ + of_device_uevent(dev, env); + + /* have the bus specific function add its stuff */ + if (dev->bus && dev->bus->uevent) { + retval = dev->bus->uevent(dev, env); + if (retval) + pr_debug("device: '%s': %s: bus uevent() returned %d\n", + dev_name(dev), __func__, retval); + } + + /* have the class specific function add its stuff */ + if (dev->class && dev->class->dev_uevent) { + retval = dev->class->dev_uevent(dev, env); + if (retval) + pr_debug("device: '%s': %s: class uevent() " + "returned %d\n", dev_name(dev), + __func__, retval); + } + + /* have the device type specific function add its stuff */ + if (dev->type && dev->type->uevent) { + retval = dev->type->uevent(dev, env); + if (retval) + pr_debug("device: '%s': %s: dev_type uevent() " + "returned %d\n", dev_name(dev), + __func__, retval); + } + + return retval; +} + +static const struct kset_uevent_ops device_uevent_ops = { + .filter = dev_uevent_filter, + .name = dev_uevent_name, + .uevent = dev_uevent, +}; + +static ssize_t uevent_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct kobject *top_kobj; + struct kset *kset; + struct kobj_uevent_env *env = NULL; + int i; + size_t count = 0; + int retval; + + /* search the kset, the device belongs to */ + top_kobj = &dev->kobj; + while (!top_kobj->kset && top_kobj->parent) + top_kobj = top_kobj->parent; + if (!top_kobj->kset) + goto out; + + kset = top_kobj->kset; + if (!kset->uevent_ops || !kset->uevent_ops->uevent) + goto out; + + /* respect filter */ + if (kset->uevent_ops && kset->uevent_ops->filter) + if (!kset->uevent_ops->filter(kset, &dev->kobj)) + goto out; + + env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL); + if (!env) + return -ENOMEM; + + /* let the kset specific function add its keys */ + retval = kset->uevent_ops->uevent(kset, &dev->kobj, env); + if (retval) + goto out; + + /* copy keys to file */ + for (i = 0; i < env->envp_idx; i++) + count += sprintf(&buf[count], "%s\n", env->envp[i]); +out: + kfree(env); + return count; +} + +static ssize_t uevent_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + int rc; + + rc = kobject_synth_uevent(&dev->kobj, buf, count); + + if (rc) { + dev_err(dev, "uevent: failed to send synthetic uevent\n"); + return rc; + } + + return count; +} +static DEVICE_ATTR_RW(uevent); + +static ssize_t online_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + bool val; + + device_lock(dev); + val = !dev->offline; + device_unlock(dev); + return sprintf(buf, "%u\n", val); +} + +static ssize_t online_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + bool val; + int ret; + + ret = strtobool(buf, &val); + if (ret < 0) + return ret; + + ret = lock_device_hotplug_sysfs(); + if (ret) + return ret; + + ret = val ? device_online(dev) : device_offline(dev); + unlock_device_hotplug(); + return ret < 0 ? ret : count; +} +static DEVICE_ATTR_RW(online); + +int device_add_groups(struct device *dev, const struct attribute_group **groups) +{ + return sysfs_create_groups(&dev->kobj, groups); +} +EXPORT_SYMBOL_GPL(device_add_groups); + +void device_remove_groups(struct device *dev, + const struct attribute_group **groups) +{ + sysfs_remove_groups(&dev->kobj, groups); +} +EXPORT_SYMBOL_GPL(device_remove_groups); + +union device_attr_group_devres { + const struct attribute_group *group; + const struct attribute_group **groups; +}; + +static int devm_attr_group_match(struct device *dev, void *res, void *data) +{ + return ((union device_attr_group_devres *)res)->group == data; +} + +static void devm_attr_group_remove(struct device *dev, void *res) +{ + union device_attr_group_devres *devres = res; + const struct attribute_group *group = devres->group; + + dev_dbg(dev, "%s: removing group %p\n", __func__, group); + sysfs_remove_group(&dev->kobj, group); +} + +static void devm_attr_groups_remove(struct device *dev, void *res) +{ + union device_attr_group_devres *devres = res; + const struct attribute_group **groups = devres->groups; + + dev_dbg(dev, "%s: removing groups %p\n", __func__, groups); + sysfs_remove_groups(&dev->kobj, groups); +} + +/** + * devm_device_add_group - given a device, create a managed attribute group + * @dev: The device to create the group for + * @grp: The attribute group to create + * + * This function creates a group for the first time. It will explicitly + * warn and error if any of the attribute files being created already exist. + * + * Returns 0 on success or error code on failure. + */ +int devm_device_add_group(struct device *dev, const struct attribute_group *grp) +{ + union device_attr_group_devres *devres; + int error; + + devres = devres_alloc(devm_attr_group_remove, + sizeof(*devres), GFP_KERNEL); + if (!devres) + return -ENOMEM; + + error = sysfs_create_group(&dev->kobj, grp); + if (error) { + devres_free(devres); + return error; + } + + devres->group = grp; + devres_add(dev, devres); + return 0; +} +EXPORT_SYMBOL_GPL(devm_device_add_group); + +/** + * devm_device_remove_group: remove a managed group from a device + * @dev: device to remove the group from + * @grp: group to remove + * + * This function removes a group of attributes from a device. The attributes + * previously have to have been created for this group, otherwise it will fail. + */ +void devm_device_remove_group(struct device *dev, + const struct attribute_group *grp) +{ + WARN_ON(devres_release(dev, devm_attr_group_remove, + devm_attr_group_match, + /* cast away const */ (void *)grp)); +} +EXPORT_SYMBOL_GPL(devm_device_remove_group); + +/** + * devm_device_add_groups - create a bunch of managed attribute groups + * @dev: The device to create the group for + * @groups: The attribute groups to create, NULL terminated + * + * This function creates a bunch of managed attribute groups. If an error + * occurs when creating a group, all previously created groups will be + * removed, unwinding everything back to the original state when this + * function was called. It will explicitly warn and error if any of the + * attribute files being created already exist. + * + * Returns 0 on success or error code from sysfs_create_group on failure. + */ +int devm_device_add_groups(struct device *dev, + const struct attribute_group **groups) +{ + union device_attr_group_devres *devres; + int error; + + devres = devres_alloc(devm_attr_groups_remove, + sizeof(*devres), GFP_KERNEL); + if (!devres) + return -ENOMEM; + + error = sysfs_create_groups(&dev->kobj, groups); + if (error) { + devres_free(devres); + return error; + } + + devres->groups = groups; + devres_add(dev, devres); + return 0; +} +EXPORT_SYMBOL_GPL(devm_device_add_groups); + +/** + * devm_device_remove_groups - remove a list of managed groups + * + * @dev: The device for the groups to be removed from + * @groups: NULL terminated list of groups to be removed + * + * If groups is not NULL, remove the specified groups from the device. + */ +void devm_device_remove_groups(struct device *dev, + const struct attribute_group **groups) +{ + WARN_ON(devres_release(dev, devm_attr_groups_remove, + devm_attr_group_match, + /* cast away const */ (void *)groups)); +} +EXPORT_SYMBOL_GPL(devm_device_remove_groups); + +static int device_add_attrs(struct device *dev) +{ + struct class *class = dev->class; + const struct device_type *type = dev->type; + int error; + + if (class) { + error = device_add_groups(dev, class->dev_groups); + if (error) + return error; + } + + if (type) { + error = device_add_groups(dev, type->groups); + if (error) + goto err_remove_class_groups; + } + + error = device_add_groups(dev, dev->groups); + if (error) + goto err_remove_type_groups; + + if (device_supports_offline(dev) && !dev->offline_disabled) { + error = device_create_file(dev, &dev_attr_online); + if (error) + goto err_remove_dev_groups; + } + + return 0; + + err_remove_dev_groups: + device_remove_groups(dev, dev->groups); + err_remove_type_groups: + if (type) + device_remove_groups(dev, type->groups); + err_remove_class_groups: + if (class) + device_remove_groups(dev, class->dev_groups); + + return error; +} + +static void device_remove_attrs(struct device *dev) +{ + struct class *class = dev->class; + const struct device_type *type = dev->type; + + device_remove_file(dev, &dev_attr_online); + device_remove_groups(dev, dev->groups); + + if (type) + device_remove_groups(dev, type->groups); + + if (class) + device_remove_groups(dev, class->dev_groups); +} + +static ssize_t dev_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + return print_dev_t(buf, dev->devt); +} +static DEVICE_ATTR_RO(dev); + +/* /sys/devices/ */ +struct kset *devices_kset; + +/** + * devices_kset_move_before - Move device in the devices_kset's list. + * @deva: Device to move. + * @devb: Device @deva should come before. + */ +static void devices_kset_move_before(struct device *deva, struct device *devb) +{ + if (!devices_kset) + return; + pr_debug("devices_kset: Moving %s before %s\n", + dev_name(deva), dev_name(devb)); + spin_lock(&devices_kset->list_lock); + list_move_tail(&deva->kobj.entry, &devb->kobj.entry); + spin_unlock(&devices_kset->list_lock); +} + +/** + * devices_kset_move_after - Move device in the devices_kset's list. + * @deva: Device to move + * @devb: Device @deva should come after. + */ +static void devices_kset_move_after(struct device *deva, struct device *devb) +{ + if (!devices_kset) + return; + pr_debug("devices_kset: Moving %s after %s\n", + dev_name(deva), dev_name(devb)); + spin_lock(&devices_kset->list_lock); + list_move(&deva->kobj.entry, &devb->kobj.entry); + spin_unlock(&devices_kset->list_lock); +} + +/** + * devices_kset_move_last - move the device to the end of devices_kset's list. + * @dev: device to move + */ +void devices_kset_move_last(struct device *dev) +{ + if (!devices_kset) + return; + pr_debug("devices_kset: Moving %s to end of list\n", dev_name(dev)); + spin_lock(&devices_kset->list_lock); + list_move_tail(&dev->kobj.entry, &devices_kset->list); + spin_unlock(&devices_kset->list_lock); +} + +/** + * device_create_file - create sysfs attribute file for device. + * @dev: device. + * @attr: device attribute descriptor. + */ +int device_create_file(struct device *dev, + const struct device_attribute *attr) +{ + int error = 0; + + if (dev) { + WARN(((attr->attr.mode & S_IWUGO) && !attr->store), + "Attribute %s: write permission without 'store'\n", + attr->attr.name); + WARN(((attr->attr.mode & S_IRUGO) && !attr->show), + "Attribute %s: read permission without 'show'\n", + attr->attr.name); + error = sysfs_create_file(&dev->kobj, &attr->attr); + } + + return error; +} +EXPORT_SYMBOL_GPL(device_create_file); + +/** + * device_remove_file - remove sysfs attribute file. + * @dev: device. + * @attr: device attribute descriptor. + */ +void device_remove_file(struct device *dev, + const struct device_attribute *attr) +{ + if (dev) + sysfs_remove_file(&dev->kobj, &attr->attr); +} +EXPORT_SYMBOL_GPL(device_remove_file); + +/** + * device_remove_file_self - remove sysfs attribute file from its own method. + * @dev: device. + * @attr: device attribute descriptor. + * + * See kernfs_remove_self() for details. + */ +bool device_remove_file_self(struct device *dev, + const struct device_attribute *attr) +{ + if (dev) + return sysfs_remove_file_self(&dev->kobj, &attr->attr); + else + return false; +} +EXPORT_SYMBOL_GPL(device_remove_file_self); + +/** + * device_create_bin_file - create sysfs binary attribute file for device. + * @dev: device. + * @attr: device binary attribute descriptor. + */ +int device_create_bin_file(struct device *dev, + const struct bin_attribute *attr) +{ + int error = -EINVAL; + if (dev) + error = sysfs_create_bin_file(&dev->kobj, attr); + return error; +} +EXPORT_SYMBOL_GPL(device_create_bin_file); + +/** + * device_remove_bin_file - remove sysfs binary attribute file + * @dev: device. + * @attr: device binary attribute descriptor. + */ +void device_remove_bin_file(struct device *dev, + const struct bin_attribute *attr) +{ + if (dev) + sysfs_remove_bin_file(&dev->kobj, attr); +} +EXPORT_SYMBOL_GPL(device_remove_bin_file); + +static void klist_children_get(struct klist_node *n) +{ + struct device_private *p = to_device_private_parent(n); + struct device *dev = p->device; + + get_device(dev); +} + +static void klist_children_put(struct klist_node *n) +{ + struct device_private *p = to_device_private_parent(n); + struct device *dev = p->device; + + put_device(dev); +} + +/** + * device_initialize - init device structure. + * @dev: device. + * + * This prepares the device for use by other layers by initializing + * its fields. + * It is the first half of device_register(), if called by + * that function, though it can also be called separately, so one + * may use @dev's fields. In particular, get_device()/put_device() + * may be used for reference counting of @dev after calling this + * function. + * + * All fields in @dev must be initialized by the caller to 0, except + * for those explicitly set to some other value. The simplest + * approach is to use kzalloc() to allocate the structure containing + * @dev. + * + * NOTE: Use put_device() to give up your reference instead of freeing + * @dev directly once you have called this function. + */ +void device_initialize(struct device *dev) +{ + dev->kobj.kset = devices_kset; + kobject_init(&dev->kobj, &device_ktype); + INIT_LIST_HEAD(&dev->dma_pools); + mutex_init(&dev->mutex); + lockdep_set_novalidate_class(&dev->mutex); + spin_lock_init(&dev->devres_lock); + INIT_LIST_HEAD(&dev->devres_head); + device_pm_init(dev); + set_dev_node(dev, -1); +#ifdef CONFIG_GENERIC_MSI_IRQ + raw_spin_lock_init(&dev->msi_lock); + INIT_LIST_HEAD(&dev->msi_list); +#endif + INIT_LIST_HEAD(&dev->links.consumers); + INIT_LIST_HEAD(&dev->links.suppliers); + dev->links.status = DL_DEV_NO_DRIVER; +} +EXPORT_SYMBOL_GPL(device_initialize); + +struct kobject *virtual_device_parent(struct device *dev) +{ + static struct kobject *virtual_dir = NULL; + + if (!virtual_dir) + virtual_dir = kobject_create_and_add("virtual", + &devices_kset->kobj); + + return virtual_dir; +} + +struct class_dir { + struct kobject kobj; + struct class *class; +}; + +#define to_class_dir(obj) container_of(obj, struct class_dir, kobj) + +static void class_dir_release(struct kobject *kobj) +{ + struct class_dir *dir = to_class_dir(kobj); + kfree(dir); +} + +static const +struct kobj_ns_type_operations *class_dir_child_ns_type(struct kobject *kobj) +{ + struct class_dir *dir = to_class_dir(kobj); + return dir->class->ns_type; +} + +static struct kobj_type class_dir_ktype = { + .release = class_dir_release, + .sysfs_ops = &kobj_sysfs_ops, + .child_ns_type = class_dir_child_ns_type +}; + +static struct kobject * +class_dir_create_and_add(struct class *class, struct kobject *parent_kobj) +{ + struct class_dir *dir; + int retval; + + dir = kzalloc(sizeof(*dir), GFP_KERNEL); + if (!dir) + return ERR_PTR(-ENOMEM); + + dir->class = class; + kobject_init(&dir->kobj, &class_dir_ktype); + + dir->kobj.kset = &class->p->glue_dirs; + + retval = kobject_add(&dir->kobj, parent_kobj, "%s", class->name); + if (retval < 0) { + kobject_put(&dir->kobj); + return ERR_PTR(retval); + } + return &dir->kobj; +} + +static DEFINE_MUTEX(gdp_mutex); + +static struct kobject *get_device_parent(struct device *dev, + struct device *parent) +{ + if (dev->class) { + struct kobject *kobj = NULL; + struct kobject *parent_kobj; + struct kobject *k; + +#ifdef CONFIG_BLOCK + /* block disks show up in /sys/block */ + if (sysfs_deprecated && dev->class == &block_class) { + if (parent && parent->class == &block_class) + return &parent->kobj; + return &block_class.p->subsys.kobj; + } +#endif + + /* + * If we have no parent, we live in "virtual". + * Class-devices with a non class-device as parent, live + * in a "glue" directory to prevent namespace collisions. + */ + if (parent == NULL) + parent_kobj = virtual_device_parent(dev); + else if (parent->class && !dev->class->ns_type) + return &parent->kobj; + else + parent_kobj = &parent->kobj; + + mutex_lock(&gdp_mutex); + + /* find our class-directory at the parent and reference it */ + spin_lock(&dev->class->p->glue_dirs.list_lock); + list_for_each_entry(k, &dev->class->p->glue_dirs.list, entry) + if (k->parent == parent_kobj) { + kobj = kobject_get(k); + break; + } + spin_unlock(&dev->class->p->glue_dirs.list_lock); + if (kobj) { + mutex_unlock(&gdp_mutex); + return kobj; + } + + /* or create a new class-directory at the parent device */ + k = class_dir_create_and_add(dev->class, parent_kobj); + /* do not emit an uevent for this simple "glue" directory */ + mutex_unlock(&gdp_mutex); + return k; + } + + /* subsystems can specify a default root directory for their devices */ + if (!parent && dev->bus && dev->bus->dev_root) + return &dev->bus->dev_root->kobj; + + if (parent) + return &parent->kobj; + return NULL; +} + +static inline bool live_in_glue_dir(struct kobject *kobj, + struct device *dev) +{ + if (!kobj || !dev->class || + kobj->kset != &dev->class->p->glue_dirs) + return false; + return true; +} + +static inline struct kobject *get_glue_dir(struct device *dev) +{ + return dev->kobj.parent; +} + +/* + * make sure cleaning up dir as the last step, we need to make + * sure .release handler of kobject is run with holding the + * global lock + */ +static void cleanup_glue_dir(struct device *dev, struct kobject *glue_dir) +{ + unsigned int ref; + + /* see if we live in a "glue" directory */ + if (!live_in_glue_dir(glue_dir, dev)) + return; + + mutex_lock(&gdp_mutex); + /** + * There is a race condition between removing glue directory + * and adding a new device under the glue directory. + * + * CPU1: CPU2: + * + * device_add() + * get_device_parent() + * class_dir_create_and_add() + * kobject_add_internal() + * create_dir() // create glue_dir + * + * device_add() + * get_device_parent() + * kobject_get() // get glue_dir + * + * device_del() + * cleanup_glue_dir() + * kobject_del(glue_dir) + * + * kobject_add() + * kobject_add_internal() + * create_dir() // in glue_dir + * sysfs_create_dir_ns() + * kernfs_create_dir_ns(sd) + * + * sysfs_remove_dir() // glue_dir->sd=NULL + * sysfs_put() // free glue_dir->sd + * + * // sd is freed + * kernfs_new_node(sd) + * kernfs_get(glue_dir) + * kernfs_add_one() + * kernfs_put() + * + * Before CPU1 remove last child device under glue dir, if CPU2 add + * a new device under glue dir, the glue_dir kobject reference count + * will be increase to 2 in kobject_get(k). And CPU2 has been called + * kernfs_create_dir_ns(). Meanwhile, CPU1 call sysfs_remove_dir() + * and sysfs_put(). This result in glue_dir->sd is freed. + * + * Then the CPU2 will see a stale "empty" but still potentially used + * glue dir around in kernfs_new_node(). + * + * In order to avoid this happening, we also should make sure that + * kernfs_node for glue_dir is released in CPU1 only when refcount + * for glue_dir kobj is 1. + */ + ref = kref_read(&glue_dir->kref); + if (!kobject_has_children(glue_dir) && !--ref) + kobject_del(glue_dir); + kobject_put(glue_dir); + mutex_unlock(&gdp_mutex); +} + +static int device_add_class_symlinks(struct device *dev) +{ + struct device_node *of_node = dev_of_node(dev); + int error; + + if (of_node) { + error = sysfs_create_link(&dev->kobj, of_node_kobj(of_node), "of_node"); + if (error) + dev_warn(dev, "Error %d creating of_node link\n",error); + /* An error here doesn't warrant bringing down the device */ + } + + if (!dev->class) + return 0; + + error = sysfs_create_link(&dev->kobj, + &dev->class->p->subsys.kobj, + "subsystem"); + if (error) + goto out_devnode; + + if (dev->parent && device_is_not_partition(dev)) { + error = sysfs_create_link(&dev->kobj, &dev->parent->kobj, + "device"); + if (error) + goto out_subsys; + } + +#ifdef CONFIG_BLOCK + /* /sys/block has directories and does not need symlinks */ + if (sysfs_deprecated && dev->class == &block_class) + return 0; +#endif + + /* link in the class directory pointing to the device */ + error = sysfs_create_link(&dev->class->p->subsys.kobj, + &dev->kobj, dev_name(dev)); + if (error) + goto out_device; + + return 0; + +out_device: + sysfs_remove_link(&dev->kobj, "device"); + +out_subsys: + sysfs_remove_link(&dev->kobj, "subsystem"); +out_devnode: + sysfs_remove_link(&dev->kobj, "of_node"); + return error; +} + +static void device_remove_class_symlinks(struct device *dev) +{ + if (dev_of_node(dev)) + sysfs_remove_link(&dev->kobj, "of_node"); + + if (!dev->class) + return; + + if (dev->parent && device_is_not_partition(dev)) + sysfs_remove_link(&dev->kobj, "device"); + sysfs_remove_link(&dev->kobj, "subsystem"); +#ifdef CONFIG_BLOCK + if (sysfs_deprecated && dev->class == &block_class) + return; +#endif + sysfs_delete_link(&dev->class->p->subsys.kobj, &dev->kobj, dev_name(dev)); +} + +/** + * dev_set_name - set a device name + * @dev: device + * @fmt: format string for the device's name + */ +int dev_set_name(struct device *dev, const char *fmt, ...) +{ + va_list vargs; + int err; + + va_start(vargs, fmt); + err = kobject_set_name_vargs(&dev->kobj, fmt, vargs); + va_end(vargs); + return err; +} +EXPORT_SYMBOL_GPL(dev_set_name); + +/** + * device_to_dev_kobj - select a /sys/dev/ directory for the device + * @dev: device + * + * By default we select char/ for new entries. Setting class->dev_obj + * to NULL prevents an entry from being created. class->dev_kobj must + * be set (or cleared) before any devices are registered to the class + * otherwise device_create_sys_dev_entry() and + * device_remove_sys_dev_entry() will disagree about the presence of + * the link. + */ +static struct kobject *device_to_dev_kobj(struct device *dev) +{ + struct kobject *kobj; + + if (dev->class) + kobj = dev->class->dev_kobj; + else + kobj = sysfs_dev_char_kobj; + + return kobj; +} + +static int device_create_sys_dev_entry(struct device *dev) +{ + struct kobject *kobj = device_to_dev_kobj(dev); + int error = 0; + char devt_str[15]; + + if (kobj) { + format_dev_t(devt_str, dev->devt); + error = sysfs_create_link(kobj, &dev->kobj, devt_str); + } + + return error; +} + +static void device_remove_sys_dev_entry(struct device *dev) +{ + struct kobject *kobj = device_to_dev_kobj(dev); + char devt_str[15]; + + if (kobj) { + format_dev_t(devt_str, dev->devt); + sysfs_remove_link(kobj, devt_str); + } +} + +static int device_private_init(struct device *dev) +{ + dev->p = kzalloc(sizeof(*dev->p), GFP_KERNEL); + if (!dev->p) + return -ENOMEM; + dev->p->device = dev; + klist_init(&dev->p->klist_children, klist_children_get, + klist_children_put); + INIT_LIST_HEAD(&dev->p->deferred_probe); + return 0; +} + +/** + * device_add - add device to device hierarchy. + * @dev: device. + * + * This is part 2 of device_register(), though may be called + * separately _iff_ device_initialize() has been called separately. + * + * This adds @dev to the kobject hierarchy via kobject_add(), adds it + * to the global and sibling lists for the device, then + * adds it to the other relevant subsystems of the driver model. + * + * Do not call this routine or device_register() more than once for + * any device structure. The driver model core is not designed to work + * with devices that get unregistered and then spring back to life. + * (Among other things, it's very hard to guarantee that all references + * to the previous incarnation of @dev have been dropped.) Allocate + * and register a fresh new struct device instead. + * + * NOTE: _Never_ directly free @dev after calling this function, even + * if it returned an error! Always use put_device() to give up your + * reference instead. + */ +int device_add(struct device *dev) +{ + struct device *parent; + struct kobject *kobj; + struct class_interface *class_intf; + int error = -EINVAL; + struct kobject *glue_dir = NULL; + + dev = get_device(dev); + if (!dev) + goto done; + + if (!dev->p) { + error = device_private_init(dev); + if (error) + goto done; + } + + /* + * for statically allocated devices, which should all be converted + * some day, we need to initialize the name. We prevent reading back + * the name, and force the use of dev_name() + */ + if (dev->init_name) { + dev_set_name(dev, "%s", dev->init_name); + dev->init_name = NULL; + } + + /* subsystems can specify simple device enumeration */ + if (!dev_name(dev) && dev->bus && dev->bus->dev_name) + dev_set_name(dev, "%s%u", dev->bus->dev_name, dev->id); + + if (!dev_name(dev)) { + error = -EINVAL; + goto name_error; + } + + pr_debug("device: '%s': %s\n", dev_name(dev), __func__); + + parent = get_device(dev->parent); + kobj = get_device_parent(dev, parent); + if (IS_ERR(kobj)) { + error = PTR_ERR(kobj); + goto parent_error; + } + if (kobj) + dev->kobj.parent = kobj; + + /* use parent numa_node */ + if (parent && (dev_to_node(dev) == NUMA_NO_NODE)) + set_dev_node(dev, dev_to_node(parent)); + + /* first, register with generic layer. */ + /* we require the name to be set before, and pass NULL */ + error = kobject_add(&dev->kobj, dev->kobj.parent, NULL); + if (error) { + glue_dir = get_glue_dir(dev); + goto Error; + } + + /* notify platform of device entry */ + if (platform_notify) + platform_notify(dev); + + error = device_create_file(dev, &dev_attr_uevent); + if (error) + goto attrError; + + error = device_add_class_symlinks(dev); + if (error) + goto SymlinkError; + error = device_add_attrs(dev); + if (error) + goto AttrsError; + error = bus_add_device(dev); + if (error) + goto BusError; + error = dpm_sysfs_add(dev); + if (error) + goto DPMError; + device_pm_add(dev); + + if (MAJOR(dev->devt)) { + error = device_create_file(dev, &dev_attr_dev); + if (error) + goto DevAttrError; + + error = device_create_sys_dev_entry(dev); + if (error) + goto SysEntryError; + + devtmpfs_create_node(dev); + } + + /* Notify clients of device addition. This call must come + * after dpm_sysfs_add() and before kobject_uevent(). + */ + if (dev->bus) + blocking_notifier_call_chain(&dev->bus->p->bus_notifier, + BUS_NOTIFY_ADD_DEVICE, dev); + + kobject_uevent(&dev->kobj, KOBJ_ADD); + bus_probe_device(dev); + if (parent) + klist_add_tail(&dev->p->knode_parent, + &parent->p->klist_children); + + if (dev->class) { + mutex_lock(&dev->class->p->mutex); + /* tie the class to the device */ + klist_add_tail(&dev->knode_class, + &dev->class->p->klist_devices); + + /* notify any interfaces that the device is here */ + list_for_each_entry(class_intf, + &dev->class->p->interfaces, node) + if (class_intf->add_dev) + class_intf->add_dev(dev, class_intf); + mutex_unlock(&dev->class->p->mutex); + } +done: + put_device(dev); + return error; + SysEntryError: + if (MAJOR(dev->devt)) + device_remove_file(dev, &dev_attr_dev); + DevAttrError: + device_pm_remove(dev); + dpm_sysfs_remove(dev); + DPMError: + bus_remove_device(dev); + BusError: + device_remove_attrs(dev); + AttrsError: + device_remove_class_symlinks(dev); + SymlinkError: + device_remove_file(dev, &dev_attr_uevent); + attrError: + kobject_uevent(&dev->kobj, KOBJ_REMOVE); + glue_dir = get_glue_dir(dev); + kobject_del(&dev->kobj); + Error: + cleanup_glue_dir(dev, glue_dir); +parent_error: + put_device(parent); +name_error: + kfree(dev->p); + dev->p = NULL; + goto done; +} +EXPORT_SYMBOL_GPL(device_add); + +/** + * device_register - register a device with the system. + * @dev: pointer to the device structure + * + * This happens in two clean steps - initialize the device + * and add it to the system. The two steps can be called + * separately, but this is the easiest and most common. + * I.e. you should only call the two helpers separately if + * have a clearly defined need to use and refcount the device + * before it is added to the hierarchy. + * + * For more information, see the kerneldoc for device_initialize() + * and device_add(). + * + * NOTE: _Never_ directly free @dev after calling this function, even + * if it returned an error! Always use put_device() to give up the + * reference initialized in this function instead. + */ +int device_register(struct device *dev) +{ + device_initialize(dev); + return device_add(dev); +} +EXPORT_SYMBOL_GPL(device_register); + +/** + * get_device - increment reference count for device. + * @dev: device. + * + * This simply forwards the call to kobject_get(), though + * we do take care to provide for the case that we get a NULL + * pointer passed in. + */ +struct device *get_device(struct device *dev) +{ + return dev ? kobj_to_dev(kobject_get(&dev->kobj)) : NULL; +} +EXPORT_SYMBOL_GPL(get_device); + +/** + * put_device - decrement reference count. + * @dev: device in question. + */ +void put_device(struct device *dev) +{ + /* might_sleep(); */ + if (dev) + kobject_put(&dev->kobj); +} +EXPORT_SYMBOL_GPL(put_device); + +bool kill_device(struct device *dev) +{ + /* + * Require the device lock and set the "dead" flag to guarantee that + * the update behavior is consistent with the other bitfields near + * it and that we cannot have an asynchronous probe routine trying + * to run while we are tearing out the bus/class/sysfs from + * underneath the device. + */ + lockdep_assert_held(&dev->mutex); + + if (dev->p->dead) + return false; + dev->p->dead = true; + return true; +} +EXPORT_SYMBOL_GPL(kill_device); + +/** + * device_del - delete device from system. + * @dev: device. + * + * This is the first part of the device unregistration + * sequence. This removes the device from the lists we control + * from here, has it removed from the other driver model + * subsystems it was added to in device_add(), and removes it + * from the kobject hierarchy. + * + * NOTE: this should be called manually _iff_ device_add() was + * also called manually. + */ +void device_del(struct device *dev) +{ + struct device *parent = dev->parent; + struct kobject *glue_dir = NULL; + struct class_interface *class_intf; + + device_lock(dev); + kill_device(dev); + device_unlock(dev); + + /* Notify clients of device removal. This call must come + * before dpm_sysfs_remove(). + */ + if (dev->bus) + blocking_notifier_call_chain(&dev->bus->p->bus_notifier, + BUS_NOTIFY_DEL_DEVICE, dev); + + dpm_sysfs_remove(dev); + if (parent) + klist_del(&dev->p->knode_parent); + if (MAJOR(dev->devt)) { + devtmpfs_delete_node(dev); + device_remove_sys_dev_entry(dev); + device_remove_file(dev, &dev_attr_dev); + } + if (dev->class) { + device_remove_class_symlinks(dev); + + mutex_lock(&dev->class->p->mutex); + /* notify any interfaces that the device is now gone */ + list_for_each_entry(class_intf, + &dev->class->p->interfaces, node) + if (class_intf->remove_dev) + class_intf->remove_dev(dev, class_intf); + /* remove the device from the class list */ + klist_del(&dev->knode_class); + mutex_unlock(&dev->class->p->mutex); + } + device_remove_file(dev, &dev_attr_uevent); + device_remove_attrs(dev); + bus_remove_device(dev); + device_pm_remove(dev); + driver_deferred_probe_del(dev); + device_remove_properties(dev); + device_links_purge(dev); + + /* Notify the platform of the removal, in case they + * need to do anything... + */ + if (platform_notify_remove) + platform_notify_remove(dev); + if (dev->bus) + blocking_notifier_call_chain(&dev->bus->p->bus_notifier, + BUS_NOTIFY_REMOVED_DEVICE, dev); + kobject_uevent(&dev->kobj, KOBJ_REMOVE); + glue_dir = get_glue_dir(dev); + kobject_del(&dev->kobj); + cleanup_glue_dir(dev, glue_dir); + put_device(parent); +} +EXPORT_SYMBOL_GPL(device_del); + +/** + * device_unregister - unregister device from system. + * @dev: device going away. + * + * We do this in two parts, like we do device_register(). First, + * we remove it from all the subsystems with device_del(), then + * we decrement the reference count via put_device(). If that + * is the final reference count, the device will be cleaned up + * via device_release() above. Otherwise, the structure will + * stick around until the final reference to the device is dropped. + */ +void device_unregister(struct device *dev) +{ + pr_debug("device: '%s': %s\n", dev_name(dev), __func__); + device_del(dev); + put_device(dev); +} +EXPORT_SYMBOL_GPL(device_unregister); + +static struct device *prev_device(struct klist_iter *i) +{ + struct klist_node *n = klist_prev(i); + struct device *dev = NULL; + struct device_private *p; + + if (n) { + p = to_device_private_parent(n); + dev = p->device; + } + return dev; +} + +static struct device *next_device(struct klist_iter *i) +{ + struct klist_node *n = klist_next(i); + struct device *dev = NULL; + struct device_private *p; + + if (n) { + p = to_device_private_parent(n); + dev = p->device; + } + return dev; +} + +/** + * device_get_devnode - path of device node file + * @dev: device + * @mode: returned file access mode + * @uid: returned file owner + * @gid: returned file group + * @tmp: possibly allocated string + * + * Return the relative path of a possible device node. + * Non-default names may need to allocate a memory to compose + * a name. This memory is returned in tmp and needs to be + * freed by the caller. + */ +const char *device_get_devnode(struct device *dev, + umode_t *mode, kuid_t *uid, kgid_t *gid, + const char **tmp) +{ + char *s; + + *tmp = NULL; + + /* the device type may provide a specific name */ + if (dev->type && dev->type->devnode) + *tmp = dev->type->devnode(dev, mode, uid, gid); + if (*tmp) + return *tmp; + + /* the class may provide a specific name */ + if (dev->class && dev->class->devnode) + *tmp = dev->class->devnode(dev, mode); + if (*tmp) + return *tmp; + + /* return name without allocation, tmp == NULL */ + if (strchr(dev_name(dev), '!') == NULL) + return dev_name(dev); + + /* replace '!' in the name with '/' */ + s = kstrdup(dev_name(dev), GFP_KERNEL); + if (!s) + return NULL; + strreplace(s, '!', '/'); + return *tmp = s; +} + +/** + * device_for_each_child - device child iterator. + * @parent: parent struct device. + * @fn: function to be called for each device. + * @data: data for the callback. + * + * Iterate over @parent's child devices, and call @fn for each, + * passing it @data. + * + * We check the return of @fn each time. If it returns anything + * other than 0, we break out and return that value. + */ +int device_for_each_child(struct device *parent, void *data, + int (*fn)(struct device *dev, void *data)) +{ + struct klist_iter i; + struct device *child; + int error = 0; + + if (!parent->p) + return 0; + + klist_iter_init(&parent->p->klist_children, &i); + while (!error && (child = next_device(&i))) + error = fn(child, data); + klist_iter_exit(&i); + return error; +} +EXPORT_SYMBOL_GPL(device_for_each_child); + +/** + * device_for_each_child_reverse - device child iterator in reversed order. + * @parent: parent struct device. + * @fn: function to be called for each device. + * @data: data for the callback. + * + * Iterate over @parent's child devices, and call @fn for each, + * passing it @data. + * + * We check the return of @fn each time. If it returns anything + * other than 0, we break out and return that value. + */ +int device_for_each_child_reverse(struct device *parent, void *data, + int (*fn)(struct device *dev, void *data)) +{ + struct klist_iter i; + struct device *child; + int error = 0; + + if (!parent->p) + return 0; + + klist_iter_init(&parent->p->klist_children, &i); + while ((child = prev_device(&i)) && !error) + error = fn(child, data); + klist_iter_exit(&i); + return error; +} +EXPORT_SYMBOL_GPL(device_for_each_child_reverse); + +/** + * device_find_child - device iterator for locating a particular device. + * @parent: parent struct device + * @match: Callback function to check device + * @data: Data to pass to match function + * + * This is similar to the device_for_each_child() function above, but it + * returns a reference to a device that is 'found' for later use, as + * determined by the @match callback. + * + * The callback should return 0 if the device doesn't match and non-zero + * if it does. If the callback returns non-zero and a reference to the + * current device can be obtained, this function will return to the caller + * and not iterate over any more devices. + * + * NOTE: you will need to drop the reference with put_device() after use. + */ +struct device *device_find_child(struct device *parent, void *data, + int (*match)(struct device *dev, void *data)) +{ + struct klist_iter i; + struct device *child; + + if (!parent) + return NULL; + + klist_iter_init(&parent->p->klist_children, &i); + while ((child = next_device(&i))) + if (match(child, data) && get_device(child)) + break; + klist_iter_exit(&i); + return child; +} +EXPORT_SYMBOL_GPL(device_find_child); + +int __init devices_init(void) +{ + devices_kset = kset_create_and_add("devices", &device_uevent_ops, NULL); + if (!devices_kset) + return -ENOMEM; + dev_kobj = kobject_create_and_add("dev", NULL); + if (!dev_kobj) + goto dev_kobj_err; + sysfs_dev_block_kobj = kobject_create_and_add("block", dev_kobj); + if (!sysfs_dev_block_kobj) + goto block_kobj_err; + sysfs_dev_char_kobj = kobject_create_and_add("char", dev_kobj); + if (!sysfs_dev_char_kobj) + goto char_kobj_err; + + return 0; + + char_kobj_err: + kobject_put(sysfs_dev_block_kobj); + block_kobj_err: + kobject_put(dev_kobj); + dev_kobj_err: + kset_unregister(devices_kset); + return -ENOMEM; +} + +static int device_check_offline(struct device *dev, void *not_used) +{ + int ret; + + ret = device_for_each_child(dev, NULL, device_check_offline); + if (ret) + return ret; + + return device_supports_offline(dev) && !dev->offline ? -EBUSY : 0; +} + +/** + * device_offline - Prepare the device for hot-removal. + * @dev: Device to be put offline. + * + * Execute the device bus type's .offline() callback, if present, to prepare + * the device for a subsequent hot-removal. If that succeeds, the device must + * not be used until either it is removed or its bus type's .online() callback + * is executed. + * + * Call under device_hotplug_lock. + */ +int device_offline(struct device *dev) +{ + int ret; + + if (dev->offline_disabled) + return -EPERM; + + ret = device_for_each_child(dev, NULL, device_check_offline); + if (ret) + return ret; + + device_lock(dev); + if (device_supports_offline(dev)) { + if (dev->offline) { + ret = 1; + } else { + ret = dev->bus->offline(dev); + if (!ret) { + kobject_uevent(&dev->kobj, KOBJ_OFFLINE); + dev->offline = true; + } + } + } + device_unlock(dev); + + return ret; +} + +/** + * device_online - Put the device back online after successful device_offline(). + * @dev: Device to be put back online. + * + * If device_offline() has been successfully executed for @dev, but the device + * has not been removed subsequently, execute its bus type's .online() callback + * to indicate that the device can be used again. + * + * Call under device_hotplug_lock. + */ +int device_online(struct device *dev) +{ + int ret = 0; + + device_lock(dev); + if (device_supports_offline(dev)) { + if (dev->offline) { + ret = dev->bus->online(dev); + if (!ret) { + kobject_uevent(&dev->kobj, KOBJ_ONLINE); + dev->offline = false; + } + } else { + ret = 1; + } + } + device_unlock(dev); + + return ret; +} + +struct root_device { + struct device dev; + struct module *owner; +}; + +static inline struct root_device *to_root_device(struct device *d) +{ + return container_of(d, struct root_device, dev); +} + +static void root_device_release(struct device *dev) +{ + kfree(to_root_device(dev)); +} + +/** + * __root_device_register - allocate and register a root device + * @name: root device name + * @owner: owner module of the root device, usually THIS_MODULE + * + * This function allocates a root device and registers it + * using device_register(). In order to free the returned + * device, use root_device_unregister(). + * + * Root devices are dummy devices which allow other devices + * to be grouped under /sys/devices. Use this function to + * allocate a root device and then use it as the parent of + * any device which should appear under /sys/devices/{name} + * + * The /sys/devices/{name} directory will also contain a + * 'module' symlink which points to the @owner directory + * in sysfs. + * + * Returns &struct device pointer on success, or ERR_PTR() on error. + * + * Note: You probably want to use root_device_register(). + */ +struct device *__root_device_register(const char *name, struct module *owner) +{ + struct root_device *root; + int err = -ENOMEM; + + root = kzalloc(sizeof(struct root_device), GFP_KERNEL); + if (!root) + return ERR_PTR(err); + + err = dev_set_name(&root->dev, "%s", name); + if (err) { + kfree(root); + return ERR_PTR(err); + } + + root->dev.release = root_device_release; + + err = device_register(&root->dev); + if (err) { + put_device(&root->dev); + return ERR_PTR(err); + } + +#ifdef CONFIG_MODULES /* gotta find a "cleaner" way to do this */ + if (owner) { + struct module_kobject *mk = &owner->mkobj; + + err = sysfs_create_link(&root->dev.kobj, &mk->kobj, "module"); + if (err) { + device_unregister(&root->dev); + return ERR_PTR(err); + } + root->owner = owner; + } +#endif + + return &root->dev; +} +EXPORT_SYMBOL_GPL(__root_device_register); + +/** + * root_device_unregister - unregister and free a root device + * @dev: device going away + * + * This function unregisters and cleans up a device that was created by + * root_device_register(). + */ +void root_device_unregister(struct device *dev) +{ + struct root_device *root = to_root_device(dev); + + if (root->owner) + sysfs_remove_link(&root->dev.kobj, "module"); + + device_unregister(dev); +} +EXPORT_SYMBOL_GPL(root_device_unregister); + + +static void device_create_release(struct device *dev) +{ + pr_debug("device: '%s': %s\n", dev_name(dev), __func__); + kfree(dev); +} + +static __printf(6, 0) struct device * +device_create_groups_vargs(struct class *class, struct device *parent, + dev_t devt, void *drvdata, + const struct attribute_group **groups, + const char *fmt, va_list args) +{ + struct device *dev = NULL; + int retval = -ENODEV; + + if (class == NULL || IS_ERR(class)) + goto error; + + dev = kzalloc(sizeof(*dev), GFP_KERNEL); + if (!dev) { + retval = -ENOMEM; + goto error; + } + + device_initialize(dev); + dev->devt = devt; + dev->class = class; + dev->parent = parent; + dev->groups = groups; + dev->release = device_create_release; + dev_set_drvdata(dev, drvdata); + + retval = kobject_set_name_vargs(&dev->kobj, fmt, args); + if (retval) + goto error; + + retval = device_add(dev); + if (retval) + goto error; + + return dev; + +error: + put_device(dev); + return ERR_PTR(retval); +} + +/** + * device_create_vargs - creates a device and registers it with sysfs + * @class: pointer to the struct class that this device should be registered to + * @parent: pointer to the parent struct device of this new device, if any + * @devt: the dev_t for the char device to be added + * @drvdata: the data to be added to the device for callbacks + * @fmt: string for the device's name + * @args: va_list for the device's name + * + * This function can be used by char device classes. A struct device + * will be created in sysfs, registered to the specified class. + * + * A "dev" file will be created, showing the dev_t for the device, if + * the dev_t is not 0,0. + * If a pointer to a parent struct device is passed in, the newly created + * struct device will be a child of that device in sysfs. + * The pointer to the struct device will be returned from the call. + * Any further sysfs files that might be required can be created using this + * pointer. + * + * Returns &struct device pointer on success, or ERR_PTR() on error. + * + * Note: the struct class passed to this function must have previously + * been created with a call to class_create(). + */ +struct device *device_create_vargs(struct class *class, struct device *parent, + dev_t devt, void *drvdata, const char *fmt, + va_list args) +{ + return device_create_groups_vargs(class, parent, devt, drvdata, NULL, + fmt, args); +} +EXPORT_SYMBOL_GPL(device_create_vargs); + +/** + * device_create - creates a device and registers it with sysfs + * @class: pointer to the struct class that this device should be registered to + * @parent: pointer to the parent struct device of this new device, if any + * @devt: the dev_t for the char device to be added + * @drvdata: the data to be added to the device for callbacks + * @fmt: string for the device's name + * + * This function can be used by char device classes. A struct device + * will be created in sysfs, registered to the specified class. + * + * A "dev" file will be created, showing the dev_t for the device, if + * the dev_t is not 0,0. + * If a pointer to a parent struct device is passed in, the newly created + * struct device will be a child of that device in sysfs. + * The pointer to the struct device will be returned from the call. + * Any further sysfs files that might be required can be created using this + * pointer. + * + * Returns &struct device pointer on success, or ERR_PTR() on error. + * + * Note: the struct class passed to this function must have previously + * been created with a call to class_create(). + */ +struct device *device_create(struct class *class, struct device *parent, + dev_t devt, void *drvdata, const char *fmt, ...) +{ + va_list vargs; + struct device *dev; + + va_start(vargs, fmt); + dev = device_create_vargs(class, parent, devt, drvdata, fmt, vargs); + va_end(vargs); + return dev; +} +EXPORT_SYMBOL_GPL(device_create); + +/** + * device_create_with_groups - creates a device and registers it with sysfs + * @class: pointer to the struct class that this device should be registered to + * @parent: pointer to the parent struct device of this new device, if any + * @devt: the dev_t for the char device to be added + * @drvdata: the data to be added to the device for callbacks + * @groups: NULL-terminated list of attribute groups to be created + * @fmt: string for the device's name + * + * This function can be used by char device classes. A struct device + * will be created in sysfs, registered to the specified class. + * Additional attributes specified in the groups parameter will also + * be created automatically. + * + * A "dev" file will be created, showing the dev_t for the device, if + * the dev_t is not 0,0. + * If a pointer to a parent struct device is passed in, the newly created + * struct device will be a child of that device in sysfs. + * The pointer to the struct device will be returned from the call. + * Any further sysfs files that might be required can be created using this + * pointer. + * + * Returns &struct device pointer on success, or ERR_PTR() on error. + * + * Note: the struct class passed to this function must have previously + * been created with a call to class_create(). + */ +struct device *device_create_with_groups(struct class *class, + struct device *parent, dev_t devt, + void *drvdata, + const struct attribute_group **groups, + const char *fmt, ...) +{ + va_list vargs; + struct device *dev; + + va_start(vargs, fmt); + dev = device_create_groups_vargs(class, parent, devt, drvdata, groups, + fmt, vargs); + va_end(vargs); + return dev; +} +EXPORT_SYMBOL_GPL(device_create_with_groups); + +static int __match_devt(struct device *dev, const void *data) +{ + const dev_t *devt = data; + + return dev->devt == *devt; +} + +/** + * device_destroy - removes a device that was created with device_create() + * @class: pointer to the struct class that this device was registered with + * @devt: the dev_t of the device that was previously registered + * + * This call unregisters and cleans up a device that was created with a + * call to device_create(). + */ +void device_destroy(struct class *class, dev_t devt) +{ + struct device *dev; + + dev = class_find_device(class, NULL, &devt, __match_devt); + if (dev) { + put_device(dev); + device_unregister(dev); + } +} +EXPORT_SYMBOL_GPL(device_destroy); + +/** + * device_rename - renames a device + * @dev: the pointer to the struct device to be renamed + * @new_name: the new name of the device + * + * It is the responsibility of the caller to provide mutual + * exclusion between two different calls of device_rename + * on the same device to ensure that new_name is valid and + * won't conflict with other devices. + * + * Note: Don't call this function. Currently, the networking layer calls this + * function, but that will change. The following text from Kay Sievers offers + * some insight: + * + * Renaming devices is racy at many levels, symlinks and other stuff are not + * replaced atomically, and you get a "move" uevent, but it's not easy to + * connect the event to the old and new device. Device nodes are not renamed at + * all, there isn't even support for that in the kernel now. + * + * In the meantime, during renaming, your target name might be taken by another + * driver, creating conflicts. Or the old name is taken directly after you + * renamed it -- then you get events for the same DEVPATH, before you even see + * the "move" event. It's just a mess, and nothing new should ever rely on + * kernel device renaming. Besides that, it's not even implemented now for + * other things than (driver-core wise very simple) network devices. + * + * We are currently about to change network renaming in udev to completely + * disallow renaming of devices in the same namespace as the kernel uses, + * because we can't solve the problems properly, that arise with swapping names + * of multiple interfaces without races. Means, renaming of eth[0-9]* will only + * be allowed to some other name than eth[0-9]*, for the aforementioned + * reasons. + * + * Make up a "real" name in the driver before you register anything, or add + * some other attributes for userspace to find the device, or use udev to add + * symlinks -- but never rename kernel devices later, it's a complete mess. We + * don't even want to get into that and try to implement the missing pieces in + * the core. We really have other pieces to fix in the driver core mess. :) + */ +int device_rename(struct device *dev, const char *new_name) +{ + struct kobject *kobj = &dev->kobj; + char *old_device_name = NULL; + int error; + + dev = get_device(dev); + if (!dev) + return -EINVAL; + + dev_dbg(dev, "renaming to %s\n", new_name); + + old_device_name = kstrdup(dev_name(dev), GFP_KERNEL); + if (!old_device_name) { + error = -ENOMEM; + goto out; + } + + if (dev->class) { + error = sysfs_rename_link_ns(&dev->class->p->subsys.kobj, + kobj, old_device_name, + new_name, kobject_namespace(kobj)); + if (error) + goto out; + } + + error = kobject_rename(kobj, new_name); + if (error) + goto out; + +out: + put_device(dev); + + kfree(old_device_name); + + return error; +} +EXPORT_SYMBOL_GPL(device_rename); + +static int device_move_class_links(struct device *dev, + struct device *old_parent, + struct device *new_parent) +{ + int error = 0; + + if (old_parent) + sysfs_remove_link(&dev->kobj, "device"); + if (new_parent) + error = sysfs_create_link(&dev->kobj, &new_parent->kobj, + "device"); + return error; +} + +/** + * device_move - moves a device to a new parent + * @dev: the pointer to the struct device to be moved + * @new_parent: the new parent of the device (can be NULL) + * @dpm_order: how to reorder the dpm_list + */ +int device_move(struct device *dev, struct device *new_parent, + enum dpm_order dpm_order) +{ + int error; + struct device *old_parent; + struct kobject *new_parent_kobj; + + dev = get_device(dev); + if (!dev) + return -EINVAL; + + device_pm_lock(); + new_parent = get_device(new_parent); + new_parent_kobj = get_device_parent(dev, new_parent); + if (IS_ERR(new_parent_kobj)) { + error = PTR_ERR(new_parent_kobj); + put_device(new_parent); + goto out; + } + + pr_debug("device: '%s': %s: moving to '%s'\n", dev_name(dev), + __func__, new_parent ? dev_name(new_parent) : "<NULL>"); + error = kobject_move(&dev->kobj, new_parent_kobj); + if (error) { + cleanup_glue_dir(dev, new_parent_kobj); + put_device(new_parent); + goto out; + } + old_parent = dev->parent; + dev->parent = new_parent; + if (old_parent) + klist_remove(&dev->p->knode_parent); + if (new_parent) { + klist_add_tail(&dev->p->knode_parent, + &new_parent->p->klist_children); + set_dev_node(dev, dev_to_node(new_parent)); + } + + if (dev->class) { + error = device_move_class_links(dev, old_parent, new_parent); + if (error) { + /* We ignore errors on cleanup since we're hosed anyway... */ + device_move_class_links(dev, new_parent, old_parent); + if (!kobject_move(&dev->kobj, &old_parent->kobj)) { + if (new_parent) + klist_remove(&dev->p->knode_parent); + dev->parent = old_parent; + if (old_parent) { + klist_add_tail(&dev->p->knode_parent, + &old_parent->p->klist_children); + set_dev_node(dev, dev_to_node(old_parent)); + } + } + cleanup_glue_dir(dev, new_parent_kobj); + put_device(new_parent); + goto out; + } + } + switch (dpm_order) { + case DPM_ORDER_NONE: + break; + case DPM_ORDER_DEV_AFTER_PARENT: + device_pm_move_after(dev, new_parent); + devices_kset_move_after(dev, new_parent); + break; + case DPM_ORDER_PARENT_BEFORE_DEV: + device_pm_move_before(new_parent, dev); + devices_kset_move_before(new_parent, dev); + break; + case DPM_ORDER_DEV_LAST: + device_pm_move_last(dev); + devices_kset_move_last(dev); + break; + } + + put_device(old_parent); +out: + device_pm_unlock(); + put_device(dev); + return error; +} +EXPORT_SYMBOL_GPL(device_move); + +/** + * device_shutdown - call ->shutdown() on each device to shutdown. + */ +void device_shutdown(void) +{ + struct device *dev, *parent; + + wait_for_device_probe(); + device_block_probing(); + + cpufreq_suspend(); + + spin_lock(&devices_kset->list_lock); + /* + * Walk the devices list backward, shutting down each in turn. + * Beware that device unplug events may also start pulling + * devices offline, even as the system is shutting down. + */ + while (!list_empty(&devices_kset->list)) { + dev = list_entry(devices_kset->list.prev, struct device, + kobj.entry); + + /* + * hold reference count of device's parent to + * prevent it from being freed because parent's + * lock is to be held + */ + parent = get_device(dev->parent); + get_device(dev); + /* + * Make sure the device is off the kset list, in the + * event that dev->*->shutdown() doesn't remove it. + */ + list_del_init(&dev->kobj.entry); + spin_unlock(&devices_kset->list_lock); + + /* hold lock to avoid race with probe/release */ + if (parent) + device_lock(parent); + device_lock(dev); + + /* Don't allow any more runtime suspends */ + pm_runtime_get_noresume(dev); + pm_runtime_barrier(dev); + + if (dev->class && dev->class->shutdown_pre) { + if (initcall_debug) + dev_info(dev, "shutdown_pre\n"); + dev->class->shutdown_pre(dev); + } + if (dev->bus && dev->bus->shutdown) { + if (initcall_debug) + dev_info(dev, "shutdown\n"); + dev->bus->shutdown(dev); + } else if (dev->driver && dev->driver->shutdown) { + if (initcall_debug) + dev_info(dev, "shutdown\n"); + dev->driver->shutdown(dev); + } + + device_unlock(dev); + if (parent) + device_unlock(parent); + + put_device(dev); + put_device(parent); + + spin_lock(&devices_kset->list_lock); + } + spin_unlock(&devices_kset->list_lock); +} + +/* + * Device logging functions + */ + +#ifdef CONFIG_PRINTK +static int +create_syslog_header(const struct device *dev, char *hdr, size_t hdrlen) +{ + const char *subsys; + size_t pos = 0; + + if (dev->class) + subsys = dev->class->name; + else if (dev->bus) + subsys = dev->bus->name; + else + return 0; + + pos += snprintf(hdr + pos, hdrlen - pos, "SUBSYSTEM=%s", subsys); + if (pos >= hdrlen) + goto overflow; + + /* + * Add device identifier DEVICE=: + * b12:8 block dev_t + * c127:3 char dev_t + * n8 netdev ifindex + * +sound:card0 subsystem:devname + */ + if (MAJOR(dev->devt)) { + char c; + + if (strcmp(subsys, "block") == 0) + c = 'b'; + else + c = 'c'; + pos++; + pos += snprintf(hdr + pos, hdrlen - pos, + "DEVICE=%c%u:%u", + c, MAJOR(dev->devt), MINOR(dev->devt)); + } else if (strcmp(subsys, "net") == 0) { + struct net_device *net = to_net_dev(dev); + + pos++; + pos += snprintf(hdr + pos, hdrlen - pos, + "DEVICE=n%u", net->ifindex); + } else { + pos++; + pos += snprintf(hdr + pos, hdrlen - pos, + "DEVICE=+%s:%s", subsys, dev_name(dev)); + } + + if (pos >= hdrlen) + goto overflow; + + return pos; + +overflow: + dev_WARN(dev, "device/subsystem name too long"); + return 0; +} + +int dev_vprintk_emit(int level, const struct device *dev, + const char *fmt, va_list args) +{ + char hdr[128]; + size_t hdrlen; + + hdrlen = create_syslog_header(dev, hdr, sizeof(hdr)); + + return vprintk_emit(0, level, hdrlen ? hdr : NULL, hdrlen, fmt, args); +} +EXPORT_SYMBOL(dev_vprintk_emit); + +int dev_printk_emit(int level, const struct device *dev, const char *fmt, ...) +{ + va_list args; + int r; + + va_start(args, fmt); + + r = dev_vprintk_emit(level, dev, fmt, args); + + va_end(args); + + return r; +} +EXPORT_SYMBOL(dev_printk_emit); + +static void __dev_printk(const char *level, const struct device *dev, + struct va_format *vaf) +{ + if (dev) + dev_printk_emit(level[1] - '0', dev, "%s %s: %pV", + dev_driver_string(dev), dev_name(dev), vaf); + else + printk("%s(NULL device *): %pV", level, vaf); +} + +void dev_printk(const char *level, const struct device *dev, + const char *fmt, ...) +{ + struct va_format vaf; + va_list args; + + va_start(args, fmt); + + vaf.fmt = fmt; + vaf.va = &args; + + __dev_printk(level, dev, &vaf); + + va_end(args); +} +EXPORT_SYMBOL(dev_printk); + +#define define_dev_printk_level(func, kern_level) \ +void func(const struct device *dev, const char *fmt, ...) \ +{ \ + struct va_format vaf; \ + va_list args; \ + \ + va_start(args, fmt); \ + \ + vaf.fmt = fmt; \ + vaf.va = &args; \ + \ + __dev_printk(kern_level, dev, &vaf); \ + \ + va_end(args); \ +} \ +EXPORT_SYMBOL(func); + +define_dev_printk_level(_dev_emerg, KERN_EMERG); +define_dev_printk_level(_dev_alert, KERN_ALERT); +define_dev_printk_level(_dev_crit, KERN_CRIT); +define_dev_printk_level(_dev_err, KERN_ERR); +define_dev_printk_level(_dev_warn, KERN_WARNING); +define_dev_printk_level(_dev_notice, KERN_NOTICE); +define_dev_printk_level(_dev_info, KERN_INFO); + +#endif + +static inline bool fwnode_is_primary(struct fwnode_handle *fwnode) +{ + return fwnode && !IS_ERR(fwnode->secondary); +} + +/** + * set_primary_fwnode - Change the primary firmware node of a given device. + * @dev: Device to handle. + * @fwnode: New primary firmware node of the device. + * + * Set the device's firmware node pointer to @fwnode, but if a secondary + * firmware node of the device is present, preserve it. + */ +void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode) +{ + struct device *parent = dev->parent; + struct fwnode_handle *fn = dev->fwnode; + + if (fwnode) { + if (fwnode_is_primary(fn)) + fn = fn->secondary; + + if (fn) { + WARN_ON(fwnode->secondary); + fwnode->secondary = fn; + } + dev->fwnode = fwnode; + } else { + if (fwnode_is_primary(fn)) { + dev->fwnode = fn->secondary; + if (!(parent && fn == parent->fwnode)) + fn->secondary = NULL; + } else { + dev->fwnode = NULL; + } + } +} +EXPORT_SYMBOL_GPL(set_primary_fwnode); + +/** + * set_secondary_fwnode - Change the secondary firmware node of a given device. + * @dev: Device to handle. + * @fwnode: New secondary firmware node of the device. + * + * If a primary firmware node of the device is present, set its secondary + * pointer to @fwnode. Otherwise, set the device's firmware node pointer to + * @fwnode. + */ +void set_secondary_fwnode(struct device *dev, struct fwnode_handle *fwnode) +{ + if (fwnode) + fwnode->secondary = ERR_PTR(-ENODEV); + + if (fwnode_is_primary(dev->fwnode)) + dev->fwnode->secondary = fwnode; + else + dev->fwnode = fwnode; +} + +/** + * device_set_of_node_from_dev - reuse device-tree node of another device + * @dev: device whose device-tree node is being set + * @dev2: device whose device-tree node is being reused + * + * Takes another reference to the new device-tree node after first dropping + * any reference held to the old node. + */ +void device_set_of_node_from_dev(struct device *dev, const struct device *dev2) +{ + of_node_put(dev->of_node); + dev->of_node = of_node_get(dev2->of_node); + dev->of_node_reused = true; +} +EXPORT_SYMBOL_GPL(device_set_of_node_from_dev); |