diff options
Diffstat (limited to 'drivers/base/core.c')
| -rw-r--r-- | drivers/base/core.c | 4202 |
1 files changed, 3691 insertions, 511 deletions
diff --git a/drivers/base/core.c b/drivers/base/core.c index dc3ea237f086..40de2f51a1b1 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -1,3 +1,4 @@ +// SPDX-License-Identifier: GPL-2.0 /* * drivers/base/core.c - core driver model code (device registration, etc) * @@ -5,49 +6,2359 @@ * Copyright (c) 2002-3 Open Source Development Labs * Copyright (c) 2006 Greg Kroah-Hartman <gregkh@suse.de> * Copyright (c) 2006 Novell, Inc. - * - * This file is released under the GPLv2 - * */ +#include <linux/acpi.h> +#include <linux/blkdev.h> +#include <linux/cleanup.h> +#include <linux/cpufreq.h> #include <linux/device.h> +#include <linux/dma-map-ops.h> /* for dma_default_coherent */ #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/kstrtox.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/netdevice.h> #include <linux/notifier.h> #include <linux/of.h> #include <linux/of_device.h> -#include <linux/genhd.h> -#include <linux/kallsyms.h> -#include <linux/mutex.h> -#include <linux/async.h> #include <linux/pm_runtime.h> -#include <linux/netdevice.h> +#include <linux/sched/mm.h> +#include <linux/sched/signal.h> +#include <linux/slab.h> +#include <linux/string_helpers.h> +#include <linux/swiotlb.h> +#include <linux/sysfs.h> #include "base.h" +#include "physical_location.h" #include "power/power.h" -#ifdef CONFIG_SYSFS_DEPRECATED -#ifdef CONFIG_SYSFS_DEPRECATED_V2 -long sysfs_deprecated = 1; +/* Device links support. */ +static LIST_HEAD(deferred_sync); +static unsigned int defer_sync_state_count = 1; +static DEFINE_MUTEX(fwnode_link_lock); +static bool fw_devlink_is_permissive(void); +static void __fw_devlink_link_to_consumers(struct device *dev); +static bool fw_devlink_drv_reg_done; +static bool fw_devlink_best_effort; +static struct workqueue_struct *device_link_wq; + +/** + * __fwnode_link_add - Create a link between two fwnode_handles. + * @con: Consumer end of the link. + * @sup: Supplier end of the link. + * @flags: Link flags. + * + * Create a fwnode link between fwnode handles @con and @sup. The fwnode link + * represents the detail that the firmware lists @sup fwnode as supplying a + * resource to @con. + * + * The driver core will use the fwnode link to create a device link between the + * two device objects corresponding to @con and @sup when they are created. The + * driver core will automatically delete the fwnode link between @con and @sup + * after doing that. + * + * Attempts to create duplicate links between the same pair of fwnode handles + * are ignored and there is no reference counting. + */ +static int __fwnode_link_add(struct fwnode_handle *con, + struct fwnode_handle *sup, u8 flags) +{ + struct fwnode_link *link; + + list_for_each_entry(link, &sup->consumers, s_hook) + if (link->consumer == con) { + link->flags |= flags; + return 0; + } + + link = kzalloc(sizeof(*link), GFP_KERNEL); + if (!link) + return -ENOMEM; + + link->supplier = sup; + INIT_LIST_HEAD(&link->s_hook); + link->consumer = con; + INIT_LIST_HEAD(&link->c_hook); + link->flags = flags; + + list_add(&link->s_hook, &sup->consumers); + list_add(&link->c_hook, &con->suppliers); + pr_debug("%pfwf Linked as a fwnode consumer to %pfwf\n", + con, sup); + + return 0; +} + +int fwnode_link_add(struct fwnode_handle *con, struct fwnode_handle *sup, + u8 flags) +{ + guard(mutex)(&fwnode_link_lock); + + return __fwnode_link_add(con, sup, flags); +} + +/** + * __fwnode_link_del - Delete a link between two fwnode_handles. + * @link: the fwnode_link to be deleted + * + * The fwnode_link_lock needs to be held when this function is called. + */ +static void __fwnode_link_del(struct fwnode_link *link) +{ + pr_debug("%pfwf Dropping the fwnode link to %pfwf\n", + link->consumer, link->supplier); + list_del(&link->s_hook); + list_del(&link->c_hook); + kfree(link); +} + +/** + * __fwnode_link_cycle - Mark a fwnode link as being part of a cycle. + * @link: the fwnode_link to be marked + * + * The fwnode_link_lock needs to be held when this function is called. + */ +static void __fwnode_link_cycle(struct fwnode_link *link) +{ + pr_debug("%pfwf: cycle: depends on %pfwf\n", + link->consumer, link->supplier); + link->flags |= FWLINK_FLAG_CYCLE; +} + +/** + * fwnode_links_purge_suppliers - Delete all supplier links of fwnode_handle. + * @fwnode: fwnode whose supplier links need to be deleted + * + * Deletes all supplier links connecting directly to @fwnode. + */ +static void fwnode_links_purge_suppliers(struct fwnode_handle *fwnode) +{ + struct fwnode_link *link, *tmp; + + guard(mutex)(&fwnode_link_lock); + + list_for_each_entry_safe(link, tmp, &fwnode->suppliers, c_hook) + __fwnode_link_del(link); +} + +/** + * fwnode_links_purge_consumers - Delete all consumer links of fwnode_handle. + * @fwnode: fwnode whose consumer links need to be deleted + * + * Deletes all consumer links connecting directly to @fwnode. + */ +static void fwnode_links_purge_consumers(struct fwnode_handle *fwnode) +{ + struct fwnode_link *link, *tmp; + + guard(mutex)(&fwnode_link_lock); + + list_for_each_entry_safe(link, tmp, &fwnode->consumers, s_hook) + __fwnode_link_del(link); +} + +/** + * fwnode_links_purge - Delete all links connected to a fwnode_handle. + * @fwnode: fwnode whose links needs to be deleted + * + * Deletes all links connecting directly to a fwnode. + */ +void fwnode_links_purge(struct fwnode_handle *fwnode) +{ + fwnode_links_purge_suppliers(fwnode); + fwnode_links_purge_consumers(fwnode); +} + +void fw_devlink_purge_absent_suppliers(struct fwnode_handle *fwnode) +{ + struct fwnode_handle *child; + + /* Don't purge consumer links of an added child */ + if (fwnode->dev) + return; + + fwnode->flags |= FWNODE_FLAG_NOT_DEVICE; + fwnode_links_purge_consumers(fwnode); + + fwnode_for_each_available_child_node(fwnode, child) + fw_devlink_purge_absent_suppliers(child); +} +EXPORT_SYMBOL_GPL(fw_devlink_purge_absent_suppliers); + +/** + * __fwnode_links_move_consumers - Move consumer from @from to @to fwnode_handle + * @from: move consumers away from this fwnode + * @to: move consumers to this fwnode + * + * Move all consumer links from @from fwnode to @to fwnode. + */ +static void __fwnode_links_move_consumers(struct fwnode_handle *from, + struct fwnode_handle *to) +{ + struct fwnode_link *link, *tmp; + + list_for_each_entry_safe(link, tmp, &from->consumers, s_hook) { + __fwnode_link_add(link->consumer, to, link->flags); + __fwnode_link_del(link); + } +} + +/** + * __fw_devlink_pickup_dangling_consumers - Pick up dangling consumers + * @fwnode: fwnode from which to pick up dangling consumers + * @new_sup: fwnode of new supplier + * + * If the @fwnode has a corresponding struct device and the device supports + * probing (that is, added to a bus), then we want to let fw_devlink create + * MANAGED device links to this device, so leave @fwnode and its descendant's + * fwnode links alone. + * + * Otherwise, move its consumers to the new supplier @new_sup. + */ +static void __fw_devlink_pickup_dangling_consumers(struct fwnode_handle *fwnode, + struct fwnode_handle *new_sup) +{ + struct fwnode_handle *child; + + if (fwnode->dev && fwnode->dev->bus) + return; + + fwnode->flags |= FWNODE_FLAG_NOT_DEVICE; + __fwnode_links_move_consumers(fwnode, new_sup); + + fwnode_for_each_available_child_node(fwnode, child) + __fw_devlink_pickup_dangling_consumers(child, new_sup); +} + +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) __acquires(&device_links_srcu) +{ + return srcu_read_lock(&device_links_srcu); +} + +void device_links_read_unlock(int idx) __releases(&device_links_srcu) +{ + srcu_read_unlock(&device_links_srcu, idx); +} + +int device_links_read_lock_held(void) +{ + return srcu_read_lock_held(&device_links_srcu); +} + +static void device_link_synchronize_removal(void) +{ + synchronize_srcu(&device_links_srcu); +} + +static void device_link_remove_from_lists(struct device_link *link) +{ + list_del_rcu(&link->s_node); + list_del_rcu(&link->c_node); +} + +static bool device_is_ancestor(struct device *dev, struct device *target) +{ + while (target->parent) { + target = target->parent; + if (dev == target) + return true; + } + return false; +} + +#define DL_MARKER_FLAGS (DL_FLAG_INFERRED | \ + DL_FLAG_CYCLE | \ + DL_FLAG_MANAGED) +bool device_link_flag_is_sync_state_only(u32 flags) +{ + return (flags & ~DL_MARKER_FLAGS) == DL_FLAG_SYNC_STATE_ONLY; +} + +/** + * 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 (device_link_flag_is_sync_state_only(link->flags)) + continue; + + 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) { + if (device_link_flag_is_sync_state_only(link->flags)) + continue; + 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 to_devlink(dev) container_of((dev), struct device_link, link_dev) + +static ssize_t status_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + const char *output; + + switch (to_devlink(dev)->status) { + case DL_STATE_NONE: + output = "not tracked"; + break; + case DL_STATE_DORMANT: + output = "dormant"; + break; + case DL_STATE_AVAILABLE: + output = "available"; + break; + case DL_STATE_CONSUMER_PROBE: + output = "consumer probing"; + break; + case DL_STATE_ACTIVE: + output = "active"; + break; + case DL_STATE_SUPPLIER_UNBIND: + output = "supplier unbinding"; + break; + default: + output = "unknown"; + break; + } + + return sysfs_emit(buf, "%s\n", output); +} +static DEVICE_ATTR_RO(status); + +static ssize_t auto_remove_on_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct device_link *link = to_devlink(dev); + const char *output; + + if (device_link_test(link, DL_FLAG_AUTOREMOVE_SUPPLIER)) + output = "supplier unbind"; + else if (device_link_test(link, DL_FLAG_AUTOREMOVE_CONSUMER)) + output = "consumer unbind"; + else + output = "never"; + + return sysfs_emit(buf, "%s\n", output); +} +static DEVICE_ATTR_RO(auto_remove_on); + +static ssize_t runtime_pm_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct device_link *link = to_devlink(dev); + + return sysfs_emit(buf, "%d\n", device_link_test(link, DL_FLAG_PM_RUNTIME)); +} +static DEVICE_ATTR_RO(runtime_pm); + +static ssize_t sync_state_only_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct device_link *link = to_devlink(dev); + + return sysfs_emit(buf, "%d\n", device_link_test(link, DL_FLAG_SYNC_STATE_ONLY)); +} +static DEVICE_ATTR_RO(sync_state_only); + +static struct attribute *devlink_attrs[] = { + &dev_attr_status.attr, + &dev_attr_auto_remove_on.attr, + &dev_attr_runtime_pm.attr, + &dev_attr_sync_state_only.attr, + NULL, +}; +ATTRIBUTE_GROUPS(devlink); + +static void device_link_release_fn(struct work_struct *work) +{ + struct device_link *link = container_of(work, struct device_link, rm_work); + + /* Ensure that all references to the link object have been dropped. */ + device_link_synchronize_removal(); + + pm_runtime_release_supplier(link); + /* + * If supplier_preactivated is set, the link has been dropped between + * the pm_runtime_get_suppliers() and pm_runtime_put_suppliers() calls + * in __driver_probe_device(). In that case, drop the supplier's + * PM-runtime usage counter to remove the reference taken by + * pm_runtime_get_suppliers(). + */ + if (link->supplier_preactivated) + pm_runtime_put_noidle(link->supplier); + + pm_request_idle(link->supplier); + + put_device(link->consumer); + put_device(link->supplier); + kfree(link); +} + +static void devlink_dev_release(struct device *dev) +{ + struct device_link *link = to_devlink(dev); + + INIT_WORK(&link->rm_work, device_link_release_fn); + /* + * It may take a while to complete this work because of the SRCU + * synchronization in device_link_release_fn() and if the consumer or + * supplier devices get deleted when it runs, so put it into the + * dedicated workqueue. + */ + queue_work(device_link_wq, &link->rm_work); +} + +/** + * device_link_wait_removal - Wait for ongoing devlink removal jobs to terminate + */ +void device_link_wait_removal(void) +{ + /* + * devlink removal jobs are queued in the dedicated work queue. + * To be sure that all removal jobs are terminated, ensure that any + * scheduled work has run to completion. + */ + flush_workqueue(device_link_wq); +} +EXPORT_SYMBOL_GPL(device_link_wait_removal); + +static const struct class devlink_class = { + .name = "devlink", + .dev_groups = devlink_groups, + .dev_release = devlink_dev_release, +}; + +static int devlink_add_symlinks(struct device *dev) +{ + char *buf_con __free(kfree) = NULL, *buf_sup __free(kfree) = NULL; + int ret; + struct device_link *link = to_devlink(dev); + struct device *sup = link->supplier; + struct device *con = link->consumer; + + ret = sysfs_create_link(&link->link_dev.kobj, &sup->kobj, "supplier"); + if (ret) + goto out; + + ret = sysfs_create_link(&link->link_dev.kobj, &con->kobj, "consumer"); + if (ret) + goto err_con; + + buf_con = kasprintf(GFP_KERNEL, "consumer:%s:%s", dev_bus_name(con), dev_name(con)); + if (!buf_con) { + ret = -ENOMEM; + goto err_con_dev; + } + + ret = sysfs_create_link(&sup->kobj, &link->link_dev.kobj, buf_con); + if (ret) + goto err_con_dev; + + buf_sup = kasprintf(GFP_KERNEL, "supplier:%s:%s", dev_bus_name(sup), dev_name(sup)); + if (!buf_sup) { + ret = -ENOMEM; + goto err_sup_dev; + } + + ret = sysfs_create_link(&con->kobj, &link->link_dev.kobj, buf_sup); + if (ret) + goto err_sup_dev; + + goto out; + +err_sup_dev: + sysfs_remove_link(&sup->kobj, buf_con); +err_con_dev: + sysfs_remove_link(&link->link_dev.kobj, "consumer"); +err_con: + sysfs_remove_link(&link->link_dev.kobj, "supplier"); +out: + return ret; +} + +static void devlink_remove_symlinks(struct device *dev) +{ + char *buf_con __free(kfree) = NULL, *buf_sup __free(kfree) = NULL; + struct device_link *link = to_devlink(dev); + struct device *sup = link->supplier; + struct device *con = link->consumer; + + sysfs_remove_link(&link->link_dev.kobj, "consumer"); + sysfs_remove_link(&link->link_dev.kobj, "supplier"); + + if (device_is_registered(con)) { + buf_sup = kasprintf(GFP_KERNEL, "supplier:%s:%s", dev_bus_name(sup), dev_name(sup)); + if (!buf_sup) + goto out; + sysfs_remove_link(&con->kobj, buf_sup); + } + + buf_con = kasprintf(GFP_KERNEL, "consumer:%s:%s", dev_bus_name(con), dev_name(con)); + if (!buf_con) + goto out; + sysfs_remove_link(&sup->kobj, buf_con); + + return; + +out: + WARN(1, "Unable to properly free device link symlinks!\n"); +} + +static struct class_interface devlink_class_intf = { + .class = &devlink_class, + .add_dev = devlink_add_symlinks, + .remove_dev = devlink_remove_symlinks, +}; + +static int __init devlink_class_init(void) +{ + int ret; + + ret = class_register(&devlink_class); + if (ret) + return ret; + + ret = class_interface_register(&devlink_class_intf); + if (ret) + class_unregister(&devlink_class); + + return ret; +} +postcore_initcall(devlink_class_init); + +#define DL_MANAGED_LINK_FLAGS (DL_FLAG_AUTOREMOVE_CONSUMER | \ + DL_FLAG_AUTOREMOVE_SUPPLIER | \ + DL_FLAG_AUTOPROBE_CONSUMER | \ + DL_FLAG_SYNC_STATE_ONLY | \ + DL_FLAG_INFERRED | \ + DL_FLAG_CYCLE) + +#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. + * + * Return: On success, a device_link struct will be returned. + * On error or invalid flag settings, NULL will be returned. + * + * 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 meta state 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 automatically probe for a consumer + * 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 || 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; + + if (flags & DL_FLAG_SYNC_STATE_ONLY && + !device_link_flag_is_sync_state_only(flags)) + return NULL; + + device_links_write_lock(); + device_pm_lock(); + + /* + * If the supplier has not been fully registered yet or there is a + * reverse (non-SYNC_STATE_ONLY) dependency between the consumer and + * the supplier already in the graph, return NULL. If the link is a + * SYNC_STATE_ONLY link, we don't check for reverse dependencies + * because it only affects sync_state() callbacks. + */ + if (!device_pm_initialized(supplier) + || (!(flags & DL_FLAG_SYNC_STATE_ONLY) && + device_is_dependent(consumer, supplier))) { + link = NULL; + goto out; + } + + /* + * SYNC_STATE_ONLY links are useless once a consumer device has probed. + * So, only create it if the consumer hasn't probed yet. + */ + if (flags & DL_FLAG_SYNC_STATE_ONLY && + consumer->links.status != DL_DEV_NO_DRIVER && + consumer->links.status != DL_DEV_PROBING) { + 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 (device_link_test(link, DL_FLAG_INFERRED) && + !(flags & DL_FLAG_INFERRED)) + link->flags &= ~DL_FLAG_INFERRED; + + if (flags & DL_FLAG_PM_RUNTIME) { + if (!device_link_test(link, 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) { + kref_get(&link->kref); + if (device_link_test(link, DL_FLAG_SYNC_STATE_ONLY) && + !device_link_test(link, DL_FLAG_STATELESS)) { + link->flags |= DL_FLAG_STATELESS; + goto reorder; + } else { + link->flags |= DL_FLAG_STATELESS; + 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 (device_link_test(link, 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 (!device_link_test(link, DL_FLAG_MANAGED)) { + kref_get(&link->kref); + link->flags |= DL_FLAG_MANAGED; + device_link_init_status(link, consumer, supplier); + } + if (device_link_test(link, DL_FLAG_SYNC_STATE_ONLY) && + !(flags & DL_FLAG_SYNC_STATE_ONLY)) { + link->flags &= ~DL_FLAG_SYNC_STATE_ONLY; + goto reorder; + } + + goto out; + } + + link = kzalloc(sizeof(*link), GFP_KERNEL); + if (!link) + goto out; + + refcount_set(&link->rpm_active, 1); + + 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); + + link->link_dev.class = &devlink_class; + device_set_pm_not_required(&link->link_dev); + dev_set_name(&link->link_dev, "%s:%s--%s:%s", + dev_bus_name(supplier), dev_name(supplier), + dev_bus_name(consumer), dev_name(consumer)); + if (device_register(&link->link_dev)) { + put_device(&link->link_dev); + link = NULL; + goto out; + } + + if (flags & DL_FLAG_PM_RUNTIME) { + if (flags & DL_FLAG_RPM_ACTIVE) + refcount_inc(&link->rpm_active); + + pm_runtime_new_link(consumer); + } + + /* 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); + + list_add_tail_rcu(&link->s_node, &supplier->links.consumers); + list_add_tail_rcu(&link->c_node, &consumer->links.suppliers); + + if (flags & DL_FLAG_SYNC_STATE_ONLY) { + dev_dbg(consumer, + "Linked as a sync state only consumer to %s\n", + dev_name(supplier)); + goto out; + } + +reorder: + /* + * 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); + + dev_dbg(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_del(struct kref *kref) +{ + struct device_link *link = container_of(kref, struct device_link, kref); + + dev_dbg(link->consumer, "Dropping the link to %s\n", + dev_name(link->supplier)); + + pm_runtime_drop_link(link); + + device_link_remove_from_lists(link); + device_unregister(&link->link_dev); +} + +static void device_link_put_kref(struct device_link *link) +{ + if (device_link_test(link, DL_FLAG_STATELESS)) + kref_put(&link->kref, __device_link_del); + else if (!device_is_registered(link->consumer)) + __device_link_del(&link->kref); + 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_link_put_kref(link); + 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(); + + list_for_each_entry(link, &supplier->links.consumers, s_node) { + if (link->consumer == consumer) { + device_link_put_kref(link); + break; + } + } + + 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) + continue; + + if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) { + WRITE_ONCE(link->status, DL_STATE_AVAILABLE); + } else { + WARN_ON(!device_link_test(link, DL_FLAG_SYNC_STATE_ONLY)); + WRITE_ONCE(link->status, DL_STATE_DORMANT); + } + } +} + +static bool dev_is_best_effort(struct device *dev) +{ + return (fw_devlink_best_effort && dev->can_match) || + (dev->fwnode && (dev->fwnode->flags & FWNODE_FLAG_BEST_EFFORT)); +} + +static struct fwnode_handle *fwnode_links_check_suppliers( + struct fwnode_handle *fwnode) +{ + struct fwnode_link *link; + + if (!fwnode || fw_devlink_is_permissive()) + return NULL; + + list_for_each_entry(link, &fwnode->suppliers, c_hook) + if (!(link->flags & + (FWLINK_FLAG_CYCLE | FWLINK_FLAG_IGNORE))) + return link->supplier; + + return NULL; +} + +/** + * 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, fwnode_ret = 0; + struct fwnode_handle *sup_fw; + + /* + * Device waiting for supplier to become available is not allowed to + * probe. + */ + scoped_guard(mutex, &fwnode_link_lock) { + sup_fw = fwnode_links_check_suppliers(dev->fwnode); + if (sup_fw) { + if (dev_is_best_effort(dev)) + fwnode_ret = -EAGAIN; + else + return dev_err_probe(dev, -EPROBE_DEFER, + "wait for supplier %pfwf\n", sup_fw); + } + } + + device_links_write_lock(); + + list_for_each_entry(link, &dev->links.suppliers, c_node) { + if (!device_link_test(link, DL_FLAG_MANAGED)) + continue; + + if (link->status != DL_STATE_AVAILABLE && + !device_link_test(link, DL_FLAG_SYNC_STATE_ONLY)) { + + if (dev_is_best_effort(dev) && + device_link_test(link, DL_FLAG_INFERRED) && + !link->supplier->can_match) { + ret = -EAGAIN; + continue; + } + + device_links_missing_supplier(dev); + ret = dev_err_probe(dev, -EPROBE_DEFER, + "supplier %s not ready\n", dev_name(link->supplier)); + break; + } + WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE); + } + dev->links.status = DL_DEV_PROBING; + + device_links_write_unlock(); + + return ret ? ret : fwnode_ret; +} + +/** + * __device_links_queue_sync_state - Queue a device for sync_state() callback + * @dev: Device to call sync_state() on + * @list: List head to queue the @dev on + * + * Queues a device for a sync_state() callback when the device links write lock + * isn't held. This allows the sync_state() execution flow to use device links + * APIs. The caller must ensure this function is called with + * device_links_write_lock() held. + * + * This function does a get_device() to make sure the device is not freed while + * on this list. + * + * So the caller must also ensure that device_links_flush_sync_list() is called + * as soon as the caller releases device_links_write_lock(). This is necessary + * to make sure the sync_state() is called in a timely fashion and the + * put_device() is called on this device. + */ +static void __device_links_queue_sync_state(struct device *dev, + struct list_head *list) +{ + struct device_link *link; + + if (!dev_has_sync_state(dev)) + return; + if (dev->state_synced) + return; + + list_for_each_entry(link, &dev->links.consumers, s_node) { + if (!device_link_test(link, DL_FLAG_MANAGED)) + continue; + if (link->status != DL_STATE_ACTIVE) + return; + } + + /* + * Set the flag here to avoid adding the same device to a list more + * than once. This can happen if new consumers get added to the device + * and probed before the list is flushed. + */ + dev->state_synced = true; + + if (WARN_ON(!list_empty(&dev->links.defer_sync))) + return; + + get_device(dev); + list_add_tail(&dev->links.defer_sync, list); +} + +/** + * device_links_flush_sync_list - Call sync_state() on a list of devices + * @list: List of devices to call sync_state() on + * @dont_lock_dev: Device for which lock is already held by the caller + * + * Calls sync_state() on all the devices that have been queued for it. This + * function is used in conjunction with __device_links_queue_sync_state(). The + * @dont_lock_dev parameter is useful when this function is called from a + * context where a device lock is already held. + */ +static void device_links_flush_sync_list(struct list_head *list, + struct device *dont_lock_dev) +{ + struct device *dev, *tmp; + + list_for_each_entry_safe(dev, tmp, list, links.defer_sync) { + list_del_init(&dev->links.defer_sync); + + if (dev != dont_lock_dev) + device_lock(dev); + + dev_sync_state(dev); + + if (dev != dont_lock_dev) + device_unlock(dev); + + put_device(dev); + } +} + +void device_links_supplier_sync_state_pause(void) +{ + device_links_write_lock(); + defer_sync_state_count++; + device_links_write_unlock(); +} + +void device_links_supplier_sync_state_resume(void) +{ + struct device *dev, *tmp; + LIST_HEAD(sync_list); + + device_links_write_lock(); + if (!defer_sync_state_count) { + WARN(true, "Unmatched sync_state pause/resume!"); + goto out; + } + defer_sync_state_count--; + if (defer_sync_state_count) + goto out; + + list_for_each_entry_safe(dev, tmp, &deferred_sync, links.defer_sync) { + /* + * Delete from deferred_sync list before queuing it to + * sync_list because defer_sync is used for both lists. + */ + list_del_init(&dev->links.defer_sync); + __device_links_queue_sync_state(dev, &sync_list); + } +out: + device_links_write_unlock(); + + device_links_flush_sync_list(&sync_list, NULL); +} + +static int sync_state_resume_initcall(void) +{ + device_links_supplier_sync_state_resume(); + return 0; +} +late_initcall(sync_state_resume_initcall); + +static void __device_links_supplier_defer_sync(struct device *sup) +{ + if (list_empty(&sup->links.defer_sync) && dev_has_sync_state(sup)) + list_add_tail(&sup->links.defer_sync, &deferred_sync); +} + +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); +} + +static ssize_t waiting_for_supplier_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + bool val; + + device_lock(dev); + scoped_guard(mutex, &fwnode_link_lock) + val = !!fwnode_links_check_suppliers(dev->fwnode); + device_unlock(dev); + return sysfs_emit(buf, "%u\n", val); +} +static DEVICE_ATTR_RO(waiting_for_supplier); + +/** + * device_links_force_bind - Prepares device to be force bound + * @dev: Consumer device. + * + * device_bind_driver() force binds a device to a driver without calling any + * driver probe functions. So the consumer really isn't going to wait for any + * supplier before it's bound to the driver. We still want the device link + * states to be sensible when this happens. + * + * In preparation for device_bind_driver(), this function goes through each + * supplier device links and checks if the supplier is bound. If it is, then + * the device link status is set to CONSUMER_PROBE. Otherwise, the device link + * is dropped. Links without the DL_FLAG_MANAGED flag set are ignored. + */ +void device_links_force_bind(struct device *dev) +{ + struct device_link *link, *ln; + + device_links_write_lock(); + + list_for_each_entry_safe(link, ln, &dev->links.suppliers, c_node) { + if (!device_link_test(link, DL_FLAG_MANAGED)) + continue; + + if (link->status != DL_STATE_AVAILABLE) { + device_link_drop_managed(link); + continue; + } + WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE); + } + dev->links.status = DL_DEV_PROBING; + + device_links_write_unlock(); +} + +/** + * 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, *ln; + LIST_HEAD(sync_list); + + /* + * If a device binds successfully, it's expected to have created all + * the device links it needs to or make new device links as it needs + * them. So, fw_devlink no longer needs to create device links to any + * of the device's suppliers. + * + * Also, if a child firmware node of this bound device is not added as a + * device by now, assume it is never going to be added. Make this bound + * device the fallback supplier to the dangling consumers of the child + * firmware node because this bound device is probably implementing the + * child firmware node functionality and we don't want the dangling + * consumers to defer probe indefinitely waiting for a device for the + * child firmware node. + */ + if (dev->fwnode && dev->fwnode->dev == dev) { + struct fwnode_handle *child; + + fwnode_links_purge_suppliers(dev->fwnode); + + guard(mutex)(&fwnode_link_lock); + + fwnode_for_each_available_child_node(dev->fwnode, child) + __fw_devlink_pickup_dangling_consumers(child, + dev->fwnode); + __fw_devlink_link_to_consumers(dev); + } + device_remove_file(dev, &dev_attr_waiting_for_supplier); + + device_links_write_lock(); + + list_for_each_entry(link, &dev->links.consumers, s_node) { + if (!device_link_test(link, 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 (device_link_test(link, DL_FLAG_AUTOPROBE_CONSUMER)) + driver_deferred_probe_add(link->consumer); + } + + if (defer_sync_state_count) + __device_links_supplier_defer_sync(dev); + else + __device_links_queue_sync_state(dev, &sync_list); + + list_for_each_entry_safe(link, ln, &dev->links.suppliers, c_node) { + struct device *supplier; + + if (!device_link_test(link, DL_FLAG_MANAGED)) + continue; + + supplier = link->supplier; + if (device_link_test(link, DL_FLAG_SYNC_STATE_ONLY)) { + /* + * When DL_FLAG_SYNC_STATE_ONLY is set, it means no + * other DL_MANAGED_LINK_FLAGS have been set. So, it's + * save to drop the managed link completely. + */ + device_link_drop_managed(link); + } else if (dev_is_best_effort(dev) && + device_link_test(link, DL_FLAG_INFERRED) && + link->status != DL_STATE_CONSUMER_PROBE && + !link->supplier->can_match) { + /* + * When dev_is_best_effort() is true, we ignore device + * links to suppliers that don't have a driver. If the + * consumer device still managed to probe, there's no + * point in maintaining a device link in a weird state + * (consumer probed before supplier). So delete it. + */ + device_link_drop_managed(link); + } else { + WARN_ON(link->status != DL_STATE_CONSUMER_PROBE); + WRITE_ONCE(link->status, DL_STATE_ACTIVE); + } + + /* + * This needs to be done even for the deleted + * DL_FLAG_SYNC_STATE_ONLY device link in case it was the last + * device link that was preventing the supplier from getting a + * sync_state() call. + */ + if (defer_sync_state_count) + __device_links_supplier_defer_sync(supplier); + else + __device_links_queue_sync_state(supplier, &sync_list); + } + + dev->links.status = DL_DEV_DRIVER_BOUND; + + device_links_write_unlock(); + + device_links_flush_sync_list(&sync_list, dev); +} + +/** + * __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 (!device_link_test(link, DL_FLAG_MANAGED)) + continue; + + if (device_link_test(link, DL_FLAG_AUTOREMOVE_CONSUMER)) { + device_link_drop_managed(link); + continue; + } + + if (link->status != DL_STATE_CONSUMER_PROBE && + link->status != DL_STATE_ACTIVE) + continue; + + if (link->supplier->links.status == DL_DEV_DRIVER_BOUND) { + WRITE_ONCE(link->status, DL_STATE_AVAILABLE); + } else { + WARN_ON(!device_link_test(link, DL_FLAG_SYNC_STATE_ONLY)); + WRITE_ONCE(link->status, DL_STATE_DORMANT); + } + } + + 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 (!device_link_test(link, 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 (!device_link_test(link, DL_FLAG_MANAGED)) + continue; + + WARN_ON(device_link_test(link, 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 && + device_link_test(link, DL_FLAG_AUTOREMOVE_SUPPLIER)) + device_link_drop_managed(link); + + WRITE_ONCE(link->status, DL_STATE_DORMANT); + } + + list_del_init(&dev->links.defer_sync); + __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 (!device_link_test(link, 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 (!device_link_test(link, DL_FLAG_MANAGED) || + device_link_test(link, DL_FLAG_SYNC_STATE_ONLY)) + 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; + + if (dev->class == &devlink_class) + return; + + /* + * 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(); +} + +#define FW_DEVLINK_FLAGS_PERMISSIVE (DL_FLAG_INFERRED | \ + DL_FLAG_SYNC_STATE_ONLY) +#define FW_DEVLINK_FLAGS_ON (DL_FLAG_INFERRED | \ + DL_FLAG_AUTOPROBE_CONSUMER) +#define FW_DEVLINK_FLAGS_RPM (FW_DEVLINK_FLAGS_ON | \ + DL_FLAG_PM_RUNTIME) + +static u32 fw_devlink_flags = FW_DEVLINK_FLAGS_RPM; +static int __init fw_devlink_setup(char *arg) +{ + if (!arg) + return -EINVAL; + + if (strcmp(arg, "off") == 0) { + fw_devlink_flags = 0; + } else if (strcmp(arg, "permissive") == 0) { + fw_devlink_flags = FW_DEVLINK_FLAGS_PERMISSIVE; + } else if (strcmp(arg, "on") == 0) { + fw_devlink_flags = FW_DEVLINK_FLAGS_ON; + } else if (strcmp(arg, "rpm") == 0) { + fw_devlink_flags = FW_DEVLINK_FLAGS_RPM; + } + return 0; +} +early_param("fw_devlink", fw_devlink_setup); + +static bool fw_devlink_strict; +static int __init fw_devlink_strict_setup(char *arg) +{ + return kstrtobool(arg, &fw_devlink_strict); +} +early_param("fw_devlink.strict", fw_devlink_strict_setup); + +#define FW_DEVLINK_SYNC_STATE_STRICT 0 +#define FW_DEVLINK_SYNC_STATE_TIMEOUT 1 + +#ifndef CONFIG_FW_DEVLINK_SYNC_STATE_TIMEOUT +static int fw_devlink_sync_state; #else -long sysfs_deprecated = 0; +static int fw_devlink_sync_state = FW_DEVLINK_SYNC_STATE_TIMEOUT; #endif -static __init int sysfs_deprecated_setup(char *arg) + +static int __init fw_devlink_sync_state_setup(char *arg) { - return strict_strtol(arg, 10, &sysfs_deprecated); + if (!arg) + return -EINVAL; + + if (strcmp(arg, "strict") == 0) { + fw_devlink_sync_state = FW_DEVLINK_SYNC_STATE_STRICT; + return 0; + } else if (strcmp(arg, "timeout") == 0) { + fw_devlink_sync_state = FW_DEVLINK_SYNC_STATE_TIMEOUT; + return 0; + } + return -EINVAL; } -early_param("sysfs.deprecated", sysfs_deprecated_setup); -#endif +early_param("fw_devlink.sync_state", fw_devlink_sync_state_setup); + +static inline u32 fw_devlink_get_flags(u8 fwlink_flags) +{ + if (fwlink_flags & FWLINK_FLAG_CYCLE) + return FW_DEVLINK_FLAGS_PERMISSIVE | DL_FLAG_CYCLE; + + return fw_devlink_flags; +} + +static bool fw_devlink_is_permissive(void) +{ + return fw_devlink_flags == FW_DEVLINK_FLAGS_PERMISSIVE; +} + +bool fw_devlink_is_strict(void) +{ + return fw_devlink_strict && !fw_devlink_is_permissive(); +} + +static void fw_devlink_parse_fwnode(struct fwnode_handle *fwnode) +{ + if (fwnode->flags & FWNODE_FLAG_LINKS_ADDED) + return; + + fwnode_call_int_op(fwnode, add_links); + fwnode->flags |= FWNODE_FLAG_LINKS_ADDED; +} + +static void fw_devlink_parse_fwtree(struct fwnode_handle *fwnode) +{ + struct fwnode_handle *child = NULL; + + fw_devlink_parse_fwnode(fwnode); + + while ((child = fwnode_get_next_available_child_node(fwnode, child))) + fw_devlink_parse_fwtree(child); +} + +static void fw_devlink_relax_link(struct device_link *link) +{ + if (!device_link_test(link, DL_FLAG_INFERRED)) + return; + + if (device_link_flag_is_sync_state_only(link->flags)) + return; + + pm_runtime_drop_link(link); + link->flags = DL_FLAG_MANAGED | FW_DEVLINK_FLAGS_PERMISSIVE; + dev_dbg(link->consumer, "Relaxing link with %s\n", + dev_name(link->supplier)); +} + +static int fw_devlink_no_driver(struct device *dev, void *data) +{ + struct device_link *link = to_devlink(dev); + + if (!link->supplier->can_match) + fw_devlink_relax_link(link); + + return 0; +} + +void fw_devlink_drivers_done(void) +{ + fw_devlink_drv_reg_done = true; + device_links_write_lock(); + class_for_each_device(&devlink_class, NULL, NULL, + fw_devlink_no_driver); + device_links_write_unlock(); +} + +static int fw_devlink_dev_sync_state(struct device *dev, void *data) +{ + struct device_link *link = to_devlink(dev); + struct device *sup = link->supplier; + + if (!device_link_test(link, DL_FLAG_MANAGED) || + link->status == DL_STATE_ACTIVE || sup->state_synced || + !dev_has_sync_state(sup)) + return 0; + + if (fw_devlink_sync_state == FW_DEVLINK_SYNC_STATE_STRICT) { + dev_info(sup, "sync_state() pending due to %s\n", + dev_name(link->consumer)); + return 0; + } + + if (!list_empty(&sup->links.defer_sync)) + return 0; + + dev_warn(sup, "Timed out. Forcing sync_state()\n"); + sup->state_synced = true; + get_device(sup); + list_add_tail(&sup->links.defer_sync, data); + + return 0; +} + +void fw_devlink_probing_done(void) +{ + LIST_HEAD(sync_list); + + device_links_write_lock(); + class_for_each_device(&devlink_class, NULL, &sync_list, + fw_devlink_dev_sync_state); + device_links_write_unlock(); + device_links_flush_sync_list(&sync_list, NULL); +} + +/** + * wait_for_init_devices_probe - Try to probe any device needed for init + * + * Some devices might need to be probed and bound successfully before the kernel + * boot sequence can finish and move on to init/userspace. For example, a + * network interface might need to be bound to be able to mount a NFS rootfs. + * + * With fw_devlink=on by default, some of these devices might be blocked from + * probing because they are waiting on a optional supplier that doesn't have a + * driver. While fw_devlink will eventually identify such devices and unblock + * the probing automatically, it might be too late by the time it unblocks the + * probing of devices. For example, the IP4 autoconfig might timeout before + * fw_devlink unblocks probing of the network interface. + * + * This function is available to temporarily try and probe all devices that have + * a driver even if some of their suppliers haven't been added or don't have + * drivers. + * + * The drivers can then decide which of the suppliers are optional vs mandatory + * and probe the device if possible. By the time this function returns, all such + * "best effort" probes are guaranteed to be completed. If a device successfully + * probes in this mode, we delete all fw_devlink discovered dependencies of that + * device where the supplier hasn't yet probed successfully because they have to + * be optional dependencies. + * + * Any devices that didn't successfully probe go back to being treated as if + * this function was never called. + * + * This also means that some devices that aren't needed for init and could have + * waited for their optional supplier to probe (when the supplier's module is + * loaded later on) would end up probing prematurely with limited functionality. + * So call this function only when boot would fail without it. + */ +void __init wait_for_init_devices_probe(void) +{ + if (!fw_devlink_flags || fw_devlink_is_permissive()) + return; + + /* + * Wait for all ongoing probes to finish so that the "best effort" is + * only applied to devices that can't probe otherwise. + */ + wait_for_device_probe(); + + pr_info("Trying to probe devices needed for running init ...\n"); + fw_devlink_best_effort = true; + driver_deferred_probe_trigger(); + + /* + * Wait for all "best effort" probes to finish before going back to + * normal enforcement. + */ + wait_for_device_probe(); + fw_devlink_best_effort = false; +} + +static void fw_devlink_unblock_consumers(struct device *dev) +{ + struct device_link *link; + + if (!fw_devlink_flags || fw_devlink_is_permissive()) + return; + + device_links_write_lock(); + list_for_each_entry(link, &dev->links.consumers, s_node) + fw_devlink_relax_link(link); + device_links_write_unlock(); +} + +static bool fwnode_init_without_drv(struct fwnode_handle *fwnode) +{ + struct device *dev; + bool ret; + + if (!(fwnode->flags & FWNODE_FLAG_INITIALIZED)) + return false; + + dev = get_dev_from_fwnode(fwnode); + ret = !dev || dev->links.status == DL_DEV_NO_DRIVER; + put_device(dev); + + return ret; +} + +static bool fwnode_ancestor_init_without_drv(struct fwnode_handle *fwnode) +{ + struct fwnode_handle *parent; + + fwnode_for_each_parent_node(fwnode, parent) { + if (fwnode_init_without_drv(parent)) { + fwnode_handle_put(parent); + return true; + } + } + + return false; +} + +/** + * fwnode_is_ancestor_of - Test if @ancestor is ancestor of @child + * @ancestor: Firmware which is tested for being an ancestor + * @child: Firmware which is tested for being the child + * + * A node is considered an ancestor of itself too. + * + * Return: true if @ancestor is an ancestor of @child. Otherwise, returns false. + */ +static bool fwnode_is_ancestor_of(const struct fwnode_handle *ancestor, + const struct fwnode_handle *child) +{ + struct fwnode_handle *parent; + + if (IS_ERR_OR_NULL(ancestor)) + return false; + + if (child == ancestor) + return true; + + fwnode_for_each_parent_node(child, parent) { + if (parent == ancestor) { + fwnode_handle_put(parent); + return true; + } + } + return false; +} + +/** + * fwnode_get_next_parent_dev - Find device of closest ancestor fwnode + * @fwnode: firmware node + * + * Given a firmware node (@fwnode), this function finds its closest ancestor + * firmware node that has a corresponding struct device and returns that struct + * device. + * + * The caller is responsible for calling put_device() on the returned device + * pointer. + * + * Return: a pointer to the device of the @fwnode's closest ancestor. + */ +static struct device *fwnode_get_next_parent_dev(const struct fwnode_handle *fwnode) +{ + struct fwnode_handle *parent; + struct device *dev; + + fwnode_for_each_parent_node(fwnode, parent) { + dev = get_dev_from_fwnode(parent); + if (dev) { + fwnode_handle_put(parent); + return dev; + } + } + return NULL; +} + +/** + * __fw_devlink_relax_cycles - Relax and mark dependency cycles. + * @con_handle: Potential consumer device fwnode. + * @sup_handle: Potential supplier's fwnode. + * + * Needs to be called with fwnode_lock and device link lock held. + * + * Check if @sup_handle or any of its ancestors or suppliers direct/indirectly + * depend on @con. This function can detect multiple cyles between @sup_handle + * and @con. When such dependency cycles are found, convert all device links + * created solely by fw_devlink into SYNC_STATE_ONLY device links. Also, mark + * all fwnode links in the cycle with FWLINK_FLAG_CYCLE so that when they are + * converted into a device link in the future, they are created as + * SYNC_STATE_ONLY device links. This is the equivalent of doing + * fw_devlink=permissive just between the devices in the cycle. We need to do + * this because, at this point, fw_devlink can't tell which of these + * dependencies is not a real dependency. + * + * Return true if one or more cycles were found. Otherwise, return false. + */ +static bool __fw_devlink_relax_cycles(struct fwnode_handle *con_handle, + struct fwnode_handle *sup_handle) +{ + struct device *sup_dev = NULL, *par_dev = NULL, *con_dev = NULL; + struct fwnode_link *link; + struct device_link *dev_link; + bool ret = false; + + if (!sup_handle) + return false; + + /* + * We aren't trying to find all cycles. Just a cycle between con and + * sup_handle. + */ + if (sup_handle->flags & FWNODE_FLAG_VISITED) + return false; + + sup_handle->flags |= FWNODE_FLAG_VISITED; + + /* Termination condition. */ + if (sup_handle == con_handle) { + pr_debug("----- cycle: start -----\n"); + ret = true; + goto out; + } + + sup_dev = get_dev_from_fwnode(sup_handle); + con_dev = get_dev_from_fwnode(con_handle); + /* + * If sup_dev is bound to a driver and @con hasn't started binding to a + * driver, sup_dev can't be a consumer of @con. So, no need to check + * further. + */ + if (sup_dev && sup_dev->links.status == DL_DEV_DRIVER_BOUND && + con_dev && con_dev->links.status == DL_DEV_NO_DRIVER) { + ret = false; + goto out; + } + + list_for_each_entry(link, &sup_handle->suppliers, c_hook) { + if (link->flags & FWLINK_FLAG_IGNORE) + continue; + + if (__fw_devlink_relax_cycles(con_handle, link->supplier)) { + __fwnode_link_cycle(link); + ret = true; + } + } + + /* + * Give priority to device parent over fwnode parent to account for any + * quirks in how fwnodes are converted to devices. + */ + if (sup_dev) + par_dev = get_device(sup_dev->parent); + else + par_dev = fwnode_get_next_parent_dev(sup_handle); + + if (par_dev && __fw_devlink_relax_cycles(con_handle, par_dev->fwnode)) { + pr_debug("%pfwf: cycle: child of %pfwf\n", sup_handle, + par_dev->fwnode); + ret = true; + } + + if (!sup_dev) + goto out; + + list_for_each_entry(dev_link, &sup_dev->links.suppliers, c_node) { + /* + * Ignore a SYNC_STATE_ONLY flag only if it wasn't marked as + * such due to a cycle. + */ + if (device_link_flag_is_sync_state_only(dev_link->flags) && + !device_link_test(dev_link, DL_FLAG_CYCLE)) + continue; + + if (__fw_devlink_relax_cycles(con_handle, + dev_link->supplier->fwnode)) { + pr_debug("%pfwf: cycle: depends on %pfwf\n", sup_handle, + dev_link->supplier->fwnode); + fw_devlink_relax_link(dev_link); + dev_link->flags |= DL_FLAG_CYCLE; + ret = true; + } + } + +out: + sup_handle->flags &= ~FWNODE_FLAG_VISITED; + put_device(sup_dev); + put_device(con_dev); + put_device(par_dev); + return ret; +} + +/** + * fw_devlink_create_devlink - Create a device link from a consumer to fwnode + * @con: consumer device for the device link + * @sup_handle: fwnode handle of supplier + * @link: fwnode link that's being converted to a device link + * + * This function will try to create a device link between the consumer device + * @con and the supplier device represented by @sup_handle. + * + * The supplier has to be provided as a fwnode because incorrect cycles in + * fwnode links can sometimes cause the supplier device to never be created. + * This function detects such cases and returns an error if it cannot create a + * device link from the consumer to a missing supplier. + * + * Returns, + * 0 on successfully creating a device link + * -EINVAL if the device link cannot be created as expected + * -EAGAIN if the device link cannot be created right now, but it may be + * possible to do that in the future + */ +static int fw_devlink_create_devlink(struct device *con, + struct fwnode_handle *sup_handle, + struct fwnode_link *link) +{ + struct device *sup_dev; + int ret = 0; + u32 flags; + + if (link->flags & FWLINK_FLAG_IGNORE) + return 0; + + /* + * In some cases, a device P might also be a supplier to its child node + * C. However, this would defer the probe of C until the probe of P + * completes successfully. This is perfectly fine in the device driver + * model. device_add() doesn't guarantee probe completion of the device + * by the time it returns. + * + * However, there are a few drivers that assume C will finish probing + * as soon as it's added and before P finishes probing. So, we provide + * a flag to let fw_devlink know not to delay the probe of C until the + * probe of P completes successfully. + * + * When such a flag is set, we can't create device links where P is the + * supplier of C as that would delay the probe of C. + */ + if (sup_handle->flags & FWNODE_FLAG_NEEDS_CHILD_BOUND_ON_ADD && + fwnode_is_ancestor_of(sup_handle, con->fwnode)) + return -EINVAL; + + /* + * Don't try to optimize by not calling the cycle detection logic under + * certain conditions. There's always some corner case that won't get + * detected. + */ + device_links_write_lock(); + if (__fw_devlink_relax_cycles(link->consumer, sup_handle)) { + __fwnode_link_cycle(link); + pr_debug("----- cycle: end -----\n"); + pr_info("%pfwf: Fixed dependency cycle(s) with %pfwf\n", + link->consumer, sup_handle); + } + device_links_write_unlock(); + + if (con->fwnode == link->consumer) + flags = fw_devlink_get_flags(link->flags); + else + flags = FW_DEVLINK_FLAGS_PERMISSIVE; + + if (sup_handle->flags & FWNODE_FLAG_NOT_DEVICE) + sup_dev = fwnode_get_next_parent_dev(sup_handle); + else + sup_dev = get_dev_from_fwnode(sup_handle); + + if (sup_dev) { + /* + * If it's one of those drivers that don't actually bind to + * their device using driver core, then don't wait on this + * supplier device indefinitely. + */ + if (sup_dev->links.status == DL_DEV_NO_DRIVER && + sup_handle->flags & FWNODE_FLAG_INITIALIZED) { + dev_dbg(con, + "Not linking %pfwf - dev might never probe\n", + sup_handle); + ret = -EINVAL; + goto out; + } + + if (con != sup_dev && !device_link_add(con, sup_dev, flags)) { + dev_err(con, "Failed to create device link (0x%x) with supplier %s for %pfwf\n", + flags, dev_name(sup_dev), link->consumer); + ret = -EINVAL; + } + + goto out; + } + + /* + * Supplier or supplier's ancestor already initialized without a struct + * device or being probed by a driver. + */ + if (fwnode_init_without_drv(sup_handle) || + fwnode_ancestor_init_without_drv(sup_handle)) { + dev_dbg(con, "Not linking %pfwf - might never become dev\n", + sup_handle); + return -EINVAL; + } + + ret = -EAGAIN; +out: + put_device(sup_dev); + return ret; +} + +/** + * __fw_devlink_link_to_consumers - Create device links to consumers of a device + * @dev: Device that needs to be linked to its consumers + * + * This function looks at all the consumer fwnodes of @dev and creates device + * links between the consumer device and @dev (supplier). + * + * If the consumer device has not been added yet, then this function creates a + * SYNC_STATE_ONLY link between @dev (supplier) and the closest ancestor device + * of the consumer fwnode. This is necessary to make sure @dev doesn't get a + * sync_state() callback before the real consumer device gets to be added and + * then probed. + * + * Once device links are created from the real consumer to @dev (supplier), the + * fwnode links are deleted. + */ +static void __fw_devlink_link_to_consumers(struct device *dev) +{ + struct fwnode_handle *fwnode = dev->fwnode; + struct fwnode_link *link, *tmp; + + list_for_each_entry_safe(link, tmp, &fwnode->consumers, s_hook) { + struct device *con_dev; + bool own_link = true; + int ret; + + con_dev = get_dev_from_fwnode(link->consumer); + /* + * If consumer device is not available yet, make a "proxy" + * SYNC_STATE_ONLY link from the consumer's parent device to + * the supplier device. This is necessary to make sure the + * supplier doesn't get a sync_state() callback before the real + * consumer can create a device link to the supplier. + * + * This proxy link step is needed to handle the case where the + * consumer's parent device is added before the supplier. + */ + if (!con_dev) { + con_dev = fwnode_get_next_parent_dev(link->consumer); + /* + * However, if the consumer's parent device is also the + * parent of the supplier, don't create a + * consumer-supplier link from the parent to its child + * device. Such a dependency is impossible. + */ + if (con_dev && + fwnode_is_ancestor_of(con_dev->fwnode, fwnode)) { + put_device(con_dev); + con_dev = NULL; + } else { + own_link = false; + } + } + + if (!con_dev) + continue; + + ret = fw_devlink_create_devlink(con_dev, fwnode, link); + put_device(con_dev); + if (!own_link || ret == -EAGAIN) + continue; + + __fwnode_link_del(link); + } +} + +/** + * __fw_devlink_link_to_suppliers - Create device links to suppliers of a device + * @dev: The consumer device that needs to be linked to its suppliers + * @fwnode: Root of the fwnode tree that is used to create device links + * + * This function looks at all the supplier fwnodes of fwnode tree rooted at + * @fwnode and creates device links between @dev (consumer) and all the + * supplier devices of the entire fwnode tree at @fwnode. + * + * The function creates normal (non-SYNC_STATE_ONLY) device links between @dev + * and the real suppliers of @dev. Once these device links are created, the + * fwnode links are deleted. + * + * In addition, it also looks at all the suppliers of the entire fwnode tree + * because some of the child devices of @dev that have not been added yet + * (because @dev hasn't probed) might already have their suppliers added to + * driver core. So, this function creates SYNC_STATE_ONLY device links between + * @dev (consumer) and these suppliers to make sure they don't execute their + * sync_state() callbacks before these child devices have a chance to create + * their device links. The fwnode links that correspond to the child devices + * aren't delete because they are needed later to create the device links + * between the real consumer and supplier devices. + */ +static void __fw_devlink_link_to_suppliers(struct device *dev, + struct fwnode_handle *fwnode) +{ + bool own_link = (dev->fwnode == fwnode); + struct fwnode_link *link, *tmp; + struct fwnode_handle *child = NULL; + + list_for_each_entry_safe(link, tmp, &fwnode->suppliers, c_hook) { + int ret; + struct fwnode_handle *sup = link->supplier; + + ret = fw_devlink_create_devlink(dev, sup, link); + if (!own_link || ret == -EAGAIN) + continue; + + __fwnode_link_del(link); + } + + /* + * Make "proxy" SYNC_STATE_ONLY device links to represent the needs of + * all the descendants. This proxy link step is needed to handle the + * case where the supplier is added before the consumer's parent device + * (@dev). + */ + while ((child = fwnode_get_next_available_child_node(fwnode, child))) + __fw_devlink_link_to_suppliers(dev, child); +} + +static void fw_devlink_link_device(struct device *dev) +{ + struct fwnode_handle *fwnode = dev->fwnode; + + if (!fw_devlink_flags) + return; + + fw_devlink_parse_fwtree(fwnode); + + guard(mutex)(&fwnode_link_lock); + + __fw_devlink_link_to_consumers(dev); + __fw_devlink_link_to_suppliers(dev, fwnode); +} + +/* 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; + +/* /sys/dev/char */ +static struct kobject *sysfs_dev_char_kobj; + +/* /sys/dev/block */ +static 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) @@ -61,6 +2372,20 @@ static inline int device_is_not_partition(struct device *dev) } #endif +static void device_platform_notify(struct device *dev) +{ + acpi_device_notify(dev); + + software_node_notify(dev); +} + +static void device_platform_notify_remove(struct device *dev) +{ + software_node_notify_remove(dev); + + acpi_device_notify_remove(dev); +} + /** * dev_driver_string - Return a device's driver name, if at all possible * @dev: struct device to get the name of @@ -78,10 +2403,8 @@ const char *dev_driver_string(const struct device *dev) * 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 = ACCESS_ONCE(dev->driver); - return drv ? drv->name : - (dev->bus ? dev->bus->name : - (dev->class ? dev->class->name : "")); + drv = READ_ONCE(dev->driver); + return drv ? drv->name : dev_bus_name(dev); } EXPORT_SYMBOL(dev_driver_string); @@ -97,8 +2420,8 @@ static ssize_t dev_attr_show(struct kobject *kobj, struct attribute *attr, if (dev_attr->show) ret = dev_attr->show(dev, dev_attr, buf); if (ret >= (ssize_t)PAGE_SIZE) { - print_symbol("dev_attr_show: %s returned bad count\n", - (unsigned long)dev_attr->show); + printk("dev_attr_show: %pS returned bad count\n", + dev_attr->show); } return ret; } @@ -127,10 +2450,12 @@ ssize_t device_store_ulong(struct device *dev, 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; + int ret; + unsigned long new; + + ret = kstrtoul(buf, 0, &new); + if (ret) + return ret; *(unsigned long *)(ea->var) = new; /* Always return full write size even if we didn't consume all */ return size; @@ -142,7 +2467,7 @@ ssize_t device_show_ulong(struct device *dev, char *buf) { struct dev_ext_attribute *ea = to_ext_attr(attr); - return snprintf(buf, PAGE_SIZE, "%lx\n", *(unsigned long *)(ea->var)); + return sysfs_emit(buf, "%lx\n", *(unsigned long *)(ea->var)); } EXPORT_SYMBOL_GPL(device_show_ulong); @@ -151,9 +2476,14 @@ ssize_t device_store_int(struct device *dev, 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) + int ret; + long new; + + ret = kstrtol(buf, 0, &new); + if (ret) + return ret; + + if (new > INT_MAX || new < INT_MIN) return -EINVAL; *(int *)(ea->var) = new; /* Always return full write size even if we didn't consume all */ @@ -167,7 +2497,7 @@ ssize_t device_show_int(struct device *dev, { struct dev_ext_attribute *ea = to_ext_attr(attr); - return snprintf(buf, PAGE_SIZE, "%d\n", *(int *)(ea->var)); + return sysfs_emit(buf, "%d\n", *(int *)(ea->var)); } EXPORT_SYMBOL_GPL(device_show_int); @@ -176,7 +2506,7 @@ ssize_t device_store_bool(struct device *dev, struct device_attribute *attr, { struct dev_ext_attribute *ea = to_ext_attr(attr); - if (strtobool(buf, ea->var) < 0) + if (kstrtobool(buf, ea->var) < 0) return -EINVAL; return size; @@ -188,10 +2518,19 @@ ssize_t device_show_bool(struct device *dev, struct device_attribute *attr, { struct dev_ext_attribute *ea = to_ext_attr(attr); - return snprintf(buf, PAGE_SIZE, "%d\n", *(bool *)(ea->var)); + return sysfs_emit(buf, "%d\n", *(bool *)(ea->var)); } EXPORT_SYMBOL_GPL(device_show_bool); +ssize_t device_show_string(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct dev_ext_attribute *ea = to_ext_attr(attr); + + return sysfs_emit(buf, "%s\n", (char *)ea->var); +} +EXPORT_SYMBOL_GPL(device_show_string); + /** * device_release - free device structure. * @kobj: device's kobject. @@ -216,6 +2555,8 @@ static void device_release(struct kobject *kobj) */ devres_release_all(dev); + kfree(dev->dma_range_map); + if (dev->release) dev->release(dev); else if (dev->type && dev->type->release) @@ -223,36 +2564,44 @@ static void device_release(struct kobject *kobj) 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", + WARN(1, KERN_ERR "Device '%s' does not have a release() function, it is broken and must be fixed. See Documentation/core-api/kobject.rst.\n", dev_name(dev)); kfree(p); } -static const void *device_namespace(struct kobject *kobj) +static const void *device_namespace(const struct kobject *kobj) { - struct device *dev = kobj_to_dev(kobj); + const struct device *dev = kobj_to_dev(kobj); const void *ns = NULL; - if (dev->class && dev->class->ns_type) + if (dev->class && dev->class->namespace) ns = dev->class->namespace(dev); return ns; } -static struct kobj_type device_ktype = { +static void device_get_ownership(const struct kobject *kobj, kuid_t *uid, kgid_t *gid) +{ + const struct device *dev = kobj_to_dev(kobj); + + if (dev->class && dev->class->get_ownership) + dev->class->get_ownership(dev, uid, gid); +} + +static const 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) +static int dev_uevent_filter(const struct kobject *kobj) { - struct kobj_type *ktype = get_ktype(kobj); + const struct kobj_type *ktype = get_ktype(kobj); if (ktype == &device_ktype) { - struct device *dev = kobj_to_dev(kobj); + const struct device *dev = kobj_to_dev(kobj); if (dev->bus) return 1; if (dev->class) @@ -261,9 +2610,9 @@ static int dev_uevent_filter(struct kset *kset, struct kobject *kobj) return 0; } -static const char *dev_uevent_name(struct kset *kset, struct kobject *kobj) +static const char *dev_uevent_name(const struct kobject *kobj) { - struct device *dev = kobj_to_dev(kobj); + const struct device *dev = kobj_to_dev(kobj); if (dev->bus) return dev->bus->name; @@ -272,10 +2621,38 @@ static const char *dev_uevent_name(struct kset *kset, struct kobject *kobj) return NULL; } -static int dev_uevent(struct kset *kset, struct kobject *kobj, - struct kobj_uevent_env *env) +/* + * Try filling "DRIVER=<name>" uevent variable for a device. Because this + * function may race with binding and unbinding the device from a driver, + * we need to be careful. Binding is generally safe, at worst we miss the + * fact that the device is already bound to a driver (but the driver + * information that is delivered through uevents is best-effort, it may + * become obsolete as soon as it is generated anyways). Unbinding is more + * risky as driver pointer is transitioning to NULL, so READ_ONCE() should + * be used to make sure we are dealing with the same pointer, and to + * ensure that driver structure is not going to disappear from under us + * we take bus' drivers klist lock. The assumption that only registered + * driver can be bound to a device, and to unregister a driver bus code + * will take the same lock. + */ +static void dev_driver_uevent(const struct device *dev, struct kobj_uevent_env *env) { - struct device *dev = kobj_to_dev(kobj); + struct subsys_private *sp = bus_to_subsys(dev->bus); + + if (sp) { + scoped_guard(spinlock, &sp->klist_drivers.k_lock) { + struct device_driver *drv = READ_ONCE(dev->driver); + if (drv) + add_uevent_var(env, "DRIVER=%s", drv->name); + } + + subsys_put(sp); + } +} + +static int dev_uevent(const struct kobject *kobj, struct kobj_uevent_env *env) +{ + const struct device *dev = kobj_to_dev(kobj); int retval = 0; /* add device node properties if present */ @@ -304,8 +2681,8 @@ static int dev_uevent(struct kset *kset, struct kobject *kobj, 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 "DRIVER=%s" variable if the device is bound to a driver */ + dev_driver_uevent(dev, env); /* Add common DT information about the device */ of_device_uevent(dev, env); @@ -345,14 +2722,14 @@ static const struct kset_uevent_ops device_uevent_ops = { .uevent = dev_uevent, }; -static ssize_t show_uevent(struct device *dev, struct device_attribute *attr, +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 len = 0; int retval; /* search the kset, the device belongs to */ @@ -368,7 +2745,7 @@ static ssize_t show_uevent(struct device *dev, struct device_attribute *attr, /* respect filter */ if (kset->uevent_ops && kset->uevent_ops->filter) - if (!kset->uevent_ops->filter(kset, &dev->kobj)) + if (!kset->uevent_ops->filter(&dev->kobj)) goto out; env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL); @@ -376,170 +2753,159 @@ static ssize_t show_uevent(struct device *dev, struct device_attribute *attr, return -ENOMEM; /* let the kset specific function add its keys */ - retval = kset->uevent_ops->uevent(kset, &dev->kobj, env); + retval = kset->uevent_ops->uevent(&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]); + len += sysfs_emit_at(buf, len, "%s\n", env->envp[i]); out: kfree(env); - return count; + return len; } -static ssize_t store_uevent(struct device *dev, struct device_attribute *attr, +static ssize_t uevent_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { - enum kobject_action action; + int rc; + + rc = kobject_synth_uevent(&dev->kobj, buf, count); + + if (rc) { + dev_err(dev, "uevent: failed to send synthetic uevent: %d\n", rc); + return rc; + } - if (kobject_action_type(buf, count, &action) == 0) - kobject_uevent(&dev->kobj, action); - else - dev_err(dev, "uevent: unknown action-string\n"); return count; } +static DEVICE_ATTR_RW(uevent); -static struct device_attribute uevent_attr = - __ATTR(uevent, S_IRUGO | S_IWUSR, show_uevent, store_uevent); - -static ssize_t show_online(struct device *dev, struct device_attribute *attr, +static ssize_t online_show(struct device *dev, struct device_attribute *attr, char *buf) { bool val; - lock_device_hotplug(); + device_lock(dev); val = !dev->offline; - unlock_device_hotplug(); - return sprintf(buf, "%u\n", val); + device_unlock(dev); + return sysfs_emit(buf, "%u\n", val); } -static ssize_t store_online(struct device *dev, struct device_attribute *attr, +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); + ret = kstrtobool(buf, &val); if (ret < 0) return ret; - lock_device_hotplug(); + 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); -static struct device_attribute online_attr = - __ATTR(online, S_IRUGO | S_IWUSR, show_online, store_online); - -static int device_add_attributes(struct device *dev, - struct device_attribute *attrs) +static ssize_t removable_show(struct device *dev, struct device_attribute *attr, + char *buf) { - int error = 0; - int i; + const char *loc; - if (attrs) { - for (i = 0; attr_name(attrs[i]); i++) { - error = device_create_file(dev, &attrs[i]); - if (error) - break; - } - if (error) - while (--i >= 0) - device_remove_file(dev, &attrs[i]); + switch (dev->removable) { + case DEVICE_REMOVABLE: + loc = "removable"; + break; + case DEVICE_FIXED: + loc = "fixed"; + break; + default: + loc = "unknown"; } - return error; + return sysfs_emit(buf, "%s\n", loc); } +static DEVICE_ATTR_RO(removable); -static void device_remove_attributes(struct device *dev, - struct device_attribute *attrs) +int device_add_groups(struct device *dev, const struct attribute_group **groups) { - int i; - - if (attrs) - for (i = 0; attr_name(attrs[i]); i++) - device_remove_file(dev, &attrs[i]); + return sysfs_create_groups(&dev->kobj, groups); } +EXPORT_SYMBOL_GPL(device_add_groups); -static int device_add_bin_attributes(struct device *dev, - struct bin_attribute *attrs) +void device_remove_groups(struct device *dev, + const struct attribute_group **groups) { - int error = 0; - int i; - - if (attrs) { - for (i = 0; attr_name(attrs[i]); i++) { - error = device_create_bin_file(dev, &attrs[i]); - if (error) - break; - } - if (error) - while (--i >= 0) - device_remove_bin_file(dev, &attrs[i]); - } - return error; + sysfs_remove_groups(&dev->kobj, groups); } +EXPORT_SYMBOL_GPL(device_remove_groups); -static void device_remove_bin_attributes(struct device *dev, - struct bin_attribute *attrs) +union device_attr_group_devres { + const struct attribute_group *group; + const struct attribute_group **groups; +}; + +static void devm_attr_group_remove(struct device *dev, void *res) { - int i; + union device_attr_group_devres *devres = res; + const struct attribute_group *group = devres->group; - if (attrs) - for (i = 0; attr_name(attrs[i]); i++) - device_remove_bin_file(dev, &attrs[i]); + dev_dbg(dev, "%s: removing group %p\n", __func__, group); + sysfs_remove_group(&dev->kobj, group); } -static int device_add_groups(struct device *dev, - const struct attribute_group **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) { - int error = 0; - int i; + union device_attr_group_devres *devres; + int error; - if (groups) { - for (i = 0; groups[i]; i++) { - error = sysfs_create_group(&dev->kobj, groups[i]); - if (error) { - while (--i >= 0) - sysfs_remove_group(&dev->kobj, - groups[i]); - break; - } - } - } - return error; -} + devres = devres_alloc(devm_attr_group_remove, + sizeof(*devres), GFP_KERNEL); + if (!devres) + return -ENOMEM; -static void device_remove_groups(struct device *dev, - const struct attribute_group **groups) -{ - int i; + error = sysfs_create_group(&dev->kobj, grp); + if (error) { + devres_free(devres); + return error; + } - if (groups) - for (i = 0; groups[i]; i++) - sysfs_remove_group(&dev->kobj, groups[i]); + devres->group = grp; + devres_add(dev, devres); + return 0; } +EXPORT_SYMBOL_GPL(devm_device_add_group); static int device_add_attrs(struct device *dev) { - struct class *class = dev->class; + const struct class *class = dev->class; const struct device_type *type = dev->type; int error; if (class) { - error = device_add_attributes(dev, class->dev_attrs); + error = device_add_groups(dev, class->dev_groups); if (error) return error; - error = device_add_bin_attributes(dev, class->dev_bin_attrs); - if (error) - goto err_remove_class_attrs; } if (type) { error = device_add_groups(dev, type->groups); if (error) - goto err_remove_class_bin_attrs; + goto err_remove_class_groups; } error = device_add_groups(dev, dev->groups); @@ -547,57 +2913,129 @@ static int device_add_attrs(struct device *dev) goto err_remove_type_groups; if (device_supports_offline(dev) && !dev->offline_disabled) { - error = device_create_file(dev, &online_attr); + error = device_create_file(dev, &dev_attr_online); + if (error) + goto err_remove_dev_groups; + } + + if (fw_devlink_flags && !fw_devlink_is_permissive() && dev->fwnode) { + error = device_create_file(dev, &dev_attr_waiting_for_supplier); + if (error) + goto err_remove_dev_online; + } + + if (dev_removable_is_valid(dev)) { + error = device_create_file(dev, &dev_attr_removable); if (error) - goto err_remove_type_groups; + goto err_remove_dev_waiting_for_supplier; + } + + if (dev_add_physical_location(dev)) { + error = device_add_group(dev, + &dev_attr_physical_location_group); + if (error) + goto err_remove_dev_removable; } return 0; + err_remove_dev_removable: + device_remove_file(dev, &dev_attr_removable); + err_remove_dev_waiting_for_supplier: + device_remove_file(dev, &dev_attr_waiting_for_supplier); + err_remove_dev_online: + device_remove_file(dev, &dev_attr_online); + 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_bin_attrs: + err_remove_class_groups: if (class) - device_remove_bin_attributes(dev, class->dev_bin_attrs); - err_remove_class_attrs: - if (class) - device_remove_attributes(dev, class->dev_attrs); + device_remove_groups(dev, class->dev_groups); return error; } static void device_remove_attrs(struct device *dev) { - struct class *class = dev->class; + const struct class *class = dev->class; const struct device_type *type = dev->type; - device_remove_file(dev, &online_attr); + if (dev->physical_location) { + device_remove_group(dev, &dev_attr_physical_location_group); + kfree(dev->physical_location); + } + + device_remove_file(dev, &dev_attr_removable); + device_remove_file(dev, &dev_attr_waiting_for_supplier); + 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_attributes(dev, class->dev_attrs); - device_remove_bin_attributes(dev, class->dev_bin_attrs); - } + if (class) + device_remove_groups(dev, class->dev_groups); } - -static ssize_t show_dev(struct device *dev, struct device_attribute *attr, +static ssize_t dev_show(struct device *dev, struct device_attribute *attr, char *buf) { return print_dev_t(buf, dev->devt); } - -static struct device_attribute devt_attr = - __ATTR(dev, S_IRUGO, show_dev, NULL); +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. @@ -619,6 +3057,7 @@ int device_create_file(struct device *dev, return error; } +EXPORT_SYMBOL_GPL(device_create_file); /** * device_remove_file - remove sysfs attribute file. @@ -631,6 +3070,24 @@ void device_remove_file(struct device *dev, 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. @@ -660,39 +3117,6 @@ void device_remove_bin_file(struct device *dev, } EXPORT_SYMBOL_GPL(device_remove_bin_file); -/** - * device_schedule_callback_owner - helper to schedule a callback for a device - * @dev: device. - * @func: callback function to invoke later. - * @owner: module owning the callback routine - * - * Attribute methods must not unregister themselves or their parent device - * (which would amount to the same thing). Attempts to do so will deadlock, - * since unregistration is mutually exclusive with driver callbacks. - * - * Instead methods can call this routine, which will attempt to allocate - * and schedule a workqueue request to call back @func with @dev as its - * argument in the workqueue's process context. @dev will be pinned until - * @func returns. - * - * This routine is usually called via the inline device_schedule_callback(), - * which automatically sets @owner to THIS_MODULE. - * - * Returns 0 if the request was submitted, -ENOMEM if storage could not - * be allocated, -ENODEV if a reference to @owner isn't available. - * - * NOTE: This routine won't work if CONFIG_SYSFS isn't set! It uses an - * underlying sysfs routine (since it is intended for use by attribute - * methods), and if sysfs isn't available you'll get nothing but -ENOSYS. - */ -int device_schedule_callback_owner(struct device *dev, - void (*func)(struct device *), struct module *owner) -{ - return sysfs_schedule_callback(&dev->kobj, - (void (*)(void *)) func, dev, owner); -} -EXPORT_SYMBOL_GPL(device_schedule_callback_owner); - static void klist_children_get(struct klist_node *n) { struct device_private *p = to_device_private_parent(n); @@ -739,10 +3163,21 @@ void device_initialize(struct device *dev) spin_lock_init(&dev->devres_lock); INIT_LIST_HEAD(&dev->devres_head); device_pm_init(dev); - set_dev_node(dev, -1); + set_dev_node(dev, NUMA_NO_NODE); + INIT_LIST_HEAD(&dev->links.consumers); + INIT_LIST_HEAD(&dev->links.suppliers); + INIT_LIST_HEAD(&dev->links.defer_sync); + dev->links.status = DL_DEV_NO_DRIVER; +#if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \ + defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \ + defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL) + dev->dma_coherent = dma_default_coherent; +#endif + swiotlb_dev_init(dev); } +EXPORT_SYMBOL_GPL(device_initialize); -struct kobject *virtual_device_parent(struct device *dev) +struct kobject *virtual_device_parent(void) { static struct kobject *virtual_dir = NULL; @@ -755,7 +3190,7 @@ struct kobject *virtual_device_parent(struct device *dev) struct class_dir { struct kobject kobj; - struct class *class; + const struct class *class; }; #define to_class_dir(obj) container_of(obj, struct class_dir, kobj) @@ -767,130 +3202,240 @@ static void class_dir_release(struct kobject *kobj) } static const -struct kobj_ns_type_operations *class_dir_child_ns_type(struct kobject *kobj) +struct kobj_ns_type_operations *class_dir_child_ns_type(const struct kobject *kobj) { - struct class_dir *dir = to_class_dir(kobj); + const struct class_dir *dir = to_class_dir(kobj); return dir->class->ns_type; } -static struct kobj_type class_dir_ktype = { +static const 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) +static struct kobject *class_dir_create_and_add(struct subsys_private *sp, + struct kobject *parent_kobj) { struct class_dir *dir; int retval; dir = kzalloc(sizeof(*dir), GFP_KERNEL); if (!dir) - return NULL; + return ERR_PTR(-ENOMEM); - dir->class = class; + dir->class = sp->class; kobject_init(&dir->kobj, &class_dir_ktype); - dir->kobj.kset = &class->p->glue_dirs; + dir->kobj.kset = &sp->glue_dirs; - retval = kobject_add(&dir->kobj, parent_kobj, "%s", class->name); + retval = kobject_add(&dir->kobj, parent_kobj, "%s", sp->class->name); if (retval < 0) { kobject_put(&dir->kobj); - return NULL; + 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) { - static DEFINE_MUTEX(gdp_mutex); - struct kobject *kobj = NULL; + struct subsys_private *sp = class_to_subsys(dev->class); + struct kobject *kobj = NULL; + + if (sp) { 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) + parent_kobj = virtual_device_parent(); + else if (parent->class && !dev->class->ns_type) { + subsys_put(sp); return &parent->kobj; - else + } 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) + spin_lock(&sp->glue_dirs.list_lock); + list_for_each_entry(k, &sp->glue_dirs.list, entry) if (k->parent == parent_kobj) { kobj = kobject_get(k); break; } - spin_unlock(&dev->class->p->glue_dirs.list_lock); + spin_unlock(&sp->glue_dirs.list_lock); if (kobj) { mutex_unlock(&gdp_mutex); + subsys_put(sp); return kobj; } /* or create a new class-directory at the parent device */ - k = class_dir_create_and_add(dev->class, parent_kobj); + k = class_dir_create_and_add(sp, parent_kobj); /* do not emit an uevent for this simple "glue" directory */ mutex_unlock(&gdp_mutex); + subsys_put(sp); 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 && dev->bus) { + struct device *dev_root = bus_get_dev_root(dev->bus); + + if (dev_root) { + kobj = &dev_root->kobj; + put_device(dev_root); + return kobj; + } + } if (parent) return &parent->kobj; return NULL; } +static inline bool live_in_glue_dir(struct kobject *kobj, + struct device *dev) +{ + struct subsys_private *sp; + bool retval; + + if (!kobj || !dev->class) + return false; + + sp = class_to_subsys(dev->class); + if (!sp) + return false; + + if (kobj->kset == &sp->glue_dirs) + retval = true; + else + retval = false; + + subsys_put(sp); + return retval; +} + +static inline struct kobject *get_glue_dir(struct device *dev) +{ + return dev->kobj.parent; +} + +/** + * kobject_has_children - Returns whether a kobject has children. + * @kobj: the object to test + * + * This will return whether a kobject has other kobjects as children. + * + * It does NOT account for the presence of attribute files, only sub + * directories. It also assumes there is no concurrent addition or + * removal of such children, and thus relies on external locking. + */ +static inline bool kobject_has_children(struct kobject *kobj) +{ + WARN_ON_ONCE(kref_read(&kobj->kref) == 0); + + return kobj->sd && kobj->sd->dir.subdirs; +} + +/* + * 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 (!glue_dir || !dev->class || - glue_dir->kset != &dev->class->p->glue_dirs) + 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); -} - -static void cleanup_device_parent(struct device *dev) -{ - cleanup_glue_dir(dev, dev->kobj.parent); + mutex_unlock(&gdp_mutex); } static int device_add_class_symlinks(struct device *dev) { + struct device_node *of_node = dev_of_node(dev); + struct subsys_private *sp; int error; - if (!dev->class) + 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 */ + } + + sp = class_to_subsys(dev->class); + if (!sp) return 0; - error = sysfs_create_link(&dev->kobj, - &dev->class->p->subsys.kobj, - "subsystem"); + error = sysfs_create_link(&dev->kobj, &sp->subsys.kobj, "subsystem"); if (error) - goto out; + goto out_devnode; if (dev->parent && device_is_not_partition(dev)) { error = sysfs_create_link(&dev->kobj, &dev->parent->kobj, @@ -899,42 +3444,38 @@ static int device_add_class_symlinks(struct device *dev) 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)); + error = sysfs_create_link(&sp->subsys.kobj, &dev->kobj, dev_name(dev)); if (error) goto out_device; - - return 0; + goto exit; out_device: sysfs_remove_link(&dev->kobj, "device"); - out_subsys: sysfs_remove_link(&dev->kobj, "subsystem"); -out: +out_devnode: + sysfs_remove_link(&dev->kobj, "of_node"); +exit: + subsys_put(sp); return error; } static void device_remove_class_symlinks(struct device *dev) { - if (!dev->class) + struct subsys_private *sp = class_to_subsys(dev->class); + + if (dev_of_node(dev)) + sysfs_remove_link(&dev->kobj, "of_node"); + + if (!sp) 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)); + sysfs_delete_link(&sp->subsys.kobj, &dev->kobj, dev_name(dev)); + subsys_put(sp); } /** @@ -954,27 +3495,13 @@ int dev_set_name(struct device *dev, const char *fmt, ...) } 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. - */ +/* select a /sys/dev/ directory for the device */ static struct kobject *device_to_dev_kobj(struct device *dev) { - struct kobject *kobj; - - if (dev->class) - kobj = dev->class->dev_kobj; + if (is_blockdev(dev)) + return sysfs_dev_block_kobj; else - kobj = sysfs_dev_char_kobj; - - return kobj; + return sysfs_dev_char_kobj; } static int device_create_sys_dev_entry(struct device *dev) @@ -1002,7 +3529,7 @@ static void device_remove_sys_dev_entry(struct device *dev) } } -int device_private_init(struct device *dev) +static int device_private_init(struct device *dev) { dev->p = kzalloc(sizeof(*dev->p), GFP_KERNEL); if (!dev->p) @@ -1035,13 +3562,20 @@ int device_private_init(struct device *dev) * 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. + * + * Rule of thumb is: if device_add() succeeds, you should call + * device_del() when you want to get rid of it. If device_add() has + * *not* succeeded, use *only* put_device() to drop the reference + * count. */ int device_add(struct device *dev) { - struct device *parent = NULL; + struct subsys_private *sp; + 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) @@ -1059,56 +3593,50 @@ int device_add(struct device *dev) * the name, and force the use of dev_name() */ if (dev->init_name) { - dev_set_name(dev, "%s", dev->init_name); + error = dev_set_name(dev, "%s", dev->init_name); dev->init_name = NULL; } + if (dev_name(dev)) + error = 0; /* 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)) { + else if (dev->bus && dev->bus->dev_name) + error = dev_set_name(dev, "%s%u", dev->bus->dev_name, dev->id); + else error = -EINVAL; + if (error) 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) + 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) + if (error) { + glue_dir = kobj; goto Error; + } /* notify platform of device entry */ - if (platform_notify) - platform_notify(dev); + device_platform_notify(dev); - error = device_create_file(dev, &uevent_attr); + error = device_create_file(dev, &dev_attr_uevent); if (error) goto attrError; - if (MAJOR(dev->devt)) { - error = device_create_file(dev, &devt_attr); - if (error) - goto ueventattrError; - - error = device_create_sys_dev_entry(dev); - if (error) - goto devtattrError; - - devtmpfs_create_node(dev); - } - error = device_add_class_symlinks(dev); if (error) goto SymlinkError; @@ -1123,63 +3651,101 @@ int device_add(struct device *dev) 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); - + bus_notify(dev, BUS_NOTIFY_ADD_DEVICE); kobject_uevent(&dev->kobj, KOBJ_ADD); + + /* + * Check if any of the other devices (consumers) have been waiting for + * this device (supplier) to be added so that they can create a device + * link to it. + * + * This needs to happen after device_pm_add() because device_link_add() + * requires the supplier be registered before it's called. + * + * But this also needs to happen before bus_probe_device() to make sure + * waiting consumers can link to it before the driver is bound to the + * device and the driver sync_state callback is called for this device. + */ + if (dev->fwnode && !dev->fwnode->dev) { + dev->fwnode->dev = dev; + fw_devlink_link_device(dev); + } + bus_probe_device(dev); + + /* + * If all driver registration is done and a newly added device doesn't + * match with any driver, don't block its consumers from probing in + * case the consumer device is able to operate without this supplier. + */ + if (dev->fwnode && fw_devlink_drv_reg_done && !dev->can_match) + fw_devlink_unblock_consumers(dev); + if (parent) klist_add_tail(&dev->p->knode_parent, &parent->p->klist_children); - if (dev->class) { - mutex_lock(&dev->class->p->mutex); + sp = class_to_subsys(dev->class); + if (sp) { + mutex_lock(&sp->mutex); /* tie the class to the device */ - klist_add_tail(&dev->knode_class, - &dev->class->p->klist_devices); + klist_add_tail(&dev->p->knode_class, &sp->klist_devices); /* notify any interfaces that the device is here */ - list_for_each_entry(class_intf, - &dev->class->p->interfaces, node) + list_for_each_entry(class_intf, &sp->interfaces, node) if (class_intf->add_dev) - class_intf->add_dev(dev, class_intf); - mutex_unlock(&dev->class->p->mutex); + class_intf->add_dev(dev); + mutex_unlock(&sp->mutex); + subsys_put(sp); } 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: + device_set_driver(dev, NULL); bus_remove_device(dev); BusError: device_remove_attrs(dev); AttrsError: device_remove_class_symlinks(dev); SymlinkError: - if (MAJOR(dev->devt)) - devtmpfs_delete_node(dev); - if (MAJOR(dev->devt)) - device_remove_sys_dev_entry(dev); - devtattrError: - if (MAJOR(dev->devt)) - device_remove_file(dev, &devt_attr); - ueventattrError: - device_remove_file(dev, &uevent_attr); + device_remove_file(dev, &dev_attr_uevent); attrError: + device_platform_notify_remove(dev); kobject_uevent(&dev->kobj, KOBJ_REMOVE); + glue_dir = get_glue_dir(dev); kobject_del(&dev->kobj); Error: - cleanup_device_parent(dev); - if (parent) - put_device(parent); + 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. @@ -1204,6 +3770,7 @@ 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. @@ -1217,6 +3784,7 @@ 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. @@ -1228,6 +3796,25 @@ void put_device(struct device *dev) 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. + */ + device_lock_assert(dev); + + if (dev->p->dead) + return false; + dev->p->dead = true; + return true; +} +EXPORT_SYMBOL_GPL(kill_device); /** * device_del - delete device from system. @@ -1244,52 +3831,76 @@ void put_device(struct device *dev) */ void device_del(struct device *dev) { + struct subsys_private *sp; struct device *parent = dev->parent; + struct kobject *glue_dir = NULL; struct class_interface *class_intf; + unsigned int noio_flag; + + device_lock(dev); + kill_device(dev); + device_unlock(dev); + + if (dev->fwnode && dev->fwnode->dev == dev) + dev->fwnode->dev = NULL; /* 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); + noio_flag = memalloc_noio_save(); + bus_notify(dev, BUS_NOTIFY_DEL_DEVICE); + 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, &devt_attr); + device_remove_file(dev, &dev_attr_dev); } - if (dev->class) { + + sp = class_to_subsys(dev->class); + if (sp) { device_remove_class_symlinks(dev); - mutex_lock(&dev->class->p->mutex); + mutex_lock(&sp->mutex); /* notify any interfaces that the device is now gone */ - list_for_each_entry(class_intf, - &dev->class->p->interfaces, node) + list_for_each_entry(class_intf, &sp->interfaces, node) if (class_intf->remove_dev) - class_intf->remove_dev(dev, class_intf); + class_intf->remove_dev(dev); /* remove the device from the class list */ - klist_del(&dev->knode_class); - mutex_unlock(&dev->class->p->mutex); + klist_del(&dev->p->knode_class); + mutex_unlock(&sp->mutex); + subsys_put(sp); } - device_remove_file(dev, &uevent_attr); + 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_platform_notify_remove(dev); + device_links_purge(dev); - /* Notify the platform of the removal, in case they - * need to do anything... + /* + * If a device does not have a driver attached, we need to clean + * up any managed resources. We do this in device_release(), but + * it's never called (and we leak the device) if a managed + * resource holds a reference to the device. So release all + * managed resources here, like we do in driver_detach(). We + * still need to do so again in device_release() in case someone + * adds a new resource after this point, though. */ - if (platform_notify_remove) - platform_notify_remove(dev); + devres_release_all(dev); + + bus_notify(dev, BUS_NOTIFY_REMOVED_DEVICE); kobject_uevent(&dev->kobj, KOBJ_REMOVE); - cleanup_device_parent(dev); + glue_dir = get_glue_dir(dev); kobject_del(&dev->kobj); + cleanup_glue_dir(dev, glue_dir); + memalloc_noio_restore(noio_flag); put_device(parent); } +EXPORT_SYMBOL_GPL(device_del); /** * device_unregister - unregister device from system. @@ -1308,6 +3919,20 @@ void device_unregister(struct device *dev) 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) { @@ -1335,7 +3960,7 @@ static struct device *next_device(struct klist_iter *i) * a name. This memory is returned in tmp and needs to be * freed by the caller. */ -const char *device_get_devnode(struct device *dev, +const char *device_get_devnode(const struct device *dev, umode_t *mode, kuid_t *uid, kgid_t *gid, const char **tmp) { @@ -1360,19 +3985,17 @@ const char *device_get_devnode(struct device *dev, return dev_name(dev); /* replace '!' in the name with '/' */ - *tmp = kstrdup(dev_name(dev), GFP_KERNEL); - if (!*tmp) + s = kstrdup_and_replace(dev_name(dev), '!', '/', GFP_KERNEL); + if (!s) return NULL; - while ((s = strchr(*tmp, '!'))) - s[0] = '/'; - return *tmp; + 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. + * @fn: function to be called for each device. * * Iterate over @parent's child devices, and call @fn for each, * passing it @data. @@ -1381,27 +4004,93 @@ const char *device_get_devnode(struct device *dev, * 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)) + device_iter_t fn) +{ + struct klist_iter i; + struct device *child; + int error = 0; + + if (!parent || !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. + * @data: data for the callback. + * @fn: function to be called for each device. + * + * 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, + device_iter_t fn) { struct klist_iter i; struct device *child; int error = 0; - if (!parent->p) + if (!parent || !parent->p) return 0; klist_iter_init(&parent->p->klist_children, &i); - while ((child = next_device(&i)) && !error) + 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_for_each_child_reverse_from - device child iterator in reversed order. + * @parent: parent struct device. + * @from: optional starting point in child list + * @data: data for the callback. + * @fn: function to be called for each device. + * + * Iterate over @parent's child devices, starting at @from, and call @fn + * for each, passing it @data. This helper is identical to + * device_for_each_child_reverse() when @from is NULL. + * + * @fn is checked each iteration. If it returns anything other than 0, + * iteration stop and that value is returned to the caller of + * device_for_each_child_reverse_from(); + */ +int device_for_each_child_reverse_from(struct device *parent, + struct device *from, void *data, + device_iter_t fn) +{ + struct klist_iter i; + struct device *child; + int error = 0; + + if (!parent || !parent->p) + return 0; + + klist_iter_init_node(&parent->p->klist_children, &i, + (from ? &from->p->knode_parent : NULL)); + while ((child = prev_device(&i)) && !error) + error = fn(child, data); + klist_iter_exit(&i); + return error; +} +EXPORT_SYMBOL_GPL(device_for_each_child_reverse_from); /** * 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 + * @match: Callback function to check device * * 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 @@ -1414,22 +4103,26 @@ int device_for_each_child(struct device *parent, void *data, * * 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 device *device_find_child(struct device *parent, const void *data, + device_match_t match) { struct klist_iter i; struct device *child; - if (!parent) + if (!parent || !parent->p) return NULL; klist_iter_init(&parent->p->klist_children, &i); - while ((child = next_device(&i))) - if (match(child, data) && get_device(child)) + 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) { @@ -1445,9 +4138,14 @@ int __init devices_init(void) sysfs_dev_char_kobj = kobject_create_and_add("char", dev_kobj); if (!sysfs_dev_char_kobj) goto char_kobj_err; + device_link_wq = alloc_workqueue("device_link_wq", WQ_PERCPU, 0); + if (!device_link_wq) + goto wq_err; return 0; + wq_err: + kobject_put(sysfs_dev_char_kobj); char_kobj_err: kobject_put(sysfs_dev_block_kobj); block_kobj_err: @@ -1457,33 +4155,6 @@ int __init devices_init(void) return -ENOMEM; } -EXPORT_SYMBOL_GPL(device_for_each_child); -EXPORT_SYMBOL_GPL(device_find_child); - -EXPORT_SYMBOL_GPL(device_initialize); -EXPORT_SYMBOL_GPL(device_add); -EXPORT_SYMBOL_GPL(device_register); - -EXPORT_SYMBOL_GPL(device_del); -EXPORT_SYMBOL_GPL(device_unregister); -EXPORT_SYMBOL_GPL(get_device); -EXPORT_SYMBOL_GPL(put_device); - -EXPORT_SYMBOL_GPL(device_create_file); -EXPORT_SYMBOL_GPL(device_remove_file); - -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); -} - static int device_check_offline(struct device *dev, void *not_used) { int ret; @@ -1667,39 +4338,16 @@ static void device_create_release(struct device *dev) kfree(dev); } -/** - * 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) +static __printf(6, 0) struct device * +device_create_groups_vargs(const 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)) + if (IS_ERR_OR_NULL(class)) goto error; dev = kzalloc(sizeof(*dev), GFP_KERNEL); @@ -1708,9 +4356,11 @@ struct device *device_create_vargs(struct class *class, struct device *parent, 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); @@ -1718,7 +4368,7 @@ struct device *device_create_vargs(struct class *class, struct device *parent, if (retval) goto error; - retval = device_register(dev); + retval = device_add(dev); if (retval) goto error; @@ -1728,7 +4378,6 @@ error: put_device(dev); return ERR_PTR(retval); } -EXPORT_SYMBOL_GPL(device_create_vargs); /** * device_create - creates a device and registers it with sysfs @@ -1750,29 +4399,61 @@ EXPORT_SYMBOL_GPL(device_create_vargs); * 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, +struct device *device_create(const 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); + dev = device_create_groups_vargs(class, parent, devt, drvdata, NULL, + fmt, vargs); va_end(vargs); return dev; } EXPORT_SYMBOL_GPL(device_create); -static int __match_devt(struct device *dev, const void *data) +/** + * 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. + */ +struct device *device_create_with_groups(const struct class *class, + struct device *parent, dev_t devt, + void *drvdata, + const struct attribute_group **groups, + const char *fmt, ...) { - const dev_t *devt = data; + va_list vargs; + struct device *dev; - return dev->devt == *devt; + 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); /** * device_destroy - removes a device that was created with device_create() @@ -1782,11 +4463,11 @@ static int __match_devt(struct device *dev, const void *data) * 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) +void device_destroy(const struct class *class, dev_t devt) { struct device *dev; - dev = class_find_device(class, NULL, &devt, __match_devt); + dev = class_find_device_by_devt(class, devt); if (dev) { put_device(dev); device_unregister(dev); @@ -1804,9 +4485,12 @@ EXPORT_SYMBOL_GPL(device_destroy); * 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: + * Note: given that some subsystems (networking and infiniband) use this + * function, with no immediate plans for this to change, we cannot assume or + * require that this function not be called at all. + * + * However, if you're writing new code, do not call this function. 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 @@ -1820,13 +4504,6 @@ EXPORT_SYMBOL_GPL(device_destroy); * 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 @@ -1835,15 +4512,17 @@ EXPORT_SYMBOL_GPL(device_destroy); */ int device_rename(struct device *dev, const char *new_name) { + struct subsys_private *sp = NULL; + struct kobject *kobj = &dev->kobj; char *old_device_name = NULL; int error; + bool is_link_renamed = false; dev = get_device(dev); if (!dev) return -EINVAL; - pr_debug("device: '%s': %s: renaming to '%s'\n", dev_name(dev), - __func__, new_name); + dev_dbg(dev, "renaming to %s\n", new_name); old_device_name = kstrdup(dev_name(dev), GFP_KERNEL); if (!old_device_name) { @@ -1852,17 +4531,28 @@ int device_rename(struct device *dev, const char *new_name) } if (dev->class) { - error = sysfs_rename_link(&dev->class->p->subsys.kobj, - &dev->kobj, old_device_name, new_name); + sp = class_to_subsys(dev->class); + + if (!sp) { + error = -EINVAL; + goto out; + } + + error = sysfs_rename_link_ns(&sp->subsys.kobj, kobj, old_device_name, + new_name, kobject_namespace(kobj)); if (error) goto out; - } - error = kobject_rename(&dev->kobj, new_name); - if (error) - goto out; + is_link_renamed = true; + } + error = kobject_rename(kobj, new_name); out: + if (error && is_link_renamed) + sysfs_rename_link_ns(&sp->subsys.kobj, kobj, new_name, + old_device_name, kobject_namespace(kobj)); + subsys_put(sp); + put_device(dev); kfree(old_device_name); @@ -1888,7 +4578,7 @@ static int device_move_class_links(struct device *dev, /** * 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 by NULL) + * @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, @@ -1905,6 +4595,11 @@ int device_move(struct device *dev, struct device *new_parent, 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>"); @@ -1949,12 +4644,15 @@ int device_move(struct device *dev, struct device *new_parent, 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; } @@ -1966,12 +4664,136 @@ out: } EXPORT_SYMBOL_GPL(device_move); +static int device_attrs_change_owner(struct device *dev, kuid_t kuid, + kgid_t kgid) +{ + struct kobject *kobj = &dev->kobj; + const struct class *class = dev->class; + const struct device_type *type = dev->type; + int error; + + if (class) { + /* + * Change the device groups of the device class for @dev to + * @kuid/@kgid. + */ + error = sysfs_groups_change_owner(kobj, class->dev_groups, kuid, + kgid); + if (error) + return error; + } + + if (type) { + /* + * Change the device groups of the device type for @dev to + * @kuid/@kgid. + */ + error = sysfs_groups_change_owner(kobj, type->groups, kuid, + kgid); + if (error) + return error; + } + + /* Change the device groups of @dev to @kuid/@kgid. */ + error = sysfs_groups_change_owner(kobj, dev->groups, kuid, kgid); + if (error) + return error; + + if (device_supports_offline(dev) && !dev->offline_disabled) { + /* Change online device attributes of @dev to @kuid/@kgid. */ + error = sysfs_file_change_owner(kobj, dev_attr_online.attr.name, + kuid, kgid); + if (error) + return error; + } + + return 0; +} + +/** + * device_change_owner - change the owner of an existing device. + * @dev: device. + * @kuid: new owner's kuid + * @kgid: new owner's kgid + * + * This changes the owner of @dev and its corresponding sysfs entries to + * @kuid/@kgid. This function closely mirrors how @dev was added via driver + * core. + * + * Returns 0 on success or error code on failure. + */ +int device_change_owner(struct device *dev, kuid_t kuid, kgid_t kgid) +{ + int error; + struct kobject *kobj = &dev->kobj; + struct subsys_private *sp; + + dev = get_device(dev); + if (!dev) + return -EINVAL; + + /* + * Change the kobject and the default attributes and groups of the + * ktype associated with it to @kuid/@kgid. + */ + error = sysfs_change_owner(kobj, kuid, kgid); + if (error) + goto out; + + /* + * Change the uevent file for @dev to the new owner. The uevent file + * was created in a separate step when @dev got added and we mirror + * that step here. + */ + error = sysfs_file_change_owner(kobj, dev_attr_uevent.attr.name, kuid, + kgid); + if (error) + goto out; + + /* + * Change the device groups, the device groups associated with the + * device class, and the groups associated with the device type of @dev + * to @kuid/@kgid. + */ + error = device_attrs_change_owner(dev, kuid, kgid); + if (error) + goto out; + + error = dpm_sysfs_change_owner(dev, kuid, kgid); + if (error) + goto out; + + /* + * Change the owner of the symlink located in the class directory of + * the device class associated with @dev which points to the actual + * directory entry for @dev to @kuid/@kgid. This ensures that the + * symlink shows the same permissions as its target. + */ + sp = class_to_subsys(dev->class); + if (!sp) { + error = -EINVAL; + goto out; + } + error = sysfs_link_change_owner(&sp->subsys.kobj, &dev->kobj, dev_name(dev), kuid, kgid); + subsys_put(sp); + +out: + put_device(dev); + return error; +} +EXPORT_SYMBOL_GPL(device_change_owner); + /** * device_shutdown - call ->shutdown() on each device to shutdown. */ void device_shutdown(void) { - struct device *dev; + struct device *dev, *parent; + + wait_for_device_probe(); + device_block_probing(); + + cpufreq_suspend(); spin_lock(&devices_kset->list_lock); /* @@ -1988,7 +4810,7 @@ void device_shutdown(void) * prevent it from being freed because parent's * lock is to be held */ - get_device(dev->parent); + parent = get_device(dev->parent); get_device(dev); /* * Make sure the device is off the kset list, in the @@ -1998,14 +4820,19 @@ void device_shutdown(void) spin_unlock(&devices_kset->list_lock); /* hold lock to avoid race with probe/release */ - if (dev->parent) - device_lock(dev->parent); + 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"); @@ -2017,16 +4844,15 @@ void device_shutdown(void) } device_unlock(dev); - if (dev->parent) - device_unlock(dev->parent); + if (parent) + device_unlock(parent); put_device(dev); - put_device(dev->parent); + put_device(parent); spin_lock(&devices_kset->list_lock); } spin_unlock(&devices_kset->list_lock); - async_synchronize_full(); } /* @@ -2034,20 +4860,21 @@ void device_shutdown(void) */ #ifdef CONFIG_PRINTK -static int -create_syslog_header(const struct device *dev, char *hdr, size_t hdrlen) +static void +set_dev_info(const struct device *dev, struct dev_printk_info *dev_info) { const char *subsys; - size_t pos = 0; + + memset(dev_info, 0, sizeof(*dev_info)); if (dev->class) subsys = dev->class->name; else if (dev->bus) subsys = dev->bus->name; else - return 0; + return; - pos += snprintf(hdr + pos, hdrlen - pos, "SUBSYSTEM=%s", subsys); + strscpy(dev_info->subsystem, subsys); /* * Add device identifier DEVICE=: @@ -2063,35 +4890,28 @@ create_syslog_header(const struct device *dev, char *hdr, size_t hdrlen) c = 'b'; else c = 'c'; - pos++; - pos += snprintf(hdr + pos, hdrlen - pos, - "DEVICE=%c%u:%u", - c, MAJOR(dev->devt), MINOR(dev->devt)); + + snprintf(dev_info->device, sizeof(dev_info->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); + snprintf(dev_info->device, sizeof(dev_info->device), + "n%u", net->ifindex); } else { - pos++; - pos += snprintf(hdr + pos, hdrlen - pos, - "DEVICE=+%s:%s", subsys, dev_name(dev)); + snprintf(dev_info->device, sizeof(dev_info->device), + "+%s:%s", subsys, dev_name(dev)); } - - return pos; } -EXPORT_SYMBOL(create_syslog_header); int dev_vprintk_emit(int level, const struct device *dev, const char *fmt, va_list args) { - char hdr[128]; - size_t hdrlen; + struct dev_printk_info dev_info; - hdrlen = create_syslog_header(dev, hdr, sizeof(hdr)); + set_dev_info(dev, &dev_info); - return vprintk_emit(0, level, hdrlen ? hdr : NULL, hdrlen, fmt, args); + return vprintk_emit(0, level, &dev_info, fmt, args); } EXPORT_SYMBOL(dev_vprintk_emit); @@ -2110,63 +4930,423 @@ int dev_printk_emit(int level, const struct device *dev, const char *fmt, ...) } EXPORT_SYMBOL(dev_printk_emit); -static int __dev_printk(const char *level, const struct device *dev, +static void __dev_printk(const char *level, const struct device *dev, struct va_format *vaf) { - if (!dev) - return printk("%s(NULL device *): %pV", level, vaf); - - return dev_printk_emit(level[1] - '0', dev, - "%s %s: %pV", - dev_driver_string(dev), dev_name(dev), 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); } -int dev_printk(const char *level, const struct device *dev, - const char *fmt, ...) +void _dev_printk(const char *level, const struct device *dev, + const char *fmt, ...) { struct va_format vaf; va_list args; - int r; va_start(args, fmt); vaf.fmt = fmt; vaf.va = &args; - r = __dev_printk(level, dev, &vaf); + __dev_printk(level, dev, &vaf); va_end(args); - - return r; } -EXPORT_SYMBOL(dev_printk); +EXPORT_SYMBOL(_dev_printk); #define define_dev_printk_level(func, kern_level) \ -int func(const struct device *dev, const char *fmt, ...) \ +void func(const struct device *dev, const char *fmt, ...) \ { \ struct va_format vaf; \ va_list args; \ - int r; \ \ va_start(args, fmt); \ \ vaf.fmt = fmt; \ vaf.va = &args; \ \ - r = __dev_printk(kern_level, dev, &vaf); \ + __dev_printk(kern_level, dev, &vaf); \ \ va_end(args); \ - \ - return r; \ } \ 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_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 void __dev_probe_failed(const struct device *dev, int err, bool fatal, + const char *fmt, va_list vargsp) +{ + struct va_format vaf; + va_list vargs; + + /* + * On x86_64 and possibly on other architectures, va_list is actually a + * size-1 array containing a structure. As a result, function parameter + * vargsp decays from T[1] to T*, and &vargsp has type T** rather than + * T(*)[1], which is expected by its assignment to vaf.va below. + * + * One standard way to solve this mess is by creating a copy in a local + * variable of type va_list and then using a pointer to that local copy + * instead, which is the approach employed here. + */ + va_copy(vargs, vargsp); + + vaf.fmt = fmt; + vaf.va = &vargs; + + switch (err) { + case -EPROBE_DEFER: + device_set_deferred_probe_reason(dev, &vaf); + dev_dbg(dev, "error %pe: %pV", ERR_PTR(err), &vaf); + break; + + case -ENOMEM: + /* Don't print anything on -ENOMEM, there's already enough output */ + break; + + default: + /* Log fatal final failures as errors, otherwise produce warnings */ + if (fatal) + dev_err(dev, "error %pe: %pV", ERR_PTR(err), &vaf); + else + dev_warn(dev, "error %pe: %pV", ERR_PTR(err), &vaf); + break; + } + + va_end(vargs); +} + +/** + * dev_err_probe - probe error check and log helper + * @dev: the pointer to the struct device + * @err: error value to test + * @fmt: printf-style format string + * @...: arguments as specified in the format string + * + * This helper implements common pattern present in probe functions for error + * checking: print debug or error message depending if the error value is + * -EPROBE_DEFER and propagate error upwards. + * In case of -EPROBE_DEFER it sets also defer probe reason, which can be + * checked later by reading devices_deferred debugfs attribute. + * It replaces the following code sequence:: + * + * if (err != -EPROBE_DEFER) + * dev_err(dev, ...); + * else + * dev_dbg(dev, ...); + * return err; + * + * with:: + * + * return dev_err_probe(dev, err, ...); + * + * Using this helper in your probe function is totally fine even if @err + * is known to never be -EPROBE_DEFER. + * The benefit compared to a normal dev_err() is the standardized format + * of the error code, which is emitted symbolically (i.e. you get "EAGAIN" + * instead of "-35"), and having the error code returned allows more + * compact error paths. + * + * Returns @err. + */ +int dev_err_probe(const struct device *dev, int err, const char *fmt, ...) +{ + va_list vargs; + + va_start(vargs, fmt); + + /* Use dev_err() for logging when err doesn't equal -EPROBE_DEFER */ + __dev_probe_failed(dev, err, true, fmt, vargs); + + va_end(vargs); + + return err; +} +EXPORT_SYMBOL_GPL(dev_err_probe); + +/** + * dev_warn_probe - probe error check and log helper + * @dev: the pointer to the struct device + * @err: error value to test + * @fmt: printf-style format string + * @...: arguments as specified in the format string + * + * This helper implements common pattern present in probe functions for error + * checking: print debug or warning message depending if the error value is + * -EPROBE_DEFER and propagate error upwards. + * In case of -EPROBE_DEFER it sets also defer probe reason, which can be + * checked later by reading devices_deferred debugfs attribute. + * It replaces the following code sequence:: + * + * if (err != -EPROBE_DEFER) + * dev_warn(dev, ...); + * else + * dev_dbg(dev, ...); + * return err; + * + * with:: + * + * return dev_warn_probe(dev, err, ...); + * + * Using this helper in your probe function is totally fine even if @err + * is known to never be -EPROBE_DEFER. + * The benefit compared to a normal dev_warn() is the standardized format + * of the error code, which is emitted symbolically (i.e. you get "EAGAIN" + * instead of "-35"), and having the error code returned allows more + * compact error paths. + * + * Returns @err. + */ +int dev_warn_probe(const struct device *dev, int err, const char *fmt, ...) +{ + va_list vargs; + + va_start(vargs, fmt); + + /* Use dev_warn() for logging when err doesn't equal -EPROBE_DEFER */ + __dev_probe_failed(dev, err, false, fmt, vargs); + + va_end(vargs); + + return err; +} +EXPORT_SYMBOL_GPL(dev_warn_probe); + +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. + * + * Valid fwnode cases are: + * - primary --> secondary --> -ENODEV + * - primary --> NULL + * - secondary --> -ENODEV + * - NULL + */ +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; + + /* Skip nullifying fn->secondary if the primary is shared */ + if (parent && fn == parent->fwnode) + return; + + /* Set fn->secondary = NULL, so fn remains the primary 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; +} +EXPORT_SYMBOL_GPL(set_secondary_fwnode); + +/** + * device_remove_of_node - Remove an of_node from a device + * @dev: device whose device tree node is being removed + */ +void device_remove_of_node(struct device *dev) +{ + dev = get_device(dev); + if (!dev) + return; + + if (!dev->of_node) + goto end; + + if (dev->fwnode == of_fwnode_handle(dev->of_node)) + dev->fwnode = NULL; + + of_node_put(dev->of_node); + dev->of_node = NULL; + +end: + put_device(dev); +} +EXPORT_SYMBOL_GPL(device_remove_of_node); + +/** + * device_add_of_node - Add an of_node to an existing device + * @dev: device whose device tree node is being added + * @of_node: of_node to add + * + * Return: 0 on success or error code on failure. + */ +int device_add_of_node(struct device *dev, struct device_node *of_node) +{ + int ret; + + if (!of_node) + return -EINVAL; + + dev = get_device(dev); + if (!dev) + return -EINVAL; + + if (dev->of_node) { + dev_err(dev, "Cannot replace node %pOF with %pOF\n", + dev->of_node, of_node); + ret = -EBUSY; + goto end; + } + + dev->of_node = of_node_get(of_node); + + if (!dev->fwnode) + dev->fwnode = of_fwnode_handle(of_node); + + ret = 0; +end: + put_device(dev); + return ret; +} +EXPORT_SYMBOL_GPL(device_add_of_node); + +/** + * 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); + +void device_set_node(struct device *dev, struct fwnode_handle *fwnode) +{ + dev->fwnode = fwnode; + dev->of_node = to_of_node(fwnode); +} +EXPORT_SYMBOL_GPL(device_set_node); + +/** + * get_dev_from_fwnode - Obtain a reference count of the struct device the + * struct fwnode_handle is associated with. + * @fwnode: The pointer to the struct fwnode_handle to obtain the struct device + * reference count of. + * + * This function obtains a reference count of the device the device pointer + * embedded in the struct fwnode_handle points to. + * + * Note that the struct device pointer embedded in struct fwnode_handle does + * *not* have a reference count of the struct device itself. + * + * Hence, it is a UAF (and thus a bug) to call this function if the caller can't + * guarantee that the last reference count of the corresponding struct device is + * not dropped concurrently. + * + * This is possible since struct fwnode_handle has its own reference count and + * hence can out-live the struct device it is associated with. + */ +struct device *get_dev_from_fwnode(struct fwnode_handle *fwnode) +{ + return get_device((fwnode)->dev); +} +EXPORT_SYMBOL_GPL(get_dev_from_fwnode); + +int device_match_name(struct device *dev, const void *name) +{ + return sysfs_streq(dev_name(dev), name); +} +EXPORT_SYMBOL_GPL(device_match_name); + +int device_match_type(struct device *dev, const void *type) +{ + return dev->type == type; +} +EXPORT_SYMBOL_GPL(device_match_type); + +int device_match_of_node(struct device *dev, const void *np) +{ + return np && dev->of_node == np; +} +EXPORT_SYMBOL_GPL(device_match_of_node); + +int device_match_fwnode(struct device *dev, const void *fwnode) +{ + return fwnode && dev_fwnode(dev) == fwnode; +} +EXPORT_SYMBOL_GPL(device_match_fwnode); + +int device_match_devt(struct device *dev, const void *pdevt) +{ + return dev->devt == *(dev_t *)pdevt; +} +EXPORT_SYMBOL_GPL(device_match_devt); + +int device_match_acpi_dev(struct device *dev, const void *adev) +{ + return adev && ACPI_COMPANION(dev) == adev; +} +EXPORT_SYMBOL(device_match_acpi_dev); + +int device_match_acpi_handle(struct device *dev, const void *handle) +{ + return handle && ACPI_HANDLE(dev) == handle; +} +EXPORT_SYMBOL(device_match_acpi_handle); + +int device_match_any(struct device *dev, const void *unused) +{ + return 1; +} +EXPORT_SYMBOL_GPL(device_match_any); |