blob: dbb0f9130f42d386ad815d37377782fd2695bb8a [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0
/*
* drivers/base/core.c - core driver model code (device registration, etc)
*
* Copyright (c) 2002-3 Patrick Mochel
* Copyright (c) 2002-3 Open Source Development Labs
* Copyright (c) 2006 Greg Kroah-Hartman <gregkh@suse.de>
* Copyright (c) 2006 Novell, Inc.
*/
#include <linux/acpi.h>
#include <linux/cpufreq.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/fwnode.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/kdev_t.h>
#include <linux/notifier.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/genhd.h>
#include <linux/mutex.h>
#include <linux/pm_runtime.h>
#include <linux/netdevice.h>
#include <linux/sched/signal.h>
#include <linux/sysfs.h>
#include "base.h"
#include "power/power.h"
#ifdef CONFIG_SYSFS_DEPRECATED
#ifdef CONFIG_SYSFS_DEPRECATED_V2
long sysfs_deprecated = 1;
#else
long sysfs_deprecated = 0;
#endif
static int __init sysfs_deprecated_setup(char *arg)
{
return kstrtol(arg, 10, &sysfs_deprecated);
}
early_param("sysfs.deprecated", sysfs_deprecated_setup);
#endif
/* Device links support. */
static LIST_HEAD(wait_for_suppliers);
static DEFINE_MUTEX(wfs_lock);
static LIST_HEAD(deferred_sync);
static unsigned int defer_sync_state_count = 1;
#ifdef CONFIG_SRCU
static DEFINE_MUTEX(device_links_lock);
DEFINE_STATIC_SRCU(device_links_srcu);
static inline void device_links_write_lock(void)
{
mutex_lock(&device_links_lock);
}
static inline void device_links_write_unlock(void)
{
mutex_unlock(&device_links_lock);
}
int device_links_read_lock(void)
{
return srcu_read_lock(&device_links_srcu);
}
void device_links_read_unlock(int idx)
{
srcu_read_unlock(&device_links_srcu, idx);
}
int device_links_read_lock_held(void)
{
return srcu_read_lock_held(&device_links_srcu);
}
#else /* !CONFIG_SRCU */
static DECLARE_RWSEM(device_links_lock);
static inline void device_links_write_lock(void)
{
down_write(&device_links_lock);
}
static inline void device_links_write_unlock(void)
{
up_write(&device_links_lock);
}
int device_links_read_lock(void)
{
down_read(&device_links_lock);
return 0;
}
void device_links_read_unlock(int not_used)
{
up_read(&device_links_lock);
}
#ifdef CONFIG_DEBUG_LOCK_ALLOC
int device_links_read_lock_held(void)
{
return lockdep_is_held(&device_links_lock);
}
#endif
#endif /* !CONFIG_SRCU */
/**
* 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;
if (dev == target)
return 1;
ret = device_for_each_child(dev, target, device_is_dependent);
if (ret)
return ret;
list_for_each_entry(link, &dev->links.consumers, s_node) {
if (link->flags == (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED))
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 (link->flags == (DL_FLAG_SYNC_STATE_ONLY | DL_FLAG_MANAGED))
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 DL_MANAGED_LINK_FLAGS (DL_FLAG_AUTOREMOVE_CONSUMER | \
DL_FLAG_AUTOREMOVE_SUPPLIER | \
DL_FLAG_AUTOPROBE_CONSUMER | \
DL_FLAG_SYNC_STATE_ONLY)
#define DL_ADD_VALID_FLAGS (DL_MANAGED_LINK_FLAGS | DL_FLAG_STATELESS | \
DL_FLAG_PM_RUNTIME | DL_FLAG_RPM_ACTIVE)
/**
* device_link_add - Create a link between two devices.
* @consumer: Consumer end of the link.
* @supplier: Supplier end of the link.
* @flags: Link flags.
*
* The caller is responsible for the proper synchronization of the link creation
* with runtime PM. First, setting the DL_FLAG_PM_RUNTIME flag will cause the
* runtime PM framework to take the link into account. Second, if the
* DL_FLAG_RPM_ACTIVE flag is set in addition to it, the supplier devices will
* be forced into the active metastate and reference-counted upon the creation
* of the link. If DL_FLAG_PM_RUNTIME is not set, DL_FLAG_RPM_ACTIVE will be
* ignored.
*
* If DL_FLAG_STATELESS is set in @flags, the caller of this function is
* expected to release the link returned by it directly with the help of either
* device_link_del() or device_link_remove().
*
* If that flag is not set, however, the caller of this function is handing the
* management of the link over to the driver core entirely and its return value
* can only be used to check whether or not the link is present. In that case,
* the DL_FLAG_AUTOREMOVE_CONSUMER and DL_FLAG_AUTOREMOVE_SUPPLIER device link
* flags can be used to indicate to the driver core when the link can be safely
* deleted. Namely, setting one of them in @flags indicates to the driver core
* that the link is not going to be used (by the given caller of this function)
* after unbinding the consumer or supplier driver, respectively, from its
* device, so the link can be deleted at that point. If none of them is set,
* the link will be maintained until one of the devices pointed to by it (either
* the consumer or the supplier) is unregistered.
*
* Also, if DL_FLAG_STATELESS, DL_FLAG_AUTOREMOVE_CONSUMER and
* DL_FLAG_AUTOREMOVE_SUPPLIER are not set in @flags (that is, a persistent
* managed device link is being added), the DL_FLAG_AUTOPROBE_CONSUMER flag can
* be used to request the driver core to automaticall probe for a consmer
* driver after successfully binding a driver to the supplier device.
*
* The combination of DL_FLAG_STATELESS and one of DL_FLAG_AUTOREMOVE_CONSUMER,
* DL_FLAG_AUTOREMOVE_SUPPLIER, or DL_FLAG_AUTOPROBE_CONSUMER set in @flags at
* the same time is invalid and will cause NULL to be returned upfront.
* However, if a device link between the given @consumer and @supplier pair
* exists already when this function is called for them, the existing link will
* be returned regardless of its current type and status (the link's flags may
* be modified then). The caller of this function is then expected to treat
* the link as though it has just been created, so (in particular) if
* DL_FLAG_STATELESS was passed in @flags, the link needs to be released
* explicitly when not needed any more (as stated above).
*
* A side effect of the link creation is re-ordering of dpm_list and the
* devices_kset list by moving the consumer device and all devices depending
* on it to the ends of these lists (that does not happen to devices that have
* not been registered when this function is called).
*
* The supplier device is required to be registered when this function is called
* and NULL will be returned if that is not the case. The consumer device need
* not be registered, however.
*/
struct device_link *device_link_add(struct device *consumer,
struct device *supplier, u32 flags)
{
struct device_link *link;
if (!consumer || !supplier || flags & ~DL_ADD_VALID_FLAGS ||
(flags & DL_FLAG_STATELESS && flags & DL_MANAGED_LINK_FLAGS) ||
(flags & DL_FLAG_SYNC_STATE_ONLY &&
flags != DL_FLAG_SYNC_STATE_ONLY) ||
(flags & DL_FLAG_AUTOPROBE_CONSUMER &&
flags & (DL_FLAG_AUTOREMOVE_CONSUMER |
DL_FLAG_AUTOREMOVE_SUPPLIER)))
return NULL;
if (flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) {
if (pm_runtime_get_sync(supplier) < 0) {
pm_runtime_put_noidle(supplier);
return NULL;
}
}
if (!(flags & DL_FLAG_STATELESS))
flags |= DL_FLAG_MANAGED;
device_links_write_lock();
device_pm_lock();
/*
* If the supplier has not been fully registered yet or there is a
* reverse (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;
}
/*
* DL_FLAG_AUTOREMOVE_SUPPLIER indicates that the link will be needed
* longer than for DL_FLAG_AUTOREMOVE_CONSUMER and setting them both
* together doesn't make sense, so prefer DL_FLAG_AUTOREMOVE_SUPPLIER.
*/
if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER;
list_for_each_entry(link, &supplier->links.consumers, s_node) {
if (link->consumer != consumer)
continue;
if (flags & DL_FLAG_PM_RUNTIME) {
if (!(link->flags & DL_FLAG_PM_RUNTIME)) {
pm_runtime_new_link(consumer);
link->flags |= DL_FLAG_PM_RUNTIME;
}
if (flags & DL_FLAG_RPM_ACTIVE)
refcount_inc(&link->rpm_active);
}
if (flags & DL_FLAG_STATELESS) {
kref_get(&link->kref);
if (link->flags & DL_FLAG_SYNC_STATE_ONLY &&
!(link->flags & DL_FLAG_STATELESS)) {
link->flags |= DL_FLAG_STATELESS;
goto reorder;
} else {
goto out;
}
}
/*
* If the life time of the link following from the new flags is
* longer than indicated by the flags of the existing link,
* update the existing link to stay around longer.
*/
if (flags & DL_FLAG_AUTOREMOVE_SUPPLIER) {
if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER) {
link->flags &= ~DL_FLAG_AUTOREMOVE_CONSUMER;
link->flags |= DL_FLAG_AUTOREMOVE_SUPPLIER;
}
} else if (!(flags & DL_FLAG_AUTOREMOVE_CONSUMER)) {
link->flags &= ~(DL_FLAG_AUTOREMOVE_CONSUMER |
DL_FLAG_AUTOREMOVE_SUPPLIER);
}
if (!(link->flags & DL_FLAG_MANAGED)) {
kref_get(&link->kref);
link->flags |= DL_FLAG_MANAGED;
device_link_init_status(link, consumer, supplier);
}
if (link->flags & 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);
if (flags & DL_FLAG_PM_RUNTIME) {
if (flags & DL_FLAG_RPM_ACTIVE)
refcount_inc(&link->rpm_active);
pm_runtime_new_link(consumer);
}
get_device(supplier);
link->supplier = supplier;
INIT_LIST_HEAD(&link->s_node);
get_device(consumer);
link->consumer = consumer;
INIT_LIST_HEAD(&link->c_node);
link->flags = flags;
kref_init(&link->kref);
/* Determine the initial link state. */
if (flags & DL_FLAG_STATELESS)
link->status = DL_STATE_NONE;
else
device_link_init_status(link, consumer, supplier);
/*
* Some callers expect the link creation during consumer driver probe to
* resume the supplier even without DL_FLAG_RPM_ACTIVE.
*/
if (link->status == DL_STATE_CONSUMER_PROBE &&
flags & DL_FLAG_PM_RUNTIME)
pm_runtime_resume(supplier);
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);
list_add_tail_rcu(&link->s_node, &supplier->links.consumers);
list_add_tail_rcu(&link->c_node, &consumer->links.suppliers);
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);
/**
* device_link_wait_for_supplier - Add device to wait_for_suppliers list
* @consumer: Consumer device
*
* Marks the @consumer device as waiting for suppliers to become available by
* adding it to the wait_for_suppliers list. The consumer device will never be
* probed until it's removed from the wait_for_suppliers list.
*
* The caller is responsible for adding the links to the supplier devices once
* they are available and removing the @consumer device from the
* wait_for_suppliers list once links to all the suppliers have been created.
*
* This function is NOT meant to be called from the probe function of the
* consumer but rather from code that creates/adds the consumer device.
*/
static void device_link_wait_for_supplier(struct device *consumer,
bool need_for_probe)
{
mutex_lock(&wfs_lock);
list_add_tail(&consumer->links.needs_suppliers, &wait_for_suppliers);
consumer->links.need_for_probe = need_for_probe;
mutex_unlock(&wfs_lock);
}
static void device_link_wait_for_mandatory_supplier(struct device *consumer)
{
device_link_wait_for_supplier(consumer, true);
}
static void device_link_wait_for_optional_supplier(struct device *consumer)
{
device_link_wait_for_supplier(consumer, false);
}
/**
* device_link_add_missing_supplier_links - Add links from consumer devices to
* supplier devices, leaving any
* consumer with inactive suppliers on
* the wait_for_suppliers list
*
* Loops through all consumers waiting on suppliers and tries to add all their
* supplier links. If that succeeds, the consumer device is removed from
* wait_for_suppliers list. Otherwise, they are left in the wait_for_suppliers
* list. Devices left on the wait_for_suppliers list will not be probed.
*
* The fwnode add_links callback is expected to return 0 if it has found and
* added all the supplier links for the consumer device. It should return an
* error if it isn't able to do so.
*
* The caller of device_link_wait_for_supplier() is expected to call this once
* it's aware of potential suppliers becoming available.
*/
static void device_link_add_missing_supplier_links(void)
{
struct device *dev, *tmp;
mutex_lock(&wfs_lock);
list_for_each_entry_safe(dev, tmp, &wait_for_suppliers,
links.needs_suppliers)
if (!fwnode_call_int_op(dev->fwnode, add_links, dev))
list_del_init(&dev->links.needs_suppliers);
mutex_unlock(&wfs_lock);
}
static void device_link_free(struct device_link *link)
{
while (refcount_dec_not_one(&link->rpm_active))
pm_runtime_put(link->supplier);
put_device(link->consumer);
put_device(link->supplier);
kfree(link);
}
#ifdef CONFIG_SRCU
static void __device_link_free_srcu(struct rcu_head *rhead)
{
device_link_free(container_of(rhead, struct device_link, rcu_head));
}
static void __device_link_del(struct kref *kref)
{
struct device_link *link = container_of(kref, struct device_link, kref);
dev_dbg(link->consumer, "Dropping the link to %s\n",
dev_name(link->supplier));
if (link->flags & DL_FLAG_PM_RUNTIME)
pm_runtime_drop_link(link->consumer);
list_del_rcu(&link->s_node);
list_del_rcu(&link->c_node);
call_srcu(&device_links_srcu, &link->rcu_head, __device_link_free_srcu);
}
#else /* !CONFIG_SRCU */
static void __device_link_del(struct kref *kref)
{
struct device_link *link = container_of(kref, struct device_link, kref);
dev_info(link->consumer, "Dropping the link to %s\n",
dev_name(link->supplier));
if (link->flags & DL_FLAG_PM_RUNTIME)
pm_runtime_drop_link(link->consumer);
list_del(&link->s_node);
list_del(&link->c_node);
device_link_free(link);
}
#endif /* !CONFIG_SRCU */
static void device_link_put_kref(struct device_link *link)
{
if (link->flags & DL_FLAG_STATELESS)
kref_put(&link->kref, __device_link_del);
else
WARN(1, "Unable to drop a managed device link reference\n");
}
/**
* device_link_del - Delete a stateless link between two devices.
* @link: Device link to delete.
*
* The caller must ensure proper synchronization of this function with runtime
* PM. If the link was added multiple times, it needs to be deleted as often.
* Care is required for hotplugged devices: Their links are purged on removal
* and calling device_link_del() is then no longer allowed.
*/
void device_link_del(struct device_link *link)
{
device_links_write_lock();
device_pm_lock();
device_link_put_kref(link);
device_pm_unlock();
device_links_write_unlock();
}
EXPORT_SYMBOL_GPL(device_link_del);
/**
* device_link_remove - Delete a stateless link between two devices.
* @consumer: Consumer end of the link.
* @supplier: Supplier end of the link.
*
* The caller must ensure proper synchronization of this function with runtime
* PM.
*/
void device_link_remove(void *consumer, struct device *supplier)
{
struct device_link *link;
if (WARN_ON(consumer == supplier))
return;
device_links_write_lock();
device_pm_lock();
list_for_each_entry(link, &supplier->links.consumers, s_node) {
if (link->consumer == consumer) {
device_link_put_kref(link);
break;
}
}
device_pm_unlock();
device_links_write_unlock();
}
EXPORT_SYMBOL_GPL(device_link_remove);
static void device_links_missing_supplier(struct device *dev)
{
struct device_link *link;
list_for_each_entry(link, &dev->links.suppliers, c_node)
if (link->status == DL_STATE_CONSUMER_PROBE)
WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
}
/**
* device_links_check_suppliers - Check presence of supplier drivers.
* @dev: Consumer device.
*
* Check links from this device to any suppliers. Walk the list of the device's
* links to suppliers and see if all of them are available. If not, simply
* return -EPROBE_DEFER.
*
* We need to guarantee that the supplier will not go away after the check has
* been positive here. It only can go away in __device_release_driver() and
* that function checks the device's links to consumers. This means we need to
* mark the link as "consumer probe in progress" to make the supplier removal
* wait for us to complete (or bad things may happen).
*
* Links without the DL_FLAG_MANAGED flag set are ignored.
*/
int device_links_check_suppliers(struct device *dev)
{
struct device_link *link;
int ret = 0;
/*
* Device waiting for supplier to become available is not allowed to
* probe.
*/
mutex_lock(&wfs_lock);
if (!list_empty(&dev->links.needs_suppliers) &&
dev->links.need_for_probe) {
mutex_unlock(&wfs_lock);
return -EPROBE_DEFER;
}
mutex_unlock(&wfs_lock);
device_links_write_lock();
list_for_each_entry(link, &dev->links.suppliers, c_node) {
if (!(link->flags & DL_FLAG_MANAGED) ||
link->flags & DL_FLAG_SYNC_STATE_ONLY)
continue;
if (link->status != DL_STATE_AVAILABLE) {
device_links_missing_supplier(dev);
ret = -EPROBE_DEFER;
break;
}
WRITE_ONCE(link->status, DL_STATE_CONSUMER_PROBE);
}
dev->links.status = DL_DEV_PROBING;
device_links_write_unlock();
return ret;
}
/**
* __device_links_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 (!(link->flags & 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);
if (dev->bus->sync_state)
dev->bus->sync_state(dev);
else if (dev->driver && dev->driver->sync_state)
dev->driver->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);
}
/**
* 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;
LIST_HEAD(sync_list);
/*
* If a device probes successfully, it's expected to have created all
* the device links it needs to or make new device links as it needs
* them. So, it no longer needs to wait on any suppliers.
*/
mutex_lock(&wfs_lock);
list_del_init(&dev->links.needs_suppliers);
mutex_unlock(&wfs_lock);
device_links_write_lock();
list_for_each_entry(link, &dev->links.consumers, s_node) {
if (!(link->flags & DL_FLAG_MANAGED))
continue;
/*
* Links created during consumer probe may be in the "consumer
* probe" state to start with if the supplier is still probing
* when they are created and they may become "active" if the
* consumer probe returns first. Skip them here.
*/
if (link->status == DL_STATE_CONSUMER_PROBE ||
link->status == DL_STATE_ACTIVE)
continue;
WARN_ON(link->status != DL_STATE_DORMANT);
WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
if (link->flags & DL_FLAG_AUTOPROBE_CONSUMER)
driver_deferred_probe_add(link->consumer);
}
if (defer_sync_state_count)
__device_links_supplier_defer_sync(dev);
else
__device_links_queue_sync_state(dev, &sync_list);
list_for_each_entry(link, &dev->links.suppliers, c_node) {
if (!(link->flags & DL_FLAG_MANAGED))
continue;
WARN_ON(link->status != DL_STATE_CONSUMER_PROBE);
WRITE_ONCE(link->status, DL_STATE_ACTIVE);
if (defer_sync_state_count)
__device_links_supplier_defer_sync(link->supplier);
else
__device_links_queue_sync_state(link->supplier,
&sync_list);
}
dev->links.status = DL_DEV_DRIVER_BOUND;
device_links_write_unlock();
device_links_flush_sync_list(&sync_list, dev);
}
static void device_link_drop_managed(struct device_link *link)
{
link->flags &= ~DL_FLAG_MANAGED;
WRITE_ONCE(link->status, DL_STATE_NONE);
kref_put(&link->kref, __device_link_del);
}
/**
* __device_links_no_driver - Update links of a device without a driver.
* @dev: Device without a drvier.
*
* Delete all non-persistent links from this device to any suppliers.
*
* Persistent links stay around, but their status is changed to "available",
* unless they already are in the "supplier unbind in progress" state in which
* case they need not be updated.
*
* Links without the DL_FLAG_MANAGED flag set are ignored.
*/
static void __device_links_no_driver(struct device *dev)
{
struct device_link *link, *ln;
list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
if (!(link->flags & DL_FLAG_MANAGED))
continue;
if (link->flags & DL_FLAG_AUTOREMOVE_CONSUMER)
device_link_drop_managed(link);
else if (link->status == DL_STATE_CONSUMER_PROBE ||
link->status == DL_STATE_ACTIVE)
WRITE_ONCE(link->status, DL_STATE_AVAILABLE);
}
dev->links.status = DL_DEV_NO_DRIVER;
}
/**
* device_links_no_driver - Update links after failing driver probe.
* @dev: Device whose driver has just failed to probe.
*
* Clean up leftover links to consumers for @dev and invoke
* %__device_links_no_driver() to update links to suppliers for it as
* appropriate.
*
* Links without the DL_FLAG_MANAGED flag set are ignored.
*/
void device_links_no_driver(struct device *dev)
{
struct device_link *link;
device_links_write_lock();
list_for_each_entry(link, &dev->links.consumers, s_node) {
if (!(link->flags & DL_FLAG_MANAGED))
continue;
/*
* The probe has failed, so if the status of the link is
* "consumer probe" or "active", it must have been added by
* a probing consumer while this device was still probing.
* Change its state to "dormant", as it represents a valid
* relationship, but it is not functionally meaningful.
*/
if (link->status == DL_STATE_CONSUMER_PROBE ||
link->status == DL_STATE_ACTIVE)
WRITE_ONCE(link->status, DL_STATE_DORMANT);
}
__device_links_no_driver(dev);
device_links_write_unlock();
}
/**
* device_links_driver_cleanup - Update links after driver removal.
* @dev: Device whose driver has just gone away.
*
* Update links to consumers for @dev by changing their status to "dormant" and
* invoke %__device_links_no_driver() to update links to suppliers for it as
* appropriate.
*
* Links without the DL_FLAG_MANAGED flag set are ignored.
*/
void device_links_driver_cleanup(struct device *dev)
{
struct device_link *link, *ln;
device_links_write_lock();
list_for_each_entry_safe(link, ln, &dev->links.consumers, s_node) {
if (!(link->flags & DL_FLAG_MANAGED))
continue;
WARN_ON(link->flags & DL_FLAG_AUTOREMOVE_CONSUMER);
WARN_ON(link->status != DL_STATE_SUPPLIER_UNBIND);
/*
* autoremove the links between this @dev and its consumer
* devices that are not active, i.e. where the link state
* has moved to DL_STATE_SUPPLIER_UNBIND.
*/
if (link->status == DL_STATE_SUPPLIER_UNBIND &&
link->flags & DL_FLAG_AUTOREMOVE_SUPPLIER)
device_link_drop_managed(link);
WRITE_ONCE(link->status, DL_STATE_DORMANT);
}
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 (!(link->flags & DL_FLAG_MANAGED))
continue;
if (link->status == DL_STATE_CONSUMER_PROBE
|| link->status == DL_STATE_ACTIVE) {
ret = true;
break;
}
WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND);
}
dev->links.status = DL_DEV_UNBINDING;
device_links_write_unlock();
return ret;
}
/**
* device_links_unbind_consumers - Force unbind consumers of the given device.
* @dev: Device to unbind the consumers of.
*
* Walk the list of links to consumers for @dev and if any of them is in the
* "consumer probe" state, wait for all device probes in progress to complete
* and start over.
*
* If that's not the case, change the status of the link to "supplier unbind"
* and check if the link was in the "active" state. If so, force the consumer
* driver to unbind and start over (the consumer will not re-probe as we have
* changed the state of the link already).
*
* Links without the DL_FLAG_MANAGED flag set are ignored.
*/
void device_links_unbind_consumers(struct device *dev)
{
struct device_link *link;
start:
device_links_write_lock();
list_for_each_entry(link, &dev->links.consumers, s_node) {
enum device_link_state status;
if (!(link->flags & DL_FLAG_MANAGED) ||
link->flags & 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;
mutex_lock(&wfs_lock);
list_del(&dev->links.needs_suppliers);
mutex_unlock(&wfs_lock);
/*
* Delete all of the remaining links from this device to any other
* devices (either consumers or suppliers).
*/
device_links_write_lock();
list_for_each_entry_safe_reverse(link, ln, &dev->links.suppliers, c_node) {
WARN_ON(link->status == DL_STATE_ACTIVE);
__device_link_del(&link->kref);
}
list_for_each_entry_safe_reverse(link, ln, &dev->links.consumers, s_node) {
WARN_ON(link->status != DL_STATE_DORMANT &&
link->status != DL_STATE_NONE);
__device_link_del(&link->kref);
}
device_links_write_unlock();
}
/* Device links support end. */
int (*platform_notify)(struct device *dev) = NULL;
int (*platform_notify_remove)(struct device *dev) = NULL;
static struct kobject *dev_kobj;
struct kobject *sysfs_dev_char_kobj;
struct kobject *sysfs_dev_block_kobj;
static DEFINE_MUTEX(device_hotplug_lock);
void lock_device_hotplug(void)
{
mutex_lock(&device_hotplug_lock);
}
void unlock_device_hotplug(void)
{
mutex_unlock(&device_hotplug_lock);
}
int lock_device_hotplug_sysfs(void)
{
if (mutex_trylock(&device_hotplug_lock))
return 0;
/* Avoid busy looping (5 ms of sleep should do). */
msleep(5);
return restart_syscall();
}
#ifdef CONFIG_BLOCK
static inline int device_is_not_partition(struct device *dev)
{
return !(dev->type == &part_type);
}
#else
static inline int device_is_not_partition(struct device *dev)
{
return 1;
}
#endif
static int
device_platform_notify(struct device *dev, enum kobject_action action)
{
int ret;
ret = acpi_platform_notify(dev, action);
if (ret)
return ret;
ret = software_node_notify(dev, action);
if (ret)
return ret;
if (platform_notify && action == KOBJ_ADD)
platform_notify(dev);
else if (platform_notify_remove && action == KOBJ_REMOVE)
platform_notify_remove(dev);
return 0;
}
/**
* dev_driver_string - Return a device's driver name, if at all possible
* @dev: struct device to get the name of
*
* Will return the device's driver's name if it is bound to a device. If
* the device is not bound to a driver, it will return the name of the bus
* it is attached to. If it is not attached to a bus either, an empty
* string will be returned.
*/
const char *dev_driver_string(const struct device *dev)
{
struct device_driver *drv;
/* dev->driver can change to NULL underneath us because of unbinding,
* so be careful about accessing it. dev->bus and dev->class should
* never change once they are set, so they don't need special care.
*/
drv = READ_ONCE(dev->driver);
return drv ? drv->name :
(dev->bus ? dev->bus->name :
(dev->class ? dev->class->name : ""));
}
EXPORT_SYMBOL(dev_driver_string);
#define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
static ssize_t dev_attr_show(struct kobject *kobj, struct attribute *attr,
char *buf)
{
struct device_attribute *dev_attr = to_dev_attr(attr);
struct device *dev = kobj_to_dev(kobj);
ssize_t ret = -EIO;
if (dev_attr->show)
ret = dev_attr->show(dev, dev_attr, buf);
if (ret >= (ssize_t)PAGE_SIZE) {
printk("dev_attr_show: %pS returned bad count\n",
dev_attr->show);
}
return ret;
}
static ssize_t dev_attr_store(struct kobject *kobj, struct attribute *attr,
const char *buf, size_t count)
{
struct device_attribute *dev_attr = to_dev_attr(attr);
struct device *dev = kobj_to_dev(kobj);
ssize_t ret = -EIO;
if (dev_attr->store)
ret = dev_attr->store(dev, dev_attr, buf, count);
return ret;
}
static const struct sysfs_ops dev_sysfs_ops = {
.show = dev_attr_show,
.store = dev_attr_store,
};
#define to_ext_attr(x) container_of(x, struct dev_ext_attribute, attr)
ssize_t device_store_ulong(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t size)
{
struct dev_ext_attribute *ea = to_ext_attr(attr);
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;
}
EXPORT_SYMBOL_GPL(device_store_ulong);
ssize_t device_show_ulong(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct dev_ext_attribute *ea = to_ext_attr(attr);
return snprintf(buf, PAGE_SIZE, "%lx\n", *(unsigned long *)(ea->var));
}
EXPORT_SYMBOL_GPL(device_show_ulong);
ssize_t device_store_int(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t size)
{
struct dev_ext_attribute *ea = to_ext_attr(attr);
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 */
return size;
}
EXPORT_SYMBOL_GPL(device_store_int);
ssize_t device_show_int(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct dev_ext_attribute *ea = to_ext_attr(attr);
return snprintf(buf, PAGE_SIZE, "%d\n", *(int *)(ea->var));
}
EXPORT_SYMBOL_GPL(device_show_int);
ssize_t device_store_bool(struct device *dev, struct device_attribute *attr,
const char *buf, size_t size)
{
struct dev_ext_attribute *ea = to_ext_attr(attr);
if (strtobool(buf, ea->var) < 0)
return -EINVAL;
return size;
}
EXPORT_SYMBOL_GPL(device_store_bool);
ssize_t device_show_bool(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct dev_ext_attribute *ea = to_ext_attr(attr);
return snprintf(buf, PAGE_SIZE, "%d\n", *(bool *)(ea->var));
}
EXPORT_SYMBOL_GPL(device_show_bool);
/**
* device_release - free device structure.
* @kobj: device's kobject.
*
* This is called once the reference count for the object
* reaches 0. We forward the call to the device's release
* method, which should handle actually freeing the structure.
*/
static void device_release(struct kobject *kobj)
{
struct device *dev = kobj_to_dev(kobj);
struct device_private *p = dev->p;
/*
* Some platform devices are driven without driver attached
* and managed resources may have been acquired. Make sure
* all resources are released.
*
* Drivers still can add resources into device after device
* is deleted but alive, so release devres here to avoid
* possible memory leak.
*/
devres_release_all(dev);
if (dev->release)
dev->release(dev);
else if (dev->type && dev->type->release)
dev->type->release(dev);
else if (dev->class && dev->class->dev_release)
dev->class->dev_release(dev);
else
WARN(1, KERN_ERR "Device '%s' does not have a release() function, it is broken and must be fixed. See Documentation/kobject.txt.\n",
dev_name(dev));
kfree(p);
}
static const void *device_namespace(struct kobject *kobj)
{
struct device *dev = kobj_to_dev(kobj);
const void *ns = NULL;
if (dev->class && dev->class->ns_type)
ns = dev->class->namespace(dev);
return ns;
}
static void device_get_ownership(struct kobject *kobj, kuid_t *uid, kgid_t *gid)
{
struct device *dev = kobj_to_dev(kobj);
if (dev->class && dev->class->get_ownership)
dev->class->get_ownership(dev, uid, gid);
}
static struct kobj_type device_ktype = {
.release = device_release,
.sysfs_ops = &dev_sysfs_ops,
.namespace = device_namespace,
.get_ownership = device_get_ownership,
};
static int dev_uevent_filter(struct kset *kset, struct kobject *kobj)
{
struct kobj_type *ktype = get_ktype(kobj);
if (ktype == &device_ktype) {
struct device *dev = kobj_to_dev(kobj);
if (dev->bus)
return 1;
if (dev->class)
return 1;
}
return 0;
}
static const char *dev_uevent_name(struct kset *kset, struct kobject *kobj)
{
struct device *dev = kobj_to_dev(kobj);
if (dev->bus)
return dev->bus->name;
if (dev->class)
return dev->class->name;
return NULL;
}
static int dev_uevent(struct kset *kset, struct kobject *kobj,
struct kobj_uevent_env *env)
{
struct device *dev = kobj_to_dev(kobj);
int retval = 0;
/* add device node properties if present */
if (MAJOR(dev->devt)) {
const char *tmp;
const char *name;
umode_t mode = 0;
kuid_t uid = GLOBAL_ROOT_UID;
kgid_t gid = GLOBAL_ROOT_GID;
add_uevent_var(env, "MAJOR=%u", MAJOR(dev->devt));
add_uevent_var(env, "MINOR=%u", MINOR(dev->devt));
name = device_get_devnode(dev, &mode, &uid, &gid, &tmp);
if (name) {
add_uevent_var(env, "DEVNAME=%s", name);
if (mode)
add_uevent_var(env, "DEVMODE=%#o", mode & 0777);
if (!uid_eq(uid, GLOBAL_ROOT_UID))
add_uevent_var(env, "DEVUID=%u", from_kuid(&init_user_ns, uid));
if (!gid_eq(gid, GLOBAL_ROOT_GID))
add_uevent_var(env, "DEVGID=%u", from_kgid(&init_user_ns, gid));
kfree(tmp);
}
}
if (dev->type && dev->type->name)
add_uevent_var(env, "DEVTYPE=%s", dev->type->name);
if (dev->driver)
add_uevent_var(env, "DRIVER=%s", dev->driver->name);
/* Add common DT information about the device */
of_device_uevent(dev, env);
/* have the bus specific function add its stuff */
if (dev->bus && dev->bus->uevent) {
retval = dev->bus->uevent(dev, env);
if (retval)
pr_debug("device: '%s': %s: bus uevent() returned %d\n",
dev_name(dev), __func__, retval);
}
/* have the class specific function add its stuff */
if (dev->class && dev->class->dev_uevent) {
retval = dev->class->dev_uevent(dev, env);
if (retval)
pr_debug("device: '%s': %s: class uevent() "
"returned %d\n", dev_name(dev),
__func__, retval);
}
/* have the device type specific function add its stuff */
if (dev->type && dev->type->uevent) {
retval = dev->type->uevent(dev, env);
if (retval)
pr_debug("device: '%s': %s: dev_type uevent() "
"returned %d\n", dev_name(dev),
__func__, retval);
}
return retval;
}
static const struct kset_uevent_ops device_uevent_ops = {
.filter = dev_uevent_filter,
.name = dev_uevent_name,
.uevent = dev_uevent,
};
static ssize_t uevent_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct kobject *top_kobj;
struct kset *kset;
struct kobj_uevent_env *env = NULL;
int i;
size_t count = 0;
int retval;
/* search the kset, the device belongs to */
top_kobj = &dev->kobj;
while (!top_kobj->kset && top_kobj->parent)
top_kobj = top_kobj->parent;
if (!top_kobj->kset)
goto out;
kset = top_kobj->kset;
if (!kset->uevent_ops || !kset->uevent_ops->uevent)
goto out;
/* respect filter */
if (kset->uevent_ops && kset->uevent_ops->filter)
if (!kset->uevent_ops->filter(kset, &dev->kobj))
goto out;
env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
if (!env)
return -ENOMEM;
/* let the kset specific function add its keys */
retval = kset->uevent_ops->uevent(kset, &dev->kobj, env);
if (retval)
goto out;
/* copy keys to file */
for (i = 0; i < env->envp_idx; i++)
count += sprintf(&buf[count], "%s\n", env->envp[i]);
out:
kfree(env);
return count;
}
static ssize_t uevent_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
int rc;
rc = kobject_synth_uevent(&dev->kobj, buf, count);
if (rc) {
dev_err(dev, "uevent: failed to send synthetic uevent\n");
return rc;
}
return count;
}
static DEVICE_ATTR_RW(uevent);
static ssize_t online_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
bool val;
device_lock(dev);
val = !dev->offline;
device_unlock(dev);
return sprintf(buf, "%u\n", val);
}
static ssize_t online_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
bool val;
int ret;
ret = strtobool(buf, &val);
if (ret < 0)
return ret;
ret = lock_device_hotplug_sysfs();
if (ret)
return ret;
ret = val ? device_online(dev) : device_offline(dev);
unlock_device_hotplug();
return ret < 0 ? ret : count;
}
static DEVICE_ATTR_RW(online);
int device_add_groups(struct device *dev, const struct attribute_group **groups)
{
return sysfs_create_groups(&dev->kobj, groups);
}
EXPORT_SYMBOL_GPL(device_add_groups);
void device_remove_groups(struct device *dev,
const struct attribute_group **groups)
{
sysfs_remove_groups(&dev->kobj, groups);
}
EXPORT_SYMBOL_GPL(device_remove_groups);
union device_attr_group_devres {
const struct attribute_group *group;
const struct attribute_group **groups;
};
static int devm_attr_group_match(struct device *dev, void *res, void *data)
{
return ((union device_attr_group_devres *)res)->group == data;
}
static void devm_attr_group_remove(struct device *dev, void *res)
{
union device_attr_group_devres *devres = res;
const struct attribute_group *group = devres->group;
dev_dbg(dev, "%s: removing group %p\n", __func__, group);
sysfs_remove_group(&dev->kobj, group);
}
static void devm_attr_groups_remove(struct device *dev, void *res)
{
union device_attr_group_devres *devres = res;
const struct attribute_group **groups = devres->groups;
dev_dbg(dev, "%s: removing groups %p\n", __func__, groups);
sysfs_remove_groups(&dev->kobj, groups);
}
/**
* devm_device_add_group - given a device, create a managed attribute group
* @dev: The device to create the group for
* @grp: The attribute group to create
*
* This function creates a group for the first time. It will explicitly
* warn and error if any of the attribute files being created already exist.
*
* Returns 0 on success or error code on failure.
*/
int devm_device_add_group(struct device *dev, const struct attribute_group *grp)
{
union device_attr_group_devres *devres;
int error;
devres = devres_alloc(devm_attr_group_remove,
sizeof(*devres), GFP_KERNEL);
if (!devres)
return -ENOMEM;
error = sysfs_create_group(&dev->kobj, grp);
if (error) {
devres_free(devres);
return error;
}
devres->group = grp;
devres_add(dev, devres);
return 0;
}
EXPORT_SYMBOL_GPL(devm_device_add_group);
/**
* devm_device_remove_group: remove a managed group from a device
* @dev: device to remove the group from
* @grp: group to remove
*
* This function removes a group of attributes from a device. The attributes
* previously have to have been created for this group, otherwise it will fail.
*/
void devm_device_remove_group(struct device *dev,
const struct attribute_group *grp)
{
WARN_ON(devres_release(dev, devm_attr_group_remove,
devm_attr_group_match,
/* cast away const */ (void *)grp));
}
EXPORT_SYMBOL_GPL(devm_device_remove_group);
/**
* devm_device_add_groups - create a bunch of managed attribute groups
* @dev: The device to create the group for
* @groups: The attribute groups to create, NULL terminated
*
* This function creates a bunch of managed attribute groups. If an error
* occurs when creating a group, all previously created groups will be
* removed, unwinding everything back to the original state when this
* function was called. It will explicitly warn and error if any of the
* attribute files being created already exist.
*
* Returns 0 on success or error code from sysfs_create_group on failure.
*/
int devm_device_add_groups(struct device *dev,
const struct attribute_group **groups)
{
union device_attr_group_devres *devres;
int error;
devres = devres_alloc(devm_attr_groups_remove,
sizeof(*devres), GFP_KERNEL);
if (!devres)
return -ENOMEM;
error = sysfs_create_groups(&dev->kobj, groups);
if (error) {
devres_free(devres);
return error;
}
devres->groups = groups;
devres_add(dev, devres);
return 0;
}
EXPORT_SYMBOL_GPL(devm_device_add_groups);
/**
* devm_device_remove_groups - remove a list of managed groups
*
* @dev: The device for the groups to be removed from
* @groups: NULL terminated list of groups to be removed
*
* If groups is not NULL, remove the specified groups from the device.
*/
void devm_device_remove_groups(struct device *dev,
const struct attribute_group **groups)
{
WARN_ON(devres_release(dev, devm_attr_groups_remove,
devm_attr_group_match,
/* cast away const */ (void *)groups));
}
EXPORT_SYMBOL_GPL(devm_device_remove_groups);
static int device_add_attrs(struct device *dev)
{
struct class *class = dev->class;
const struct device_type *type = dev->type;
int error;
if (class) {
error = device_add_groups(dev, class->dev_groups);
if (error)
return error;
}
if (type) {
error = device_add_groups(dev, type->groups);
if (error)
goto err_remove_class_groups;
}
error = device_add_groups(dev, dev->groups);
if (error)
goto err_remove_type_groups;
if (device_supports_offline(dev) && !dev->offline_disabled) {
error = device_create_file(dev, &dev_attr_online);
if (error)
goto err_remove_dev_groups;
}
return 0;
err_remove_dev_groups:
device_remove_groups(dev, dev->groups);
err_remove_type_groups:
if (type)
device_remove_groups(dev, type->groups);
err_remove_class_groups:
if (class)
device_remove_groups(dev, class->dev_groups);
return error;
}
static void device_remove_attrs(struct device *dev)
{
struct class *class = dev->class;
const struct device_type *type = dev->type;
device_remove_file(dev, &dev_attr_online);
device_remove_groups(dev, dev->groups);
if (type)
device_remove_groups(dev, type->groups);
if (class)
device_remove_groups(dev, class->dev_groups);
}
static ssize_t dev_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
return print_dev_t(buf, dev->devt);
}
static DEVICE_ATTR_RO(dev);
/* /sys/devices/ */
struct kset *devices_kset;
/**
* devices_kset_move_before - Move device in the devices_kset's list.
* @deva: Device to move.
* @devb: Device @deva should come before.
*/
static void devices_kset_move_before(struct device *deva, struct device *devb)
{
if (!devices_kset)
return;
pr_debug("devices_kset: Moving %s before %s\n",
dev_name(deva), dev_name(devb));
spin_lock(&devices_kset->list_lock);
list_move_tail(&deva->kobj.entry, &devb->kobj.entry);
spin_unlock(&devices_kset->list_lock);
}
/**
* devices_kset_move_after - Move device in the devices_kset's list.
* @deva: Device to move
* @devb: Device @deva should come after.
*/
static void devices_kset_move_after(struct device *deva, struct device *devb)
{
if (!devices_kset)
return;
pr_debug("devices_kset: Moving %s after %s\n",
dev_name(deva), dev_name(devb));
spin_lock(&devices_kset->list_lock);
list_move(&deva->kobj.entry, &devb->kobj.entry);
spin_unlock(&devices_kset->list_lock);
}
/**
* devices_kset_move_last - move the device to the end of devices_kset's list.
* @dev: device to move
*/
void devices_kset_move_last(struct device *dev)
{
if (!devices_kset)
return;
pr_debug("devices_kset: Moving %s to end of list\n", dev_name(dev));
spin_lock(&devices_kset->list_lock);
list_move_tail(&dev->kobj.entry, &devices_kset->list);
spin_unlock(&devices_kset->list_lock);
}
/**
* device_create_file - create sysfs attribute file for device.
* @dev: device.
* @attr: device attribute descriptor.
*/
int device_create_file(struct device *dev,
const struct device_attribute *attr)
{
int error = 0;
if (dev) {
WARN(((attr->attr.mode & S_IWUGO) && !attr->store),
"Attribute %s: write permission without 'store'\n",
attr->attr.name);
WARN(((attr->attr.mode & S_IRUGO) && !attr->show),
"Attribute %s: read permission without 'show'\n",
attr->attr.name);
error = sysfs_create_file(&dev->kobj, &attr->attr);
}
return error;
}
EXPORT_SYMBOL_GPL(device_create_file);
/**
* device_remove_file - remove sysfs attribute file.
* @dev: device.
* @attr: device attribute descriptor.
*/
void device_remove_file(struct device *dev,
const struct device_attribute *attr)
{
if (dev)
sysfs_remove_file(&dev->kobj, &attr->attr);
}
EXPORT_SYMBOL_GPL(device_remove_file);
/**
* device_remove_file_self - remove sysfs attribute file from its own method.
* @dev: device.
* @attr: device attribute descriptor.
*
* See kernfs_remove_self() for details.
*/
bool device_remove_file_self(struct device *dev,
const struct device_attribute *attr)
{
if (dev)
return sysfs_remove_file_self(&dev->kobj, &attr->attr);
else
return false;
}
EXPORT_SYMBOL_GPL(device_remove_file_self);
/**
* device_create_bin_file - create sysfs binary attribute file for device.
* @dev: device.
* @attr: device binary attribute descriptor.
*/
int device_create_bin_file(struct device *dev,
const struct bin_attribute *attr)
{
int error = -EINVAL;
if (dev)
error = sysfs_create_bin_file(&dev->kobj, attr);
return error;
}
EXPORT_SYMBOL_GPL(device_create_bin_file);
/**
* device_remove_bin_file - remove sysfs binary attribute file
* @dev: device.
* @attr: device binary attribute descriptor.
*/
void device_remove_bin_file(struct device *dev,
const struct bin_attribute *attr)
{
if (dev)
sysfs_remove_bin_file(&dev->kobj, attr);
}
EXPORT_SYMBOL_GPL(device_remove_bin_file);
static void klist_children_get(struct klist_node *n)
{
struct device_private *p = to_device_private_parent(n);
struct device *dev = p->device;
get_device(dev);
}
static void klist_children_put(struct klist_node *n)
{
struct device_private *p = to_device_private_parent(n);
struct device *dev = p->device;
put_device(dev);
}
/**
* device_initialize - init device structure.
* @dev: device.
*
* This prepares the device for use by other layers by initializing
* its fields.
* It is the first half of device_register(), if called by
* that function, though it can also be called separately, so one
* may use @dev's fields. In particular, get_device()/put_device()
* may be used for reference counting of @dev after calling this
* function.
*
* All fields in @dev must be initialized by the caller to 0, except
* for those explicitly set to some other value. The simplest
* approach is to use kzalloc() to allocate the structure containing
* @dev.
*
* NOTE: Use put_device() to give up your reference instead of freeing
* @dev directly once you have called this function.
*/
void device_initialize(struct device *dev)
{
dev->kobj.kset = devices_kset;
kobject_init(&dev->kobj, &device_ktype);
INIT_LIST_HEAD(&dev->dma_pools);
mutex_init(&dev->mutex);
#ifdef CONFIG_PROVE_LOCKING
mutex_init(&dev->lockdep_mutex);
#endif
lockdep_set_novalidate_class(&dev->mutex);
spin_lock_init(&dev->devres_lock);
INIT_LIST_HEAD(&dev->devres_head);
device_pm_init(dev);
set_dev_node(dev, -1);
#ifdef CONFIG_GENERIC_MSI_IRQ
INIT_LIST_HEAD(&dev->msi_list);
#endif
INIT_LIST_HEAD(&dev->links.consumers);
INIT_LIST_HEAD(&dev->links.suppliers);
INIT_LIST_HEAD(&dev->links.needs_suppliers);
INIT_LIST_HEAD(&dev->links.defer_sync);
dev->links.status = DL_DEV_NO_DRIVER;
}
EXPORT_SYMBOL_GPL(device_initialize);
struct kobject *virtual_device_parent(struct device *dev)
{
static struct kobject *virtual_dir = NULL;
if (!virtual_dir)
virtual_dir = kobject_create_and_add("virtual",
&devices_kset->kobj);
return virtual_dir;
}
struct class_dir {
struct kobject kobj;
struct class *class;
};
#define to_class_dir(obj) container_of(obj, struct class_dir, kobj)
static void class_dir_release(struct kobject *kobj)
{
struct class_dir *dir = to_class_dir(kobj);
kfree(dir);
}
static const
struct kobj_ns_type_operations *class_dir_child_ns_type(struct kobject *kobj)
{
struct class_dir *dir = to_class_dir(kobj);
return dir->class->ns_type;
}
static struct kobj_type class_dir_ktype = {
.release = class_dir_release,
.sysfs_ops = &kobj_sysfs_ops,
.child_ns_type = class_dir_child_ns_type
};
static struct kobject *
class_dir_create_and_add(struct class *class, struct kobject *parent_kobj)
{
struct class_dir *dir;
int retval;
dir = kzalloc(sizeof(*dir), GFP_KERNEL);
if (!dir)
return ERR_PTR(-ENOMEM);
dir->class = class;
kobject_init(&dir->kobj, &class_dir_ktype);
dir->kobj.kset = &class->p->glue_dirs;
retval = kobject_add(&dir->kobj, parent_kobj, "%s", class->name);
if (retval < 0) {
kobject_put(&dir->kobj);
return ERR_PTR(retval);
}
return &dir->kobj;
}
static DEFINE_MUTEX(gdp_mutex);
static struct kobject *get_device_parent(struct device *dev,
struct device *parent)
{
if (dev->class) {
struct kobject *kobj = NULL;
struct kobject *parent_kobj;
struct kobject *k;
#ifdef CONFIG_BLOCK
/* block disks show up in /sys/block */
if (sysfs_deprecated && dev->class == &block_class) {
if (parent && parent->class == &block_class)
return &parent->kobj;
return &block_class.p->subsys.kobj;
}
#endif
/*
* If we have no parent, we live in "virtual".
* Class-devices with a non class-device as parent, live
* in a "glue" directory to prevent namespace collisions.
*/
if (parent == NULL)
parent_kobj = virtual_device_parent(dev);
else if (parent->class && !dev->class->ns_type)
return &parent->kobj;
else
parent_kobj = &parent->kobj;
mutex_lock(&gdp_mutex);
/* find our class-directory at the parent and reference it */
spin_lock(&dev->class->p->glue_dirs.list_lock);
list_for_each_entry(k, &dev->class->p->glue_dirs.list, entry)
if (k->parent == parent_kobj) {
kobj = kobject_get(k);
break;
}
spin_unlock(&dev->class->p->glue_dirs.list_lock);
if (kobj) {
mutex_unlock(&gdp_mutex);
return kobj;
}
/* or create a new class-directory at the parent device */
k = class_dir_create_and_add(dev->class, parent_kobj);
/* do not emit an uevent for this simple "glue" directory */
mutex_unlock(&gdp_mutex);
return k;
}
/* subsystems can specify a default root directory for their devices */
if (!parent && dev->bus && dev->bus->dev_root)
return &dev->bus->dev_root->kobj;
if (parent)
return &parent->kobj;
return NULL;
}
static inline bool live_in_glue_dir(struct kobject *kobj,
struct device *dev)
{
if (!kobj || !dev->class ||
kobj->kset != &dev->class->p->glue_dirs)
return false;
return true;
}
static inline struct kobject *get_glue_dir(struct device *dev)
{
return dev->kobj.parent;
}
/*
* make sure cleaning up dir as the last step, we need to make
* sure .release handler of kobject is run with holding the
* global lock
*/
static void cleanup_glue_dir(struct device *dev, struct kobject *glue_dir)
{
unsigned int ref;
/* see if we live in a "glue" directory */
if (!live_in_glue_dir(glue_dir, dev))
return;
mutex_lock(&gdp_mutex);
/**
* There is a race condition between removing glue directory
* and adding a new device under the glue directory.
*
* CPU1: CPU2:
*
* device_add()
* get_device_parent()
* class_dir_create_and_add()
* kobject_add_internal()
* create_dir() // create glue_dir
*
* device_add()
* get_device_parent()
* kobject_get() // get glue_dir
*
* device_del()
* cleanup_glue_dir()
* kobject_del(glue_dir)
*
* kobject_add()
* kobject_add_internal()
* create_dir() // in glue_dir
* sysfs_create_dir_ns()
* kernfs_create_dir_ns(sd)
*
* sysfs_remove_dir() // glue_dir->sd=NULL
* sysfs_put() // free glue_dir->sd
*
* // sd is freed
* kernfs_new_node(sd)
* kernfs_get(glue_dir)
* kernfs_add_one()
* kernfs_put()
*
* Before CPU1 remove last child device under glue dir, if CPU2 add
* a new device under glue dir, the glue_dir kobject reference count
* will be increase to 2 in kobject_get(k). And CPU2 has been called
* kernfs_create_dir_ns(). Meanwhile, CPU1 call sysfs_remove_dir()
* and sysfs_put(). This result in glue_dir->sd is freed.
*
* Then the CPU2 will see a stale "empty" but still potentially used
* glue dir around in kernfs_new_node().
*
* In order to avoid this happening, we also should make sure that
* kernfs_node for glue_dir is released in CPU1 only when refcount
* for glue_dir kobj is 1.
*/
ref = kref_read(&glue_dir->kref);
if (!kobject_has_children(glue_dir) && !--ref)
kobject_del(glue_dir);
kobject_put(glue_dir);
mutex_unlock(&gdp_mutex);
}
static int device_add_class_symlinks(struct device *dev)
{
struct device_node *of_node = dev_of_node(dev);
int error;
if (of_node) {
error = sysfs_create_link(&dev->kobj, of_node_kobj(of_node), "of_node");
if (error)
dev_warn(dev, "Error %d creating of_node link\n",error);
/* An error here doesn't warrant bringing down the device */
}
if (!dev->class)
return 0;
error = sysfs_create_link(&dev->kobj,
&dev->class->p->subsys.kobj,
"subsystem");
if (error)
goto out_devnode;
if (dev->parent && device_is_not_partition(dev)) {
error = sysfs_create_link(&dev->kobj, &dev->parent->kobj,
"device");
if (error)
goto out_subsys;
}
#ifdef CONFIG_BLOCK
/* /sys/block has directories and does not need symlinks */
if (sysfs_deprecated && dev->class == &block_class)
return 0;
#endif
/* link in the class directory pointing to the device */
error = sysfs_create_link(&dev->class->p->subsys.kobj,
&dev->kobj, dev_name(dev));
if (error)
goto out_device;
return 0;
out_device:
sysfs_remove_link(&dev->kobj, "device");
out_subsys:
sysfs_remove_link(&dev->kobj, "subsystem");
out_devnode:
sysfs_remove_link(&dev->kobj, "of_node");
return error;
}
static void device_remove_class_symlinks(struct device *dev)
{
if (dev_of_node(dev))
sysfs_remove_link(&dev->kobj, "of_node");
if (!dev->class)
return;
if (dev->parent && device_is_not_partition(dev))
sysfs_remove_link(&dev->kobj, "device");
sysfs_remove_link(&dev->kobj, "subsystem");
#ifdef CONFIG_BLOCK
if (sysfs_deprecated && dev->class == &block_class)
return;
#endif
sysfs_delete_link(&dev->class->p->subsys.kobj, &dev->kobj, dev_name(dev));
}
/**
* dev_set_name - set a device name
* @dev: device
* @fmt: format string for the device's name
*/
int dev_set_name(struct device *dev, const char *fmt, ...)
{
va_list vargs;
int err;
va_start(vargs, fmt);
err = kobject_set_name_vargs(&dev->kobj, fmt, vargs);
va_end(vargs);
return err;
}
EXPORT_SYMBOL_GPL(dev_set_name);
/**
* device_to_dev_kobj - select a /sys/dev/ directory for the device
* @dev: device
*
* By default we select char/ for new entries. Setting class->dev_obj
* to NULL prevents an entry from being created. class->dev_kobj must
* be set (or cleared) before any devices are registered to the class
* otherwise device_create_sys_dev_entry() and
* device_remove_sys_dev_entry() will disagree about the presence of
* the link.
*/
static struct kobject *device_to_dev_kobj(struct device *dev)
{
struct kobject *kobj;
if (dev->class)
kobj = dev->class->dev_kobj;
else
kobj = sysfs_dev_char_kobj;
return kobj;
}
static int device_create_sys_dev_entry(struct device *dev)
{
struct kobject *kobj = device_to_dev_kobj(dev);
int error = 0;
char devt_str[15];
if (kobj) {
format_dev_t(devt_str, dev->devt);
error = sysfs_create_link(kobj, &dev->kobj, devt_str);
}
return error;
}
static void device_remove_sys_dev_entry(struct device *dev)
{
struct kobject *kobj = device_to_dev_kobj(dev);
char devt_str[15];
if (kobj) {
format_dev_t(devt_str, dev->devt);
sysfs_remove_link(kobj, devt_str);
}
}
static int device_private_init(struct device *dev)
{
dev->p = kzalloc(sizeof(*dev->p), GFP_KERNEL);
if (!dev->p)
return -ENOMEM;
dev->p->device = dev;
klist_init(&dev->p->klist_children, klist_children_get,
klist_children_put);
INIT_LIST_HEAD(&dev->p->deferred_probe);
return 0;
}
/**
* device_add - add device to device hierarchy.
* @dev: device.
*
* This is part 2 of device_register(), though may be called
* separately _iff_ device_initialize() has been called separately.
*
* This adds @dev to the kobject hierarchy via kobject_add(), adds it
* to the global and sibling lists for the device, then
* adds it to the other relevant subsystems of the driver model.
*
* Do not call this routine or device_register() more than once for
* any device structure. The driver model core is not designed to work
* with devices that get unregistered and then spring back to life.
* (Among other things, it's very hard to guarantee that all references
* to the previous incarnation of @dev have been dropped.) Allocate
* and register a fresh new struct device instead.
*
* NOTE: _Never_ directly free @dev after calling this function, even
* if it returned an error! Always use put_device() to give up your
* reference instead.
*
* 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;
struct kobject *kobj;
struct class_interface *class_intf;
int error = -EINVAL, fw_ret;
struct kobject *glue_dir = NULL;
dev = get_device(dev);
if (!dev)
goto done;
if (!dev->p) {
error = device_private_init(dev);
if (error)
goto done;
}
/*
* for statically allocated devices, which should all be converted
* some day, we need to initialize the name. We prevent reading back
* the name, and force the use of dev_name()
*/
if (dev->init_name) {
dev_set_name(dev, "%s", dev->init_name);
dev->init_name = NULL;
}
/* subsystems can specify simple device enumeration */
if (!dev_name(dev) && dev->bus && dev->bus->dev_name)
dev_set_name(dev, "%s%u", dev->bus->dev_name, dev->id);
if (!dev_name(dev)) {
error = -EINVAL;
goto name_error;
}
pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
parent = get_device(dev->parent);
kobj = get_device_parent(dev, parent);
if (IS_ERR(kobj)) {
error = PTR_ERR(kobj);
goto parent_error;
}
if (kobj)
dev->kobj.parent = kobj;
/* use parent numa_node */
if (parent && (dev_to_node(dev) == NUMA_NO_NODE))
set_dev_node(dev, dev_to_node(parent));
/* first, register with generic layer. */
/* we require the name to be set before, and pass NULL */
error = kobject_add(&dev->kobj, dev->kobj.parent, NULL);
if (error) {
glue_dir = get_glue_dir(dev);
goto Error;
}
/* notify platform of device entry */
error = device_platform_notify(dev, KOBJ_ADD);
if (error)
goto platform_error;
error = device_create_file(dev, &dev_attr_uevent);
if (error)
goto attrError;
error = device_add_class_symlinks(dev);
if (error)
goto SymlinkError;
error = device_add_attrs(dev);
if (error)
goto AttrsError;
error = bus_add_device(dev);
if (error)
goto BusError;
error = dpm_sysfs_add(dev);
if (error)
goto DPMError;
device_pm_add(dev);
if (MAJOR(dev->devt)) {
error = device_create_file(dev, &dev_attr_dev);
if (error)
goto DevAttrError;
error = device_create_sys_dev_entry(dev);
if (error)
goto SysEntryError;
devtmpfs_create_node(dev);
}
/* Notify clients of device addition. This call must come
* after dpm_sysfs_add() and before kobject_uevent().
*/
if (dev->bus)
blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
BUS_NOTIFY_ADD_DEVICE, dev);
kobject_uevent(&dev->kobj, KOBJ_ADD);
if (dev->fwnode && !dev->fwnode->dev)
dev->fwnode->dev = dev;
/*
* 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 happe 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.
*/
device_link_add_missing_supplier_links();
if (fwnode_has_op(dev->fwnode, add_links)) {
fw_ret = fwnode_call_int_op(dev->fwnode, add_links, dev);
if (fw_ret == -ENODEV)
device_link_wait_for_mandatory_supplier(dev);
else if (fw_ret)
device_link_wait_for_optional_supplier(dev);
}
bus_probe_device(dev);
if (parent)
klist_add_tail(&dev->p->knode_parent,
&parent->p->klist_children);
if (dev->class) {
mutex_lock(&dev->class->p->mutex);
/* tie the class to the device */
klist_add_tail(&dev->p->knode_class,
&dev->class->p->klist_devices);
/* notify any interfaces that the device is here */
list_for_each_entry(class_intf,
&dev->class->p->interfaces, node)
if (class_intf->add_dev)
class_intf->add_dev(dev, class_intf);
mutex_unlock(&dev->class->p->mutex);
}
done:
put_device(dev);
return error;
SysEntryError:
if (MAJOR(dev->devt))
device_remove_file(dev, &dev_attr_dev);
DevAttrError:
device_pm_remove(dev);
dpm_sysfs_remove(dev);
DPMError:
bus_remove_device(dev);
BusError:
device_remove_attrs(dev);
AttrsError:
device_remove_class_symlinks(dev);
SymlinkError:
device_remove_file(dev, &dev_attr_uevent);
attrError:
device_platform_notify(dev, KOBJ_REMOVE);
platform_error:
kobject_uevent(&dev->kobj, KOBJ_REMOVE);
glue_dir = get_glue_dir(dev);
kobject_del(&dev->kobj);
Error:
cleanup_glue_dir(dev, glue_dir);
parent_error:
put_device(parent);
name_error:
kfree(dev->p);
dev->p = NULL;
goto done;
}
EXPORT_SYMBOL_GPL(device_add);
/**
* device_register - register a device with the system.
* @dev: pointer to the device structure
*
* This happens in two clean steps - initialize the device
* and add it to the system. The two steps can be called
* separately, but this is the easiest and most common.
* I.e. you should only call the two helpers separately if
* have a clearly defined need to use and refcount the device
* before it is added to the hierarchy.
*
* For more information, see the kerneldoc for device_initialize()
* and device_add().
*
* NOTE: _Never_ directly free @dev after calling this function, even
* if it returned an error! Always use put_device() to give up the
* reference initialized in this function instead.
*/
int device_register(struct device *dev)
{
device_initialize(dev);
return device_add(dev);
}
EXPORT_SYMBOL_GPL(device_register);
/**
* get_device - increment reference count for device.
* @dev: device.
*
* This simply forwards the call to kobject_get(), though
* we do take care to provide for the case that we get a NULL
* pointer passed in.
*/
struct device *get_device(struct device *dev)
{
return dev ? kobj_to_dev(kobject_get(&dev->kobj)) : NULL;
}
EXPORT_SYMBOL_GPL(get_device);
/**
* put_device - decrement reference count.
* @dev: device in question.
*/
void put_device(struct device *dev)
{
/* might_sleep(); */
if (dev)
kobject_put(&dev->kobj);
}
EXPORT_SYMBOL_GPL(put_device);
bool kill_device(struct device *dev)
{
/*
* Require the device lock and set the "dead" flag to guarantee that
* the update behavior is consistent with the other bitfields near
* it and that we cannot have an asynchronous probe routine trying
* to run while we are tearing out the bus/class/sysfs from
* underneath the device.
*/
lockdep_assert_held(&dev->mutex);
if (dev->p->dead)
return false;
dev->p->dead = true;
return true;
}
EXPORT_SYMBOL_GPL(kill_device);
/**
* device_del - delete device from system.
* @dev: device.
*
* This is the first part of the device unregistration
* sequence. This removes the device from the lists we control
* from here, has it removed from the other driver model
* subsystems it was added to in device_add(), and removes it
* from the kobject hierarchy.
*
* NOTE: this should be called manually _iff_ device_add() was
* also called manually.
*/
void device_del(struct device *dev)
{
struct device *parent = dev->parent;
struct kobject *glue_dir = NULL;
struct class_interface *class_intf;
device_lock(dev);
kill_device(dev);
device_unlock(dev);
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);
dpm_sysfs_remove(dev);
if (parent)
klist_del(&dev->p->knode_parent);
if (MAJOR(dev->devt)) {
devtmpfs_delete_node(dev);
device_remove_sys_dev_entry(dev);
device_remove_file(dev, &dev_attr_dev);
}
if (dev->class) {
device_remove_class_symlinks(dev);
mutex_lock(&dev->class->p->mutex);
/* notify any interfaces that the device is now gone */
list_for_each_entry(class_intf,
&dev->class->p->interfaces, node)
if (class_intf->remove_dev)
class_intf->remove_dev(dev, class_intf);
/* remove the device from the class list */
klist_del(&dev->p->knode_class);
mutex_unlock(&dev->class->p->mutex);
}
device_remove_file(dev, &dev_attr_uevent);
device_remove_attrs(dev);
bus_remove_device(dev);
device_pm_remove(dev);
driver_deferred_probe_del(dev);
device_platform_notify(dev, KOBJ_REMOVE);
device_remove_properties(dev);
device_links_purge(dev);
if (dev->bus)
blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
BUS_NOTIFY_REMOVED_DEVICE, dev);
kobject_uevent(&dev->kobj, KOBJ_REMOVE);
glue_dir = get_glue_dir(dev);
kobject_del(&dev->kobj);
cleanup_glue_dir(dev, glue_dir);
put_device(parent);
}
EXPORT_SYMBOL_GPL(device_del);
/**
* device_unregister - unregister device from system.
* @dev: device going away.
*
* We do this in two parts, like we do device_register(). First,
* we remove it from all the subsystems with device_del(), then
* we decrement the reference count via put_device(). If that
* is the final reference count, the device will be cleaned up
* via device_release() above. Otherwise, the structure will
* stick around until the final reference to the device is dropped.
*/
void device_unregister(struct device *dev)
{
pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
device_del(dev);
put_device(dev);
}
EXPORT_SYMBOL_GPL(device_unregister);
static struct device *prev_device(struct klist_iter *i)
{
struct klist_node *n = klist_prev(i);
struct device *dev = NULL;
struct device_private *p;
if (n) {
p = to_device_private_parent(n);
dev = p->device;
}
return dev;
}
static struct device *next_device(struct klist_iter *i)
{
struct klist_node *n = klist_next(i);
struct device *dev = NULL;
struct device_private *p;
if (n) {
p = to_device_private_parent(n);
dev = p->device;
}
return dev;
}
/**
* device_get_devnode - path of device node file
* @dev: device
* @mode: returned file access mode
* @uid: returned file owner
* @gid: returned file group
* @tmp: possibly allocated string
*
* Return the relative path of a possible device node.
* Non-default names may need to allocate a memory to compose
* a name. This memory is returned in tmp and needs to be
* freed by the caller.
*/
const char *device_get_devnode(struct device *dev,
umode_t *mode, kuid_t *uid, kgid_t *gid,
const char **tmp)
{
char *s;
*tmp = NULL;
/* the device type may provide a specific name */
if (dev->type && dev->type->devnode)
*tmp = dev->type->devnode(dev, mode, uid, gid);
if (*tmp)
return *tmp;
/* the class may provide a specific name */
if (dev->class && dev->class->devnode)
*tmp = dev->class->devnode(dev, mode);
if (*tmp)
return *tmp;
/* return name without allocation, tmp == NULL */
if (strchr(dev_name(dev), '!') == NULL)
return dev_name(dev);
/* replace '!' in the name with '/' */
s = kstrdup(dev_name(dev), GFP_KERNEL);
if (!s)
return NULL;
strreplace(s, '!', '/');
return *tmp = s;
}
/**
* device_for_each_child - device child iterator.
* @parent: parent struct device.
* @fn: function to be called for each device.
* @data: data for the callback.
*
* Iterate over @parent's child devices, and call @fn for each,
* passing it @data.
*
* We check the return of @fn each time. If it returns anything
* other than 0, we break out and return that value.
*/
int device_for_each_child(struct device *parent, void *data,
int (*fn)(struct device *dev, void *data))
{
struct klist_iter i;
struct device *child;
int error = 0;
if (!parent->p)
return 0;
klist_iter_init(&parent->p->klist_children, &i);
while (!error && (child = next_device(&i)))
error = fn(child, data);
klist_iter_exit(&i);
return error;
}
EXPORT_SYMBOL_GPL(device_for_each_child);
/**
* device_for_each_child_reverse - device child iterator in reversed order.
* @parent: parent struct device.
* @fn: function to be called for each device.
* @data: data for the callback.
*
* Iterate over @parent's child devices, and call @fn for each,
* passing it @data.
*
* We check the return of @fn each time. If it returns anything
* other than 0, we break out and return that value.
*/
int device_for_each_child_reverse(struct device *parent, void *data,
int (*fn)(struct device *dev, void *data))
{
struct klist_iter i;
struct device *child;
int error = 0;
if (!parent->p)
return 0;
klist_iter_init(&parent->p->klist_children, &i);
while ((child = prev_device(&i)) && !error)
error = fn(child, data);
klist_iter_exit(&i);
return error;
}
EXPORT_SYMBOL_GPL(device_for_each_child_reverse);
/**
* device_find_child - device iterator for locating a particular device.
* @parent: parent struct device
* @match: Callback function to check device
* @data: Data to pass to match function
*
* This is similar to the device_for_each_child() function above, but it
* returns a reference to a device that is 'found' for later use, as
* determined by the @match callback.
*
* The callback should return 0 if the device doesn't match and non-zero
* if it does. If the callback returns non-zero and a reference to the
* current device can be obtained, this function will return to the caller
* and not iterate over any more devices.
*
* NOTE: you will need to drop the reference with put_device() after use.
*/
struct device *device_find_child(struct device *parent, void *data,
int (*match)(struct device *dev, void *data))
{
struct klist_iter i;
struct device *child;
if (!parent)
return NULL;
klist_iter_init(&parent->p->klist_children, &i);
while ((child = next_device(&i)))
if (match(child, data) && get_device(child))
break;
klist_iter_exit(&i);
return child;
}
EXPORT_SYMBOL_GPL(device_find_child);
/**
* device_find_child_by_name - device iterator for locating a child device.
* @parent: parent struct device
* @name: name of the child device
*
* This is similar to the device_find_child() function above, but it
* returns a reference to a device that has the name @name.
*
* NOTE: you will need to drop the reference with put_device() after use.
*/
struct device *device_find_child_by_name(struct device *parent,
const char *name)
{
struct klist_iter i;
struct device *child;
if (!parent)
return NULL;
klist_iter_init(&parent->p->klist_children, &i);
while ((child = next_device(&i)))
if (!strcmp(dev_name(child), name) && get_device(child))
break;
klist_iter_exit(&i);
return child;
}
EXPORT_SYMBOL_GPL(device_find_child_by_name);
int __init devices_init(void)
{
devices_kset = kset_create_and_add("devices", &device_uevent_ops, NULL);
if (!devices_kset)
return -ENOMEM;
dev_kobj = kobject_create_and_add("dev", NULL);
if (!dev_kobj)
goto dev_kobj_err;
sysfs_dev_block_kobj = kobject_create_and_add("block", dev_kobj);
if (!sysfs_dev_block_kobj)
goto block_kobj_err;
sysfs_dev_char_kobj = kobject_create_and_add("char", dev_kobj);
if (!sysfs_dev_char_kobj)
goto char_kobj_err;
return 0;
char_kobj_err:
kobject_put(sysfs_dev_block_kobj);
block_kobj_err:
kobject_put(dev_kobj);
dev_kobj_err:
kset_unregister(devices_kset);
return -ENOMEM;
}
static int device_check_offline(struct device *dev, void *not_used)
{