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path: root/drivers/base/bus.c
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Diffstat (limited to 'drivers/base/bus.c')
-rw-r--r--drivers/base/bus.c293
1 files changed, 274 insertions, 19 deletions
diff --git a/drivers/base/bus.c b/drivers/base/bus.c
index 000e7b2006f..99dc5921e1d 100644
--- a/drivers/base/bus.c
+++ b/drivers/base/bus.c
@@ -16,9 +16,14 @@
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/string.h>
+#include <linux/mutex.h>
#include "base.h"
#include "power/power.h"
+/* /sys/devices/system */
+/* FIXME: make static after drivers/base/sys.c is deleted */
+struct kset *system_kset;
+
#define to_bus_attr(_attr) container_of(_attr, struct bus_attribute, attr)
/*
@@ -360,6 +365,47 @@ struct device *bus_find_device_by_name(struct bus_type *bus,
}
EXPORT_SYMBOL_GPL(bus_find_device_by_name);
+/**
+ * subsys_find_device_by_id - find a device with a specific enumeration number
+ * @subsys: subsystem
+ * @id: index 'id' in struct device
+ * @hint: device to check first
+ *
+ * Check the hint's next object and if it is a match return it directly,
+ * otherwise, fall back to a full list search. Either way a reference for
+ * the returned object is taken.
+ */
+struct device *subsys_find_device_by_id(struct bus_type *subsys, unsigned int id,
+ struct device *hint)
+{
+ struct klist_iter i;
+ struct device *dev;
+
+ if (!subsys)
+ return NULL;
+
+ if (hint) {
+ klist_iter_init_node(&subsys->p->klist_devices, &i, &hint->p->knode_bus);
+ dev = next_device(&i);
+ if (dev && dev->id == id && get_device(dev)) {
+ klist_iter_exit(&i);
+ return dev;
+ }
+ klist_iter_exit(&i);
+ }
+
+ klist_iter_init_node(&subsys->p->klist_devices, &i, NULL);
+ while ((dev = next_device(&i))) {
+ if (dev->id == id && get_device(dev)) {
+ klist_iter_exit(&i);
+ return dev;
+ }
+ }
+ klist_iter_exit(&i);
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(subsys_find_device_by_id);
+
static struct device_driver *next_driver(struct klist_iter *i)
{
struct klist_node *n = klist_next(i);
@@ -487,38 +533,59 @@ out_put:
void bus_probe_device(struct device *dev)
{
struct bus_type *bus = dev->bus;
+ struct subsys_interface *sif;
int ret;
- if (bus && bus->p->drivers_autoprobe) {
+ if (!bus)
+ return;
+
+ if (bus->p->drivers_autoprobe) {
ret = device_attach(dev);
WARN_ON(ret < 0);
}
+
+ mutex_lock(&bus->p->mutex);
+ list_for_each_entry(sif, &bus->p->interfaces, node)
+ if (sif->add_dev)
+ sif->add_dev(dev, sif);
+ mutex_unlock(&bus->p->mutex);
}
/**
* bus_remove_device - remove device from bus
* @dev: device to be removed
*
- * - Remove symlink from bus's directory.
+ * - Remove device from all interfaces.
+ * - Remove symlink from bus' directory.
* - Delete device from bus's list.
* - Detach from its driver.
* - Drop reference taken in bus_add_device().
*/
void bus_remove_device(struct device *dev)
{
- if (dev->bus) {
- sysfs_remove_link(&dev->kobj, "subsystem");
- sysfs_remove_link(&dev->bus->p->devices_kset->kobj,
- dev_name(dev));
- device_remove_attrs(dev->bus, dev);
- if (klist_node_attached(&dev->p->knode_bus))
- klist_del(&dev->p->knode_bus);
-
- pr_debug("bus: '%s': remove device %s\n",
- dev->bus->name, dev_name(dev));
- device_release_driver(dev);
- bus_put(dev->bus);
- }
+ struct bus_type *bus = dev->bus;
+ struct subsys_interface *sif;
+
+ if (!bus)
+ return;
+
+ mutex_lock(&bus->p->mutex);
+ list_for_each_entry(sif, &bus->p->interfaces, node)
+ if (sif->remove_dev)
+ sif->remove_dev(dev, sif);
+ mutex_unlock(&bus->p->mutex);
+
+ sysfs_remove_link(&dev->kobj, "subsystem");
+ sysfs_remove_link(&dev->bus->p->devices_kset->kobj,
+ dev_name(dev));
+ device_remove_attrs(dev->bus, dev);
+ if (klist_node_attached(&dev->p->knode_bus))
+ klist_del(&dev->p->knode_bus);
+
+ pr_debug("bus: '%s': remove device %s\n",
+ dev->bus->name, dev_name(dev));
+ device_release_driver(dev);
+ bus_put(dev->bus);
}
static int driver_add_attrs(struct bus_type *bus, struct device_driver *drv)
@@ -847,14 +914,14 @@ static ssize_t bus_uevent_store(struct bus_type *bus,
static BUS_ATTR(uevent, S_IWUSR, NULL, bus_uevent_store);
/**
- * bus_register - register a bus with the system.
+ * __bus_register - register a driver-core subsystem
* @bus: bus.
*
* Once we have that, we registered the bus with the kobject
* infrastructure, then register the children subsystems it has:
- * the devices and drivers that belong to the bus.
+ * the devices and drivers that belong to the subsystem.
*/
-int bus_register(struct bus_type *bus)
+int __bus_register(struct bus_type *bus, struct lock_class_key *key)
{
int retval;
struct subsys_private *priv;
@@ -898,6 +965,8 @@ int bus_register(struct bus_type *bus)
goto bus_drivers_fail;
}
+ INIT_LIST_HEAD(&priv->interfaces);
+ __mutex_init(&priv->mutex, "subsys mutex", key);
klist_init(&priv->klist_devices, klist_devices_get, klist_devices_put);
klist_init(&priv->klist_drivers, NULL, NULL);
@@ -927,7 +996,7 @@ out:
bus->p = NULL;
return retval;
}
-EXPORT_SYMBOL_GPL(bus_register);
+EXPORT_SYMBOL_GPL(__bus_register);
/**
* bus_unregister - remove a bus from the system
@@ -939,6 +1008,8 @@ EXPORT_SYMBOL_GPL(bus_register);
void bus_unregister(struct bus_type *bus)
{
pr_debug("bus: '%s': unregistering\n", bus->name);
+ if (bus->dev_root)
+ device_unregister(bus->dev_root);
bus_remove_attrs(bus);
remove_probe_files(bus);
kset_unregister(bus->p->drivers_kset);
@@ -1028,10 +1099,194 @@ void bus_sort_breadthfirst(struct bus_type *bus,
}
EXPORT_SYMBOL_GPL(bus_sort_breadthfirst);
+/**
+ * subsys_dev_iter_init - initialize subsys device iterator
+ * @iter: subsys iterator to initialize
+ * @subsys: the subsys we wanna iterate over
+ * @start: the device to start iterating from, if any
+ * @type: device_type of the devices to iterate over, NULL for all
+ *
+ * Initialize subsys iterator @iter such that it iterates over devices
+ * of @subsys. If @start is set, the list iteration will start there,
+ * otherwise if it is NULL, the iteration starts at the beginning of
+ * the list.
+ */
+void subsys_dev_iter_init(struct subsys_dev_iter *iter, struct bus_type *subsys,
+ struct device *start, const struct device_type *type)
+{
+ struct klist_node *start_knode = NULL;
+
+ if (start)
+ start_knode = &start->p->knode_bus;
+ klist_iter_init_node(&subsys->p->klist_devices, &iter->ki, start_knode);
+ iter->type = type;
+}
+EXPORT_SYMBOL_GPL(subsys_dev_iter_init);
+
+/**
+ * subsys_dev_iter_next - iterate to the next device
+ * @iter: subsys iterator to proceed
+ *
+ * Proceed @iter to the next device and return it. Returns NULL if
+ * iteration is complete.
+ *
+ * The returned device is referenced and won't be released till
+ * iterator is proceed to the next device or exited. The caller is
+ * free to do whatever it wants to do with the device including
+ * calling back into subsys code.
+ */
+struct device *subsys_dev_iter_next(struct subsys_dev_iter *iter)
+{
+ struct klist_node *knode;
+ struct device *dev;
+
+ for (;;) {
+ knode = klist_next(&iter->ki);
+ if (!knode)
+ return NULL;
+ dev = container_of(knode, struct device_private, knode_bus)->device;
+ if (!iter->type || iter->type == dev->type)
+ return dev;
+ }
+}
+EXPORT_SYMBOL_GPL(subsys_dev_iter_next);
+
+/**
+ * subsys_dev_iter_exit - finish iteration
+ * @iter: subsys iterator to finish
+ *
+ * Finish an iteration. Always call this function after iteration is
+ * complete whether the iteration ran till the end or not.
+ */
+void subsys_dev_iter_exit(struct subsys_dev_iter *iter)
+{
+ klist_iter_exit(&iter->ki);
+}
+EXPORT_SYMBOL_GPL(subsys_dev_iter_exit);
+
+int subsys_interface_register(struct subsys_interface *sif)
+{
+ struct bus_type *subsys;
+ struct subsys_dev_iter iter;
+ struct device *dev;
+
+ if (!sif || !sif->subsys)
+ return -ENODEV;
+
+ subsys = bus_get(sif->subsys);
+ if (!subsys)
+ return -EINVAL;
+
+ mutex_lock(&subsys->p->mutex);
+ list_add_tail(&sif->node, &subsys->p->interfaces);
+ if (sif->add_dev) {
+ subsys_dev_iter_init(&iter, subsys, NULL, NULL);
+ while ((dev = subsys_dev_iter_next(&iter)))
+ sif->add_dev(dev, sif);
+ subsys_dev_iter_exit(&iter);
+ }
+ mutex_unlock(&subsys->p->mutex);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(subsys_interface_register);
+
+void subsys_interface_unregister(struct subsys_interface *sif)
+{
+ struct bus_type *subsys = sif->subsys;
+ struct subsys_dev_iter iter;
+ struct device *dev;
+
+ if (!sif)
+ return;
+
+ mutex_lock(&subsys->p->mutex);
+ list_del_init(&sif->node);
+ if (sif->remove_dev) {
+ subsys_dev_iter_init(&iter, subsys, NULL, NULL);
+ while ((dev = subsys_dev_iter_next(&iter)))
+ sif->remove_dev(dev, sif);
+ subsys_dev_iter_exit(&iter);
+ }
+ mutex_unlock(&subsys->p->mutex);
+
+ bus_put(subsys);
+}
+EXPORT_SYMBOL_GPL(subsys_interface_unregister);
+
+static void system_root_device_release(struct device *dev)
+{
+ kfree(dev);
+}
+/**
+ * subsys_system_register - register a subsystem at /sys/devices/system/
+ * @subsys - system subsystem
+ * @groups - default attributes for the root device
+ *
+ * All 'system' subsystems have a /sys/devices/system/<name> root device
+ * with the name of the subsystem. The root device can carry subsystem-
+ * wide attributes. All registered devices are below this single root
+ * device and are named after the subsystem with a simple enumeration
+ * number appended. The registered devices are not explicitely named;
+ * only 'id' in the device needs to be set.
+ *
+ * Do not use this interface for anything new, it exists for compatibility
+ * with bad ideas only. New subsystems should use plain subsystems; and
+ * add the subsystem-wide attributes should be added to the subsystem
+ * directory itself and not some create fake root-device placed in
+ * /sys/devices/system/<name>.
+ */
+int subsys_system_register(struct bus_type *subsys,
+ const struct attribute_group **groups)
+{
+ struct device *dev;
+ int err;
+
+ err = bus_register(subsys);
+ if (err < 0)
+ return err;
+
+ dev = kzalloc(sizeof(struct device), GFP_KERNEL);
+ if (!dev) {
+ err = -ENOMEM;
+ goto err_dev;
+ }
+
+ err = dev_set_name(dev, "%s", subsys->name);
+ if (err < 0)
+ goto err_name;
+
+ dev->kobj.parent = &system_kset->kobj;
+ dev->groups = groups;
+ dev->release = system_root_device_release;
+
+ err = device_register(dev);
+ if (err < 0)
+ goto err_dev_reg;
+
+ subsys->dev_root = dev;
+ return 0;
+
+err_dev_reg:
+ put_device(dev);
+ dev = NULL;
+err_name:
+ kfree(dev);
+err_dev:
+ bus_unregister(subsys);
+ return err;
+}
+EXPORT_SYMBOL_GPL(subsys_system_register);
+
int __init buses_init(void)
{
bus_kset = kset_create_and_add("bus", &bus_uevent_ops, NULL);
if (!bus_kset)
return -ENOMEM;
+
+ system_kset = kset_create_and_add("system", NULL, &devices_kset->kobj);
+ if (!system_kset)
+ return -ENOMEM;
+
return 0;
}