/**
* bus_register - register a driver-core subsystem
* @bus: bus to register
*
* Once we have that, we register the bus with the kobject
* infrastructure, then register the children subsystems it has:
* the devices and drivers that belong to the subsystem.
*/
int bus_register(struct bus_type *bus)
{
int retval;
struct subsys_private *priv;
struct lock_class_key *key = &bus->lock_key;
priv = kzalloc(sizeof(struct subsys_private), GFP_KERNEL);
if (!priv)
return -ENOMEM;
priv->bus = bus;
bus->p = priv;
BLOCKING_INIT_NOTIFIER_HEAD(&priv->bus_notifier);
retval = kobject_set_name(&priv->subsys.kobj, "%s", bus->name);
if (retval)
goto out;
priv->subsys.kobj.kset = bus_kset;
priv->subsys.kobj.ktype = &bus_ktype;
priv->drivers_autoprobe = 1;
retval = kset_register(&priv->subsys);
if (retval)
goto out;
retval = bus_create_file(bus, &bus_attr_uevent);
if (retval)
goto bus_uevent_fail;
priv->devices_kset = kset_create_and_add("devices", NULL,
&priv->subsys.kobj);
if (!priv->devices_kset) {
retval = -ENOMEM;
goto bus_devices_fail;
}
priv->drivers_kset = kset_create_and_add("drivers", NULL,
&priv->subsys.kobj);
if (!priv->drivers_kset) {
retval = -ENOMEM;
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);
retval = add_probe_files(bus);
if (retval)
goto bus_probe_files_fail;
retval = bus_add_attrs(bus);
if (retval)
goto bus_attrs_fail;
pr_debug("bus: '%s': registered\n", bus->name);
return 0;
bus_attrs_fail:
remove_probe_files(bus);
bus_probe_files_fail:
kset_unregister(bus->p->drivers_kset);
bus_drivers_fail:
kset_unregister(bus->p->devices_kset);
bus_devices_fail:
bus_remove_file(bus, &bus_attr_uevent);
bus_uevent_fail:
kset_unregister(&bus->p->subsys);
out:
kfree(bus->p);
bus->p = NULL;
return retval;
}
//向系统添加一个新总线
int bus_register(struct bus_type * bus)
{
int retval;
BLOCKING_INIT_NOTIFIER_HEAD(&bus->bus_notifier);
//通过嵌入的kset类型成员subsys，将新总线添加到总线子系统
retval = kobject_set_name(&bus->subsys.kobj, "%s", bus->name);
if (retval)
goto out;
bus->subsys.kobj.kset = &bus_subsys;
retval = subsystem_register(&bus->subsys);
if (retval)
goto out;
retval = bus_create_file(bus, &bus_attr_uevent);
if (retval)
goto bus_uevent_fail;
//总线需要连接相关设备及其驱动程序的所有有关信息，
//因此总线对二者注册了kset。两个kset分别是drivers和devices，都将总线作为父结点
kobject_set_name(&bus->devices.kobj, "devices");
bus->devices.kobj.parent = &bus->subsys.kobj;
retval = kset_register(&bus->devices);
if (retval)
goto bus_devices_fail;
kobject_set_name(&bus->drivers.kobj, "drivers");
bus->drivers.kobj.parent = &bus->subsys.kobj;
bus->drivers.ktype = &driver_ktype;
retval = kset_register(&bus->drivers);
if (retval)
goto bus_drivers_fail;
klist_init(&bus->klist_devices, klist_devices_get, klist_devices_put);
klist_init(&bus->klist_drivers, NULL, NULL);
bus->drivers_autoprobe = 1;
retval = add_probe_files(bus);
if (retval)
goto bus_probe_files_fail;
retval = bus_add_attrs(bus);
if (retval)
goto bus_attrs_fail;
pr_debug("bus type '%s' registered\n", bus->name);
return 0;
bus_attrs_fail:
remove_probe_files(bus);
bus_probe_files_fail:
kset_unregister(&bus->drivers);
bus_drivers_fail:
kset_unregister(&bus->devices);
bus_devices_fail:
bus_remove_file(bus, &bus_attr_uevent);
bus_uevent_fail:
subsystem_unregister(&bus->subsys);
out:
return retval;
}
