| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * bus.c - bus driver management |
| * |
| * Copyright (c) 2002-3 Patrick Mochel |
| * Copyright (c) 2002-3 Open Source Development Labs |
| * Copyright (c) 2007 Greg Kroah-Hartman <gregkh@suse.de> |
| * Copyright (c) 2007 Novell Inc. |
| */ |
| |
| #include <linux/async.h> |
| #include <linux/device/bus.h> |
| #include <linux/device.h> |
| #include <linux/module.h> |
| #include <linux/errno.h> |
| #include <linux/slab.h> |
| #include <linux/init.h> |
| #include <linux/string.h> |
| #include <linux/mutex.h> |
| #include <linux/sysfs.h> |
| #include "base.h" |
| #include "power/power.h" |
| |
| /* /sys/devices/system */ |
| static struct kset *system_kset; |
| |
| #define to_bus_attr(_attr) container_of(_attr, struct bus_attribute, attr) |
| |
| /* |
| * sysfs bindings for drivers |
| */ |
| |
| #define to_drv_attr(_attr) container_of(_attr, struct driver_attribute, attr) |
| |
| #define DRIVER_ATTR_IGNORE_LOCKDEP(_name, _mode, _show, _store) \ |
| struct driver_attribute driver_attr_##_name = \ |
| __ATTR_IGNORE_LOCKDEP(_name, _mode, _show, _store) |
| |
| static int __must_check bus_rescan_devices_helper(struct device *dev, |
| void *data); |
| |
| static struct bus_type *bus_get(struct bus_type *bus) |
| { |
| if (bus) { |
| kset_get(&bus->p->subsys); |
| return bus; |
| } |
| return NULL; |
| } |
| |
| static void bus_put(struct bus_type *bus) |
| { |
| if (bus) |
| kset_put(&bus->p->subsys); |
| } |
| |
| static ssize_t drv_attr_show(struct kobject *kobj, struct attribute *attr, |
| char *buf) |
| { |
| struct driver_attribute *drv_attr = to_drv_attr(attr); |
| struct driver_private *drv_priv = to_driver(kobj); |
| ssize_t ret = -EIO; |
| |
| if (drv_attr->show) |
| ret = drv_attr->show(drv_priv->driver, buf); |
| return ret; |
| } |
| |
| static ssize_t drv_attr_store(struct kobject *kobj, struct attribute *attr, |
| const char *buf, size_t count) |
| { |
| struct driver_attribute *drv_attr = to_drv_attr(attr); |
| struct driver_private *drv_priv = to_driver(kobj); |
| ssize_t ret = -EIO; |
| |
| if (drv_attr->store) |
| ret = drv_attr->store(drv_priv->driver, buf, count); |
| return ret; |
| } |
| |
| static const struct sysfs_ops driver_sysfs_ops = { |
| .show = drv_attr_show, |
| .store = drv_attr_store, |
| }; |
| |
| static void driver_release(struct kobject *kobj) |
| { |
| struct driver_private *drv_priv = to_driver(kobj); |
| |
| pr_debug("driver: '%s': %s\n", kobject_name(kobj), __func__); |
| kfree(drv_priv); |
| } |
| |
| static struct kobj_type driver_ktype = { |
| .sysfs_ops = &driver_sysfs_ops, |
| .release = driver_release, |
| }; |
| |
| /* |
| * sysfs bindings for buses |
| */ |
| static ssize_t bus_attr_show(struct kobject *kobj, struct attribute *attr, |
| char *buf) |
| { |
| struct bus_attribute *bus_attr = to_bus_attr(attr); |
| struct subsys_private *subsys_priv = to_subsys_private(kobj); |
| ssize_t ret = 0; |
| |
| if (bus_attr->show) |
| ret = bus_attr->show(subsys_priv->bus, buf); |
| return ret; |
| } |
| |
| static ssize_t bus_attr_store(struct kobject *kobj, struct attribute *attr, |
| const char *buf, size_t count) |
| { |
| struct bus_attribute *bus_attr = to_bus_attr(attr); |
| struct subsys_private *subsys_priv = to_subsys_private(kobj); |
| ssize_t ret = 0; |
| |
| if (bus_attr->store) |
| ret = bus_attr->store(subsys_priv->bus, buf, count); |
| return ret; |
| } |
| |
| static const struct sysfs_ops bus_sysfs_ops = { |
| .show = bus_attr_show, |
| .store = bus_attr_store, |
| }; |
| |
| int bus_create_file(struct bus_type *bus, struct bus_attribute *attr) |
| { |
| int error; |
| if (bus_get(bus)) { |
| error = sysfs_create_file(&bus->p->subsys.kobj, &attr->attr); |
| bus_put(bus); |
| } else |
| error = -EINVAL; |
| return error; |
| } |
| EXPORT_SYMBOL_GPL(bus_create_file); |
| |
| void bus_remove_file(struct bus_type *bus, struct bus_attribute *attr) |
| { |
| if (bus_get(bus)) { |
| sysfs_remove_file(&bus->p->subsys.kobj, &attr->attr); |
| bus_put(bus); |
| } |
| } |
| EXPORT_SYMBOL_GPL(bus_remove_file); |
| |
| static void bus_release(struct kobject *kobj) |
| { |
| struct subsys_private *priv = to_subsys_private(kobj); |
| struct bus_type *bus = priv->bus; |
| |
| kfree(priv); |
| bus->p = NULL; |
| } |
| |
| static struct kobj_type bus_ktype = { |
| .sysfs_ops = &bus_sysfs_ops, |
| .release = bus_release, |
| }; |
| |
| static int bus_uevent_filter(struct kset *kset, struct kobject *kobj) |
| { |
| struct kobj_type *ktype = get_ktype(kobj); |
| |
| if (ktype == &bus_ktype) |
| return 1; |
| return 0; |
| } |
| |
| static const struct kset_uevent_ops bus_uevent_ops = { |
| .filter = bus_uevent_filter, |
| }; |
| |
| static struct kset *bus_kset; |
| |
| /* Manually detach a device from its associated driver. */ |
| static ssize_t unbind_store(struct device_driver *drv, const char *buf, |
| size_t count) |
| { |
| struct bus_type *bus = bus_get(drv->bus); |
| struct device *dev; |
| int err = -ENODEV; |
| |
| dev = bus_find_device_by_name(bus, NULL, buf); |
| if (dev && dev->driver == drv) { |
| device_driver_detach(dev); |
| err = count; |
| } |
| put_device(dev); |
| bus_put(bus); |
| return err; |
| } |
| static DRIVER_ATTR_IGNORE_LOCKDEP(unbind, S_IWUSR, NULL, unbind_store); |
| |
| /* |
| * Manually attach a device to a driver. |
| * Note: the driver must want to bind to the device, |
| * it is not possible to override the driver's id table. |
| */ |
| static ssize_t bind_store(struct device_driver *drv, const char *buf, |
| size_t count) |
| { |
| struct bus_type *bus = bus_get(drv->bus); |
| struct device *dev; |
| int err = -ENODEV; |
| |
| dev = bus_find_device_by_name(bus, NULL, buf); |
| if (dev && dev->driver == NULL && driver_match_device(drv, dev)) { |
| err = device_driver_attach(drv, dev); |
| |
| if (err > 0) { |
| /* success */ |
| err = count; |
| } else if (err == 0) { |
| /* driver didn't accept device */ |
| err = -ENODEV; |
| } |
| } |
| put_device(dev); |
| bus_put(bus); |
| return err; |
| } |
| static DRIVER_ATTR_IGNORE_LOCKDEP(bind, S_IWUSR, NULL, bind_store); |
| |
| static ssize_t drivers_autoprobe_show(struct bus_type *bus, char *buf) |
| { |
| return sysfs_emit(buf, "%d\n", bus->p->drivers_autoprobe); |
| } |
| |
| static ssize_t drivers_autoprobe_store(struct bus_type *bus, |
| const char *buf, size_t count) |
| { |
| if (buf[0] == '0') |
| bus->p->drivers_autoprobe = 0; |
| else |
| bus->p->drivers_autoprobe = 1; |
| return count; |
| } |
| |
| static ssize_t drivers_probe_store(struct bus_type *bus, |
| const char *buf, size_t count) |
| { |
| struct device *dev; |
| int err = -EINVAL; |
| |
| dev = bus_find_device_by_name(bus, NULL, buf); |
| if (!dev) |
| return -ENODEV; |
| if (bus_rescan_devices_helper(dev, NULL) == 0) |
| err = count; |
| put_device(dev); |
| return err; |
| } |
| |
| static struct device *next_device(struct klist_iter *i) |
| { |
| struct klist_node *n = klist_next(i); |
| struct device *dev = NULL; |
| struct device_private *dev_prv; |
| |
| if (n) { |
| dev_prv = to_device_private_bus(n); |
| dev = dev_prv->device; |
| } |
| return dev; |
| } |
| |
| /** |
| * bus_for_each_dev - device iterator. |
| * @bus: bus type. |
| * @start: device to start iterating from. |
| * @data: data for the callback. |
| * @fn: function to be called for each device. |
| * |
| * Iterate over @bus's list of devices, and call @fn for each, |
| * passing it @data. If @start is not NULL, we use that device to |
| * begin iterating from. |
| * |
| * We check the return of @fn each time. If it returns anything |
| * other than 0, we break out and return that value. |
| * |
| * NOTE: The device that returns a non-zero value is not retained |
| * in any way, nor is its refcount incremented. If the caller needs |
| * to retain this data, it should do so, and increment the reference |
| * count in the supplied callback. |
| */ |
| int bus_for_each_dev(struct bus_type *bus, struct device *start, |
| void *data, int (*fn)(struct device *, void *)) |
| { |
| struct klist_iter i; |
| struct device *dev; |
| int error = 0; |
| |
| if (!bus || !bus->p) |
| return -EINVAL; |
| |
| klist_iter_init_node(&bus->p->klist_devices, &i, |
| (start ? &start->p->knode_bus : NULL)); |
| while (!error && (dev = next_device(&i))) |
| error = fn(dev, data); |
| klist_iter_exit(&i); |
| return error; |
| } |
| EXPORT_SYMBOL_GPL(bus_for_each_dev); |
| |
| /** |
| * bus_find_device - device iterator for locating a particular device. |
| * @bus: bus type |
| * @start: Device to begin with |
| * @data: Data to pass to match function |
| * @match: Callback function to check device |
| * |
| * This is similar to the bus_for_each_dev() 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, this function will |
| * return to the caller and not iterate over any more devices. |
| */ |
| struct device *bus_find_device(struct bus_type *bus, |
| struct device *start, const void *data, |
| int (*match)(struct device *dev, const void *data)) |
| { |
| struct klist_iter i; |
| struct device *dev; |
| |
| if (!bus || !bus->p) |
| return NULL; |
| |
| klist_iter_init_node(&bus->p->klist_devices, &i, |
| (start ? &start->p->knode_bus : NULL)); |
| while ((dev = next_device(&i))) |
| if (match(dev, data) && get_device(dev)) |
| break; |
| klist_iter_exit(&i); |
| return dev; |
| } |
| EXPORT_SYMBOL_GPL(bus_find_device); |
| |
| /** |
| * 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); |
| struct driver_private *drv_priv; |
| |
| if (n) { |
| drv_priv = container_of(n, struct driver_private, knode_bus); |
| return drv_priv->driver; |
| } |
| return NULL; |
| } |
| |
| /** |
| * bus_for_each_drv - driver iterator |
| * @bus: bus we're dealing with. |
| * @start: driver to start iterating on. |
| * @data: data to pass to the callback. |
| * @fn: function to call for each driver. |
| * |
| * This is nearly identical to the device iterator above. |
| * We iterate over each driver that belongs to @bus, and call |
| * @fn for each. If @fn returns anything but 0, we break out |
| * and return it. If @start is not NULL, we use it as the head |
| * of the list. |
| * |
| * NOTE: we don't return the driver that returns a non-zero |
| * value, nor do we leave the reference count incremented for that |
| * driver. If the caller needs to know that info, it must set it |
| * in the callback. It must also be sure to increment the refcount |
| * so it doesn't disappear before returning to the caller. |
| */ |
| int bus_for_each_drv(struct bus_type *bus, struct device_driver *start, |
| void *data, int (*fn)(struct device_driver *, void *)) |
| { |
| struct klist_iter i; |
| struct device_driver *drv; |
| int error = 0; |
| |
| if (!bus) |
| return -EINVAL; |
| |
| klist_iter_init_node(&bus->p->klist_drivers, &i, |
| start ? &start->p->knode_bus : NULL); |
| while ((drv = next_driver(&i)) && !error) |
| error = fn(drv, data); |
| klist_iter_exit(&i); |
| return error; |
| } |
| EXPORT_SYMBOL_GPL(bus_for_each_drv); |
| |
| /** |
| * bus_add_device - add device to bus |
| * @dev: device being added |
| * |
| * - Add device's bus attributes. |
| * - Create links to device's bus. |
| * - Add the device to its bus's list of devices. |
| */ |
| int bus_add_device(struct device *dev) |
| { |
| struct bus_type *bus = bus_get(dev->bus); |
| int error = 0; |
| |
| if (bus) { |
| pr_debug("bus: '%s': add device %s\n", bus->name, dev_name(dev)); |
| error = device_add_groups(dev, bus->dev_groups); |
| if (error) |
| goto out_put; |
| error = sysfs_create_link(&bus->p->devices_kset->kobj, |
| &dev->kobj, dev_name(dev)); |
| if (error) |
| goto out_groups; |
| error = sysfs_create_link(&dev->kobj, |
| &dev->bus->p->subsys.kobj, "subsystem"); |
| if (error) |
| goto out_subsys; |
| klist_add_tail(&dev->p->knode_bus, &bus->p->klist_devices); |
| } |
| return 0; |
| |
| out_subsys: |
| sysfs_remove_link(&bus->p->devices_kset->kobj, dev_name(dev)); |
| out_groups: |
| device_remove_groups(dev, bus->dev_groups); |
| out_put: |
| bus_put(dev->bus); |
| return error; |
| } |
| |
| /** |
| * bus_probe_device - probe drivers for a new device |
| * @dev: device to probe |
| * |
| * - Automatically probe for a driver if the bus allows it. |
| */ |
| void bus_probe_device(struct device *dev) |
| { |
| struct bus_type *bus = dev->bus; |
| struct subsys_interface *sif; |
| |
| if (!bus) |
| return; |
| |
| if (bus->p->drivers_autoprobe) |
| device_initial_probe(dev); |
| |
| 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 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) |
| { |
| 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_groups(dev, dev->bus->dev_groups); |
| 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 __must_check add_bind_files(struct device_driver *drv) |
| { |
| int ret; |
| |
| ret = driver_create_file(drv, &driver_attr_unbind); |
| if (ret == 0) { |
| ret = driver_create_file(drv, &driver_attr_bind); |
| if (ret) |
| driver_remove_file(drv, &driver_attr_unbind); |
| } |
| return ret; |
| } |
| |
| static void remove_bind_files(struct device_driver *drv) |
| { |
| driver_remove_file(drv, &driver_attr_bind); |
| driver_remove_file(drv, &driver_attr_unbind); |
| } |
| |
| static BUS_ATTR_WO(drivers_probe); |
| static BUS_ATTR_RW(drivers_autoprobe); |
| |
| static int add_probe_files(struct bus_type *bus) |
| { |
| int retval; |
| |
| retval = bus_create_file(bus, &bus_attr_drivers_probe); |
| if (retval) |
| goto out; |
| |
| retval = bus_create_file(bus, &bus_attr_drivers_autoprobe); |
| if (retval) |
| bus_remove_file(bus, &bus_attr_drivers_probe); |
| out: |
| return retval; |
| } |
| |
| static void remove_probe_files(struct bus_type *bus) |
| { |
| bus_remove_file(bus, &bus_attr_drivers_autoprobe); |
| bus_remove_file(bus, &bus_attr_drivers_probe); |
| } |
| |
| static ssize_t uevent_store(struct device_driver *drv, const char *buf, |
| size_t count) |
| { |
| int rc; |
| |
| rc = kobject_synth_uevent(&drv->p->kobj, buf, count); |
| return rc ? rc : count; |
| } |
| static DRIVER_ATTR_WO(uevent); |
| |
| /** |
| * bus_add_driver - Add a driver to the bus. |
| * @drv: driver. |
| */ |
| int bus_add_driver(struct device_driver *drv) |
| { |
| struct bus_type *bus; |
| struct driver_private *priv; |
| int error = 0; |
| |
| bus = bus_get(drv->bus); |
| if (!bus) |
| return -EINVAL; |
| |
| pr_debug("bus: '%s': add driver %s\n", bus->name, drv->name); |
| |
| priv = kzalloc(sizeof(*priv), GFP_KERNEL); |
| if (!priv) { |
| error = -ENOMEM; |
| goto out_put_bus; |
| } |
| klist_init(&priv->klist_devices, NULL, NULL); |
| priv->driver = drv; |
| drv->p = priv; |
| priv->kobj.kset = bus->p->drivers_kset; |
| error = kobject_init_and_add(&priv->kobj, &driver_ktype, NULL, |
| "%s", drv->name); |
| if (error) |
| goto out_unregister; |
| |
| klist_add_tail(&priv->knode_bus, &bus->p->klist_drivers); |
| if (drv->bus->p->drivers_autoprobe) { |
| error = driver_attach(drv); |
| if (error) |
| goto out_del_list; |
| } |
| module_add_driver(drv->owner, drv); |
| |
| error = driver_create_file(drv, &driver_attr_uevent); |
| if (error) { |
| printk(KERN_ERR "%s: uevent attr (%s) failed\n", |
| __func__, drv->name); |
| } |
| error = driver_add_groups(drv, bus->drv_groups); |
| if (error) { |
| /* How the hell do we get out of this pickle? Give up */ |
| printk(KERN_ERR "%s: driver_create_groups(%s) failed\n", |
| __func__, drv->name); |
| } |
| |
| if (!drv->suppress_bind_attrs) { |
| error = add_bind_files(drv); |
| if (error) { |
| /* Ditto */ |
| printk(KERN_ERR "%s: add_bind_files(%s) failed\n", |
| __func__, drv->name); |
| } |
| } |
| |
| return 0; |
| |
| out_del_list: |
| klist_del(&priv->knode_bus); |
| out_unregister: |
| kobject_put(&priv->kobj); |
| /* drv->p is freed in driver_release() */ |
| drv->p = NULL; |
| out_put_bus: |
| bus_put(bus); |
| return error; |
| } |
| |
| /** |
| * bus_remove_driver - delete driver from bus's knowledge. |
| * @drv: driver. |
| * |
| * Detach the driver from the devices it controls, and remove |
| * it from its bus's list of drivers. Finally, we drop the reference |
| * to the bus we took in bus_add_driver(). |
| */ |
| void bus_remove_driver(struct device_driver *drv) |
| { |
| if (!drv->bus) |
| return; |
| |
| if (!drv->suppress_bind_attrs) |
| remove_bind_files(drv); |
| driver_remove_groups(drv, drv->bus->drv_groups); |
| driver_remove_file(drv, &driver_attr_uevent); |
| klist_remove(&drv->p->knode_bus); |
| pr_debug("bus: '%s': remove driver %s\n", drv->bus->name, drv->name); |
| driver_detach(drv); |
| module_remove_driver(drv); |
| kobject_put(&drv->p->kobj); |
| bus_put(drv->bus); |
| } |
| |
| /* Helper for bus_rescan_devices's iter */ |
| static int __must_check bus_rescan_devices_helper(struct device *dev, |
| void *data) |
| { |
| int ret = 0; |
| |
| if (!dev->driver) { |
| if (dev->parent && dev->bus->need_parent_lock) |
| device_lock(dev->parent); |
| ret = device_attach(dev); |
| if (dev->parent && dev->bus->need_parent_lock) |
| device_unlock(dev->parent); |
| } |
| return ret < 0 ? ret : 0; |
| } |
| |
| /** |
| * bus_rescan_devices - rescan devices on the bus for possible drivers |
| * @bus: the bus to scan. |
| * |
| * This function will look for devices on the bus with no driver |
| * attached and rescan it against existing drivers to see if it matches |
| * any by calling device_attach() for the unbound devices. |
| */ |
| int bus_rescan_devices(struct bus_type *bus) |
| { |
| return bus_for_each_dev(bus, NULL, NULL, bus_rescan_devices_helper); |
| } |
| EXPORT_SYMBOL_GPL(bus_rescan_devices); |
| |
| /** |
| * device_reprobe - remove driver for a device and probe for a new driver |
| * @dev: the device to reprobe |
| * |
| * This function detaches the attached driver (if any) for the given |
| * device and restarts the driver probing process. It is intended |
| * to use if probing criteria changed during a devices lifetime and |
| * driver attachment should change accordingly. |
| */ |
| int device_reprobe(struct device *dev) |
| { |
| if (dev->driver) |
| device_driver_detach(dev); |
| return bus_rescan_devices_helper(dev, NULL); |
| } |
| EXPORT_SYMBOL_GPL(device_reprobe); |
| |
| /** |
| * find_bus - locate bus by name. |
| * @name: name of bus. |
| * |
| * Call kset_find_obj() to iterate over list of buses to |
| * find a bus by name. Return bus if found. |
| * |
| * Note that kset_find_obj increments bus' reference count. |
| */ |
| #if 0 |
| struct bus_type *find_bus(char *name) |
| { |
| struct kobject *k = kset_find_obj(bus_kset, name); |
| return k ? to_bus(k) : NULL; |
| } |
| #endif /* 0 */ |
| |
| static int bus_add_groups(struct bus_type *bus, |
| const struct attribute_group **groups) |
| { |
| return sysfs_create_groups(&bus->p->subsys.kobj, groups); |
| } |
| |
| static void bus_remove_groups(struct bus_type *bus, |
| const struct attribute_group **groups) |
| { |
| sysfs_remove_groups(&bus->p->subsys.kobj, groups); |
| } |
| |
| static void klist_devices_get(struct klist_node *n) |
| { |
| struct device_private *dev_prv = to_device_private_bus(n); |
| struct device *dev = dev_prv->device; |
| |
| get_device(dev); |
| } |
| |
| static void klist_devices_put(struct klist_node *n) |
| { |
| struct device_private *dev_prv = to_device_private_bus(n); |
| struct device *dev = dev_prv->device; |
| |
| put_device(dev); |
| } |
| |
| static ssize_t bus_uevent_store(struct bus_type *bus, |
| const char *buf, size_t count) |
| { |
| int rc; |
| |
| rc = kobject_synth_uevent(&bus->p->subsys.kobj, buf, count); |
| return rc ? rc : count; |
| } |
| /* |
| * "open code" the old BUS_ATTR() macro here. We want to use BUS_ATTR_WO() |
| * here, but can not use it as earlier in the file we have |
| * DEVICE_ATTR_WO(uevent), which would cause a clash with the with the store |
| * function name. |
| */ |
| static struct bus_attribute bus_attr_uevent = __ATTR(uevent, S_IWUSR, NULL, |
| bus_uevent_store); |
| |
| /** |
| * 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_groups(bus, bus->bus_groups); |
| if (retval) |
| goto bus_groups_fail; |
| |
| pr_debug("bus: '%s': registered\n", bus->name); |
| return 0; |
| |
| bus_groups_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; |
| } |
| EXPORT_SYMBOL_GPL(bus_register); |
| |
| /** |
| * bus_unregister - remove a bus from the system |
| * @bus: bus. |
| * |
| * Unregister the child subsystems and the bus itself. |
| * Finally, we call bus_put() to release the refcount |
| */ |
| 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_groups(bus, bus->bus_groups); |
| remove_probe_files(bus); |
| kset_unregister(bus->p->drivers_kset); |
| kset_unregister(bus->p->devices_kset); |
| bus_remove_file(bus, &bus_attr_uevent); |
| kset_unregister(&bus->p->subsys); |
| } |
| EXPORT_SYMBOL_GPL(bus_unregister); |
| |
| int bus_register_notifier(struct bus_type *bus, struct notifier_block *nb) |
| { |
| return blocking_notifier_chain_register(&bus->p->bus_notifier, nb); |
| } |
| EXPORT_SYMBOL_GPL(bus_register_notifier); |
| |
| int bus_unregister_notifier(struct bus_type *bus, struct notifier_block *nb) |
| { |
| return blocking_notifier_chain_unregister(&bus->p->bus_notifier, nb); |
| } |
| EXPORT_SYMBOL_GPL(bus_unregister_notifier); |
| |
| struct kset *bus_get_kset(struct bus_type *bus) |
| { |
| return &bus->p->subsys; |
| } |
| EXPORT_SYMBOL_GPL(bus_get_kset); |
| |
| struct klist *bus_get_device_klist(struct bus_type *bus) |
| { |
| return &bus->p->klist_devices; |
| } |
| EXPORT_SYMBOL_GPL(bus_get_device_klist); |
| |
| /* |
| * Yes, this forcibly breaks the klist abstraction temporarily. It |
| * just wants to sort the klist, not change reference counts and |
| * take/drop locks rapidly in the process. It does all this while |
| * holding the lock for the list, so objects can't otherwise be |
| * added/removed while we're swizzling. |
| */ |
| static void device_insertion_sort_klist(struct device *a, struct list_head *list, |
| int (*compare)(const struct device *a, |
| const struct device *b)) |
| { |
| struct klist_node *n; |
| struct device_private *dev_prv; |
| struct device *b; |
| |
| list_for_each_entry(n, list, n_node) { |
| dev_prv = to_device_private_bus(n); |
| b = dev_prv->device; |
| if (compare(a, b) <= 0) { |
| list_move_tail(&a->p->knode_bus.n_node, |
| &b->p->knode_bus.n_node); |
| return; |
| } |
| } |
| list_move_tail(&a->p->knode_bus.n_node, list); |
| } |
| |
| void bus_sort_breadthfirst(struct bus_type *bus, |
| int (*compare)(const struct device *a, |
| const struct device *b)) |
| { |
| LIST_HEAD(sorted_devices); |
| struct klist_node *n, *tmp; |
| struct device_private *dev_prv; |
| struct device *dev; |
| struct klist *device_klist; |
| |
| device_klist = bus_get_device_klist(bus); |
| |
| spin_lock(&device_klist->k_lock); |
| list_for_each_entry_safe(n, tmp, &device_klist->k_list, n_node) { |
| dev_prv = to_device_private_bus(n); |
| dev = dev_prv->device; |
| device_insertion_sort_klist(dev, &sorted_devices, compare); |
| } |
| list_splice(&sorted_devices, &device_klist->k_list); |
| spin_unlock(&device_klist->k_lock); |
| } |
| 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 = to_device_private_bus(knode)->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; |
| struct subsys_dev_iter iter; |
| struct device *dev; |
| |
| if (!sif || !sif->subsys) |
| return; |
| |
| subsys = sif->subsys; |
| |
| 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); |
| } |
| |
| static int subsys_register(struct bus_type *subsys, |
| const struct attribute_group **groups, |
| struct kobject *parent_of_root) |
| { |
| 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 = parent_of_root; |
| 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; |
| } |
| |
| /** |
| * 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 explicitly 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) |
| { |
| return subsys_register(subsys, groups, &system_kset->kobj); |
| } |
| EXPORT_SYMBOL_GPL(subsys_system_register); |
| |
| /** |
| * subsys_virtual_register - register a subsystem at /sys/devices/virtual/ |
| * @subsys: virtual subsystem |
| * @groups: default attributes for the root device |
| * |
| * All 'virtual' subsystems have a /sys/devices/system/<name> root device |
| * with the name of the subystem. The root device can carry subsystem-wide |
| * attributes. All registered devices are below this single root device. |
| * There's no restriction on device naming. This is for kernel software |
| * constructs which need sysfs interface. |
| */ |
| int subsys_virtual_register(struct bus_type *subsys, |
| const struct attribute_group **groups) |
| { |
| struct kobject *virtual_dir; |
| |
| virtual_dir = virtual_device_parent(NULL); |
| if (!virtual_dir) |
| return -ENOMEM; |
| |
| return subsys_register(subsys, groups, virtual_dir); |
| } |
| EXPORT_SYMBOL_GPL(subsys_virtual_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; |
| } |