forked from Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
1182 lines
30 KiB
1182 lines
30 KiB
// 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 <[email protected]> |
|
* 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_unregister; |
|
} |
|
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_add_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_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); |
|
|
|
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; |
|
}
|
|
|