1242 строки
31 KiB
C
1242 строки
31 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* bus.c - bus driver management
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*
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* Copyright (c) 2002-3 Patrick Mochel
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* Copyright (c) 2002-3 Open Source Development Labs
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* Copyright (c) 2007 Greg Kroah-Hartman <gregkh@suse.de>
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* Copyright (c) 2007 Novell Inc.
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*/
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#include <linux/async.h>
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#include <linux/device.h>
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#include <linux/module.h>
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#include <linux/errno.h>
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#include <linux/slab.h>
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#include <linux/init.h>
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#include <linux/string.h>
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#include <linux/mutex.h>
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#include <linux/sysfs.h>
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#include "base.h"
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#include "power/power.h"
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/* /sys/devices/system */
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static struct kset *system_kset;
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#define to_bus_attr(_attr) container_of(_attr, struct bus_attribute, attr)
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/*
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* sysfs bindings for drivers
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*/
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#define to_drv_attr(_attr) container_of(_attr, struct driver_attribute, attr)
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static int __must_check bus_rescan_devices_helper(struct device *dev,
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void *data);
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static struct bus_type *bus_get(struct bus_type *bus)
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{
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if (bus) {
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kset_get(&bus->p->subsys);
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return bus;
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}
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return NULL;
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}
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static void bus_put(struct bus_type *bus)
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{
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if (bus)
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kset_put(&bus->p->subsys);
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}
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static ssize_t drv_attr_show(struct kobject *kobj, struct attribute *attr,
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char *buf)
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{
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struct driver_attribute *drv_attr = to_drv_attr(attr);
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struct driver_private *drv_priv = to_driver(kobj);
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ssize_t ret = -EIO;
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if (drv_attr->show)
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ret = drv_attr->show(drv_priv->driver, buf);
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return ret;
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}
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static ssize_t drv_attr_store(struct kobject *kobj, struct attribute *attr,
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const char *buf, size_t count)
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{
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struct driver_attribute *drv_attr = to_drv_attr(attr);
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struct driver_private *drv_priv = to_driver(kobj);
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ssize_t ret = -EIO;
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if (drv_attr->store)
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ret = drv_attr->store(drv_priv->driver, buf, count);
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return ret;
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}
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static const struct sysfs_ops driver_sysfs_ops = {
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.show = drv_attr_show,
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.store = drv_attr_store,
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};
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static void driver_release(struct kobject *kobj)
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{
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struct driver_private *drv_priv = to_driver(kobj);
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pr_debug("driver: '%s': %s\n", kobject_name(kobj), __func__);
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kfree(drv_priv);
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}
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static struct kobj_type driver_ktype = {
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.sysfs_ops = &driver_sysfs_ops,
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.release = driver_release,
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};
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/*
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* sysfs bindings for buses
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*/
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static ssize_t bus_attr_show(struct kobject *kobj, struct attribute *attr,
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char *buf)
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{
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struct bus_attribute *bus_attr = to_bus_attr(attr);
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struct subsys_private *subsys_priv = to_subsys_private(kobj);
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ssize_t ret = 0;
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if (bus_attr->show)
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ret = bus_attr->show(subsys_priv->bus, buf);
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return ret;
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}
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static ssize_t bus_attr_store(struct kobject *kobj, struct attribute *attr,
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const char *buf, size_t count)
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{
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struct bus_attribute *bus_attr = to_bus_attr(attr);
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struct subsys_private *subsys_priv = to_subsys_private(kobj);
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ssize_t ret = 0;
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if (bus_attr->store)
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ret = bus_attr->store(subsys_priv->bus, buf, count);
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return ret;
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}
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static const struct sysfs_ops bus_sysfs_ops = {
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.show = bus_attr_show,
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.store = bus_attr_store,
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};
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int bus_create_file(struct bus_type *bus, struct bus_attribute *attr)
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{
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int error;
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if (bus_get(bus)) {
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error = sysfs_create_file(&bus->p->subsys.kobj, &attr->attr);
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bus_put(bus);
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} else
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error = -EINVAL;
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return error;
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}
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EXPORT_SYMBOL_GPL(bus_create_file);
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void bus_remove_file(struct bus_type *bus, struct bus_attribute *attr)
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{
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if (bus_get(bus)) {
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sysfs_remove_file(&bus->p->subsys.kobj, &attr->attr);
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bus_put(bus);
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}
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}
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EXPORT_SYMBOL_GPL(bus_remove_file);
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static void bus_release(struct kobject *kobj)
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{
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struct subsys_private *priv = to_subsys_private(kobj);
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struct bus_type *bus = priv->bus;
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kfree(priv);
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bus->p = NULL;
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}
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static struct kobj_type bus_ktype = {
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.sysfs_ops = &bus_sysfs_ops,
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.release = bus_release,
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};
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static int bus_uevent_filter(struct kset *kset, struct kobject *kobj)
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{
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struct kobj_type *ktype = get_ktype(kobj);
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if (ktype == &bus_ktype)
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return 1;
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return 0;
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}
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static const struct kset_uevent_ops bus_uevent_ops = {
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.filter = bus_uevent_filter,
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};
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static struct kset *bus_kset;
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/* Manually detach a device from its associated driver. */
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static ssize_t unbind_store(struct device_driver *drv, const char *buf,
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size_t count)
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{
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struct bus_type *bus = bus_get(drv->bus);
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struct device *dev;
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int err = -ENODEV;
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dev = bus_find_device_by_name(bus, NULL, buf);
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if (dev && dev->driver == drv) {
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if (dev->parent && dev->bus->need_parent_lock)
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device_lock(dev->parent);
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device_release_driver(dev);
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if (dev->parent && dev->bus->need_parent_lock)
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device_unlock(dev->parent);
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err = count;
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}
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put_device(dev);
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bus_put(bus);
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return err;
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}
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static DRIVER_ATTR_WO(unbind);
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/*
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* Manually attach a device to a driver.
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* Note: the driver must want to bind to the device,
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* it is not possible to override the driver's id table.
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*/
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static ssize_t bind_store(struct device_driver *drv, const char *buf,
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size_t count)
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{
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struct bus_type *bus = bus_get(drv->bus);
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struct device *dev;
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int err = -ENODEV;
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dev = bus_find_device_by_name(bus, NULL, buf);
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if (dev && dev->driver == NULL && driver_match_device(drv, dev)) {
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if (dev->parent && bus->need_parent_lock)
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device_lock(dev->parent);
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device_lock(dev);
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err = driver_probe_device(drv, dev);
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device_unlock(dev);
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if (dev->parent && bus->need_parent_lock)
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device_unlock(dev->parent);
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if (err > 0) {
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/* success */
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err = count;
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} else if (err == 0) {
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/* driver didn't accept device */
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err = -ENODEV;
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}
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}
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put_device(dev);
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bus_put(bus);
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return err;
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}
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static DRIVER_ATTR_WO(bind);
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static ssize_t show_drivers_autoprobe(struct bus_type *bus, char *buf)
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{
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return sprintf(buf, "%d\n", bus->p->drivers_autoprobe);
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}
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static ssize_t store_drivers_autoprobe(struct bus_type *bus,
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const char *buf, size_t count)
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{
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if (buf[0] == '0')
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bus->p->drivers_autoprobe = 0;
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else
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bus->p->drivers_autoprobe = 1;
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return count;
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}
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static ssize_t store_drivers_probe(struct bus_type *bus,
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const char *buf, size_t count)
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{
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struct device *dev;
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int err = -EINVAL;
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dev = bus_find_device_by_name(bus, NULL, buf);
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if (!dev)
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return -ENODEV;
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if (bus_rescan_devices_helper(dev, NULL) == 0)
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err = count;
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put_device(dev);
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return err;
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}
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static struct device *next_device(struct klist_iter *i)
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{
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struct klist_node *n = klist_next(i);
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struct device *dev = NULL;
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struct device_private *dev_prv;
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if (n) {
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dev_prv = to_device_private_bus(n);
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dev = dev_prv->device;
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}
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return dev;
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}
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/**
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* bus_for_each_dev - device iterator.
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* @bus: bus type.
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* @start: device to start iterating from.
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* @data: data for the callback.
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* @fn: function to be called for each device.
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*
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* Iterate over @bus's list of devices, and call @fn for each,
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* passing it @data. If @start is not NULL, we use that device to
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* begin iterating from.
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*
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* We check the return of @fn each time. If it returns anything
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* other than 0, we break out and return that value.
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*
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* NOTE: The device that returns a non-zero value is not retained
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* in any way, nor is its refcount incremented. If the caller needs
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* to retain this data, it should do so, and increment the reference
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* count in the supplied callback.
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*/
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int bus_for_each_dev(struct bus_type *bus, struct device *start,
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void *data, int (*fn)(struct device *, void *))
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{
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struct klist_iter i;
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struct device *dev;
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int error = 0;
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if (!bus || !bus->p)
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return -EINVAL;
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klist_iter_init_node(&bus->p->klist_devices, &i,
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(start ? &start->p->knode_bus : NULL));
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while (!error && (dev = next_device(&i)))
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error = fn(dev, data);
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klist_iter_exit(&i);
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return error;
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}
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EXPORT_SYMBOL_GPL(bus_for_each_dev);
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/**
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* bus_find_device - device iterator for locating a particular device.
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* @bus: bus type
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* @start: Device to begin with
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* @data: Data to pass to match function
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* @match: Callback function to check device
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*
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* This is similar to the bus_for_each_dev() function above, but it
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* returns a reference to a device that is 'found' for later use, as
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* determined by the @match callback.
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*
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* The callback should return 0 if the device doesn't match and non-zero
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* if it does. If the callback returns non-zero, this function will
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* return to the caller and not iterate over any more devices.
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*/
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struct device *bus_find_device(struct bus_type *bus,
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struct device *start, void *data,
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int (*match)(struct device *dev, void *data))
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{
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struct klist_iter i;
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struct device *dev;
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if (!bus || !bus->p)
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return NULL;
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klist_iter_init_node(&bus->p->klist_devices, &i,
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(start ? &start->p->knode_bus : NULL));
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while ((dev = next_device(&i)))
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if (match(dev, data) && get_device(dev))
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break;
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klist_iter_exit(&i);
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return dev;
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}
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EXPORT_SYMBOL_GPL(bus_find_device);
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static int match_name(struct device *dev, void *data)
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{
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const char *name = data;
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return sysfs_streq(name, dev_name(dev));
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}
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/**
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* bus_find_device_by_name - device iterator for locating a particular device of a specific name
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* @bus: bus type
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* @start: Device to begin with
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* @name: name of the device to match
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*
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* This is similar to the bus_find_device() function above, but it handles
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* searching by a name automatically, no need to write another strcmp matching
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* function.
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*/
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struct device *bus_find_device_by_name(struct bus_type *bus,
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struct device *start, const char *name)
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{
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return bus_find_device(bus, start, (void *)name, match_name);
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}
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EXPORT_SYMBOL_GPL(bus_find_device_by_name);
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/**
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* subsys_find_device_by_id - find a device with a specific enumeration number
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* @subsys: subsystem
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* @id: index 'id' in struct device
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* @hint: device to check first
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*
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* Check the hint's next object and if it is a match return it directly,
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* otherwise, fall back to a full list search. Either way a reference for
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* the returned object is taken.
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*/
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struct device *subsys_find_device_by_id(struct bus_type *subsys, unsigned int id,
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struct device *hint)
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{
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struct klist_iter i;
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struct device *dev;
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if (!subsys)
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return NULL;
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if (hint) {
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klist_iter_init_node(&subsys->p->klist_devices, &i, &hint->p->knode_bus);
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dev = next_device(&i);
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if (dev && dev->id == id && get_device(dev)) {
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klist_iter_exit(&i);
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return dev;
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}
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klist_iter_exit(&i);
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}
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klist_iter_init_node(&subsys->p->klist_devices, &i, NULL);
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while ((dev = next_device(&i))) {
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if (dev->id == id && get_device(dev)) {
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klist_iter_exit(&i);
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return dev;
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}
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}
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klist_iter_exit(&i);
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return NULL;
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}
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EXPORT_SYMBOL_GPL(subsys_find_device_by_id);
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static struct device_driver *next_driver(struct klist_iter *i)
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{
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struct klist_node *n = klist_next(i);
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struct driver_private *drv_priv;
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if (n) {
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drv_priv = container_of(n, struct driver_private, knode_bus);
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return drv_priv->driver;
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}
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return NULL;
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}
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/**
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* bus_for_each_drv - driver iterator
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* @bus: bus we're dealing with.
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* @start: driver to start iterating on.
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* @data: data to pass to the callback.
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* @fn: function to call for each driver.
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*
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* This is nearly identical to the device iterator above.
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* We iterate over each driver that belongs to @bus, and call
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* @fn for each. If @fn returns anything but 0, we break out
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* and return it. If @start is not NULL, we use it as the head
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* of the list.
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*
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* NOTE: we don't return the driver that returns a non-zero
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* value, nor do we leave the reference count incremented for that
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* driver. If the caller needs to know that info, it must set it
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* in the callback. It must also be sure to increment the refcount
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* so it doesn't disappear before returning to the caller.
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*/
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int bus_for_each_drv(struct bus_type *bus, struct device_driver *start,
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void *data, int (*fn)(struct device_driver *, void *))
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{
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struct klist_iter i;
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struct device_driver *drv;
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int error = 0;
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if (!bus)
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return -EINVAL;
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klist_iter_init_node(&bus->p->klist_drivers, &i,
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start ? &start->p->knode_bus : NULL);
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while ((drv = next_driver(&i)) && !error)
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error = fn(drv, data);
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klist_iter_exit(&i);
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return error;
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}
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EXPORT_SYMBOL_GPL(bus_for_each_drv);
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/**
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* bus_add_device - add device to bus
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* @dev: device being added
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*
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* - Add device's bus attributes.
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* - Create links to device's bus.
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* - Add the device to its bus's list of devices.
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*/
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int bus_add_device(struct device *dev)
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{
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struct bus_type *bus = bus_get(dev->bus);
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int error = 0;
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if (bus) {
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pr_debug("bus: '%s': add device %s\n", bus->name, dev_name(dev));
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error = device_add_groups(dev, bus->dev_groups);
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if (error)
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goto out_put;
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error = sysfs_create_link(&bus->p->devices_kset->kobj,
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&dev->kobj, dev_name(dev));
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if (error)
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goto out_groups;
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error = sysfs_create_link(&dev->kobj,
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&dev->bus->p->subsys.kobj, "subsystem");
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if (error)
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goto out_subsys;
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klist_add_tail(&dev->p->knode_bus, &bus->p->klist_devices);
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}
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return 0;
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out_subsys:
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sysfs_remove_link(&bus->p->devices_kset->kobj, dev_name(dev));
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out_groups:
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device_remove_groups(dev, bus->dev_groups);
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out_put:
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bus_put(dev->bus);
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return error;
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}
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/**
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* bus_probe_device - probe drivers for a new device
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* @dev: device to probe
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*
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* - Automatically probe for a driver if the bus allows it.
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*/
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void bus_probe_device(struct device *dev)
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{
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struct bus_type *bus = dev->bus;
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struct subsys_interface *sif;
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if (!bus)
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return;
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if (bus->p->drivers_autoprobe)
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device_initial_probe(dev);
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mutex_lock(&bus->p->mutex);
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list_for_each_entry(sif, &bus->p->interfaces, node)
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if (sif->add_dev)
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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(drivers_probe, S_IWUSR, NULL, store_drivers_probe);
|
|
static BUS_ATTR(drivers_autoprobe, S_IWUSR | S_IRUGO,
|
|
show_drivers_autoprobe, store_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)
|
|
{
|
|
kobject_synth_uevent(&drv->p->kobj, buf, count);
|
|
return count;
|
|
}
|
|
static DRIVER_ATTR_WO(uevent);
|
|
|
|
static void driver_attach_async(void *_drv, async_cookie_t cookie)
|
|
{
|
|
struct device_driver *drv = _drv;
|
|
int ret;
|
|
|
|
ret = driver_attach(drv);
|
|
|
|
pr_debug("bus: '%s': driver %s async attach completed: %d\n",
|
|
drv->bus->name, drv->name, ret);
|
|
}
|
|
|
|
/**
|
|
* 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) {
|
|
if (driver_allows_async_probing(drv)) {
|
|
pr_debug("bus: '%s': probing driver %s asynchronously\n",
|
|
drv->bus->name, drv->name);
|
|
async_schedule(driver_attach_async, drv);
|
|
} else {
|
|
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_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_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) {
|
|
if (dev->parent && dev->bus->need_parent_lock)
|
|
device_lock(dev->parent);
|
|
device_release_driver(dev);
|
|
if (dev->parent && dev->bus->need_parent_lock)
|
|
device_unlock(dev->parent);
|
|
}
|
|
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)
|
|
{
|
|
kobject_synth_uevent(&bus->p->subsys.kobj, buf, count);
|
|
return count;
|
|
}
|
|
static BUS_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;
|
|
}
|