756 lines
18 KiB
C
756 lines
18 KiB
C
/*
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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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*
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* This file is released under the GPLv2
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*
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*/
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#include <linux/config.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/init.h>
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#include <linux/string.h>
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#include "base.h"
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#include "power/power.h"
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#define to_bus_attr(_attr) container_of(_attr, struct bus_attribute, attr)
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#define to_bus(obj) container_of(obj, struct bus_type, subsys.kset.kobj)
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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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#define to_driver(obj) container_of(obj, struct device_driver, kobj)
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static ssize_t
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drv_attr_show(struct kobject * kobj, struct attribute * attr, char * buf)
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{
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struct driver_attribute * drv_attr = to_drv_attr(attr);
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struct device_driver * drv = 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, buf);
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return ret;
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}
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static ssize_t
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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 device_driver * drv = 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, buf, count);
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return ret;
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}
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static 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 device_driver * drv = to_driver(kobj);
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complete(&drv->unloaded);
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}
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static struct kobj_type ktype_driver = {
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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
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bus_attr_show(struct kobject * kobj, struct attribute * attr, char * buf)
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{
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struct bus_attribute * bus_attr = to_bus_attr(attr);
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struct bus_type * bus = to_bus(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(bus, buf);
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return ret;
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}
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static ssize_t
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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 bus_type * bus = to_bus(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(bus, buf, count);
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return ret;
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}
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static 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 (get_bus(bus)) {
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error = sysfs_create_file(&bus->subsys.kset.kobj, &attr->attr);
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put_bus(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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void bus_remove_file(struct bus_type * bus, struct bus_attribute * attr)
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{
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if (get_bus(bus)) {
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sysfs_remove_file(&bus->subsys.kset.kobj, &attr->attr);
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put_bus(bus);
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}
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}
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static struct kobj_type ktype_bus = {
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.sysfs_ops = &bus_sysfs_ops,
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};
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decl_subsys(bus, &ktype_bus, NULL);
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#ifdef CONFIG_HOTPLUG
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/* Manually detach a device from its associated driver. */
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static int driver_helper(struct device *dev, void *data)
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{
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const char *name = data;
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if (strcmp(name, dev->bus_id) == 0)
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return 1;
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return 0;
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}
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static ssize_t driver_unbind(struct device_driver *drv,
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const char *buf, size_t count)
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{
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struct bus_type *bus = get_bus(drv->bus);
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struct device *dev;
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int err = -ENODEV;
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dev = bus_find_device(bus, NULL, (void *)buf, driver_helper);
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if (dev && dev->driver == drv) {
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if (dev->parent) /* Needed for USB */
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down(&dev->parent->sem);
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device_release_driver(dev);
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if (dev->parent)
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up(&dev->parent->sem);
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err = count;
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}
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put_device(dev);
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put_bus(bus);
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return err;
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}
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static DRIVER_ATTR(unbind, S_IWUSR, NULL, driver_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 driver_bind(struct device_driver *drv,
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const char *buf, size_t count)
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{
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struct bus_type *bus = get_bus(drv->bus);
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struct device *dev;
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int err = -ENODEV;
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dev = bus_find_device(bus, NULL, (void *)buf, driver_helper);
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if (dev && dev->driver == NULL) {
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if (dev->parent) /* Needed for USB */
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down(&dev->parent->sem);
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down(&dev->sem);
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err = driver_probe_device(drv, dev);
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up(&dev->sem);
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if (dev->parent)
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up(&dev->parent->sem);
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if (err > 0) /* success */
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err = count;
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else if (err == 0) /* driver didn't accept device */
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err = -ENODEV;
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}
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put_device(dev);
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put_bus(bus);
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return err;
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}
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static DRIVER_ATTR(bind, S_IWUSR, NULL, driver_bind);
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#endif
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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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return n ? container_of(n, struct device, knode_bus) : NULL;
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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, 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)
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return -EINVAL;
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klist_iter_init_node(&bus->klist_devices, &i,
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(start ? &start->knode_bus : NULL));
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while ((dev = next_device(&i)) && !error)
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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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/**
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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 *, void *))
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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)
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return NULL;
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klist_iter_init_node(&bus->klist_devices, &i,
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(start ? &start->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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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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return n ? container_of(n, struct device_driver, knode_bus) : 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->klist_drivers, &i,
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start ? &start->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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static int device_add_attrs(struct bus_type * bus, struct device * dev)
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{
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int error = 0;
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int i;
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if (bus->dev_attrs) {
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for (i = 0; attr_name(bus->dev_attrs[i]); i++) {
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error = device_create_file(dev,&bus->dev_attrs[i]);
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if (error)
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goto Err;
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}
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}
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Done:
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return error;
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Err:
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while (--i >= 0)
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device_remove_file(dev,&bus->dev_attrs[i]);
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goto Done;
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}
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static void device_remove_attrs(struct bus_type * bus, struct device * dev)
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{
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int i;
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if (bus->dev_attrs) {
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for (i = 0; attr_name(bus->dev_attrs[i]); i++)
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device_remove_file(dev,&bus->dev_attrs[i]);
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}
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}
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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 the device to its bus's list of devices.
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* - Create link to device's bus.
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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 = get_bus(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->bus_id);
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error = device_add_attrs(bus, dev);
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if (!error) {
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sysfs_create_link(&bus->devices.kobj, &dev->kobj, dev->bus_id);
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sysfs_create_link(&dev->kobj, &dev->bus->subsys.kset.kobj, "subsystem");
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sysfs_create_link(&dev->kobj, &dev->bus->subsys.kset.kobj, "bus");
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}
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}
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return error;
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}
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/**
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* bus_attach_device - add device to bus
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* @dev: device tried to attach to a driver
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*
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* - Try to attach to driver.
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*/
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void bus_attach_device(struct device * dev)
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{
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struct bus_type * bus = dev->bus;
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if (bus) {
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device_attach(dev);
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klist_add_tail(&dev->knode_bus, &bus->klist_devices);
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}
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}
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/**
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* bus_remove_device - remove device from bus
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* @dev: device to be removed
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*
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* - Remove symlink from bus's directory.
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* - Delete device from bus's list.
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* - Detach from its driver.
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* - Drop reference taken in bus_add_device().
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*/
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void bus_remove_device(struct device * dev)
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{
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if (dev->bus) {
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sysfs_remove_link(&dev->kobj, "subsystem");
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sysfs_remove_link(&dev->kobj, "bus");
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sysfs_remove_link(&dev->bus->devices.kobj, dev->bus_id);
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device_remove_attrs(dev->bus, dev);
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klist_remove(&dev->knode_bus);
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pr_debug("bus %s: remove device %s\n", dev->bus->name, dev->bus_id);
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device_release_driver(dev);
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put_bus(dev->bus);
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}
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}
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static int driver_add_attrs(struct bus_type * bus, struct device_driver * drv)
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{
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int error = 0;
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int i;
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if (bus->drv_attrs) {
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for (i = 0; attr_name(bus->drv_attrs[i]); i++) {
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error = driver_create_file(drv, &bus->drv_attrs[i]);
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if (error)
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goto Err;
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}
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}
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Done:
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return error;
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Err:
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while (--i >= 0)
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driver_remove_file(drv, &bus->drv_attrs[i]);
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goto Done;
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}
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static void driver_remove_attrs(struct bus_type * bus, struct device_driver * drv)
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{
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int i;
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if (bus->drv_attrs) {
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for (i = 0; attr_name(bus->drv_attrs[i]); i++)
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driver_remove_file(drv, &bus->drv_attrs[i]);
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}
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}
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#ifdef CONFIG_HOTPLUG
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/*
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* Thanks to drivers making their tables __devinit, we can't allow manual
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* bind and unbind from userspace unless CONFIG_HOTPLUG is enabled.
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*/
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static void add_bind_files(struct device_driver *drv)
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{
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driver_create_file(drv, &driver_attr_unbind);
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driver_create_file(drv, &driver_attr_bind);
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}
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static void remove_bind_files(struct device_driver *drv)
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{
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driver_remove_file(drv, &driver_attr_bind);
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driver_remove_file(drv, &driver_attr_unbind);
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}
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#else
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static inline void add_bind_files(struct device_driver *drv) {}
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static inline void remove_bind_files(struct device_driver *drv) {}
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#endif
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/**
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* bus_add_driver - Add a driver to the bus.
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* @drv: driver.
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*
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*/
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int bus_add_driver(struct device_driver * drv)
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{
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struct bus_type * bus = get_bus(drv->bus);
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int error = 0;
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if (bus) {
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pr_debug("bus %s: add driver %s\n", bus->name, drv->name);
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error = kobject_set_name(&drv->kobj, "%s", drv->name);
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if (error) {
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put_bus(bus);
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return error;
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}
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drv->kobj.kset = &bus->drivers;
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if ((error = kobject_register(&drv->kobj))) {
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put_bus(bus);
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return error;
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}
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driver_attach(drv);
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klist_add_tail(&drv->knode_bus, &bus->klist_drivers);
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module_add_driver(drv->owner, drv);
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driver_add_attrs(bus, drv);
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add_bind_files(drv);
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}
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return error;
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}
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/**
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* bus_remove_driver - delete driver from bus's knowledge.
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* @drv: driver.
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*
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* Detach the driver from the devices it controls, and remove
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* it from its bus's list of drivers. Finally, we drop the reference
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* to the bus we took in bus_add_driver().
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*/
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void bus_remove_driver(struct device_driver * drv)
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{
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if (drv->bus) {
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remove_bind_files(drv);
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driver_remove_attrs(drv->bus, drv);
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klist_remove(&drv->knode_bus);
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pr_debug("bus %s: remove driver %s\n", drv->bus->name, drv->name);
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driver_detach(drv);
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module_remove_driver(drv);
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kobject_unregister(&drv->kobj);
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put_bus(drv->bus);
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}
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}
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/* Helper for bus_rescan_devices's iter */
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static int bus_rescan_devices_helper(struct device *dev, void *data)
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{
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if (!dev->driver) {
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if (dev->parent) /* Needed for USB */
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down(&dev->parent->sem);
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device_attach(dev);
|
|
if (dev->parent)
|
|
up(&dev->parent->sem);
|
|
}
|
|
return 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.
|
|
*/
|
|
void bus_rescan_devices(struct bus_type * bus)
|
|
{
|
|
bus_for_each_dev(bus, NULL, NULL, bus_rescan_devices_helper);
|
|
}
|
|
|
|
/**
|
|
* 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.
|
|
*/
|
|
void device_reprobe(struct device *dev)
|
|
{
|
|
if (dev->driver) {
|
|
if (dev->parent) /* Needed for USB */
|
|
down(&dev->parent->sem);
|
|
device_release_driver(dev);
|
|
if (dev->parent)
|
|
up(&dev->parent->sem);
|
|
}
|
|
|
|
bus_rescan_devices_helper(dev, NULL);
|
|
}
|
|
EXPORT_SYMBOL_GPL(device_reprobe);
|
|
|
|
struct bus_type * get_bus(struct bus_type * bus)
|
|
{
|
|
return bus ? container_of(subsys_get(&bus->subsys), struct bus_type, subsys) : NULL;
|
|
}
|
|
|
|
void put_bus(struct bus_type * bus)
|
|
{
|
|
subsys_put(&bus->subsys);
|
|
}
|
|
|
|
|
|
/**
|
|
* 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.
|
|
*/
|
|
|
|
struct bus_type * find_bus(char * name)
|
|
{
|
|
struct kobject * k = kset_find_obj(&bus_subsys.kset, name);
|
|
return k ? to_bus(k) : NULL;
|
|
}
|
|
|
|
|
|
/**
|
|
* bus_add_attrs - Add default attributes for this bus.
|
|
* @bus: Bus that has just been registered.
|
|
*/
|
|
|
|
static int bus_add_attrs(struct bus_type * bus)
|
|
{
|
|
int error = 0;
|
|
int i;
|
|
|
|
if (bus->bus_attrs) {
|
|
for (i = 0; attr_name(bus->bus_attrs[i]); i++) {
|
|
if ((error = bus_create_file(bus,&bus->bus_attrs[i])))
|
|
goto Err;
|
|
}
|
|
}
|
|
Done:
|
|
return error;
|
|
Err:
|
|
while (--i >= 0)
|
|
bus_remove_file(bus,&bus->bus_attrs[i]);
|
|
goto Done;
|
|
}
|
|
|
|
static void bus_remove_attrs(struct bus_type * bus)
|
|
{
|
|
int i;
|
|
|
|
if (bus->bus_attrs) {
|
|
for (i = 0; attr_name(bus->bus_attrs[i]); i++)
|
|
bus_remove_file(bus,&bus->bus_attrs[i]);
|
|
}
|
|
}
|
|
|
|
static void klist_devices_get(struct klist_node *n)
|
|
{
|
|
struct device *dev = container_of(n, struct device, knode_bus);
|
|
|
|
get_device(dev);
|
|
}
|
|
|
|
static void klist_devices_put(struct klist_node *n)
|
|
{
|
|
struct device *dev = container_of(n, struct device, knode_bus);
|
|
|
|
put_device(dev);
|
|
}
|
|
|
|
static void klist_drivers_get(struct klist_node *n)
|
|
{
|
|
struct device_driver *drv = container_of(n, struct device_driver,
|
|
knode_bus);
|
|
|
|
get_driver(drv);
|
|
}
|
|
|
|
static void klist_drivers_put(struct klist_node *n)
|
|
{
|
|
struct device_driver *drv = container_of(n, struct device_driver,
|
|
knode_bus);
|
|
|
|
put_driver(drv);
|
|
}
|
|
|
|
/**
|
|
* bus_register - register a bus with the system.
|
|
* @bus: bus.
|
|
*
|
|
* Once we have that, we registered the bus with the kobject
|
|
* infrastructure, then register the children subsystems it has:
|
|
* the devices and drivers that belong to the bus.
|
|
*/
|
|
int bus_register(struct bus_type * bus)
|
|
{
|
|
int retval;
|
|
|
|
retval = kobject_set_name(&bus->subsys.kset.kobj, "%s", bus->name);
|
|
if (retval)
|
|
goto out;
|
|
|
|
subsys_set_kset(bus, bus_subsys);
|
|
retval = subsystem_register(&bus->subsys);
|
|
if (retval)
|
|
goto out;
|
|
|
|
kobject_set_name(&bus->devices.kobj, "devices");
|
|
bus->devices.subsys = &bus->subsys;
|
|
retval = kset_register(&bus->devices);
|
|
if (retval)
|
|
goto bus_devices_fail;
|
|
|
|
kobject_set_name(&bus->drivers.kobj, "drivers");
|
|
bus->drivers.subsys = &bus->subsys;
|
|
bus->drivers.ktype = &ktype_driver;
|
|
retval = kset_register(&bus->drivers);
|
|
if (retval)
|
|
goto bus_drivers_fail;
|
|
|
|
klist_init(&bus->klist_devices, klist_devices_get, klist_devices_put);
|
|
klist_init(&bus->klist_drivers, klist_drivers_get, klist_drivers_put);
|
|
bus_add_attrs(bus);
|
|
|
|
pr_debug("bus type '%s' registered\n", bus->name);
|
|
return 0;
|
|
|
|
bus_drivers_fail:
|
|
kset_unregister(&bus->devices);
|
|
bus_devices_fail:
|
|
subsystem_unregister(&bus->subsys);
|
|
out:
|
|
return retval;
|
|
}
|
|
|
|
|
|
/**
|
|
* bus_unregister - remove a bus from the system
|
|
* @bus: bus.
|
|
*
|
|
* Unregister the child subsystems and the bus itself.
|
|
* Finally, we call put_bus() to release the refcount
|
|
*/
|
|
void bus_unregister(struct bus_type * bus)
|
|
{
|
|
pr_debug("bus %s: unregistering\n", bus->name);
|
|
bus_remove_attrs(bus);
|
|
kset_unregister(&bus->drivers);
|
|
kset_unregister(&bus->devices);
|
|
subsystem_unregister(&bus->subsys);
|
|
}
|
|
|
|
int __init buses_init(void)
|
|
{
|
|
return subsystem_register(&bus_subsys);
|
|
}
|
|
|
|
|
|
EXPORT_SYMBOL_GPL(bus_for_each_dev);
|
|
EXPORT_SYMBOL_GPL(bus_find_device);
|
|
EXPORT_SYMBOL_GPL(bus_for_each_drv);
|
|
|
|
EXPORT_SYMBOL_GPL(bus_register);
|
|
EXPORT_SYMBOL_GPL(bus_unregister);
|
|
EXPORT_SYMBOL_GPL(bus_rescan_devices);
|
|
|
|
EXPORT_SYMBOL_GPL(bus_create_file);
|
|
EXPORT_SYMBOL_GPL(bus_remove_file);
|