linux/drivers/base/core.c

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/*
* drivers/base/core.c - core driver model code (device registration, etc)
*
* Copyright (c) 2002-3 Patrick Mochel
* Copyright (c) 2002-3 Open Source Development Labs
* Copyright (c) 2006 Greg Kroah-Hartman <gregkh@suse.de>
* Copyright (c) 2006 Novell, Inc.
*
* This file is released under the GPLv2
*
*/
#include <linux/device.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/kdev_t.h>
Driver core: add notification of bus events I finally did as you suggested and added the notifier to the struct bus_type itself. There are still problems to be expected is something attaches to a bus type where the code can hook in different struct device sub-classes (which is imho a big bogosity but I won't even try to argue that case now) but it will solve nicely a number of issues I've had so far. That also means that clients interested in registering for such notifications have to do it before devices are added and after bus types are registered. Fortunately, most bus types that matter for the various usage scenarios I have in mind are registerd at postcore_initcall time, which means I have a really nice spot at arch_initcall time to add my notifiers. There are 4 notifications provided. Device being added (before hooked to the bus) and removed (failure of previous case or after being unhooked from the bus), along with driver being bound to a device and about to be unbound. The usage I have for these are: - The 2 first ones are used to maintain a struct device_ext that is hooked to struct device.firmware_data. This structure contains for now a pointer to the Open Firmware node related to the device (if any), the NUMA node ID (for quick access to it) and the DMA operations pointers & iommu table instance for DMA to/from this device. For bus types I own (like IBM VIO or EBUS), I just maintain that structure directly from the bus code when creating the devices. But for bus types managed by generic code like PCI or platform (actually, of_platform which is a variation of platform linked to Open Firmware device-tree), I need this notifier. - The other two ones have a completely different usage scenario. I have cases where multiple devices and their drivers depend on each other. For example, the IBM EMAC network driver needs to attach to a MAL DMA engine which is a separate device, and a PHY interface which is also a separate device. They are all of_platform_device's (well, about to be with my upcoming patches) but there is no say in what precise order the core will "probe" them and instanciate the various modules. The solution I found for that is to have the drivers for emac to use multithread_probe, and wait for a driver to be bound to the target MAL and PHY control devices (the device-tree contains reference to the MAL and PHY interface nodes, which I can then match to of_platform_devices). Right now, I've been polling, but with that notifier, I can more cleanly wait (with a timeout of course). Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-10-25 03:44:59 +00:00
#include <linux/notifier.h>
#include <asm/semaphore.h>
#include "base.h"
#include "power/power.h"
int (*platform_notify)(struct device * dev) = NULL;
int (*platform_notify_remove)(struct device * dev) = NULL;
/*
* Detect the LANANA-assigned LOCAL/EXPERIMENTAL majors
*/
bool is_lanana_major(unsigned int major)
{
if (major >= 60 && major <= 63)
return 1;
if (major >= 120 && major <= 127)
return 1;
if (major >= 240 && major <= 254)
return 1;
return 0;
}
/*
* sysfs bindings for devices.
*/
/**
* dev_driver_string - Return a device's driver name, if at all possible
* @dev: struct device to get the name of
*
* Will return the device's driver's name if it is bound to a device. If
* the device is not bound to a device, it will return the name of the bus
* it is attached to. If it is not attached to a bus either, an empty
* string will be returned.
*/
const char *dev_driver_string(struct device *dev)
{
return dev->driver ? dev->driver->name :
(dev->bus ? dev->bus->name : "");
}
EXPORT_SYMBOL(dev_driver_string);
#define to_dev(obj) container_of(obj, struct device, kobj)
#define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
static ssize_t
dev_attr_show(struct kobject * kobj, struct attribute * attr, char * buf)
{
struct device_attribute * dev_attr = to_dev_attr(attr);
struct device * dev = to_dev(kobj);
ssize_t ret = -EIO;
if (dev_attr->show)
ret = dev_attr->show(dev, dev_attr, buf);
return ret;
}
static ssize_t
dev_attr_store(struct kobject * kobj, struct attribute * attr,
const char * buf, size_t count)
{
struct device_attribute * dev_attr = to_dev_attr(attr);
struct device * dev = to_dev(kobj);
ssize_t ret = -EIO;
if (dev_attr->store)
ret = dev_attr->store(dev, dev_attr, buf, count);
return ret;
}
static struct sysfs_ops dev_sysfs_ops = {
.show = dev_attr_show,
.store = dev_attr_store,
};
/**
* device_release - free device structure.
* @kobj: device's kobject.
*
* This is called once the reference count for the object
* reaches 0. We forward the call to the device's release
* method, which should handle actually freeing the structure.
*/
static void device_release(struct kobject * kobj)
{
struct device * dev = to_dev(kobj);
if (dev->release)
dev->release(dev);
else if (dev->type && dev->type->release)
dev->type->release(dev);
else if (dev->class && dev->class->dev_release)
dev->class->dev_release(dev);
else {
printk(KERN_ERR "Device '%s' does not have a release() function, "
"it is broken and must be fixed.\n",
dev->bus_id);
WARN_ON(1);
}
}
static struct kobj_type ktype_device = {
.release = device_release,
.sysfs_ops = &dev_sysfs_ops,
};
static int dev_uevent_filter(struct kset *kset, struct kobject *kobj)
{
struct kobj_type *ktype = get_ktype(kobj);
if (ktype == &ktype_device) {
struct device *dev = to_dev(kobj);
if (dev->bus)
return 1;
if (dev->class)
return 1;
}
return 0;
}
static const char *dev_uevent_name(struct kset *kset, struct kobject *kobj)
{
struct device *dev = to_dev(kobj);
if (dev->bus)
return dev->bus->name;
if (dev->class)
return dev->class->name;
return NULL;
}
static int dev_uevent(struct kset *kset, struct kobject *kobj, char **envp,
int num_envp, char *buffer, int buffer_size)
{
struct device *dev = to_dev(kobj);
int i = 0;
int length = 0;
int retval = 0;
/* add the major/minor if present */
if (MAJOR(dev->devt)) {
add_uevent_var(envp, num_envp, &i,
buffer, buffer_size, &length,
"MAJOR=%u", MAJOR(dev->devt));
add_uevent_var(envp, num_envp, &i,
buffer, buffer_size, &length,
"MINOR=%u", MINOR(dev->devt));
}
if (dev->driver)
add_uevent_var(envp, num_envp, &i,
buffer, buffer_size, &length,
"DRIVER=%s", dev->driver->name);
#ifdef CONFIG_SYSFS_DEPRECATED
if (dev->class) {
struct device *parent = dev->parent;
/* find first bus device in parent chain */
while (parent && !parent->bus)
parent = parent->parent;
if (parent && parent->bus) {
const char *path;
path = kobject_get_path(&parent->kobj, GFP_KERNEL);
add_uevent_var(envp, num_envp, &i,
buffer, buffer_size, &length,
"PHYSDEVPATH=%s", path);
kfree(path);
add_uevent_var(envp, num_envp, &i,
buffer, buffer_size, &length,
"PHYSDEVBUS=%s", parent->bus->name);
if (parent->driver)
add_uevent_var(envp, num_envp, &i,
buffer, buffer_size, &length,
"PHYSDEVDRIVER=%s", parent->driver->name);
}
} else if (dev->bus) {
add_uevent_var(envp, num_envp, &i,
buffer, buffer_size, &length,
"PHYSDEVBUS=%s", dev->bus->name);
if (dev->driver)
add_uevent_var(envp, num_envp, &i,
buffer, buffer_size, &length,
"PHYSDEVDRIVER=%s", dev->driver->name);
}
#endif
/* terminate, set to next free slot, shrink available space */
envp[i] = NULL;
envp = &envp[i];
num_envp -= i;
buffer = &buffer[length];
buffer_size -= length;
if (dev->bus && dev->bus->uevent) {
/* have the bus specific function add its stuff */
retval = dev->bus->uevent(dev, envp, num_envp, buffer, buffer_size);
if (retval)
pr_debug ("%s: bus uevent() returned %d\n",
__FUNCTION__, retval);
}
if (dev->class && dev->class->dev_uevent) {
/* have the class specific function add its stuff */
retval = dev->class->dev_uevent(dev, envp, num_envp, buffer, buffer_size);
if (retval)
pr_debug("%s: class uevent() returned %d\n",
__FUNCTION__, retval);
}
if (dev->type && dev->type->uevent) {
/* have the device type specific fuction add its stuff */
retval = dev->type->uevent(dev, envp, num_envp, buffer, buffer_size);
if (retval)
pr_debug("%s: dev_type uevent() returned %d\n",
__FUNCTION__, retval);
}
return retval;
}
static struct kset_uevent_ops device_uevent_ops = {
.filter = dev_uevent_filter,
.name = dev_uevent_name,
.uevent = dev_uevent,
};
static ssize_t store_uevent(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
kobject_uevent(&dev->kobj, KOBJ_ADD);
return count;
}
static int device_add_groups(struct device *dev)
{
int i;
int error = 0;
if (dev->groups) {
for (i = 0; dev->groups[i]; i++) {
error = sysfs_create_group(&dev->kobj, dev->groups[i]);
if (error) {
while (--i >= 0)
sysfs_remove_group(&dev->kobj, dev->groups[i]);
goto out;
}
}
}
out:
return error;
}
static void device_remove_groups(struct device *dev)
{
int i;
if (dev->groups) {
for (i = 0; dev->groups[i]; i++) {
sysfs_remove_group(&dev->kobj, dev->groups[i]);
}
}
}
static int device_add_attrs(struct device *dev)
{
struct class *class = dev->class;
struct device_type *type = dev->type;
int error = 0;
int i;
if (class && class->dev_attrs) {
for (i = 0; attr_name(class->dev_attrs[i]); i++) {
error = device_create_file(dev, &class->dev_attrs[i]);
if (error)
break;
}
if (error)
while (--i >= 0)
device_remove_file(dev, &class->dev_attrs[i]);
}
if (type && type->attrs) {
for (i = 0; attr_name(type->attrs[i]); i++) {
error = device_create_file(dev, &type->attrs[i]);
if (error)
break;
}
if (error)
while (--i >= 0)
device_remove_file(dev, &type->attrs[i]);
}
return error;
}
static void device_remove_attrs(struct device *dev)
{
struct class *class = dev->class;
struct device_type *type = dev->type;
int i;
if (class && class->dev_attrs) {
for (i = 0; attr_name(class->dev_attrs[i]); i++)
device_remove_file(dev, &class->dev_attrs[i]);
}
if (type && type->attrs) {
for (i = 0; attr_name(type->attrs[i]); i++)
device_remove_file(dev, &type->attrs[i]);
}
}
static ssize_t show_dev(struct device *dev, struct device_attribute *attr,
char *buf)
{
return print_dev_t(buf, dev->devt);
}
/*
* devices_subsys - structure to be registered with kobject core.
*/
decl_subsys(devices, &ktype_device, &device_uevent_ops);
/**
* device_create_file - create sysfs attribute file for device.
* @dev: device.
* @attr: device attribute descriptor.
*/
int device_create_file(struct device * dev, struct device_attribute * attr)
{
int error = 0;
if (get_device(dev)) {
error = sysfs_create_file(&dev->kobj, &attr->attr);
put_device(dev);
}
return error;
}
/**
* device_remove_file - remove sysfs attribute file.
* @dev: device.
* @attr: device attribute descriptor.
*/
void device_remove_file(struct device * dev, struct device_attribute * attr)
{
if (get_device(dev)) {
sysfs_remove_file(&dev->kobj, &attr->attr);
put_device(dev);
}
}
/**
* device_create_bin_file - create sysfs binary attribute file for device.
* @dev: device.
* @attr: device binary attribute descriptor.
*/
int device_create_bin_file(struct device *dev, struct bin_attribute *attr)
{
int error = -EINVAL;
if (dev)
error = sysfs_create_bin_file(&dev->kobj, attr);
return error;
}
EXPORT_SYMBOL_GPL(device_create_bin_file);
/**
* device_remove_bin_file - remove sysfs binary attribute file
* @dev: device.
* @attr: device binary attribute descriptor.
*/
void device_remove_bin_file(struct device *dev, struct bin_attribute *attr)
{
if (dev)
sysfs_remove_bin_file(&dev->kobj, attr);
}
EXPORT_SYMBOL_GPL(device_remove_bin_file);
static void klist_children_get(struct klist_node *n)
{
struct device *dev = container_of(n, struct device, knode_parent);
get_device(dev);
}
static void klist_children_put(struct klist_node *n)
{
struct device *dev = container_of(n, struct device, knode_parent);
put_device(dev);
}
/**
* device_initialize - init device structure.
* @dev: device.
*
* This prepares the device for use by other layers,
* including adding it to the device hierarchy.
* It is the first half of device_register(), if called by
* that, though it can also be called separately, so one
* may use @dev's fields (e.g. the refcount).
*/
void device_initialize(struct device *dev)
{
kobj_set_kset_s(dev, devices_subsys);
kobject_init(&dev->kobj);
klist_init(&dev->klist_children, klist_children_get,
klist_children_put);
INIT_LIST_HEAD(&dev->dma_pools);
INIT_LIST_HEAD(&dev->node);
init_MUTEX(&dev->sem);
spin_lock_init(&dev->devres_lock);
INIT_LIST_HEAD(&dev->devres_head);
device_init_wakeup(dev, 0);
set_dev_node(dev, -1);
}
#ifdef CONFIG_SYSFS_DEPRECATED
static struct kobject * get_device_parent(struct device *dev,
struct device *parent)
{
/* Set the parent to the class, not the parent device */
/* this keeps sysfs from having a symlink to make old udevs happy */
if (dev->class)
return &dev->class->subsys.kset.kobj;
else if (parent)
return &parent->kobj;
return NULL;
}
#else
static struct kobject * virtual_device_parent(struct device *dev)
{
if (!dev->class)
return ERR_PTR(-ENODEV);
if (!dev->class->virtual_dir) {
static struct kobject *virtual_dir = NULL;
if (!virtual_dir)
virtual_dir = kobject_add_dir(&devices_subsys.kset.kobj, "virtual");
dev->class->virtual_dir = kobject_add_dir(virtual_dir, dev->class->name);
}
return dev->class->virtual_dir;
}
static struct kobject * get_device_parent(struct device *dev,
struct device *parent)
{
/* if this is a class device, and has no parent, create one */
if ((dev->class) && (parent == NULL)) {
return virtual_device_parent(dev);
} else if (parent)
return &parent->kobj;
return NULL;
}
#endif
static int setup_parent(struct device *dev, struct device *parent)
{
struct kobject *kobj;
kobj = get_device_parent(dev, parent);
if (IS_ERR(kobj))
return PTR_ERR(kobj);
if (kobj)
dev->kobj.parent = kobj;
return 0;
}
/**
* device_add - add device to device hierarchy.
* @dev: device.
*
* This is part 2 of device_register(), though may be called
* separately _iff_ device_initialize() has been called separately.
*
* This adds it to the kobject hierarchy via kobject_add(), adds it
* to the global and sibling lists for the device, then
* adds it to the other relevant subsystems of the driver model.
*/
int device_add(struct device *dev)
{
struct device *parent = NULL;
char *class_name = NULL;
struct class_interface *class_intf;
int error = -EINVAL;
dev = get_device(dev);
if (!dev || !strlen(dev->bus_id))
goto Error;
pr_debug("DEV: registering device: ID = '%s'\n", dev->bus_id);
parent = get_device(dev->parent);
error = setup_parent(dev, parent);
if (error)
goto Error;
/* first, register with generic layer. */
kobject_set_name(&dev->kobj, "%s", dev->bus_id);
error = kobject_add(&dev->kobj);
if (error)
goto Error;
/* notify platform of device entry */
if (platform_notify)
platform_notify(dev);
Driver core: add notification of bus events I finally did as you suggested and added the notifier to the struct bus_type itself. There are still problems to be expected is something attaches to a bus type where the code can hook in different struct device sub-classes (which is imho a big bogosity but I won't even try to argue that case now) but it will solve nicely a number of issues I've had so far. That also means that clients interested in registering for such notifications have to do it before devices are added and after bus types are registered. Fortunately, most bus types that matter for the various usage scenarios I have in mind are registerd at postcore_initcall time, which means I have a really nice spot at arch_initcall time to add my notifiers. There are 4 notifications provided. Device being added (before hooked to the bus) and removed (failure of previous case or after being unhooked from the bus), along with driver being bound to a device and about to be unbound. The usage I have for these are: - The 2 first ones are used to maintain a struct device_ext that is hooked to struct device.firmware_data. This structure contains for now a pointer to the Open Firmware node related to the device (if any), the NUMA node ID (for quick access to it) and the DMA operations pointers & iommu table instance for DMA to/from this device. For bus types I own (like IBM VIO or EBUS), I just maintain that structure directly from the bus code when creating the devices. But for bus types managed by generic code like PCI or platform (actually, of_platform which is a variation of platform linked to Open Firmware device-tree), I need this notifier. - The other two ones have a completely different usage scenario. I have cases where multiple devices and their drivers depend on each other. For example, the IBM EMAC network driver needs to attach to a MAL DMA engine which is a separate device, and a PHY interface which is also a separate device. They are all of_platform_device's (well, about to be with my upcoming patches) but there is no say in what precise order the core will "probe" them and instanciate the various modules. The solution I found for that is to have the drivers for emac to use multithread_probe, and wait for a driver to be bound to the target MAL and PHY control devices (the device-tree contains reference to the MAL and PHY interface nodes, which I can then match to of_platform_devices). Right now, I've been polling, but with that notifier, I can more cleanly wait (with a timeout of course). Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-10-25 03:44:59 +00:00
/* notify clients of device entry (new way) */
if (dev->bus)
blocking_notifier_call_chain(&dev->bus->bus_notifier,
BUS_NOTIFY_ADD_DEVICE, dev);
dev->uevent_attr.attr.name = "uevent";
dev->uevent_attr.attr.mode = S_IWUSR;
if (dev->driver)
dev->uevent_attr.attr.owner = dev->driver->owner;
dev->uevent_attr.store = store_uevent;
error = device_create_file(dev, &dev->uevent_attr);
if (error)
goto attrError;
if (MAJOR(dev->devt)) {
struct device_attribute *attr;
attr = kzalloc(sizeof(*attr), GFP_KERNEL);
if (!attr) {
error = -ENOMEM;
goto ueventattrError;
}
attr->attr.name = "dev";
attr->attr.mode = S_IRUGO;
if (dev->driver)
attr->attr.owner = dev->driver->owner;
attr->show = show_dev;
error = device_create_file(dev, attr);
if (error) {
kfree(attr);
goto ueventattrError;
}
dev->devt_attr = attr;
}
if (dev->class) {
sysfs_create_link(&dev->kobj, &dev->class->subsys.kset.kobj,
"subsystem");
/* If this is not a "fake" compatible device, then create the
* symlink from the class to the device. */
if (dev->kobj.parent != &dev->class->subsys.kset.kobj)
sysfs_create_link(&dev->class->subsys.kset.kobj,
&dev->kobj, dev->bus_id);
if (parent) {
sysfs_create_link(&dev->kobj, &dev->parent->kobj,
"device");
#ifdef CONFIG_SYSFS_DEPRECATED
class_name = make_class_name(dev->class->name,
&dev->kobj);
if (class_name)
sysfs_create_link(&dev->parent->kobj,
&dev->kobj, class_name);
#endif
}
}
if ((error = device_add_attrs(dev)))
goto AttrsError;
if ((error = device_add_groups(dev)))
goto GroupError;
if ((error = device_pm_add(dev)))
goto PMError;
if ((error = bus_add_device(dev)))
goto BusError;
if (!dev->uevent_suppress)
kobject_uevent(&dev->kobj, KOBJ_ADD);
if ((error = bus_attach_device(dev)))
goto AttachError;
if (parent)
klist_add_tail(&dev->knode_parent, &parent->klist_children);
if (dev->class) {
down(&dev->class->sem);
/* tie the class to the device */
list_add_tail(&dev->node, &dev->class->devices);
/* notify any interfaces that the device is here */
list_for_each_entry(class_intf, &dev->class->interfaces, node)
if (class_intf->add_dev)
class_intf->add_dev(dev, class_intf);
up(&dev->class->sem);
}
Done:
kfree(class_name);
put_device(dev);
return error;
AttachError:
bus_remove_device(dev);
BusError:
device_pm_remove(dev);
PMError:
Driver core: add notification of bus events I finally did as you suggested and added the notifier to the struct bus_type itself. There are still problems to be expected is something attaches to a bus type where the code can hook in different struct device sub-classes (which is imho a big bogosity but I won't even try to argue that case now) but it will solve nicely a number of issues I've had so far. That also means that clients interested in registering for such notifications have to do it before devices are added and after bus types are registered. Fortunately, most bus types that matter for the various usage scenarios I have in mind are registerd at postcore_initcall time, which means I have a really nice spot at arch_initcall time to add my notifiers. There are 4 notifications provided. Device being added (before hooked to the bus) and removed (failure of previous case or after being unhooked from the bus), along with driver being bound to a device and about to be unbound. The usage I have for these are: - The 2 first ones are used to maintain a struct device_ext that is hooked to struct device.firmware_data. This structure contains for now a pointer to the Open Firmware node related to the device (if any), the NUMA node ID (for quick access to it) and the DMA operations pointers & iommu table instance for DMA to/from this device. For bus types I own (like IBM VIO or EBUS), I just maintain that structure directly from the bus code when creating the devices. But for bus types managed by generic code like PCI or platform (actually, of_platform which is a variation of platform linked to Open Firmware device-tree), I need this notifier. - The other two ones have a completely different usage scenario. I have cases where multiple devices and their drivers depend on each other. For example, the IBM EMAC network driver needs to attach to a MAL DMA engine which is a separate device, and a PHY interface which is also a separate device. They are all of_platform_device's (well, about to be with my upcoming patches) but there is no say in what precise order the core will "probe" them and instanciate the various modules. The solution I found for that is to have the drivers for emac to use multithread_probe, and wait for a driver to be bound to the target MAL and PHY control devices (the device-tree contains reference to the MAL and PHY interface nodes, which I can then match to of_platform_devices). Right now, I've been polling, but with that notifier, I can more cleanly wait (with a timeout of course). Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-10-25 03:44:59 +00:00
if (dev->bus)
blocking_notifier_call_chain(&dev->bus->bus_notifier,
BUS_NOTIFY_DEL_DEVICE, dev);
device_remove_groups(dev);
GroupError:
device_remove_attrs(dev);
AttrsError:
if (dev->devt_attr) {
device_remove_file(dev, dev->devt_attr);
kfree(dev->devt_attr);
}
if (dev->class) {
sysfs_remove_link(&dev->kobj, "subsystem");
/* If this is not a "fake" compatible device, remove the
* symlink from the class to the device. */
if (dev->kobj.parent != &dev->class->subsys.kset.kobj)
sysfs_remove_link(&dev->class->subsys.kset.kobj,
dev->bus_id);
if (parent) {
#ifdef CONFIG_SYSFS_DEPRECATED
char *class_name = make_class_name(dev->class->name,
&dev->kobj);
if (class_name)
sysfs_remove_link(&dev->parent->kobj,
class_name);
kfree(class_name);
#endif
sysfs_remove_link(&dev->kobj, "device");
}
down(&dev->class->sem);
/* notify any interfaces that the device is now gone */
list_for_each_entry(class_intf, &dev->class->interfaces, node)
if (class_intf->remove_dev)
class_intf->remove_dev(dev, class_intf);
/* remove the device from the class list */
list_del_init(&dev->node);
up(&dev->class->sem);
}
ueventattrError:
device_remove_file(dev, &dev->uevent_attr);
attrError:
kobject_uevent(&dev->kobj, KOBJ_REMOVE);
kobject_del(&dev->kobj);
Error:
if (parent)
put_device(parent);
goto Done;
}
/**
* device_register - register a device with the system.
* @dev: pointer to the device structure
*
* This happens in two clean steps - initialize the device
* and add it to the system. The two steps can be called
* separately, but this is the easiest and most common.
* I.e. you should only call the two helpers separately if
* have a clearly defined need to use and refcount the device
* before it is added to the hierarchy.
*/
int device_register(struct device *dev)
{
device_initialize(dev);
return device_add(dev);
}
/**
* get_device - increment reference count for device.
* @dev: device.
*
* This simply forwards the call to kobject_get(), though
* we do take care to provide for the case that we get a NULL
* pointer passed in.
*/
struct device * get_device(struct device * dev)
{
return dev ? to_dev(kobject_get(&dev->kobj)) : NULL;
}
/**
* put_device - decrement reference count.
* @dev: device in question.
*/
void put_device(struct device * dev)
{
if (dev)
kobject_put(&dev->kobj);
}
/**
* device_del - delete device from system.
* @dev: device.
*
* This is the first part of the device unregistration
* sequence. This removes the device from the lists we control
* from here, has it removed from the other driver model
* subsystems it was added to in device_add(), and removes it
* from the kobject hierarchy.
*
* NOTE: this should be called manually _iff_ device_add() was
* also called manually.
*/
void device_del(struct device * dev)
{
struct device * parent = dev->parent;
struct class_interface *class_intf;
if (parent)
klist_del(&dev->knode_parent);
if (dev->devt_attr) {
device_remove_file(dev, dev->devt_attr);
kfree(dev->devt_attr);
}
if (dev->class) {
sysfs_remove_link(&dev->kobj, "subsystem");
/* If this is not a "fake" compatible device, remove the
* symlink from the class to the device. */
if (dev->kobj.parent != &dev->class->subsys.kset.kobj)
sysfs_remove_link(&dev->class->subsys.kset.kobj,
dev->bus_id);
if (parent) {
#ifdef CONFIG_SYSFS_DEPRECATED
char *class_name = make_class_name(dev->class->name,
&dev->kobj);
if (class_name)
sysfs_remove_link(&dev->parent->kobj,
class_name);
kfree(class_name);
#endif
sysfs_remove_link(&dev->kobj, "device");
}
down(&dev->class->sem);
/* notify any interfaces that the device is now gone */
list_for_each_entry(class_intf, &dev->class->interfaces, node)
if (class_intf->remove_dev)
class_intf->remove_dev(dev, class_intf);
/* remove the device from the class list */
list_del_init(&dev->node);
up(&dev->class->sem);
}
device_remove_file(dev, &dev->uevent_attr);
device_remove_groups(dev);
device_remove_attrs(dev);
bus_remove_device(dev);
/*
* Some platform devices are driven without driver attached
* and managed resources may have been acquired. Make sure
* all resources are released.
*/
devres_release_all(dev);
/* Notify the platform of the removal, in case they
* need to do anything...
*/
if (platform_notify_remove)
platform_notify_remove(dev);
Driver core: add notification of bus events I finally did as you suggested and added the notifier to the struct bus_type itself. There are still problems to be expected is something attaches to a bus type where the code can hook in different struct device sub-classes (which is imho a big bogosity but I won't even try to argue that case now) but it will solve nicely a number of issues I've had so far. That also means that clients interested in registering for such notifications have to do it before devices are added and after bus types are registered. Fortunately, most bus types that matter for the various usage scenarios I have in mind are registerd at postcore_initcall time, which means I have a really nice spot at arch_initcall time to add my notifiers. There are 4 notifications provided. Device being added (before hooked to the bus) and removed (failure of previous case or after being unhooked from the bus), along with driver being bound to a device and about to be unbound. The usage I have for these are: - The 2 first ones are used to maintain a struct device_ext that is hooked to struct device.firmware_data. This structure contains for now a pointer to the Open Firmware node related to the device (if any), the NUMA node ID (for quick access to it) and the DMA operations pointers & iommu table instance for DMA to/from this device. For bus types I own (like IBM VIO or EBUS), I just maintain that structure directly from the bus code when creating the devices. But for bus types managed by generic code like PCI or platform (actually, of_platform which is a variation of platform linked to Open Firmware device-tree), I need this notifier. - The other two ones have a completely different usage scenario. I have cases where multiple devices and their drivers depend on each other. For example, the IBM EMAC network driver needs to attach to a MAL DMA engine which is a separate device, and a PHY interface which is also a separate device. They are all of_platform_device's (well, about to be with my upcoming patches) but there is no say in what precise order the core will "probe" them and instanciate the various modules. The solution I found for that is to have the drivers for emac to use multithread_probe, and wait for a driver to be bound to the target MAL and PHY control devices (the device-tree contains reference to the MAL and PHY interface nodes, which I can then match to of_platform_devices). Right now, I've been polling, but with that notifier, I can more cleanly wait (with a timeout of course). Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-10-25 03:44:59 +00:00
if (dev->bus)
blocking_notifier_call_chain(&dev->bus->bus_notifier,
BUS_NOTIFY_DEL_DEVICE, dev);
device_pm_remove(dev);
kobject_uevent(&dev->kobj, KOBJ_REMOVE);
kobject_del(&dev->kobj);
if (parent)
put_device(parent);
}
/**
* device_unregister - unregister device from system.
* @dev: device going away.
*
* We do this in two parts, like we do device_register(). First,
* we remove it from all the subsystems with device_del(), then
* we decrement the reference count via put_device(). If that
* is the final reference count, the device will be cleaned up
* via device_release() above. Otherwise, the structure will
* stick around until the final reference to the device is dropped.
*/
void device_unregister(struct device * dev)
{
pr_debug("DEV: Unregistering device. ID = '%s'\n", dev->bus_id);
device_del(dev);
put_device(dev);
}
static struct device * next_device(struct klist_iter * i)
{
struct klist_node * n = klist_next(i);
return n ? container_of(n, struct device, knode_parent) : NULL;
}
/**
* device_for_each_child - device child iterator.
* @parent: parent struct device.
* @data: data for the callback.
* @fn: function to be called for each device.
*
* Iterate over @parent's child devices, and call @fn for each,
* passing it @data.
*
* We check the return of @fn each time. If it returns anything
* other than 0, we break out and return that value.
*/
int device_for_each_child(struct device * parent, void * data,
int (*fn)(struct device *, void *))
{
struct klist_iter i;
struct device * child;
int error = 0;
klist_iter_init(&parent->klist_children, &i);
while ((child = next_device(&i)) && !error)
error = fn(child, data);
klist_iter_exit(&i);
return error;
}
/**
* device_find_child - device iterator for locating a particular device.
* @parent: parent struct device
* @data: Data to pass to match function
* @match: Callback function to check device
*
* This is similar to the device_for_each_child() function above, but it
* returns a reference to a device that is 'found' for later use, as
* determined by the @match callback.
*
* The callback should return 0 if the device doesn't match and non-zero
* if it does. If the callback returns non-zero and a reference to the
* current device can be obtained, this function will return to the caller
* and not iterate over any more devices.
*/
struct device * device_find_child(struct device *parent, void *data,
int (*match)(struct device *, void *))
{
struct klist_iter i;
struct device *child;
if (!parent)
return NULL;
klist_iter_init(&parent->klist_children, &i);
while ((child = next_device(&i)))
if (match(child, data) && get_device(child))
break;
klist_iter_exit(&i);
return child;
}
int __init devices_init(void)
{
return subsystem_register(&devices_subsys);
}
EXPORT_SYMBOL_GPL(device_for_each_child);
EXPORT_SYMBOL_GPL(device_find_child);
EXPORT_SYMBOL_GPL(device_initialize);
EXPORT_SYMBOL_GPL(device_add);
EXPORT_SYMBOL_GPL(device_register);
EXPORT_SYMBOL_GPL(device_del);
EXPORT_SYMBOL_GPL(device_unregister);
EXPORT_SYMBOL_GPL(get_device);
EXPORT_SYMBOL_GPL(put_device);
EXPORT_SYMBOL_GPL(device_create_file);
EXPORT_SYMBOL_GPL(device_remove_file);
static void device_create_release(struct device *dev)
{
pr_debug("%s called for %s\n", __FUNCTION__, dev->bus_id);
kfree(dev);
}
/**
* device_create - creates a device and registers it with sysfs
* @class: pointer to the struct class that this device should be registered to
* @parent: pointer to the parent struct device of this new device, if any
* @devt: the dev_t for the char device to be added
* @fmt: string for the device's name
*
* This function can be used by char device classes. A struct device
* will be created in sysfs, registered to the specified class.
*
* A "dev" file will be created, showing the dev_t for the device, if
* the dev_t is not 0,0.
* If a pointer to a parent struct device is passed in, the newly created
* struct device will be a child of that device in sysfs.
* The pointer to the struct device will be returned from the call.
* Any further sysfs files that might be required can be created using this
* pointer.
*
* Note: the struct class passed to this function must have previously
* been created with a call to class_create().
*/
struct device *device_create(struct class *class, struct device *parent,
dev_t devt, const char *fmt, ...)
{
va_list args;
struct device *dev = NULL;
int retval = -ENODEV;
if (class == NULL || IS_ERR(class))
goto error;
dev = kzalloc(sizeof(*dev), GFP_KERNEL);
if (!dev) {
retval = -ENOMEM;
goto error;
}
dev->devt = devt;
dev->class = class;
dev->parent = parent;
dev->release = device_create_release;
va_start(args, fmt);
vsnprintf(dev->bus_id, BUS_ID_SIZE, fmt, args);
va_end(args);
retval = device_register(dev);
if (retval)
goto error;
return dev;
error:
kfree(dev);
return ERR_PTR(retval);
}
EXPORT_SYMBOL_GPL(device_create);
/**
* device_destroy - removes a device that was created with device_create()
* @class: pointer to the struct class that this device was registered with
* @devt: the dev_t of the device that was previously registered
*
* This call unregisters and cleans up a device that was created with a
* call to device_create().
*/
void device_destroy(struct class *class, dev_t devt)
{
struct device *dev = NULL;
struct device *dev_tmp;
down(&class->sem);
list_for_each_entry(dev_tmp, &class->devices, node) {
if (dev_tmp->devt == devt) {
dev = dev_tmp;
break;
}
}
up(&class->sem);
if (dev)
device_unregister(dev);
}
EXPORT_SYMBOL_GPL(device_destroy);
/**
* device_rename - renames a device
* @dev: the pointer to the struct device to be renamed
* @new_name: the new name of the device
*/
int device_rename(struct device *dev, char *new_name)
{
char *old_class_name = NULL;
char *new_class_name = NULL;
char *old_symlink_name = NULL;
int error;
dev = get_device(dev);
if (!dev)
return -EINVAL;
pr_debug("DEVICE: renaming '%s' to '%s'\n", dev->bus_id, new_name);
#ifdef CONFIG_SYSFS_DEPRECATED
if ((dev->class) && (dev->parent))
old_class_name = make_class_name(dev->class->name, &dev->kobj);
#endif
if (dev->class) {
old_symlink_name = kmalloc(BUS_ID_SIZE, GFP_KERNEL);
if (!old_symlink_name) {
error = -ENOMEM;
goto out_free_old_class;
}
strlcpy(old_symlink_name, dev->bus_id, BUS_ID_SIZE);
}
strlcpy(dev->bus_id, new_name, BUS_ID_SIZE);
error = kobject_rename(&dev->kobj, new_name);
#ifdef CONFIG_SYSFS_DEPRECATED
if (old_class_name) {
new_class_name = make_class_name(dev->class->name, &dev->kobj);
if (new_class_name) {
sysfs_create_link(&dev->parent->kobj, &dev->kobj,
new_class_name);
sysfs_remove_link(&dev->parent->kobj, old_class_name);
}
}
#endif
if (dev->class) {
sysfs_remove_link(&dev->class->subsys.kset.kobj,
old_symlink_name);
sysfs_create_link(&dev->class->subsys.kset.kobj, &dev->kobj,
dev->bus_id);
}
put_device(dev);
kfree(new_class_name);
kfree(old_symlink_name);
out_free_old_class:
kfree(old_class_name);
return error;
}
EXPORT_SYMBOL_GPL(device_rename);
static int device_move_class_links(struct device *dev,
struct device *old_parent,
struct device *new_parent)
{
int error = 0;
#ifdef CONFIG_SYSFS_DEPRECATED
char *class_name;
class_name = make_class_name(dev->class->name, &dev->kobj);
if (!class_name) {
error = -ENOMEM;
goto out;
}
if (old_parent) {
sysfs_remove_link(&dev->kobj, "device");
sysfs_remove_link(&old_parent->kobj, class_name);
}
if (new_parent) {
error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
"device");
if (error)
goto out;
error = sysfs_create_link(&new_parent->kobj, &dev->kobj,
class_name);
if (error)
sysfs_remove_link(&dev->kobj, "device");
}
else
error = 0;
out:
kfree(class_name);
return error;
#else
if (old_parent)
sysfs_remove_link(&dev->kobj, "device");
if (new_parent)
error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
"device");
return error;
#endif
}
/**
* device_move - moves a device to a new parent
* @dev: the pointer to the struct device to be moved
* @new_parent: the new parent of the device (can by NULL)
*/
int device_move(struct device *dev, struct device *new_parent)
{
int error;
struct device *old_parent;
struct kobject *new_parent_kobj;
dev = get_device(dev);
if (!dev)
return -EINVAL;
new_parent = get_device(new_parent);
new_parent_kobj = get_device_parent (dev, new_parent);
if (IS_ERR(new_parent_kobj)) {
error = PTR_ERR(new_parent_kobj);
put_device(new_parent);
goto out;
}
pr_debug("DEVICE: moving '%s' to '%s'\n", dev->bus_id,
new_parent ? new_parent->bus_id : "<NULL>");
error = kobject_move(&dev->kobj, new_parent_kobj);
if (error) {
put_device(new_parent);
goto out;
}
old_parent = dev->parent;
dev->parent = new_parent;
if (old_parent)
klist_remove(&dev->knode_parent);
if (new_parent)
klist_add_tail(&dev->knode_parent, &new_parent->klist_children);
if (!dev->class)
goto out_put;
error = device_move_class_links(dev, old_parent, new_parent);
if (error) {
/* We ignore errors on cleanup since we're hosed anyway... */
device_move_class_links(dev, new_parent, old_parent);
if (!kobject_move(&dev->kobj, &old_parent->kobj)) {
if (new_parent)
klist_remove(&dev->knode_parent);
if (old_parent)
klist_add_tail(&dev->knode_parent,
&old_parent->klist_children);
}
put_device(new_parent);
goto out;
}
out_put:
put_device(old_parent);
out:
put_device(dev);
return error;
}
EXPORT_SYMBOL_GPL(device_move);