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linux-next/include/linux/device.h
David Brownell 49a4ec188f fix hotplug for legacy platform drivers 
We've had various reports of some legacy "probe the hardware" style
platform drivers having nasty problems with hotplug support.

The core issue is that those legacy drivers don't fully conform to the
driver model.  They assume a role that should be the responsibility of
infrastructure code: creating device nodes.

The "modprobe" step in hotplugging relies on drivers to have split those
roles into different modules.  The lack of this split causes the problems.
When a driver creates nodes for devices that don't exist (sending a hotplug
event), then exits (aborting one modprobe) before the "modprobe $MODALIAS"
step completes (by failing, since it's in the middle of a modprobe), the
result can be an endless loop of modprobe invocations ...  badness.

This fix uses the newish per-device flag controlling issuance of "add"
events.  (A previous version of this patch used a per-device "driver can
hotplug" flag, which only scrubbed $MODALIAS from the environment rather
than suppressing the entire hotplug event.) It also shrinks that flag to
one bit, saving a word in "struct device".

So the net of this patch is removing some nasty failures with legacy
drivers, while retaining hotplug capability for the majority of platform
drivers.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Greg KH <gregkh@suse.de>
Cc: Andres Salomon <dilinger@debian.org>
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-08 11:15:10 -07:00

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/*
* device.h - generic, centralized driver model
*
* Copyright (c) 2001-2003 Patrick Mochel <mochel@osdl.org>
* Copyright (c) 2004-2007 Greg Kroah-Hartman <gregkh@suse.de>
*
* This file is released under the GPLv2
*
* See Documentation/driver-model/ for more information.
*/
#ifndef _DEVICE_H_
#define _DEVICE_H_
#include <linux/ioport.h>
#include <linux/kobject.h>
#include <linux/klist.h>
#include <linux/list.h>
#include <linux/compiler.h>
#include <linux/types.h>
#include <linux/module.h>
#include <linux/pm.h>
#include <asm/semaphore.h>
#include <asm/atomic.h>
#include <asm/device.h>
#define DEVICE_NAME_SIZE 50
#define DEVICE_NAME_HALF __stringify(20) /* Less than half to accommodate slop */
#define DEVICE_ID_SIZE 32
#define BUS_ID_SIZE KOBJ_NAME_LEN
struct device;
struct device_driver;
struct class;
struct class_device;
struct bus_type;
struct bus_attribute {
struct attribute attr;
ssize_t (*show)(struct bus_type *, char * buf);
ssize_t (*store)(struct bus_type *, const char * buf, size_t count);
};
#define BUS_ATTR(_name,_mode,_show,_store) \
struct bus_attribute bus_attr_##_name = __ATTR(_name,_mode,_show,_store)
extern int __must_check bus_create_file(struct bus_type *,
struct bus_attribute *);
extern void bus_remove_file(struct bus_type *, struct bus_attribute *);
struct bus_type {
const char * name;
struct module * owner;
struct kset subsys;
struct kset drivers;
struct kset devices;
struct klist klist_devices;
struct klist klist_drivers;
struct blocking_notifier_head bus_notifier;
struct bus_attribute * bus_attrs;
struct device_attribute * dev_attrs;
struct driver_attribute * drv_attrs;
struct bus_attribute drivers_autoprobe_attr;
struct bus_attribute drivers_probe_attr;
int (*match)(struct device * dev, struct device_driver * drv);
int (*uevent)(struct device *dev, char **envp,
int num_envp, char *buffer, int buffer_size);
int (*probe)(struct device * dev);
int (*remove)(struct device * dev);
void (*shutdown)(struct device * dev);
int (*suspend)(struct device * dev, pm_message_t state);
int (*suspend_late)(struct device * dev, pm_message_t state);
int (*resume_early)(struct device * dev);
int (*resume)(struct device * dev);
unsigned int drivers_autoprobe:1;
};
extern int __must_check bus_register(struct bus_type * bus);
extern void bus_unregister(struct bus_type * bus);
extern int __must_check bus_rescan_devices(struct bus_type * bus);
/* iterator helpers for buses */
int bus_for_each_dev(struct bus_type * bus, struct device * start, void * data,
int (*fn)(struct device *, void *));
struct device * bus_find_device(struct bus_type *bus, struct device *start,
void *data, int (*match)(struct device *, void *));
int __must_check bus_for_each_drv(struct bus_type *bus,
struct device_driver *start, void *data,
int (*fn)(struct device_driver *, void *));
/*
* Bus notifiers: Get notified of addition/removal of devices
* and binding/unbinding of drivers to devices.
* In the long run, it should be a replacement for the platform
* notify hooks.
*/
struct notifier_block;
extern int bus_register_notifier(struct bus_type *bus,
struct notifier_block *nb);
extern int bus_unregister_notifier(struct bus_type *bus,
struct notifier_block *nb);
/* All 4 notifers below get called with the target struct device *
* as an argument. Note that those functions are likely to be called
* with the device semaphore held in the core, so be careful.
*/
#define BUS_NOTIFY_ADD_DEVICE 0x00000001 /* device added */
#define BUS_NOTIFY_DEL_DEVICE 0x00000002 /* device removed */
#define BUS_NOTIFY_BOUND_DRIVER 0x00000003 /* driver bound to device */
#define BUS_NOTIFY_UNBIND_DRIVER 0x00000004 /* driver about to be
unbound */
struct device_driver {
const char * name;
struct bus_type * bus;
struct kobject kobj;
struct klist klist_devices;
struct klist_node knode_bus;
struct module * owner;
const char * mod_name; /* used for built-in modules */
struct module_kobject * mkobj;
int (*probe) (struct device * dev);
int (*remove) (struct device * dev);
void (*shutdown) (struct device * dev);
int (*suspend) (struct device * dev, pm_message_t state);
int (*resume) (struct device * dev);
};
extern int __must_check driver_register(struct device_driver * drv);
extern void driver_unregister(struct device_driver * drv);
extern struct device_driver * get_driver(struct device_driver * drv);
extern void put_driver(struct device_driver * drv);
extern struct device_driver *driver_find(const char *name, struct bus_type *bus);
extern int driver_probe_done(void);
/* sysfs interface for exporting driver attributes */
struct driver_attribute {
struct attribute attr;
ssize_t (*show)(struct device_driver *, char * buf);
ssize_t (*store)(struct device_driver *, const char * buf, size_t count);
};
#define DRIVER_ATTR(_name,_mode,_show,_store) \
struct driver_attribute driver_attr_##_name = __ATTR(_name,_mode,_show,_store)
extern int __must_check driver_create_file(struct device_driver *,
struct driver_attribute *);
extern void driver_remove_file(struct device_driver *, struct driver_attribute *);
extern int __must_check driver_for_each_device(struct device_driver * drv,
struct device *start, void *data,
int (*fn)(struct device *, void *));
struct device * driver_find_device(struct device_driver *drv,
struct device *start, void *data,
int (*match)(struct device *, void *));
/*
* device classes
*/
struct class {
const char * name;
struct module * owner;
struct kset subsys;
struct list_head children;
struct list_head devices;
struct list_head interfaces;
struct kset class_dirs;
struct semaphore sem; /* locks both the children and interfaces lists */
struct class_attribute * class_attrs;
struct class_device_attribute * class_dev_attrs;
struct device_attribute * dev_attrs;
int (*uevent)(struct class_device *dev, char **envp,
int num_envp, char *buffer, int buffer_size);
int (*dev_uevent)(struct device *dev, char **envp, int num_envp,
char *buffer, int buffer_size);
void (*release)(struct class_device *dev);
void (*class_release)(struct class *class);
void (*dev_release)(struct device *dev);
int (*suspend)(struct device *, pm_message_t state);
int (*resume)(struct device *);
};
extern int __must_check class_register(struct class *);
extern void class_unregister(struct class *);
struct class_attribute {
struct attribute attr;
ssize_t (*show)(struct class *, char * buf);
ssize_t (*store)(struct class *, const char * buf, size_t count);
};
#define CLASS_ATTR(_name,_mode,_show,_store) \
struct class_attribute class_attr_##_name = __ATTR(_name,_mode,_show,_store)
extern int __must_check class_create_file(struct class *,
const struct class_attribute *);
extern void class_remove_file(struct class *, const struct class_attribute *);
struct class_device_attribute {
struct attribute attr;
ssize_t (*show)(struct class_device *, char * buf);
ssize_t (*store)(struct class_device *, const char * buf, size_t count);
};
#define CLASS_DEVICE_ATTR(_name,_mode,_show,_store) \
struct class_device_attribute class_device_attr_##_name = \
__ATTR(_name,_mode,_show,_store)
extern int __must_check class_device_create_file(struct class_device *,
const struct class_device_attribute *);
/**
* struct class_device - class devices
* @class: pointer to the parent class for this class device. This is required.
* @devt: for internal use by the driver core only.
* @node: for internal use by the driver core only.
* @kobj: for internal use by the driver core only.
* @devt_attr: for internal use by the driver core only.
* @groups: optional additional groups to be created
* @dev: if set, a symlink to the struct device is created in the sysfs
* directory for this struct class device.
* @class_data: pointer to whatever you want to store here for this struct
* class_device. Use class_get_devdata() and class_set_devdata() to get and
* set this pointer.
* @parent: pointer to a struct class_device that is the parent of this struct
* class_device. If NULL, this class_device will show up at the root of the
* struct class in sysfs (which is probably what you want to have happen.)
* @release: pointer to a release function for this struct class_device. If
* set, this will be called instead of the class specific release function.
* Only use this if you want to override the default release function, like
* when you are nesting class_device structures.
* @uevent: pointer to a uevent function for this struct class_device. If
* set, this will be called instead of the class specific uevent function.
* Only use this if you want to override the default uevent function, like
* when you are nesting class_device structures.
*/
struct class_device {
struct list_head node;
struct kobject kobj;
struct class * class; /* required */
dev_t devt; /* dev_t, creates the sysfs "dev" */
struct class_device_attribute *devt_attr;
struct class_device_attribute uevent_attr;
struct device * dev; /* not necessary, but nice to have */
void * class_data; /* class-specific data */
struct class_device *parent; /* parent of this child device, if there is one */
struct attribute_group ** groups; /* optional groups */
void (*release)(struct class_device *dev);
int (*uevent)(struct class_device *dev, char **envp,
int num_envp, char *buffer, int buffer_size);
char class_id[BUS_ID_SIZE]; /* unique to this class */
};
static inline void *
class_get_devdata (struct class_device *dev)
{
return dev->class_data;
}
static inline void
class_set_devdata (struct class_device *dev, void *data)
{
dev->class_data = data;
}
extern int __must_check class_device_register(struct class_device *);
extern void class_device_unregister(struct class_device *);
extern void class_device_initialize(struct class_device *);
extern int __must_check class_device_add(struct class_device *);
extern void class_device_del(struct class_device *);
extern struct class_device * class_device_get(struct class_device *);
extern void class_device_put(struct class_device *);
extern void class_device_remove_file(struct class_device *,
const struct class_device_attribute *);
extern int __must_check class_device_create_bin_file(struct class_device *,
struct bin_attribute *);
extern void class_device_remove_bin_file(struct class_device *,
struct bin_attribute *);
struct class_interface {
struct list_head node;
struct class *class;
int (*add) (struct class_device *, struct class_interface *);
void (*remove) (struct class_device *, struct class_interface *);
int (*add_dev) (struct device *, struct class_interface *);
void (*remove_dev) (struct device *, struct class_interface *);
};
extern int __must_check class_interface_register(struct class_interface *);
extern void class_interface_unregister(struct class_interface *);
extern struct class *class_create(struct module *owner, const char *name);
extern void class_destroy(struct class *cls);
extern struct class_device *class_device_create(struct class *cls,
struct class_device *parent,
dev_t devt,
struct device *device,
const char *fmt, ...)
__attribute__((format(printf,5,6)));
extern void class_device_destroy(struct class *cls, dev_t devt);
/*
* The type of device, "struct device" is embedded in. A class
* or bus can contain devices of different types
* like "partitions" and "disks", "mouse" and "event".
* This identifies the device type and carries type-specific
* information, equivalent to the kobj_type of a kobject.
* If "name" is specified, the uevent will contain it in
* the DEVTYPE variable.
*/
struct device_type {
const char *name;
struct attribute_group **groups;
int (*uevent)(struct device *dev, char **envp, int num_envp,
char *buffer, int buffer_size);
void (*release)(struct device *dev);
int (*suspend)(struct device * dev, pm_message_t state);
int (*resume)(struct device * dev);
};
/* interface for exporting device attributes */
struct device_attribute {
struct attribute attr;
ssize_t (*show)(struct device *dev, struct device_attribute *attr,
char *buf);
ssize_t (*store)(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count);
};
#define DEVICE_ATTR(_name,_mode,_show,_store) \
struct device_attribute dev_attr_##_name = __ATTR(_name,_mode,_show,_store)
extern int __must_check device_create_file(struct device *device,
struct device_attribute * entry);
extern void device_remove_file(struct device * dev, struct device_attribute * attr);
extern int __must_check device_create_bin_file(struct device *dev,
struct bin_attribute *attr);
extern void device_remove_bin_file(struct device *dev,
struct bin_attribute *attr);
extern int device_schedule_callback_owner(struct device *dev,
void (*func)(struct device *), struct module *owner);
/* This is a macro to avoid include problems with THIS_MODULE */
#define device_schedule_callback(dev, func) \
device_schedule_callback_owner(dev, func, THIS_MODULE)
/* device resource management */
typedef void (*dr_release_t)(struct device *dev, void *res);
typedef int (*dr_match_t)(struct device *dev, void *res, void *match_data);
#ifdef CONFIG_DEBUG_DEVRES
extern void * __devres_alloc(dr_release_t release, size_t size, gfp_t gfp,
const char *name);
#define devres_alloc(release, size, gfp) \
__devres_alloc(release, size, gfp, #release)
#else
extern void * devres_alloc(dr_release_t release, size_t size, gfp_t gfp);
#endif
extern void devres_free(void *res);
extern void devres_add(struct device *dev, void *res);
extern void * devres_find(struct device *dev, dr_release_t release,
dr_match_t match, void *match_data);
extern void * devres_get(struct device *dev, void *new_res,
dr_match_t match, void *match_data);
extern void * devres_remove(struct device *dev, dr_release_t release,
dr_match_t match, void *match_data);
extern int devres_destroy(struct device *dev, dr_release_t release,
dr_match_t match, void *match_data);
/* devres group */
extern void * __must_check devres_open_group(struct device *dev, void *id,
gfp_t gfp);
extern void devres_close_group(struct device *dev, void *id);
extern void devres_remove_group(struct device *dev, void *id);
extern int devres_release_group(struct device *dev, void *id);
/* managed kzalloc/kfree for device drivers, no kmalloc, always use kzalloc */
extern void *devm_kzalloc(struct device *dev, size_t size, gfp_t gfp);
extern void devm_kfree(struct device *dev, void *p);
struct device {
struct klist klist_children;
struct klist_node knode_parent; /* node in sibling list */
struct klist_node knode_driver;
struct klist_node knode_bus;
struct device *parent;
struct kobject kobj;
char bus_id[BUS_ID_SIZE]; /* position on parent bus */
struct device_type *type;
unsigned is_registered:1;
unsigned uevent_suppress:1;
struct device_attribute uevent_attr;
struct device_attribute *devt_attr;
struct semaphore sem; /* semaphore to synchronize calls to
* its driver.
*/
struct bus_type * bus; /* type of bus device is on */
struct device_driver *driver; /* which driver has allocated this
device */
void *driver_data; /* data private to the driver */
void *platform_data; /* Platform specific data, device
core doesn't touch it */
struct dev_pm_info power;
#ifdef CONFIG_NUMA
int numa_node; /* NUMA node this device is close to */
#endif
u64 *dma_mask; /* dma mask (if dma'able device) */
u64 coherent_dma_mask;/* Like dma_mask, but for
alloc_coherent mappings as
not all hardware supports
64 bit addresses for consistent
allocations such descriptors. */
struct list_head dma_pools; /* dma pools (if dma'ble) */
struct dma_coherent_mem *dma_mem; /* internal for coherent mem
override */
/* arch specific additions */
struct dev_archdata archdata;
spinlock_t devres_lock;
struct list_head devres_head;
/* class_device migration path */
struct list_head node;
struct class *class;
dev_t devt; /* dev_t, creates the sysfs "dev" */
struct attribute_group **groups; /* optional groups */
void (*release)(struct device * dev);
};
#ifdef CONFIG_NUMA
static inline int dev_to_node(struct device *dev)
{
return dev->numa_node;
}
static inline void set_dev_node(struct device *dev, int node)
{
dev->numa_node = node;
}
#else
static inline int dev_to_node(struct device *dev)
{
return -1;
}
static inline void set_dev_node(struct device *dev, int node)
{
}
#endif
static inline void *
dev_get_drvdata (struct device *dev)
{
return dev->driver_data;
}
static inline void
dev_set_drvdata (struct device *dev, void *data)
{
dev->driver_data = data;
}
static inline int device_is_registered(struct device *dev)
{
return dev->is_registered;
}
void driver_init(void);
/*
* High level routines for use by the bus drivers
*/
extern int __must_check device_register(struct device * dev);
extern void device_unregister(struct device * dev);
extern void device_initialize(struct device * dev);
extern int __must_check device_add(struct device * dev);
extern void device_del(struct device * dev);
extern int device_for_each_child(struct device *, void *,
int (*fn)(struct device *, void *));
extern struct device *device_find_child(struct device *, void *data,
int (*match)(struct device *, void *));
extern int device_rename(struct device *dev, char *new_name);
extern int device_move(struct device *dev, struct device *new_parent);
/*
* Manual binding of a device to driver. See drivers/base/bus.c
* for information on use.
*/
extern int __must_check device_bind_driver(struct device *dev);
extern void device_release_driver(struct device * dev);
extern int __must_check device_attach(struct device * dev);
extern int __must_check driver_attach(struct device_driver *drv);
extern int __must_check device_reprobe(struct device *dev);
/*
* Easy functions for dynamically creating devices on the fly
*/
extern struct device *device_create(struct class *cls, struct device *parent,
dev_t devt, const char *fmt, ...)
__attribute__((format(printf,4,5)));
extern void device_destroy(struct class *cls, dev_t devt);
/*
* Platform "fixup" functions - allow the platform to have their say
* about devices and actions that the general device layer doesn't
* know about.
*/
/* Notify platform of device discovery */
extern int (*platform_notify)(struct device * dev);
extern int (*platform_notify_remove)(struct device * dev);
/**
* get_device - atomically increment the reference count for the device.
*
*/
extern struct device * get_device(struct device * dev);
extern void put_device(struct device * dev);
/* drivers/base/power/shutdown.c */
extern void device_shutdown(void);
/* drivers/base/firmware.c */
extern int __must_check firmware_register(struct kset *);
extern void firmware_unregister(struct kset *);
/* debugging and troubleshooting/diagnostic helpers. */
extern const char *dev_driver_string(struct device *dev);
#define dev_printk(level, dev, format, arg...) \
printk(level "%s %s: " format , dev_driver_string(dev) , (dev)->bus_id , ## arg)
#ifdef DEBUG
#define dev_dbg(dev, format, arg...) \
dev_printk(KERN_DEBUG , dev , format , ## arg)
#else
static inline int __attribute__ ((format (printf, 2, 3)))
dev_dbg(struct device * dev, const char * fmt, ...)
{
return 0;
}
#endif
#define dev_err(dev, format, arg...) \
dev_printk(KERN_ERR , dev , format , ## arg)
#define dev_info(dev, format, arg...) \
dev_printk(KERN_INFO , dev , format , ## arg)
#define dev_warn(dev, format, arg...) \
dev_printk(KERN_WARNING , dev , format , ## arg)
#define dev_notice(dev, format, arg...) \
dev_printk(KERN_NOTICE , dev , format , ## arg)
/* Create alias, so I can be autoloaded. */
#define MODULE_ALIAS_CHARDEV(major,minor) \
MODULE_ALIAS("char-major-" __stringify(major) "-" __stringify(minor))
#define MODULE_ALIAS_CHARDEV_MAJOR(major) \
MODULE_ALIAS("char-major-" __stringify(major) "-*")
#endif /* _DEVICE_H_ */
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