char_dev.c File Reference

Go to the source code of this file.

Classes

struct char_device_struct

: name of this range of devices

register_chrdev() - Register a major number for character devices.
: major device number or 0 for dynamic allocation
: file operations associated with this devices
If == 0 this functions will dynamically allocate a major and return its number.
If > 0 this function will attempt to reserve a device with the given major number and will return zero on success.
Returns a -ve errno on failure.
The name of this device has nothing to do with the name of the device in /dev. It only helps to keep track of the different owners of devices. If your module name has only one type of devices it's ok to use e.g. the name of the module here.
This function registers a range of 256 minor numbers. The first minor number is 0.

struct file_operations def_chr_fops

static struct kobj_type ktype_cdev_default

static struct kobj_type ktype_cdev_dynamic

int register_chrdev (unsigned int major, const char *name, const struct file_operations *fops)

void unregister_chrdev_region (dev_t from, unsigned count)

unregister_chrdev_region() - return a range of device numbers : the first in the range of numbers to unregister : the number of device numbers to unregister

void unregister_chrdev (unsigned int major, const char *name)

static DEFINE_SPINLOCK (cdev_lock)

static struct kobject * cdev_get (struct cdev *p)

void cdev_put (struct cdev *p)

static int chrdev_open (struct inode *inode, struct file *filp)

void cd_forget (struct inode *inode)

static void cdev_purge (struct cdev *cdev)

static struct kobject * exact_match (dev_t dev, int *part, void *data)

static int exact_lock (dev_t dev, void *data)

int cdev_add (struct cdev *p, dev_t dev, unsigned count)

cdev_add() - add a char device to the system : the cdev structure for the device : the first device number for which this device is responsible : the number of consecutive minor numbers corresponding to this device

static void cdev_unmap (dev_t dev, unsigned count)

void cdev_del (struct cdev *p)

cdev_del() - remove a cdev from the system : the cdev structure to be removed

static void cdev_default_release (struct kobject *kobj)

static void cdev_dynamic_release (struct kobject *kobj)

struct cdev * cdev_alloc (void)

cdev_alloc() - allocate a cdev structure

void cdev_init (struct cdev *cdev, const struct file_operations *fops)

cdev_init() - initialize a cdev structure : the structure to initialize : the file_operations for this device

static struct kobject * base_probe (dev_t dev, int *part, void *data)

void __init chrdev_init (void)

core_initcall (chrdev_init)

EXPORT_SYMBOL (register_chrdev_region)

EXPORT_SYMBOL (unregister_chrdev_region)

EXPORT_SYMBOL (alloc_chrdev_region)

EXPORT_SYMBOL (cdev_init)

EXPORT_SYMBOL (cdev_alloc)

EXPORT_SYMBOL (cdev_del)

EXPORT_SYMBOL (cdev_add)

EXPORT_SYMBOL (register_chrdev)

EXPORT_SYMBOL (unregister_chrdev)

EXPORT_SYMBOL (directly_mappable_cdev_bdi)

Functions

static DEFINE_MUTEX (chrdevs_lock)

static int major_to_index (int major)

static struct char_device_struct * __register_chrdev_region (unsigned int major, unsigned int baseminor, int minorct, const char *name)

static struct char_device_struct * __unregister_chrdev_region (unsigned major, unsigned baseminor, int minorct)

: the name of the device or driver.

register_chrdev_region() - register a range of device numbers : the first in the desired range of device numbers; must include the major number.
: the number of consecutive device numbers required
Return value is zero on success, a negative error code on failure.

int register_chrdev_region (dev_t from, unsigned count, const char *name)

: the name of the associated device or driver

alloc_chrdev_region() - register a range of char device numbers : output parameter for first assigned number : first of the requested range of minor numbers : the number of minor numbers required
Allocates a range of char device numbers.
The major number will be chosen dynamically, and returned (along with the first minor number) in . Returns zero or a negative error code.

int alloc_chrdev_region (dev_t *dev, unsigned baseminor, unsigned count, const char *name)

Variables

struct backing_dev_info directly_mappable_cdev_bdi

static struct kobj_map * cdev_map

static struct char_device_struct * chrdevs [CHRDEV_MAJOR_HASH_SIZE]

Function Documentation

static struct char_device_struct* __register_chrdev_region	(	unsigned int	major,
		unsigned int	baseminor,
		int	minorct,
		const char *	name
	)			`[static, read]`

Definition at line 99 of file char_dev.c.

static struct char_device_struct* __unregister_chrdev_region	(	unsigned	major,
		unsigned	baseminor,
		int	minorct
	)			`[static, read]`

Definition at line 172 of file char_dev.c.

int alloc_chrdev_region	(	dev_t *	dev,
		unsigned	baseminor,
		unsigned	count,
		const char *	name
	)

Definition at line 236 of file char_dev.c.

static struct kobject* base_probe	(	dev_t	dev,
		int *	part,
		void *	data
	)			`[static, read]`

Definition at line 544 of file char_dev.c.

void cd_forget ( struct inode * inode )

Definition at line 415 of file char_dev.c.

int cdev_add	(	struct cdev *	p,
		dev_t	dev,
		unsigned	count
	)

cdev_add() - add a char device to the system : the cdev structure for the device : the first device number for which this device is responsible : the number of consecutive minor numbers corresponding to this device

cdev_add() adds the device represented by to the system, making it live immediately. A negative error code is returned on failure.

Definition at line 466 of file char_dev.c.

struct cdev* cdev_alloc ( void ) [read]

cdev_alloc() - allocate a cdev structure

Allocates and returns a cdev structure, or NULL on failure.

Definition at line 518 of file char_dev.c.

static void cdev_default_release ( struct kobject * kobj ) [static]

Definition at line 492 of file char_dev.c.

void cdev_del ( struct cdev * p )

cdev_del() - remove a cdev from the system : the cdev structure to be removed

cdev_del() removes from the system, possibly freeing the structure itself.

Definition at line 485 of file char_dev.c.

static void cdev_dynamic_release ( struct kobject * kobj ) [static]

Definition at line 498 of file char_dev.c.

static struct kobject* cdev_get ( struct cdev * p ) [static, read]

Definition at line 338 of file char_dev.c.

void cdev_init	(	struct cdev *	cdev,
		const struct file_operations *	fops
	)

cdev_init() - initialize a cdev structure : the structure to initialize : the file_operations for this device

Initializes , remembering , making it ready to add to the system with cdev_add().

Definition at line 536 of file char_dev.c.

static void cdev_purge ( struct cdev * cdev ) [static]

Definition at line 423 of file char_dev.c.

void cdev_put ( struct cdev * p )

Definition at line 351 of file char_dev.c.

static void cdev_unmap	(	dev_t	dev,
		unsigned	count
	)			`[static]`

Definition at line 473 of file char_dev.c.

void __init chrdev_init ( void )

Definition at line 552 of file char_dev.c.

static int chrdev_open	(	struct inode *	inode,
		struct file *	filp
	)			`[static]`

Definition at line 363 of file char_dev.c.

core_initcall ( chrdev_init )

static DEFINE_MUTEX ( chrdevs_lock ) [static]

static DEFINE_SPINLOCK ( cdev_lock ) [static]

static int exact_lock	(	dev_t	dev,
		void *	data
	)			`[static]`

Definition at line 450 of file char_dev.c.

static struct kobject* exact_match	(	dev_t	dev,
		int *	part,
		void *	data
	)			`[static, read]`

Definition at line 444 of file char_dev.c.

EXPORT_SYMBOL ( directly_mappable_cdev_bdi )

EXPORT_SYMBOL ( unregister_chrdev )

EXPORT_SYMBOL ( register_chrdev )

EXPORT_SYMBOL ( cdev_add )

EXPORT_SYMBOL ( cdev_del )

EXPORT_SYMBOL ( cdev_alloc )

EXPORT_SYMBOL ( cdev_init )

EXPORT_SYMBOL ( alloc_chrdev_region )

EXPORT_SYMBOL ( unregister_chrdev_region )

EXPORT_SYMBOL ( register_chrdev_region )

static int major_to_index ( int major ) [inline, static]

Definition at line 66 of file char_dev.c.

int register_chrdev	(	unsigned int	major,
		const char *	name,
		const struct file_operations *	fops
	)

Definition at line 269 of file char_dev.c.

int register_chrdev_region	(	dev_t	from,
		unsigned	count,
		const char *	name
	)

Definition at line 200 of file char_dev.c.

void unregister_chrdev	(	unsigned int	major,
		const char *	name
	)

Definition at line 327 of file char_dev.c.

void unregister_chrdev_region	(	dev_t	from,
		unsigned	count
	)

unregister_chrdev_region() - return a range of device numbers : the first in the range of numbers to unregister : the number of device numbers to unregister

This function will unregister a range of device numbers, starting with . The caller should normally be the one who allocated those numbers in the first place...

Definition at line 314 of file char_dev.c.

Variable Documentation

struct kobj_map* cdev_map [static]

Definition at line 52 of file char_dev.c.

struct char_device_struct * chrdevs[CHRDEV_MAJOR_HASH_SIZE] [static]

struct file_operations def_chr_fops

Initial value:

 {
        .open = chrdev_open,
}

Definition at line 440 of file char_dev.c.

struct backing_dev_info directly_mappable_cdev_bdi

Initial value:

 {
        .capabilities   = (




                
                BDI_CAP_MAP_DIRECT |
                BDI_CAP_READ_MAP | BDI_CAP_WRITE_MAP | BDI_CAP_EXEC_MAP),
}

Definition at line 41 of file char_dev.c.

struct kobj_type ktype_cdev_default [static]

Initial value:

 {
        .release        = cdev_default_release,
}

Definition at line 505 of file char_dev.c.

struct kobj_type ktype_cdev_dynamic [static]

Initial value:

 {
        .release        = cdev_dynamic_release,
}

Definition at line 509 of file char_dev.c.


Classes
struct	char_device_struct
: name of this range of devices
register_chrdev() - Register a major number for character devices. : major device number or 0 for dynamic allocation : file operations associated with this devices If == 0 this functions will dynamically allocate a major and return its number. If > 0 this function will attempt to reserve a device with the given major number and will return zero on success. Returns a -ve errno on failure. The name of this device has nothing to do with the name of the device in /dev. It only helps to keep track of the different owners of devices. If your module name has only one type of devices it's ok to use e.g. the name of the module here. This function registers a range of 256 minor numbers. The first minor number is 0.
struct file_operations	def_chr_fops
static struct kobj_type	ktype_cdev_default
static struct kobj_type	ktype_cdev_dynamic
int	register_chrdev (unsigned int major, const char name, const struct file_operations fops)
void	unregister_chrdev_region (dev_t from, unsigned count)
	unregister_chrdev_region() - return a range of device numbers : the first in the range of numbers to unregister : the number of device numbers to unregister
void	unregister_chrdev (unsigned int major, const char *name)
static	DEFINE_SPINLOCK (cdev_lock)
static struct kobject *	cdev_get (struct cdev *p)
void	cdev_put (struct cdev *p)
static int	chrdev_open (struct inode inode, struct file filp)
void	cd_forget (struct inode *inode)
static void	cdev_purge (struct cdev *cdev)
static struct kobject *	exact_match (dev_t dev, int part, void data)
static int	exact_lock (dev_t dev, void *data)
int	cdev_add (struct cdev *p, dev_t dev, unsigned count)
	cdev_add() - add a char device to the system : the cdev structure for the device : the first device number for which this device is responsible : the number of consecutive minor numbers corresponding to this device
static void	cdev_unmap (dev_t dev, unsigned count)
void	cdev_del (struct cdev *p)
	cdev_del() - remove a cdev from the system : the cdev structure to be removed
static void	cdev_default_release (struct kobject *kobj)
static void	cdev_dynamic_release (struct kobject *kobj)
struct cdev *	cdev_alloc (void)
	cdev_alloc() - allocate a cdev structure
void	cdev_init (struct cdev cdev, const struct file_operations fops)
	cdev_init() - initialize a cdev structure : the structure to initialize : the file_operations for this device
static struct kobject *	base_probe (dev_t dev, int part, void data)
void __init	chrdev_init (void)
	core_initcall (chrdev_init)
	EXPORT_SYMBOL (register_chrdev_region)
	EXPORT_SYMBOL (unregister_chrdev_region)
	EXPORT_SYMBOL (alloc_chrdev_region)
	EXPORT_SYMBOL (cdev_init)
	EXPORT_SYMBOL (cdev_alloc)
	EXPORT_SYMBOL (cdev_del)
	EXPORT_SYMBOL (cdev_add)
	EXPORT_SYMBOL (register_chrdev)
	EXPORT_SYMBOL (unregister_chrdev)
	EXPORT_SYMBOL (directly_mappable_cdev_bdi)
Functions
static	DEFINE_MUTEX (chrdevs_lock)
static int	major_to_index (int major)
static struct char_device_struct *	__register_chrdev_region (unsigned int major, unsigned int baseminor, int minorct, const char *name)
static struct char_device_struct *	__unregister_chrdev_region (unsigned major, unsigned baseminor, int minorct)
: the name of the device or driver.
register_chrdev_region() - register a range of device numbers : the first in the desired range of device numbers; must include the major number. : the number of consecutive device numbers required Return value is zero on success, a negative error code on failure.
int	register_chrdev_region (dev_t from, unsigned count, const char *name)
: the name of the associated device or driver
alloc_chrdev_region() - register a range of char device numbers : output parameter for first assigned number : first of the requested range of minor numbers : the number of minor numbers required Allocates a range of char device numbers. The major number will be chosen dynamically, and returned (along with the first minor number) in . Returns zero or a negative error code.
int	alloc_chrdev_region (dev_t dev, unsigned baseminor, unsigned count, const char name)
Variables
struct backing_dev_info	directly_mappable_cdev_bdi
static struct kobj_map *	cdev_map
static struct char_device_struct *	chrdevs [CHRDEV_MAJOR_HASH_SIZE]