miosix::Device Class Reference

#include <devfs.h>

Inheritance diagram for miosix::Device:

Collaboration diagram for miosix::Device:

Public Types
enum	DeviceType { STREAM, BLOCK, TTY }

Public Member Functions
	Device (DeviceType d)
int	open (intrusive_ref_ptr< FileBase > &file, intrusive_ref_ptr< FilesystemBase > fs, int flags, int mode)
int	fstat (struct stat *pstat) const
virtual int	isatty () const
virtual ssize_t	readBlock (void *buffer, size_t size, off_t where)
virtual ssize_t	writeBlock (const void *buffer, size_t size, off_t where)
virtual void	IRQwrite (const char *str)
virtual int	ioctl (int cmd, void *arg)
virtual	~Device ()
Public Member Functions inherited from miosix::IntrusiveRefCountedSharedFromThis< Device >
	IntrusiveRefCountedSharedFromThis ()
intrusive_ref_ptr< Device >	shared_from_this ()
intrusive_ref_ptr< const Device >	shared_from_this () const
virtual	~IntrusiveRefCountedSharedFromThis ()

Protected Attributes
unsigned int	st_ino
	inode of device file
short	st_dev
	device (unique id of the filesystem) of device file
const bool	seekable
	If true, device is seekable.
const bool	block
	If true, it is a block device.
const bool	tty
	If true, it is a tty.

Additional Inherited Members
Protected Member Functions inherited from miosix::IntrusiveRefCounted
	IntrusiveRefCounted ()
	IntrusiveRefCounted (const IntrusiveRefCounted &)
IntrusiveRefCounted &	operator= (const IntrusiveRefCounted &)

Detailed Description

Instances of this class are devices inside DevFs. When open is called, a DevFsFile is returned, which has its own seek point so that multiple files can be opened on the same device retaining an unique seek point. A DevFsFile then calls readBlock() and writeBlock() on this class. These functions have a third argument which is the seek point, making them stateless.

Individual devices must subclass Device and reimplement readBlock(), writeBlock() and ioctl() as needed. A mutex may be required as multiple concurrent readBlock(), writeBlock() and ioctl() can occur.

Classes of this type are reference counted, must be allocated on the heap and managed through intrusive_ref_ptr<FileBase>

This class is defined also if WITH_DEVFS is not defined as it is used by the Console interface, but in this case the interface is reduced to a minimum

Member Enumeration Documentation

enum miosix::Device::DeviceType

Possible device types

Enumerator
STREAM	Not seekable device, like /dev/random.
BLOCK	Seekable block device.
TTY	Like STREAM, but additionally is a TTY.

Constructor & Destructor Documentation

miosix::Device::Device ( DeviceType  d )

inline

Constructor

Parameters

d	device type

miosix::Device::~Device ( )

virtual

Destructor

Member Function Documentation

int miosix::Device::fstat

(

struct stat *

pstat

)

const

Obtain information for the file type managed by this Device

Parameters

pstat

file information is stored here

Returns

0 on success, or a negative number on failure

int miosix::Device::ioctl ( int  cmd, void *  arg  )

virtual

Performs device-specific operations

Parameters

cmd	specifies the operation to perform
arg	optional argument that some operation require

Returns

the exact return value depends on CMD, -1 is returned on error

void miosix::Device::IRQwrite ( const char *  str )

virtual

Write a string. An extension to the Device interface that adds a new member function, which is used by the kernel on console devices to write debug information before the kernel is started or in case of serious errors, right before rebooting. Can ONLY be called when the kernel is not yet started, paused or within an interrupt. This default implementation ignores writes.

Parameters

str	the string to write. The string must be NUL terminated.

int miosix::Device::isatty ( ) const

virtual

Check whether the file refers to a terminal.

Returns

1 if it is a terminal, 0 if it is not, or a negative number in case of errors

int miosix::Device::open	(	intrusive_ref_ptr< FileBase > &	file,
		intrusive_ref_ptr< FilesystemBase >	fs,
		int	flags,
		int	mode
	)

Return an instance of the file type managed by this Device

Parameters

file	the file object will be stored here, if the call succeeds
fs	pointer to the DevFs
flags	file flags (open for reading, writing, ...)
mode	file permissions

Returns

0 on success, or a negative number on failure

ssize_t miosix::Device::readBlock ( void *  buffer, size_t  size, off_t  where  )

virtual

Read a block of data

Parameters

buffer	buffer where read data will be stored
size	buffer size
where	where to read from

Returns

number of bytes read or a negative number on failure

ssize_t miosix::Device::writeBlock ( const void *  buffer, size_t  size, off_t  where  )

virtual

Write a block of data

Parameters

buffer	buffer where take data to write
size	buffer size
where	where to write to

Returns

number of bytes written or a negative number on failure

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The documentation for this class was generated from the following files:

• devfs.h
• devfs.cpp